Petroleum Drilling Overview

2. i
FOREWORD
This book, with named PETROLEUM DRILLING OVERVIEW is an overview of
petroleum Drilling, describe general overview of Oil and Gas Drilling, Petroleum
Reservoir, Planning, equipment and man power. This book describe The Drilling
Preparations consist of The Rigs type, Drilling Procedures and Engineering
Challenges, the Aim, Conditions location, And Drilling Program, Location Accessibility,
Tools and Equipment, then The Rigs Systems Elements And Proses comprises The
Rotating System, The Hoisting System, The Circulating System, The Prime Mover,
Pressure Control System. Beside that it describe Drilling Crew and Personnel’s consist
of The Rigs Operating Crew, The Support Personnel’s. Then Routine Drilling
Procedures such Drilling A Head, Making Connection, Round Tripping, Formation
Drilling Data, Well Logging Operations, and MWD, LWD & SWD in common.
This book also describes generally about the Drilling Problems such Stuck Pipe,
Differential Sticking & Handling, Hole Caving, Twist Offs, Lost Circulation, and Others
Problem. Also Directional & Horizontal Drilling such Directional Drilling Uses, The (S)
Shaped Directional, Horizontal Drilling. Finally describe about Running Casing and
Cement Accessory Equipment, Guide Shoe, Float Valve, Scratchers, Centralizers, The
Process of Running Cement.
Suggestions and constructive criticism is expected in the preparation of the next
book about Overview petroleum industry.
September, 2018
A. ANRIANSYAH

3. ii
TABLE OF CONTENTS
FOREWORD............................................................................................................................... ¡
TABLE OF CONTENTS.............................................................................................................. ¡¡
1. INTRODUCTION.................................................................................................................... .1
1.1 Drilling Oil and Gas Field...................................................................................................1
1.2 Petroleum Reservoirs........................................................................................................1
1.3 Wild Cat Drilling.................................................................................................................2
1.4 Planning, Equipment and Manpower.................................................................................3
2. THE DRILLING PREPARATIONS............................................................................................4
2.1 The Rigs type.....................................................................................................................4
2.2 Drilling Procedures and Engineering Challenges..............................................................6
2.3 Aim, Conditions location, And Drilling Program.................................................................6
2.4 Location Accessibility, Tools and Equipment.....................................................................7
2.5 Others Considerations.......................................................................................................8
3. THE TYPES AND MAIN SYSTEM OF RIGS....................................................................10
3.1 Land Rigs (Onshore Rigs)...............................................................................................10
3.1.1 Transported Over Local Roads...............................................................................11
3.1.2 Helicopter Rigs.......................................................................................................12
3.2 Offshore Rigs...................................................................................................................14
3.2.1 Barge Mounted Rigs...............................................................................................14
3.2.2 Jacket Rigs.............................................................................................................15
3.2.3 The Tender Supported Rigs...................................................................................16
3.2.4 The Semi-Submersible Rigs...................................................................................18
3.2.5 The Drill Ships Rigs................................................................................................21
3.2.6 The Permanent Platform Rigs................................................................................22
3.3 Five main systems of rig..................................................................................................24
3.3.1 The Rotary System.................................................................................................26
3.3.2 The Hoisting System...............................................................................................28
3.3.3 The Circulation System...........................................................................................28
3.3.4 The Powers System................................................................................................29
3.3.5 The Pressure Control System.................................................................................30
4. THE RIGS SYSTEMS ELEMENTS AND PROSES................................................................31
4.1 The Rotating System.......................................................................................................32
4.1.1 The Conventional Rotating System........................................................................32
4.1.2 The Top Drive.........................................................................................................34
4.1.3 The Down Hold Mud Motor.....................................................................................35
4.1.4 The Drill String........................................................................................................35
4.1.5 The Drill Bit.............................................................................................................39
4.2. The Hoisting System... ...................................................................................................47
4.2.1 The Hoisting System Elements...............................................................................49
4.2.2 The Hoisting System Process.................................................................................50
4.2.3 Pipe Handling Components....................................................................................52
4.3. The Circulating System... ...............................................................................................54
4.3.1 The Circulating System Proces..............................................................................54
4.3.2 The Circulating System Functions..........................................................................54
4.3.3 MPD (Managed Pressure Drilling)..........................................................................58

4. iii
4.6. The Prime Mover... ........................................................................................................62
4.7. Pressure Control System................................................................................................62
4.7.1 BOP (Blow Out Preventer) Process........................................................................65
4.7.2 Blow Out Process...................................................................................................69
4.7.3 Cap The Well..........................................................................................................74
5. DRILLING CREW AND PERSONNEL’S................................................................................75
5.1 The Rigs Operating Crew................................................................................................75
5.2 The Support Personnel’s.................................................................................................76
6. ROUTINE DRILLING PROCEDURES....................................................................................77
6.1 Drilling A Head.................................................................................................................78
6.2 Making Connection..........................................................................................................80
6.3 Round Tripping................................................................................................................81
6.4 Formation Drilling Data....................................................................................................83
6.4.1 The Drilling Rate.....................................................................................................84
6.4.2 Bottoms Up Circulation...........................................................................................85
6.4.3 Oil and Gas Shows.................................................................................................86
6.4.4 The Cuttings..... .....................................................................................................88
6.4.5 Core Sampling (Coring)..... ....................................................................................90
6.4.6 SWC (Side Wall Coring)..... ...................................................................................92
6.5 Well Logging Operations.................................................................................................93
6.6 MWD, LWD & SWD.........................................................................................................95
7. DRILLING PROBLEMS..........................................................................................................97
7.1 Stuck Pipe........................................................................................................................98
7.2 Differential Sticking..........................................................................................................99
7.3 Differential Sticking Handling.........................................................................................101
7.3.1 Reducing the Mud Weight And Eliminating The Over Balances...........................101
7.3.2 Refined Oil Or Mud Cakes Solvent.......................................................................101
7.3.3 Run free point & detonated...................................................................................102
7.4 Hole Caving...................................................................................................................104
7.5 Twist Offs.......................................................................................................................105
7.5.1 Fishing Up Process...............................................................................................105
7.6 Lost Circulation..............................................................................................................108
7.7 Others Problem..............................................................................................................109
8. DIRECTIONAL & HORIZONTAL DRILLING........................................................................111
8.1 Directional Drilling Uses.................................................................................................112
8.2 The (S) Shaped Directional...........................................................................................114
8.2 Horizontal Drilling...........................................................................................................115
9. RUNNING CASING AND CEMENT......................................................................................118
9.1 Accessory Equipment..................................................................................................118
9.1.1 Guide Shoe ........................................................................................................118
9.1.2 Float Valve..........................................................................................................119
9.1.3 Scratchers...........................................................................................................121
9.1.4 Centralizers ........................................................................................................121
9.2 The Process of Running Cement.................................................................................122
10. CONCLUSION....................................................................................................................126
REFERENCES..........................................................................................................................128

5. 1
1. INTRODUCTION
1.1 Drilling Oil and Gas Field
We are now already drilling our first wildcat well or maybe development
well. Here in in this book, we'll discussed the fundamentals of drilling in
petroleum (oil and gas) well, if all goes for the plan in the next few years will bring
a new oilfield into production (Pic. 001).
Pic. 001. Drilling oil and gas field to production
1.2 Petroleum Reservoirs
As we know that we studied how oil was formed how it accumulated and
how it was stored in underground reservoirs (Pic. 002). With this knowledge, we
were then able to go looking for oil in locations that would most likely contain
commercial petroleum accumulations, later by applying scientific principles of
petroleum reservoir formation. We acquired, processed, and interpreted data
from the most interesting locations (Pic. 003) which then, would allow us to
pinpoint exactly where we would drill our first wildcat well.

6. 2
Pic. 002. Petroleum reservoirs
Pic. 003. Subsurface Location
1.3 Wild Cat Drilling
Even though we know that there is only a one in four chance of finding oil
in commercial quantities when drilling with no one has drilled before (Pic. 004),
we obtain permission from the owners of the land.

7. 3
Pic. 004. Wild cat drilling
1.4 Planning, Equipment and Manpower
After we obtain permission of the land, the access has been secured (Pic.
005), we are ready to initiate the next important step as we get closer and closer
to actually going on site. It is during this crucial phase that many decisions about
equipment and manpower have to be made (Pic. 006).
Pic. 005. Petroleum block area

8. 4
Pic. 006. Planning decision equipment and manpower
Then what's on site there are still other additional decisions to make and
procedures to follow to ensure safe, efficient drilling throughout the entire
process whether we find oil and gas or not.
2. THE DRILLING PREPARATIONS
2.1 The Rigs Type
In this book we’ll discuss, the preparations needed to erect a functioning
appropriate rig on site. We’ll illustrate the types of rigs and their parameters to
help you select the one best suited for our particular site and drilling program
(Pic. 007), next we’ll explain the components and functions of the five main
systems of a drilling rig (Pic. 008), we’ll present the role of the rig crew and their
importance to the overall a successful safe completion of drilling for oil and gas.

9. 5
Pic. 007. Types of rigs and their parameters
Pic. 008. Five main systems of drilling rig

10. 6
2.2 Drilling Procedures and Engineering Challenges
After we discus about the Rigs type, we'll highlight some retained drilling
procedures and engineering challenges (Pic. 009) that must be closely monitored
during drilling, we’ll conclude by describing new technological advances involved
in directional and horizontal drilling and how, they can be used to expand the
reach (Pic. 010).
Pic. 009. Drilling procedures and engineering challenges
Pic. 010. Directional and horizontal drilling
2.3 Aim, Conditions Location and Drilling Program
To help us get started we must first answer some critical questions about
the aims and conditions of our location and drilling program. These choices (Pic.
011) once made will better enable us to successfully drill in the spot we have
selected, for instance what kind of rig we need, that will depend on whether we
drill on land or offshore (Pic. 007).

11. 7
Pic. 011. Choice of the aims and conditions of location and drilling program
Engineers create a well plan and a wellbore design for every well before it
is drilled. A typical wellbore architectural diagram for an onshore well is shown in
figure 011. The wellbore diagram shows the hole and casing sizes needed to drill
the well to its desired depth.
2.4 Location Accessibility, Tools and Equipment
If we drill on land then is the location, accessible by local roads or is it in a
remote location (Pic. 012). Or our tools and equipment suited for the land
conditions and whether we will find on location. if we drill over water how deep
and how come will the water be while we are drilling (Pic. 013), or our tools and
equipment suited for the offshore conditions and whether we will find on location,
do we expect the oil zone to be near the surface and what is call a shallow well
or do we expect the oil zone to be deep what is the estimated depth that we
planned to drill to reach the target.

12. 8
Pic. 012. The location - accessible by local roads or a remote location
Pic. 013. Tools and equipment suited in Deep water
2.5 Others Considerations
There are several Others Considerations such We’ll the drilling take place
in low or high pressure zones?, are there environmental restrictions?, what

13. 9
procedure will we be required to follow to protect water animals air quality what
about noise? (Pic. 014) what are the laws?, how do we ensure that we are in
compliance?, without the penalties if we are not, our trained drilling crew and
rigged equipment available during our time lines?.
Pic. 014. Pressure zones, environmental restrictions, procedure to protect water
animals air quality & noise
As you can see from this very limited list of questions that will need to be
answered at the very top is the need to select and appropriate rig for the
designated location for the specific depth and the environmental conditions (Pic.
015).

14. 10
Pic. 015. List of questions to select and appropriate rig
3. THE TYPES OF RIGS
3.1 Land Rigs (Onshore Rigs)
Let’s look at some of the major categories of land and offshore rigs. We’ll
start by looking at land rigs, as you may have guessed drilling on land is usually
easier and therefore usually cheaper than drilling over water. Land drilling is
divided into two basic categories (Pic. 016).
Pic. 016. Land drilling or Land Rigs

15. 11
3.1.1 Transported Over Local Roads
The first category includes rig that can be transported over local highway
and roads (Pic. 017), a good example of the rig in this category is the jack knife
rig (Pic. 018) which is used to drill many land wells. The reason these rigs are so
popular is that they can be broken down into piece of small enough to be
transported by trucks over existing or newly constructed road (Pic. 019)
Pic. 017. Rig that can be transported over local highway and roads
Pic. 018. The jack knife rig

16. 12
Pic. 019. Break into piece of small enough to be transported
3.1.2 Helicopter Rigs
Category two land rigs are helicopter rigs which was be moved into
remote locations where trucks cannot be used because of prohibitive costs or
because local accesses is denied these special rigs are usually manufactured so
that they can be broken down and small enough pieces for them to be sling lifted
onto a location by helicopter and then resembled on the prepared site (Pic. 020)
Pic. 020. Helicopter rigs
Let’s look at how either type of land rig is erected on location (Pic. 021),
first an operation known as building the pad is initiated. Where the ground is dry,
it is level by bulldozer and then shallow earth and pits are dug and lined with
plastic in muddier locations gravel shale or other hard material like concrete is
laid over the ground and in very wet conditions wouldn't boards may have to be
laid (Pic. 022).

17. 13
Pic. 021. Land rig erected on location
Pic. 022. Onshore Site preparation
Once the site being prepared the rig can be moved into the position and
position over the projected drilling location in preparation for spud in. the hole
once bridge and spudding in is known as the well bore or the borehole (Pic. 023)

18. 14
Pic. 023. Spud in well bore
3.2 Offshore Rigs
Drilling over water also referred to as offshore presents more challenges
than those drilled on land because the depth and the location of the body of
water become factors and dictate the kind of rig needed for those conditions (Pic.
024).
Pic. 024. Offshore site preparation
3.2.1 Barge Mounted Rigs
Here we’ll start by looking at rig used in shallow base and canals transport
with depth of from 3 to 15ft (Pic. 025) called barge mounted rigs they put on steel
barges that are pushed into place and then the barges or flooded to keep them
fixed to the bottom. The depth of the water determines the size of the barge that

19. 15
can be used. Once drilling is completed the water can be popped out of the
barges the barge floated and then told to the next location.
Pic. 025. Barge mounted rigs
3.2.2 Jacket Rigs
Second are jacket rigs effective and water depths of to 65 ft (sixty five
feet) – 400 ft (four hundred feet) (Pic. 026), they have sea the holds with three
legs that can be jacked up and down like the Jackie use in your car when
changing a flat tire (Pic. 027), told into location with the legs raised this rig is set
onto the site and then the legs or lower to the floor of the body of water, next the
hold is raised out of the water high enough so that waves can't reach it, with jack
ups are used in some wells they are cantilevered out over the platform (Pic. 028).
Pic. 026. Jacket rigs

20. 16
Pic. 027. Jacket rigs holds with three legs
Pic. 028. Jacket rigs – site preparation
3.2.3 The Tender Supported Rigs
Third are the tender supported rigs (Pic. 029), used the support small
platforms and relatively shallow waters (Pic. 030) with commerce sees these
temporary platform rigs can be supported by tenders or small boats (Pic. 031).
Once told into location the ship shape tenders are anchored besides the
platform, providing a location to place the power components the fuel for the
platform and the living quarters for the workers.

21. 17
Pic. 029. The tender supported rigs
Pic. 030. Small platforms and relatively shallow waters

22. 18
Pic. 031. Supported by tenders or small boats
3.2.4 The Semi-Submersible Rigs
Four the semi-submersible rigs (Pic. 032) used in deeper offshore
locations (Pic. 033) where the water depth is usually greater than 400ft (four
hundred feet) these large rigs float are see where they very stable in high seas
(Pic. 034).
Pic. 032. The semi-submersible rigs

23. 19
Pic. 033. Deeper offshore locations
Pic. 034. Float and very stable in high seas
The semi-submersibles rigs do not sit on the ocean for like jack ups but
are held in location by anchors and thrusters on each of the four corners to keep
them dynamically positions (Pic. 035). semi submersibles are self-propelled and
can operate offshore anywhere in the world, besides their anchors and thrusters
another thing that keeps them very stable during drilling is that parts of the ship
can be filled with ocean water to add ballast thus its name semi-submersible (Pic.

24. 20
036). After drilling is completed the water in the hole of the semi-submersible is
pumped out and then it is floated to the next location.
Pic. 035. Anchors and thrusters on each of the four corners
Pic. 036. Filled with ocean water to add ballast

25. 21
3.2.5 The Drill Ships Rigs
The fifth are the drill ships rigs (Pic. 037) dynamically positions drill ships
can be used in very deep water (Pic. 038), where anchoring is extremely difficult,
but where the sea surface is relatively calm. They can be moved rapidly from
location to another location. Because the drill ships may not be able to maintain
their position for long periods in rough seas they are favored for geological
studies and for wildcat wells were permanent structures are not yet wanted (Pic.
039).
Pic. 037. The drill ships
Pic. 038. The drill ships used in very deep water

26. 22
Pic. 039. The drill ships used for geological studies and for wildcat wells
3.2.6 The Permanent Platform Rigs
The sixth and last are the permanent platform rigs (Pic. 040). Permanent
platform rigs are used where conditions are not suitable for lifting rigs on and off
the platforms. Built on shore with rigs installed are floated out to the location and
stay on the platforms permanently (Pic. 041), they're used primarily for a field
development and can have 36 (thirty six) to 100 (one hundred) wells per
platform. As you can see there are many different types of rigs depending on the
needs of our drilling program.
Pic. 040. The permanent platform rigs

27. 23
Pic. 041. Built on shore, floated out to the location, and stay permanently
On land there are two the jack knife and helicopter rigs (Pic. 042), on
water there are six types, they are the barges mounted rigs, the Jackup rigs, the
tender supported rigs, the semi-submersible rigs, the drill ship, and the
permanent platform rigs (Pic. 043). Built to better meet the needs of the many
different locations and conditions all drilling rigs work basically in the same way
and are made up of the same basic components supporting five basic systems.

28. 24
Pic. 042. The jack knife and helicopter rigs
Pic. 043. Six types offshore rigs
3.3 Five main systems of rig
Each drilling rig no matter what it size or type has one simple task, and
that task is to connect the earth's surface to an underground reservoir, to enable

29. 25
the rig to complete this task there are five main components or systems, they are
a rotating system, an hoisting system, a circulating system, a power system, and
a pressure control system (Pic. 044).
Pic. 044. Five main components or systems of rig
We in this drawing or picture (Pic. 045) it labeled each of the five main
systems with their significant components as we can see on an operating rig, let's
take a few minutes to orient ourselves to their locations and look at how they fit
all together.

30. 26
Pic. 045. Five main components or systems of rig fit together
3.3.1 The Rotary System
Once we are familiar with the parts and their locations, we’ll describe their
function. Let’s start with the rotary system of the rig. Within this system, we have
the drill bits, the drill collars, the drill pipe, the Kelly, the Kelly bushing and the
rotary table (Pic. 046). In more modern rigs the kelly and its parts have been
replaced by the top drive also known as the power swivel and the down hold mud
motor for a direction drilling (Pic. 047).

31. 27
Pic. 046. Conventional rotary system
Pic. 047. Modern rigs with top drive rotary system

32. 28
3.3.2 The Hoisting System
In the hoisting system of the rig we can find the derrick, the drill line, the
draw work, the crown and traveling blocks and the drilling hook (Pic. 048).
Pic. 048. The hoisting system
3.3.3 The Circulation System
The circulation system of rig consists of a circulating fluid usually refer to
as mud, the mud pit, the mud pump, the rotary hose, the swivel, the flow line, the
shell shaker and other filtration devices. Between the drill pipe and the borehole
wall there is a space called the annulus that is also part of the circulation system
(Pic. 049).

33. 29
Pic. 049. The circulation system
3.3.4 The Powers System
The powers system of the rig consist mainly of diesel engines that run
electric motors, fuel storage tanks, a compound are made up of pulleys belts
shafts gears and chain and on some newer rigs a SCR (silicon controlled
rackfire) (Pic. 050).

34. 30
Pic. 050. The powers system
3.3.5 The Pressure Control System
The main component of the pressure control system of the rig is the BOP
(blow out preventer), made up of valves pressure gauge and chokes arranged in
stacks with a series of rams and preventer (Pic. 051). The BOP’s principle
function is to prevent blow out, on land rigs they are usually bolted to the top of
the well right above the well bore below the derrick floor, on offshore rigs BOP’s
are placed on the ocean bottom above the well bore on the ocean floor (Pic.
052), with its own independent power source for safety the blow preventer panel
with its controlled sits right on the derrick floor for easy access.

35. 31
Pic. 051. The pressure control system
Pic. 052. The BOP’s onshore & offshore
4. FIVE SYSTEMS ELEMENTS AND PROSES
Now that we are familiar with the different components in the five
systems it can be explain in detail how each of these five systems functions to
make and support the well bore and drilling proses (Pic. 045).

36. 32
4.1 The Rotating System
We’ll start with the rotating system, basically within the rotating system the
drill bit turns cutting the rock and making the hole as the bit rotates, drilling fluid is
forced down the drill pipe to jet nozzles in the drill bit as it cuts the rock these jets
of fluid clean in the bottom of the hole of the rock debris from the rotating drill by
moving the debris away from the bit and then up to the surface (Pic. 053).
Pic. 053. Drilling bit with mud circulation
The drills rotary system rotates the bit, what causes the drill bit to turned,
there are three ways to turn the drill bit (Pic. 054).
Pic. 054. Three ways to turn the drill bit
4.1.1 The Conventional Rotating System
The first is the conventional rotating system usually the rotary table, the
kelly bushing and Kelly (Pic. 055). The Kelly is a square or a hexagonal shaped
forty foot length the pipe that threads into the drill pipe, a swivel connects the

37. 33
kelly to the hook. The kelly is fited into a square or hexagonal opening in the
Kelly bushing which fits into the rotary table. As the rotary table moves the kelly
and the kelly bushing also rotate this turning the drill string and bit below (Pic.
056).
Pic. 055. The conventional rotating system
Pic. 056. The conventional rotating system process
As we know the top of the kelly is attached to a device called the swivel
allowing the the Kelly to rotate this swivel provides a passage for the drilling fluid
to flow from the surface to the bit below and also prevents the traveling block and
hook from rotating while the drill string is being turns (Pic. 057).

38. 34
Pic. 057. The conventional rotating system components
4.1.2 The Top Drive
Another newer type of rotating system is called the Top Drive. Top Drive
means a Power Swivel which directly turns the drill string without need for a kelly
and rotary table the driveshaft with its powerful hydraulic motors cruise directly
into the drill stem, replacing the Kelly, the kelly bushing and the rotary table, the
top drives suspends and rotates the drill stem. The drilling fluid flows through to
the top drive down through the drill stem to the bit below just like with the kelly
assemble (Pic. 058).
Pic. 058. The top drive rotating system

39. 35
The principal difference between the Kelly assembly and the top drives is
that the top drives are superior to the conventional rotating system because they
permits circulation and rotation well pulling out of the hole and they allow three
stands or ninety foot lengths of pipe to be added out of time rather than the thirty
foot. Typically a top drive can reduce drilling time by about 25% (twenty five
percent)
4.1.3 The Down Hold Mud Motor
The down hold mud motor is the third type of rotating system, used in
direction drilling the mud motor is mounted directly about a bit and its powered
by the drilling mud (Pic. 059). The drilling mud motor turn the bit without rotating
the drill string, still use older rigs, conventional rotating is still used while more
modern rigs are usually equip with top drives. All rigs engaging in directional or
horizontal drilling use the mud motor.
Pic. 059. The down hold mud motor
4.1.4 The Drill String
To unable to rotating system to work you must have the basic drill string.
Let’s discuss about the components of drill string. For all practical purposes, a
drill stirring is a tube of steel pipe with multiple connections that extends from the
surface to the bit, in other words everything in the hole (Pic. 060).

40. 36
Pic. 060. The components of drill string
The Drill String Functions
The drill string has severeals functions first it transmits rotational energy
from the surface to the bits (Pic. 061), second it conducts the mud system from
the surface to the bit, and third it puts weight on the bit to maximize it's
penetration rate (Pic. 062), also guides and controls trajectory of the bit.
Pic. 061. The drill string transmits rotational energy

41. 37
Pic. 062. The drill string conducts the mud system & maximize penetration rate
The Drill String Configurations
The drill string is the mechanical assemblage connection the rotary drive
on surface to the drilling bit on bottom of the hole, Made up of lengths of 30 ft
(thirty foot) stands of drill pipe with various diameters that can be screwed
together (Pic. 063), the drill string has 3 (three) basic configurations. Starting with
the drill pipe which makes up the vault of the string a drill bit is attached to the
end and his used to break the rock. next thick wall high density drill collars are
placed above the bit to put weight immediately above it (Pic. 064), the kelly pipe
is the top almost joined of the drill string with from four to six flattened sides and
its 40 ft (forty feet) long 10ft (ten feet) longer than drill pipe. The Kelly or top drive
transfers the torque or rotating power down to the drill string to the bit allowing
the rock to be drilled.

42. 38
Pic. 063. The drill strings (drill pipes)

43. 39
Pic. 064. The drill collars
4.1.5 The Drill Bit
Let’s now examine the drill bit and it's history, as we know drilling an oil
well appears deceptively simple. however it is quite complex involving advance
scientific principles of fluid flow pressure, heat, material designed to name a few.
the history of the technological advancements of the bit design is quite
fascinating which have led to the development of the sophisticated drilling bits we
used today (Pic. 065).

44. 40
Pic. 065. The drill bits
Drill Bit History
let's take a few minutes to look at that history, when Edwin drake drilled
the first oil well in Titusville, Pa. USA in 1859 creating the modern petroleum
industry he used technologies that were available at the time (Pic. 066), as we
know from our history humans from the dawn of civilization have dug, mine, and
drilled into the earth for access to its precious useful minerals. in china, iran,
poland and many other locations throughout the world humans had already
developed quite sophisticated drill bit technologies to extract salt, water, gold,
coal and and even oil.
Pic. 066. Edwin drake drilled the first oil well in Titusville
In fact when drake thrilled his first well he used the tools and machinery
that were being used to drill for salt in nearby salt mines in the northeastern part
of USA. He build a derrick from which he strong up throat made from ham with a
cable tool attached at the end, utilizing the generated steam to raise and lower

45. 41
the cable tool. He pound the ground until a hole formed. Intermittently he stopped
the pounding and then bail up the bits of dirt and broken rock until he had a hole,
repeating this process he was able to drill a hole 69 ft (sixty nine feet) into the
ground before striking oil. the cable tool rig that drake used was dropped
repeatedly onto the ground it was really quite effective and breaking a rock
entered so that it could be bail out or remove, simplistic enough to be powered by
human power to cable tool rig could also be raised and lowered by steam power
(Pic. 067).
Pic. 067. The cable tool rig
Surprisingly in the early days and times spill were money was tight and
technology was hard to come by, a man stepping down and into the news of the
ham probe to raise the cable to bit it could draw up to 3ft (three feet) a day, they
were then able to reach the shallow pay zones of many of the early wells in as
little as a mud.
Although effective the cable tool rig had one major floor, especially in wells
where the oil was trapped under pressure. When the cable tool penetrated into
the pay zone, the releasing pressure forces the oil up and out of the well in what
is known as a blow up. With all seen picture showing these dramatic blow out
(Pic. 068), that sometimes result in depth to those nearby destruction of the well
bore and the environment.

46. 42
Pic. 068. The drilling blow outs
The technology to prevent or less and these blow out had to be developed
as you can imagine besides the need to reduce or eliminate blow out, there were
other problems with the cable tool drill bit, operating within a hole dug into the
earth extremely dirty and hot environments the bit subject to enormous
mechanical stresses which caused them to dull quickly or to break inside the
hole. Digging up these broken bits or replacing them wasted rig time and costs a
lot of money, therefore the industry needed a better drill bit.
Although first invented in France in 1960’s the first rotary drilling bit was
used by Portillo Higins in 1901, to drill well that led to location that was to blow
out, a part of the texas oil fields that later became known as spindle top (Pic.
069).

47. 43
Pic. 069. The first rotary drilling in spindle top
And then shortly after that Howard Huges Senior patented two-cone rotary
drilling bit that cause revolutionized drilling. Because it introduced the hollow drill
stem that enable to the broken rocky debris to be washed up and out of the
boreholes. Although the design has been improved over time it remains the most
popular type of drill used today (Pic. 070).
Pic. 070. Two-cone & tricone rotary drilling bit
Cable Tool & Rotary Tool Bit
Let’s examine the broader of drill bit to better understand why at quickly
replaced the cable tool drill bit (Pic. 071). tricone roller bits are the most
commonly used bits, they clockwork rotation of the drill string causes the three
roller comes to also rotate, bringing successive teeth to grade vertically at the
bottom of the hole. with the way concentrating at the point of the teeth, the
rotated bit crushes the rock, that the debris from these cuttings are then swept
away by the mud getting out of the three downward facing nozzles (Pic. 072).

48. 44
Pic. 071. Cable tool drill bit & rotary tool bit
Pic. 072. Trycones drill bit's
Trycones Bit's
Trycones bit's can have teeth mill from hard and steel or for harder rock
small tungsten teeth inserted into a steel column (Pic. 073), regardless of the
material used the teeth eventually were down and the drilling rate slows requiring
that the drilling bit's be replaced.

49. 45
Pic. 073. Trycones drill bit's material
The PDC
A new improvement in the material used for grow it is the PDC
(polycrystalline diamond cutter) (Pic. 074), they use very hard polycrystalline
man-made diamond wafers on the face of protruding bronze basis (Pic. 075),
they differ from the trycone bits in that sense the PDC bits do not have any
moving parts either made from diamonds, they last longer one bit can sometimes
be used to drill an entire well, like the trycone bits PDC rotate, but this bit has a
sharing action while the rotary bit has a crushing action.
Pic. 074. The PDC

50. 46
Pic. 075. Use polycrystalline man-made diamond wafers
Types of Rotary Bits
The Performance parameters of drill bits is identified by its penetrating
rate or drilling speed and Bit life or depth drilled. And usually based on rock
characterization the drill bit uses divide into four category (Pic 076).
Pic. 076. Types of Rotary Bits in rock characterization

51. 47
Hybrid Bits
The Hybrid Bits is Combination of roller cone and PDC bit design (use the
best of both), Hard and interbedded formations - handles changes from soft to
hard rock, Less vibrations, Increased ROP potential, Chert drilling (Pic. 077).
Pic. 077. The Hybrid bits
Laser Drilling Technique
Applying laser technology in petroleum drilling, a fairly recent development
has the potential of mitigating the limitations of the state-of-the-art technique.
Experiments carried out so far on different types of lasers have shown very
positive tendencies. One was conducted on MIRACL (Mid Infrared Advanced
Chemical Laser) to determine its feasibility for drilling and perforating petroleum
wells and another was on COIL (Chemical Oxygen-Iodine Laser) to determine
the least specific energy (SE) needed to destroy varying rock types. Each of
these has cleared the doubts of whether or not lasers technology can be applied
in well operations.
4.2 The Hoisting System
The second system on a rig is the hoisting system, basically this system
raises and lower as the drill pipe of the drill stem in and out of the hole (Pic. 078),
it's a spends the heavyweight of the entire drill stem in the hole. A hole that can
be 5,000ft (five thousand feet), 10,000 (ten thousand feet), even 20,000 (twenty
thousand feet) deep (Pic. 079), Raising and lowering that drill pipe hundreds of

52. 48
times before the well is completed it must be strong enough to have a very heavy
weight.
Pic. 078. The hoisting system
Pic. 079. The hoisting system for deep hole

53. 49
4.2.1 The Hoisting System Elements
As we know there are essentially five major parts that comprise hoisting
system (Pic. 048), they are the Derrick, the draw works the crown, the traveling
bloks, and the hook (Pic. 080). It can be explained of their functions, first is the
derrick or mast the most distinctive part of the rig it is structural tower that
suspends and supports the hoisting system and pipe, it must be tall enough to
pull a 2 (two) or 3 (three) standard length of pipe about to the 90 ft (ninety feet)
out of the hole at one time and also strong enough to support the entire weight of
the thousands of feet of drill string below (Pic. 081).
Pic. 080. Five major parts of hoisting system

54. 50
Pic. 081. The Derrick
4.2.2 The Hoisting System Process
As we can see the hoisting system in an operation, here we have the draw
works it controls the drilling line or steel wire rope that goes from the draw work
drum on the drilling floor up through the crown block then down to the traveling
block where it is attached (Pic. 082). The draw works is a large rotating drum that
spool in and out the drilling line as it is raised and lowered with the load which is
usually the pipe (Pic. 083).

55. 51
Pic. 082. The hoisting system process
Pic. 083. The draw works
The drilling line runs up the derrick to the crown block which is another
component, as the named imply the crown blocks sit's at the very top of the
derrick like a crown. Steel wire from the draw works is threaded through the
crown block in assembly of multiple pulleys calls sheaves (Pic. 084), which
increased the steel wires load varying capacity. the number of these pulleys is

56. 52
dependent on the needs of the drilling program for example deep well require
more pulleys than shallow well because of the way from the extra drill pipe.
Pic. 084. The crown block
Next, from the crown block these multiple strands of steel wire are
attached to the traveling block, together the fixed crown block and the moving or
traveling block gives tremendous mechanical advance for hoisting very large
load, from the hook which is located below the traveling blocks. With these five
components the hoisting system (Pic. 048) can raise and lower the drill bit and its
string in and out of the hole.
4.2.3 Pipe Handling Components
Before we leave the hoisting system let we mention some components of
pipe handling the specific tools used in raising and lowering pipe into the hole are
the elevator, the slips and the tongs (Pic. 085).
Pic. 085. The elevator, the slips and the tongs

57. 53
The specific places on the rig involved in pipe handling are the finger
board the rat hole and the mouse hole (Pic. 086). It can be explain of these in
more detail, the elevators are attached to the hook and are used to lift the pipe
string, second the slips are used to hang the string from the roof floor, the tongs
are used to make up and break out the pipe stands, these power tongs can spin
a pipe while the backup tongs keep the rest of the string from turning. The finger
board can be found high up on the derrick and has proven threating fingers that
can hold stacked stands of pipe (Pic. 087). The rat hole is the hole at the rig for
whether kelly and its swivel are stored when they are not in use, and the mouse
hole like the rat hole is a hole in the ring floor. The mouse hole is a place where a
joint of pipe can be placed prior to it being added to the string. All together the
hoisting system supports the drill bit with its lifting and lowering capability.
Pic. 086. The finger board, the rat hole and the mouse hole
Pic. 087. The finger board derrickman

58. 54
4.3 The Circulating System
4.3.1 The Circulating System Process
The third is the circulating system (Pic. 049), introduced quite early in the
evolution of drilling technology it is the backbone of the rotary drilling, in this
system mud is continuously circulated down the drill string to the nozzles in the
drill bit and then back to the surface through the annulus or space between the
drill pipe and the hole (Pic. 088).
Pic. 088. The circulating system
4.3.2 The Circulating System Functions
The circulation of mud has several functions, (1) a passion of the
circulating system is to lubricate and cool the rotary blade, when it drill into the
rock at the bottom of the hole, this helps to greatly extend the bits useful life, (2)
to the mud jet in the drill bit flush the drill cuttings away from the drill bit itself thus
cleaning the rock surface and allowing the bit to penetrate more efficiently. (3)
the mud collects the loose rock and and dirt bring it back to the surface through
the annulus up out of the hole. These pieces of lose rock and dirt called cuttings
(Pic. 089).
Pic. 089. Cuttings

59. 55
(4) throughout this process the mud exert back pressure on the exposed
formation thus preventing and influx of formation fluids called a kick which could
cause a blow up, in other words the mud helps to maintain the pressure in the
hole to help prevent blow up.
This pressure is called hydrostatic pressure and it is imperative to keep
the hydrostatic the mud pressure equal to or slightly greater than the formation
pressure. By the way when hydrostatic pressure is greater it is called and over
balance, when the pressure is less it is called and underbalanced (Pic. 090).
Pic. 090. The over balance condition
(5) Finally the mud reduces friction between the drill string and the side of
the hole, because of costs the most commonly used mud system is water-based
with various additives (Pic. 091). In more technically challenging drilling programs
were greater stability justifies its additional cost, an oil based mud or water in oil
emulsion may be used (Pic. 092). In offshore wells were disposal of drill cuttings
overboard is restricted because of environmental concerns even more costly
synthetic chemicals mud are used. Because of the above reasons mud
engineers and mud loggers constantly monitor the mud characteristics and make
changes as needed (Pic. 093).

60. 56
Pic. 091. The mud reduces friction between the drill string and the side of the hole
Pic. 092. Oil based mud or water in oil emulsion
Pic. 093. Monitor the mud characteristics

61. 57
The main way of changing the down hole hydrostatic pressure is by
controlling the mud weight or it's density, here is an illustration of the circulation
system located next to the rig. As the mud comes out in the annulus it is reverted
away from the rig floor into the mud return line which takes the mud to the shell
shaker (Pic. 092). The mud falls through the shell shaker which has calibrated
mesh that screens out the large cuttings (Pic. 093). These cuttings are examined
by the site geologists to determine rock type, the large cuttings then go to the
reserve mud pit for disposal (Pic. 094). The mud following multiple steps then
flows back into the mud tank to be re circulated down the well (Pic. 086).
Pic. 094. The circulation system process
Pic. 095. Calibrated mesh

62. 58
Pic. 096. The mud pit for disposal
4.3.3 MPD (Managed Pressure Drilling)
Finally let’s mention briefly a new drilling technique for controlling
downhole pressure that is rapidly becoming widespread, it is called MPD
(managed pressure drilling) well (Pic. 097). It can be explained why it is quickly
replacing the conventional method traditionally (Pic. 088), to control the bottom
hole pressure the density or weight of the mud was changed.

63. 59
Pic. 097. The MPD
For example if the drillers needed a greater down hole pressure to control
it kick they circulate laid down a heavier mud, in manage pressure drilling this is
no longer the case, now the drillers no longer needs to stop to change the mud
weight (Pic. 098). They can now just changed the annulus pressure and the
inside drill pipe pressure, to increase or decrease the bottom hole pressure, thus
eliminating time lag for changing the mud weight, resulting a faster drilling times
fewer kicks and fewer stuck pipes in side (Pic. 099), is easy to see why MPD is
quickly becoming a preferred new drilling technique (Pic. 100).

64. 60
Pic. 098. The well control system

65. 61
Pic. 099. Faster drilling times - fewer kicks and fewer stuck
Pic. 100. MPD - a preferred new drilling technique

66. 62
4.6 The Prime Mover
The fourth system on the rig is the prime mover (Pic. 050). The prime
mover is the source of power for the entire rig which is diesel electric (Pic. 101),
using diesel engines to drive electric generators, these generators produced
direct current to power the rig hoisting, circulating, and rotary systems, as well as
all of the other electrical equipment used on the rig, on larger rig it is common to
have backup generators for emergency power failures (Pic. 102).
Pic. 101. The prime movers
Pic. 102. The prime mover offshore
4.7 Pressure Control System
The last is called the pressure control system (Pic. 050), it's principle
component is the BOP (blow up preventer) bolted to the top of a well and located
below the derrick floor or on the ocean floor offshore (Pic. 103), BOPs are used
to close off the top of the well (Pic. 104) in the event of a large pressure build up
that could lead to a blowout, if blow out is when reservoir fluid blow up out of the
hole onto the rig floor, this force can be so powerful that it can smashed tools
together and could ignite the fluids causing an out of control fire that can burn up
everything in the facility(Pic. 105).

67. 63
Pic. 103. The pressure control system
Pic. 104. The BOP (blow up preventer)
Pic. 105. The reservoir fluid blow up

68. 64
The BOPs operated from a control panel on the drill floor, because of its
importance in stopping a potential life threatening and environmental disaster,
the BOP even has its own independent power supply (Pic. 106), it has
determined that one of the reasons for the disastrous and costly Maconda gulf of
Mexico oil spill in 2010 (two thousand and ten) was the result of faulty blow up
preventer which did not stop oil from flowing into the ocean as designed, causing
loss of life and costing billions of dollars and clean up this disaster highlights (Pic.
107), the importance of monitoring and maintaining a fully functional BOP during
the entire drilling program.
Pic. 106. The BOPs has independent power supply
Pic. 107. The disastrous and costly Maconda Gulf of Mexico oil spill

69. 65
4.7.1 BOP (Blow Out Preventer) Process
let's look at how BOP (blow up preventer) works to ensure that reservoir
fluids did not get into the wellbore (Pic. 108), the driller pays close attention when
drilling into porous permeable rocks were fluids can be under pressure, therefore
when the reservoir rock is drilled it is vital for reservoir pressure to be offset by
the mud pressure (Pic. 109).
Pic. 108. BOP (blow out preventer) process

70. 66
Pic. 109. Reservoir pressure to be offset by the mud pressure
As we mentioned earlier mud pressure reflects the hydrostatic of column
of mud in the hole above the formation this downward force of the column of mud
is expressed in PSI (pounds per square inch), which indicates how mud weight is
pressing down on one square inch of an area (Pic. 110). Mud pressure increases
with the depth of the hole and the density of the mud.
Pic. 110. The mud weight pressing down
let's look an example of how to measure that pressure or measuring
hydrostatic mud pressure, mud pressure at the bottom of 7,000ft (seven

71. 67
thousand foot) hole filled with mud having a density of 10 (ten) pounds / gallon
density can be calculated as follows in a high hydrostatic gradient (Pic. 111), in
this illustration we have a column of mud that is 12”(twelve inches) by 1”(one
inch) by 1”(one inch) wing 0.51 (zero point five one) pounds, first we’ll convert the
gallons to cubic feet, then we'll divide by 144 (one hundred and forty four) to get
the weight of each 12” (twelve inch) by 1” (one inch) by 1”(one inch) column
within the cubic foot (Pic. 112) .
Pic. 111. Measure hydrostatic mud pressure
Pic. 112. Hydrostatic gradient

72. 68
This is the hydrostatic gradient showing the increase of pressure gradient
per depth, next we’ll multiply the perfoot hydrostatic gradient by the depth to get
the mud pressure at the bottom of the hole. In this example therefor our pressure
is 3605psi (three thousand six hundred and five psi) (Pic. 111).
Pic. 113. Example the mud pressure 3605psi
Since the reservoir pressure in this example is over 3500 psi (three
thousand five hundred psi) we can say the pressure is over balanced (Pic. 114),
this means that the mud pressure exceeds the reservoir pressure, causing mud
filtrate to invade the formation, the sounds from the mud, filter out the on face of
the formation which forms a filter cake. If the reservoir pressure were higher than
the mud pressure say 4000 psi (four thousand psi) this underbalanced would
cause the formation fluids to enter the well bore in a condition known as a kick
(Pic. 115), if this happens then aggressive action must be taken to prevent a
blow out.
Pic. 114. over balanced pressure

73. 69
Pic. 115. Underbalanced pressure
4.7.2 Blow out Process
Now let's look at how a blow out a might occur (Pic. 116), (1) the hydro
static pressure decreases until the reservoir pressure is higher than the mud
pressure this is called an underbalanced condition and in this condition oil and
gas enters the wellbore, (2) oil and or gas and displaces of mud in the annulus,
since the oil and or gas is lighter than displace mud, the mud column becomes
even lighter which accelerates the rate of the fluid influx (Pic. 117).
Pic. 116. A blow up

74. 70
Pic. 117. Underbalanced condition
(3) As a gas kick travels out of the annulus the mud columns above that
become shorter thus reducing pressure on the gas and along the gas to expand
which in turn displaces more mud and further accelerates the process of the kick
(Pic. 118).

75. 71
Pic. 118. The process of the kick
(4) The kick of oil and or gas reaches the surface and blows out through
the rig floors, the blow up fluid can ignite burning the crew and destroying the rig,
fortunately with modern BOPs and careful monitoring by the drillers and his crew
the above scenarios are rare (Pic. 119), every effort is made to anticipate the
changing reservoir pressures and to design mud programs to handle this
pressures.
Pic. 119. Modern BOPs and careful monitoring

76. 72
In development drilling where local pressures are known this is relatively
easy but in wildcat wells where very little is known this task is a lot more
complicated (Pic. 120), when drilling wells where pressures are not known it is
usually best to drill the non-permeable sections somewhat underbalanced and
then to wait up in the permeable zones (Pic. 121).
Pic. 120. Managing reservoir & mud pressure
Pic. 121. Drilling wells where pressures are not known

77. 73
Nevertheless the crew must be on to look up for settle signs that to kick is
developing, if a kick is detected early enough the mud can be waited up and the
kick can then circulate out of the hole (Pic. 122), if the kick developed too fast its
appears to be gaining momentum then it may be necessary to close the BOP
(blow out preventer) (Pic. 123).
Pic. 122. The kick circulate out of the hole

78. 74
Pic. 123. Close the BOP (blow out preventer)
4.7.3 Cap The Well
when activated the BOP sitting just underneath the rig floor or on the
ocean floor in an offshore rig will close, sealing the well, preventing it from
blowing out, if the blow out occur even with good technology and careful
monitoring the well must be cap, in extreme case is experts most be brought into
cap the well (Pic. 124).
Pic. 124. The well must be cap

79. 75
5. DRILLING CREW AND PERSONNEL’S
5.1 The Rigs Operating Crew
So far we have mostly discussed the tools, components and the functions,
found on a rig, it is now time to turn our attention to the men and women, the
crew who keep all of the many aspect of an operating oil well working drilling for
oil.
The rigs operating crew or employees of the drilling contractor, they
usually work from 8-12 hours shifts during the time the rigous operating which is
24 (twenty four) hours a day 7 (seven) days a week (Pic. 125), the person be in
charge of the overall operation on the rig is the tool pusher, the driller is the
hands on operator of the rig, as the foreman of the drilling crew, he is the person
who overseas the actual day to day drilling program and supervises the different
procedures, reporting directly to the driller is the derrick man, he monitor is the
upper are of the derrick that includes the crown and traveling blocks. When
required he is the person that stands on the monkey board for a bird's eye view,
his job is to stack the pipe will tripping out of the hole (Pic. 126).
Pic. 125. The rigs operating crew
Pic. 126. The rigs operating crew (Tool pusher, Driller, derrick man)

80. 76
The rest of the drilling crew are called floor hands or more commonly
known as roughnecks (Pic. 127), they perform various tests that relate to
checking and maintaining the equipment on the rig. Roustabouts perform general
labor on and around the rig, big rigs can also has specialists like motorman,
mechanic, electricians etc. they usually report to the tool pusher. In addition there
are people who operate as support personnel they are on site but not directly
involved in the actual drilling. The company man represents the operating
companies that hired the drilling contractors.
Pic. 127. The floor hands or roughnecks
5.2 The Support Personnel’s
The drilling engineer who is employed by the operating company
preparers the well plan and provides engineering input as needed during
operations, the mud engineers monitors and control the condition of the mud, the
well site geologists tracks the rock formations by examining the cutting that come
up during drilling, the mud logger monitors the shows of oil and gas in the
returning mud system (Pic. 128). With years of experience and hands on know
how these and others are the people we will meet when visit a rig.

81. 77
Pic. 128. The Support personnel’s
6. ROUTINE DRILLING PROCEDURES
Now let's turn our attention to some routine drilling procedures, reform by
the driller and his crew. These include procedures known as drilling a head,
making connection, and round tripping. Let we see these terms.
The job of a driller is very important to the successful drilling of a well and
he is the one usually in charge of implementing and overseeing routine drilling
procedures, one of his principle tasks are drilling ahead, turning to the right, or
making hole. All of these terms indicate the task of drilling one stand or one
length of pipe with around 30ft (thirty feet) or 10 m (ten meters) at a time (Pic.
129).

82. 78
Pic. 129. The routine drilling procedures
6.1 Drilling A Head
As we know, once the length of a stand drill the kelly has to be pulled up
and removed while a new length of pipe is added to the drill string (Pic. 130),
while drilling a head, the driller is also watching the weight indicators closely to
ensure that there is a proper weight on the bit, keeping a close eye on the mud
pressure of the circulating system looking for signs of kicks, maintaining the
proper rotation speed and monitoring the drilling rate as well as the powers
supply (Pic. 131).

83. 79
Pic. 130. Pulling or adding the drill string
Pic. 131. The drilling a head

84. 80
Once a stand has been drilled a new stand of pipe then must be inserted,
let's look at how a stand of pipe is added to the string and the connection made
(Pic. 130). Once in additional 30 ft (thirty foot) is drilled ahead the driller stops the
bit, raises the drill string off the bottom and shuts down the mud pump. The drill
string is raise in preparation for adding an additional stand of pipe, the kelly
assembly is then removed and placed in the rat hole. the next stand is pulled out
of the mouse hole after this pipe is attached, the kelly has reconnected and the
drill string his lowered back into the wellbore and the rotating bit resumes it's
work. This is done over and over again until the rotary bit reaches the target (Pic.
132).
Pic. 132. The drilling a head procedure
This is complicated tests require teamwork and precision, also because
during the time that the kelly assemble is off the drill string the chances of a blow
out decrease, so the team wants to complete this test by rapidly and accurately,
As we mention that when using a top drives the entire stand or about 90 ft
(ninety feet) is drill down before having to attach more pipe, using a top drive of
course shortens the drilling time, significantly because every connection takes
time and as you can imagine, making one connection takes less time with a top
drive then three connection with a kelly assembly.
6.2 Making connection
To add joints or making connection specific tools are used, these include
slips tongs and elevators. When the drill string is first brought out and while the
kelly assembly is still attach, the drill string is placed in slips. set by the
roughnecks the slips give the driller a place to suspend the drill string while more
pipe is added, meanwhile the kelly assembly with its bushing, swivel and rotary
hoes is one over to the mouse hole where it is connected to the new stand of
pipe with the tongs, the Kelly assembly is tighten to the stand, and then the kelly
assembly and the new stand is then stabbed into the top of the dill string and
again the tongs are used to tighten the new stand into the drill string, the drill
string is now lifted the roughnecks remove the slives (Pic. 133), the mud pump

85. 81
are started and the bit is run back to the bottom of the hole and as rotation is
resumed drilling begins anew. This process is repeated over and over for
thousands of feet until the target is reached, these are the basic steps used in
making a connection (Pic. 134).
Pic. 133. The drilling a head process & Making the connection
Pic. 134. Making the connection
6.3 Round tripping
Round tripping or making a round trip is the process where the drill strings
pulled out to change the bit and drill collars and or directional drilling equipment

86. 82
etc. (Pic. 133), round ripping therefore just described acts of taking out and
putting back to the drill string for a variety of tasks. in round tripping the kelly
assembly is removed and stored in the, rat hole a special piece of equipment
called the elevator is connected to the hook and pipes are pulled out.
Pic. 135. Round tripping process
The term tripping out is used in the drill string is pulled out for a different
procedure like when logging is being done (Pic. 136), when they trip out a large
stand of pipe usually about 90ft of the drill string is pulled out at a time and
stacked in the figure board it is the job of the derrick man to stack these stands of
pipe in rows like these (Pic. 137).
Pic. 136. The tripping out (e.g. for logging)

87. 83
Pic. 137. The derrick man
6.4 Formation Drilling Data
There are some methods used to collect data to evaluate wild cat well and
development wells in each method we’ll discuss how the need for different data
will influence how the data is hand and analyzed.
In this book we'll limit our discussion to open hole wells (Pic. 138). From
the day we spud in, we begin collecting drilling data, the record that we make is
called the drilling operations log or mud log, and this is continuous foot by foot or
meter by meter record of the hole as it is being drilled is refer to a mud love. all
important data gain from the cuttings and from the mud returns as well as from
the drilling operations or plotted against the depth on the same strip chart of log
so that they can be compiled on a chart, this drilling operations log is a record
with three main inputs from the driller, the mud loger, and the site geologists (Pic.
139).

88. 84
Pic. 138. Open hole and cased hole well
Pic. 139. Drilling operations log
6.4.1 The Drilling Rate
Let we discuss each input in a little more detail. we'll start with the input
from the driller, while rotating to kelly the driller measures how fast or how slow
the kelly goes down, for instance when drilling through hard rock the kelly
descends more slowly than when drilling through softer rock, the speed of the
kellys dissent is known as the drilling rate (Pic. 140).

89. 85
Pic. 140. The speed of the kellys dissent is known as the drilling rate
The drilling rate is recorded on the log as the number of minutes per foot
or meter penetrated. Rate of penetration knowing this speed helps identify the
type are rock that is being penetrated and gives a general indication of the
porosity of that zone (Pic. 141), hard rock for example is usually associated with
shale or other cap rock while softer rock is associated with sandstone or
limestone which can be oil or gas rich reservoir rock.
Pic. 141. Rate of penetration identify the rock type and indication of porosity
6.4.2 Bottoms Up Circulation
When the drill bit excess the non-porous hard rock and enters softer
porous rock the recording instruments in the log show this gap as you can see on
the illustration (Pic. 142). This gap is called the drilling break, when this happens
the driller raises the drill bit a few feet breaking off from the bottom while
continuing to rotate and circulate mud, this circulating mud scoops up the last of
the cuttings and sends them to the surface this is called bottoms up circulation.

90. 86
These cuttings from the last time of drill bit are then analyzed by the site
geologists, and our instrumental in helping it to determine future steps in the
drilling program. For example the geologists may make a determination to core
the next section of rock to be drill based on his analysis of these cutting.
Pic. 142. Bottoms up circulation
In addition the driller keeps them running count of the number of lengths
or stands of pipe that have gone down into the hole. Using pipe stand
measurements to determine exactly at which depths different types rocks or
encountered the driller can provide the data that to allow the depths and the
thickness of hard and soft rock to be tabulated (Pic. 143).
Pic. 143. Running count of the number of lengths or stands of pipe that have
gone down into the hole
6.4.3 Oil and Gas Shows
The next input is information about the mud compound by the mud logers,
his job is to constantly monitor them mud for oil and gas shows, he does this in a

91. 87
variety of ways. in addition to checking for any oil shows that may have migrated
to the surface with the mud or the floats in the mud pit, he also exposes mud
samples through ultra violet light, that will show fluorescence if oil is present.
With gas he’s looking for gas shows that bubble out of the mud and surface (Pic.
144). and not only is he on to look out for potentially hazards or kicks which is
gas is entered the wellbore from the formation, he also uses gas chromatograph
to spot signs of gas that can be measured as they are released from the
formation of the rock as it is drilled (Pic. 145).
Pic. 144. The mud loggers, oil and gas shows, samples through ultra violet light

92. 88
Pic. 145. Uses gas chromatograph to spot signs of gas
The mud loger carefully tracks and inputs both the depth and the
approximate locations of promising oil and gas shows on the log (Pic. 146).
Pic. 146. The mud loger input the data
6.4.4 The Cuttings
The third input comes from the site geologists who identifies and studies
the cuttings that are filtered out by the shale shaker as the cuttings are brought
back to the surface in the mud pit. he collect samples of these cuttings every few
feet of drilling in order to examine them under a microscope (Pic. 147).

93. 89
Pic. 147. Site geologists identifies and studies the cuttings
In studying these samples, he describes the lithology, porosity in detail,
and determines whether oil shows gas shows and hydrocarbon odor are present
(Pic. 148). For example, when describing the lithology he examines the rock to
define their characteristics or properties like color, size, shape, porosity, mineral
identification, etc (Pic. 149).
Pic. 148. Mud log-the lithology, porosity oil and gas shows

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Pic. 149. Rock characteristics
These rock type description then allow him two hypothetically place these
cutting in the appropriate zone in the stratigraphic column. The correlation will
also be necessary if data from previous drilled wells is available, as we may
expect when working with these cuttings there is usually some guesswork and
analyzing and correlating all the data from the different input. This gas work in
fact can lead to errors or miscalculations in depicting the various compositions of
the layers and their depth in the strata graphic column on the mud log.
6.4.5 Core Sampling (Coring)
When performing a bottom up circulation he will have communicated this
maneuver to this site geologist. if geologists analysis of the bottom of circulation
is favorable he make all for the capture of an actual sample of the sub surface
rock, called coring the sampling method allows him to collect and actually
examples they can be picked up examined detail, smelled, weighed, and
analyzed for key reservoir parameters (Pic. 150).
Pic. 150. Core Sampling (Coring)

95. 91
These samples will then be sent to the companies laboratories for further
and analyses. Since to round trips are required to first install the coring assembly
and then to remove it, coring is not cheap in time or money. not only as a
additional time needed for these round trip, the core bit or core barrel drills and a
much slower rate than a conventional drill bit (Pic. 151).
Pic. 151. The core bit or core barrel drills and conventional drill bit
When the geologist thinks that there's enough justification to core however
instructs the driller to trip out and prepare for coring. As we can imagine the
geologists who delays drilling to core potential pay zones can be under a lot of
pressure from the drilling department to resumes drilling as fast as possible. The
honest is there for on the geologists to course sparingly and appropriately
something not always easy to distinguish when faced with incomplete
information. In convention coring the drill string is pulled out of the hole and the
drill bit is replaced with a conventional core assembly that consists of a donut
shape diamond or pdc bit that runs on a hollow core barrel.
This string is then run back to the bottom where rotation and mud
circulation as we started. As the bit penetrates the rock faces, a solid core
undrilled, uncrushed rock rises through its center into the barrel. when the zone
of the interest has been penetrated, or when the core barrel is full with a sample
of 30ft (thirty feet) long the string with the barrel that contains the core is pulled
up to the surface with the spring load in court capture attached (Pic. 152).

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Pic. 152. Coring data acquisition process
6.4.6 SWC (Side Wall Coring)
For softer unconsolidated formations where conditions for conventional
coring are not suitable side wall coring is sometime perform instead. conducted
after coring would have been completed side wall coring is usually done at the
same time as the open hole logging, and like the open logging so it is run on a
wire line (Pic. 153). During the procedure side wall cores are taken from the side
of open hole well by shooting exploding small cylindrical bullet into the formation
with a sidewall gun, these cylinder capture formation material.
Pic. 153. Side wall coring run on a wire line get small sample

97. 93
Because the cylinder around wired tether they can be brought to the
surface at the time the gun is retreat. Although it much cheaper alternative to
conventional coring, sidewall coring is less informative then conventional cores
(Pic. 154). For example measurements for porosity and permeability can be
compromised inside well testing because the impact of the fire cylinders can
cause crushing and compaction.
Pic. 154. Conventional coring and sidewall coring cost
The main use aside well coring however is not to replace conventional
coring but to supplement the data retrieve to the open hole logging swift. it is an
excellent tool because it very accurately determines lithology or rock type by
checking specific spots especially regarding lithology and fluid saturation, the
geologists can get a clearer picture then is visible on the mud log.
6.5 Well Logging Operations
Even though new strategies logging techniques and tools are rapidly
improving and becoming available their costs can be prohibitively expensive,
Therefore we will described the traditional most common logging operations still
used in most locations (Pic. 155). In any event whether the latest technology
used to log the well are older technologies are used logging is and will remain to
be a major part of the wells overall financial costs in the foreseeable future first in
a typical scenario several sounds are combined into a single assembly and run
together (Pic. 156).

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Pic. 155. Most common logging operations still used
Pic. 156. A typical scenario several sounds are combined into a single assembly
and run together
In this method a sonde is run to the bottom of the hole and it's slowly
raised to the top recording the output and emissions on a chart as they accure,
this is called the actual logging sequence. The logs interval usually extends from

99. 95
the bottom to casing shoe. This interval is referred to as the open whole portion
of the well.
6.6 MWD, LWD &SWD
Because it is usually the team of engineers who decide what procedures
to run it is they who must justify and not only the costs of these procedures but
also the down time in the drilling program. although the industry as fast and
proving the technology to run procedure during drilling in what is called
measuring while drilling (MWD), logging while drilling (LWD) (Pic. 157) and
Seismic While Drilling (SWD) many times it is still necessary to round trip in and
out of the hole with specialized equipment, remember round tripping is when the
drill string with the drilling bit and all of the stands of pipe are pulled out of the
wellbore for testing and then put back in when it was finished (Pic. 158).
Pic. 157. Measuring while drilling (MWD), and logging while drilling (LWD)

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Pic. 158. round tripping logging
The Seismic While Drilling technique also known as Drill bit Seismic,
Seismic guided drilling, drill-noise VSP and Tomex uses acoustic energy
generated by the bit as a source for a seismic survey. As a rotationg roller-cone
drill bit pounds on the bottom of the hole, it acts as a dipole source, radiating
acoustic energy into the formation (Pic. 159).
Pic. 159. SWD (Seismic While drilling)
Drilling a head, making connection, and roundtripping are all complex
operations involving many sequential steps that must be repeated over and over
again, the driller, the derrick man who stands on the monkey board, and the
roughnecks must all work together to complete these difficult task, of course the
support personnel participate according to their expertise (Pic. 160).

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Pic. 160. Drilling process crew and personnels
In the last decade many of these procedures have been automated for
safety because rigs have a useful lifetime of thirty years or more, the automation
of any particular rig will depend on its age, when working on a rig you'll find state
of the art technology as well as all over the technology depending on the edge of
the rig and its history of its rig. and all want to be prepared for all types.
Regardless of the experience and careful planning that have gone into
drilling a well, things can still go wrong. when we discussed blow up preventer's
we discussed how pressure within a well can become under balance to cause a
blow out, remember underbalance pressure means that the hydrostatic pressure
in the borehole is less than in the formation pressure, other less dramatic events
can also occur that can impede progress.
7. DRILLING PROBLEMS
Regardless of the experience and careful planning that have gone into
drilling a well, things can still go wrong, other less dramatic events can also occur
that can impede progress, they include differential sticking, hole caving, twist-
offs, fishing, and loss circulation (Pic. 161).

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Pic. 162. Some dramatic events of drilling a well
7.1 Stuck Pipe
Let’s we see each of these in more detail, pipe that get stuck in the hole is
called stuck pipe and as a constant concerned. When this common problem
occurs it is usually quite simple to resolve so that the drilling program can
resume. In extreme cases however were efforts to unstick the pipe aren’t
successful the portion of the hole, with the stuck pipe must be abandoned (Pic.
163).
Pic. 163. The stuck pipe
Adding cost to an already extremely expensive operation, therefore the
driller tries various procedures to freeze stuck piped. Let’s look at some
differential sticking are probably the most common cause of stuck pipe and
occurs most frequently when drilling into softer unconsolidated formations typical
of continental margin (Pic. 164).

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Pic. 164. The differential sticking
7.2 Differential Sticking
Differential sticking happens while penetrating permeable formations
under overbalanced conditions some of the liquid in the mud is forced out into the
formation leaving behind the mud solids has a filter cake at the formation face
(Pic. 165). If the pipe press motionless on the side of the hole too long, while
making a connection it can become differentially stuck, when a pressure
differential is created between the mud column pressure on the inside of the hole
and the formation pressure on the outside, the pipe is pressed against the side of
the hole with such force that the pipe cannot be moved (Pic. 166). To keep
differential sticking from occurring the driller tries to keep pipe moving in over
balance pressure conditions at all time (Pic. 167).

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Pic. 165. The differential sticking in overbalanced conditions
Pic. 166. The differential pressure – pipe against formation wall

105. 101
Pic. 167. The driller keep pipe in over balance pressure at all time
7.3 Differential Sticking Handling
7.3.1 Reducing The Mud Weight And Eliminating The Over Balances
Once the pipe becomes stuck for whatever reason it is necessary to free
it, because for the pipe becoming stuck in the first place must be found. If the
pipe is differentially stuck then the first approach would be to reduce the weight
of the mud and eliminate the over balance, of course this is only possible if there
are no concerns about a permeable zone kicking (Pic. 168).
Pic. 168. Reducing the mud weight and eliminating the over balances
7.3.2 Refined Oil Or Mud Cakes Solvent
if reducing the mud weight and eliminating the over balances not possible,
then another approach might be tried, here if mud circulation is still possible, then
a few barrels of refined oil or mud cakes solvent might be circulated down pipe

106. 102
and then up the annulus until that over the stuck area. Thus by keeping the
tension and torque on the pipe with this fluid it may be enough to free the stuck
pipe (Pic. 169).
Pic. 169. Refined oil or mud cakes solvent
7.3.3 Run Free Point & Detonated
If this approach fails, it may be time to run free point indicators down the
drill string by wire line. In this approach tension is pulled on the drill string while
the three point indicators in locates the point below which the pipe is not
intention. identifying exactly the spot below which the pipe is not intention as the
place with the pipe stuck allows for a light explosive to be run down the inside of
the drill pipe and detonated immediately about the free point. Hoping that the
explosion will raddle lose a coupling so that it can be unscrewed the string is then
carefully rotated counter clock ways in an attempt to break the raddled coupling
(Pic. 170).

107. 103
Pic. 170. Run free point & detonated
Once unscrewed the string pulled out leaving the fish or bit and the stuck
part of the drill pipe still in the hole, the drill string is then reinserted with a set of
jars or devices that deliver shark blows. Once in place the jars are activated
sometimes repeatedly delivering down work hammer blows to the stuck pipe. In
most cases this approach is successful and the stuck pipe can be quickly
dislodged and recovered (Pic. 171).
Pic. 171. Leaving the fish & set of jars
If this method fails however a washed pipe can be run to wash over the
outside of the fish, hoping to remove the material that is causing the stuck. As

108. 104
you can see different procedures are tried with the hope that one of these will
free a stuck pipe but as we see before, if all the attempts fail than that portion of
the hole with the stuck pipe will have to be abandoned.
7.4 Hole caving
Hole caving is another drilling problem here the side of the hole caves in
causing the pipe of become stuck (Pic. 172). There are many reasons for caving,
here are three common. Number one absorbing the mud filtrate, some shales
swell up and slough off their outer layers into the well. Number two large
quantities of materials from uncemented or fractured formations fall into the hole.
Number three the weight of the over line rock force or squeeze out salt and
plastic shale formations into the wellbore (Pic. 173).
Pic. 172. Hole caving
Pic. 173. Common Hole caving cause

109. 105
7.5 Twist Offs
Now let's look at another type of drill pipe failure, called twist offs (Pic.
174). They occur from drilling routines of drilling operation. If twist off occur, the
first half of the broken pipe is brought to the surface and then for the piece still in
the hole it is necessary to fish it up (Pic. 175).
Pic. 174. Drill pipe failure - twist offs
Pic. 175. Fishing up
7.5.1 Fishing Up Process
It can be explained that, the first is the movable portion of the broken pipe
his brought back up to the surface so that the condition of the pipe or fish and the

110. 106
break can be exam or analyzed, next and impression using soft metal is made of
the piece still stuck in the hole to provide a better picture of its degree of
distortion and raggedness the impression block can also indicate whether the fish
is standing up right, or is leaning over against the side of the hole (Pic. 176).
Pic. 176. Fishing up process (leaning against the side or standing upright)
The process of retrieving the stuck pipe is called fishing, depending on the
raggedness and position of the stuck pipe or fish, this fish may be able to be
pulled out straightaway or it may need to be dressed off or cleaned up (Pic. 177).
The fish can be pulled out with either and overshot that fits over our swallows the
fish if it is standing up clear of the side of the hole, or a spear which hooks fits
down into the fish if it is not (Pic. 178). Over shots are preferred to spears
because spears can be difficult to remove of the fish is still stuck. Both over shots
and spears have multiple grapples, that can grip the fish securely and one script
then uses jars or hammer like blows in hopes of freeing the fish (Pic. 179).

111. 107
Pic. 177. Fishing process
Pic. 178. Fishing by overshot or Spear

112. 108
Pic. 179. The Jars (overshot and Spear)
7.6 Lost Circulation
Lost circulation is another serious problem, it is the result of hydrostatic
pressure being higher than the formation pressure in an extremely over balance
condition. the mud weight fractures the formation rock creating large channels
causing the mud to flow rapidly out of the well bor into the rock, this results in an
expensive loss of mud and can damage the formation (Pic. 180).
Pic. 180. Lost circulation

113. 109
7.7 Others Problem
There are several others in drilling problems such Shale
Problem/Borehole Instability usually in shale, Mobile formation may occur in Salt
or shale formation, Undergauge hole.
As we know Shale is sedimentary rock form by deposition and compaction
of sediments, contain clays, silt water, quartz, feldspar, compact or
unconsolidated rock depend on water content. The shale problem/borehole
instability are a condition where the shale section containing bentonite or other
hydratable clays which continually absorb water from the mud, expands, swell &
slough into the hole. And hole instability resulting from drilling shale sections.
Also Other terms: sloughing shale, heaving shale, running shale. The prevention
may use suitable mud system to inhibit hydration (high Ca & K content, OBM, oil-
emulsion, etc.) to decrease the tendency of mud to hydrate water sensitive clays,
then Increase circulation rate for more rapid removal of particles Increase mud
density for greater wall support (Phyd > Pf), Decrease water loss of mud. Avoid
fast trips or swabbing of the hole. Keep flow properties & annular velocity at such
a level as to insure good hole cleaning (Pic. 181).
Mobile Formation may occur where A salt or shale can squeeze into the
well bore because it is being compressed by the overburden forces. The
deformation results in a decrease in the well bore size, causing problems running
BHA’s, logging tools and casing and stuck pipe. A deformation occurs because
the mud weight is not sufficient to prevent the formation squeezing into the well
bore. Once broken, the hole will become enlarge. The prevention are Identify salt
dome. Monitor mud chlorides and mud resistivity, Maintain sufficient mud weight.
Select an appropriate mud system that will not aggravate the mobile formation.
Plan frequent reaming/wiper trips particularly for this section of the hole. Slow trip
speed before BHA enters the suspected area. Minimize the open hole exposure
time of these formations (Pic. 181).

114. 110
Pic. 181. Borehole Instability and Mobile Formation
Let’s review when discussing procedures like drilling a head, making a
connection, round tripping, and the advancements in automated drilling it is clear
that even with sophisticated tools and technology drilling for oil is a complicated
affair.
In addition because procedures can go all right when pressure and
temperature inspired to cause blow out and where pipe get stuck or were twist of
or lost circulation can occur midway through drilling (Pic. 182). In this little
wonder that scientists and engineers work lifelessly to help improve procedures
and solve problems like those mentioned above so that oil and gas can be
brought to market more efficiently and cost effectively and under ever increasing
hostile conditions today.

115. 111
Pic. 182. Some even can occur midway through drilling
8. DIRECTIONAL & HORIZONTAL DRILLING
Two relatively recent advances over the last several the decades have
expanded the ability of the industry to extract more oil and gas in places that
were previously inaccessible. First directional drilling and it's offshoot horizontal
drilling have revolutionized the way drilling is done (Pic. 183). Directional drilling
was first developed when the industry moved offshore, prior to that, well were
drilled vertically or relatively straight down. When drilling was exclusively on land,
a rig could more easily and cheaply be move to a new location to drill another
vertical well. Offshore especially in deep water however, the cost of building
another offshore platform in another location every time a new well is needed to
be drill proved to be prohibitive.

116. 112
Pic. 183. Directional drilling and horizontal drilling
The industry therefor developed specialized tools to perform direction
drilling so that they could drill multiple wells using rigs on the same platform.
Today this technology has advanced to the point that directional and horizontal
drilling have replace traditional vertical drilling in many instances.
8.1 Directional Drilling Uses
Let we highlight the areas were directional drilling has proven to the most
beneficial. Directional drilling has been used; (1) where vertical drilling is not
possible due to above ground restrictions imposed by mountain ranges or public
parks or the presence of existing structures like buildings dams bridges etc., and
(2) when multiple well heads can regrouped together in one location. (3) When
relief wells needs to be drill to really pressure on another well to extinguish a
burning blows out, number (4) when multiple target zones must be drilled number
(5) and when side tracks are needed to drill around obstructions like a lost string
of pipe (Pic. 184).

117. 113
Pic. 184. Directional drilling uses
Let’s look at how directional drilling is done, as this picture shows
directional drilling typically follows different figuration, it starts with a continuous
build, holds then drops off to form and (S) shaped profile (Pic. 185). as
technological advances in directional drilling have increased accuracy while
decreasing costs, the typical configuration are now drill, for example using the
bent-housing motor (Pic. 186). The bent-housing mud motor allows the bit to be
tilted and steer into a preferred direction thus allowing a directional well.
Pic. 185. Directional drilling typically - different figuration

118. 114
Pic. 186. Example using the bent-housing motor
8.2 The (S) Shaped Directional
In a (S) shaped directional growing profile, the initial section of the well is
drilled vertically. When the area where the hole needs to be slandered or where
the kickoff depth is reached, the bent-housing mud motor is activated. the pipe is
not rotated during this phase. The bent-housing mud motors only turns the bits
making hole. The bent-housing angle can be set and the drilling proceeds until
the built angle achieved. Once the initial deflection angles obtained, then the
angle is maintained as a straight line into the target zone. If a (S) shape well is
required casing is set into place and a new and smaller bent housing mud motor
is used to set up the build drop angle, returning the well to a vertical position (Pic.
187). It is this BHA (bottom hole assembly) that permits directional control, by
using a magnetic insert in the bent-sub housing the BHA can be precisely
oriented to the target area while surveying the inclination of the borehole
regularly (Pic. 188).

119. 115
Pic. 187. (S) shaped directional growing profile
Pic. 188. Using a magnetic insert in the bent-sub housing
8.3 Horizontal Drilling
Basically horizontal wells are drilled in the same way as directional drilling
using the same technology, they're called horizontal because they are commonly
defined as any well in which the lower part of the well bore parallels to oil zone at
an 85 (eighty five) degree inclination angle or greater (Pic. 189). The usual
reason to drill horizontally is to expose more of the reservoir to the wellbore so
that the production rate can be increased, in fact any reservoir is a potential
target for a horizontal drilling but it works particularly well in low permeability
reservoir with vertical fractures that can be connected with horizontal boreholes.
In addition horizontal drilling has been used successfully to drill short, lateral
extensions from the same borehole (Pic. 190).

120. 116
Pic. 189. Horizontal wells
Pic. 190. Horizontal wells example
Some applications for lateral drilling are; (1) replacing an original
completion that has been damaged, (2) increasing a wells production rate from a
tight formation by using a posed multiple laterals to achieve greater access to the
formation, (3) completing a well and multiple zones using stacked multiple
laterals (Pic. 191).

121. 117
Pic. 191. Some applications for lateral drilling
With the development and improvements in the bent-housing mud motor it
is easy to see why directional drilling with its ability to steer in and around
obstructions to get to the target is fast becoming to prefer drilling procedure (Pic.
192).

122. 118
Pic. 192. The bent-housing mud motor
9. RUNNING CASING AND CEMENT
Now let's turn our attention once again to the wellbore, in running casing
and cement the initial cementing called primary cementing creates a sheet or
cover of hard cement that fills the annulus space between the outside of casing
and the well board wall. as i mentioned earlier it's primary function is to block fluid
movement and pressure transmission up or down and the annulus, subsequent
cementing is called squeeze cementing, and it’s done to repair the primary
cementing or in connection with a work over a well that is being rework because
of declining production.
9.1 Accessory Equipment
9.1.1 Guide Shoe
Let we describe the various pieces of accessory equipment needed when
running casing, then later cementing. In the illustration (Pic.193), you can view
the typical equipment set up, at the bottom is a guide shoe it has a rounded base
that run to the casing string in the hole to prevent the casing from sticking on
lodges, it can easily be drilled through later if necessary.

123. 119
Pic. 193. Accessory equipment
9.1.2 Float Valve
Next is the float valve, it can set either in a shoe called the floats shoe or
in a float collar located a joint or two above the shoe. The function of the float
valve is to prevent mud from filling the pipe, it also provides buoyancy to the pipe
which than lessons the load derek and the top joined of the pipe, as the casing is
run in the hole, the casing pipe is periodically filled with water at the surface to
reduce differential pressure that might cause the casing to collapse (Pic. 194).

124. 120
Pic. 194. Accessory equipment – Float valve
Inside the float valve, the ball and sheet type valve keeps the pipe close
while the casing is being run and opens it while the cement is being pumped in.
The valve and seat ball also prevents back flow of the fluid or the cement into the
drill pipe (Pic. 195).
Pic. 195. Accessory equipment - The valve and seat ball

125. 121
9.1.3 Scratchers
Next are the scratchers or wall cleaners they removed mud cake from the
sides of the hole, attached to the outside of the pipe these scratchers allow the
pipe to make better contact with the size of the hole as the cement is pumped
into the annulus (Pic. 196). As you might guess, smoother walls along the sides
of the open hole allow a better seal to form between the cement and the
formation rock. Radial type scratchers required that the pipe reciprocated for
moved in and up and down motion before and during cementing. Vertically
amounted scratchers required the pipe to be rotated.
Pic. 196. Accessory equipment – scratchers
9.1.4 Centralizers
Centralizers set at the top of selected joints, they are attached to the
outside of the casing pipe to center the pipe in the hole in preparation for
cementing (Pic.197). Centralization of the pipe is essential because for maximum
functionality the cement sheaf must evenly and completely surround the pipe.
These are the essential pieces of equipment used in preparation for cementing.

126. 122
Pic. 197. Accessory equipment - Centralizers
9.2 The Process of Running Cement
Let we now described the process of running cement, first dry cement is
mixed with additives made up of accelerators, retarders, and density adjusters
(Pic. 198). The function of these additives is to adjust the dry cement properties
to fit the conditions of the well, accelerator speed up the setting time of the
cement (Pic. 199), retarders to the opposite they prevent premature setting in
deep high temperature well (Pic. 200). Density adjusters increase the cement
weight to reduce pumping pressures or to permit a higher cement column without
fracturing the formation (Pic. 201).

127. 123
Pic. 198. Cementing – Accelerators, retarders, & density adjusters
Pic. 199. Cementing - Accelerators

128. 124
Pic. 200. Cementing - Retarders
Pic. 201. Cementing - density adjusters
After the casing in place, the cement is properly blended with water and
the hole does prepared for pumping, first a hard rubber rupture plug is inserted
into the casing followed by the cement slury, this plug will separate existing mud
from the new cement (Pic. 202). Pumps to the bottom of the hole the cement
slury pushing the plug in front as it flows down forces the rupture plug into the
seat in the float collar. Once in place the driller slightly increases the well
pressure to break through this rupture plug. Once the plugs broken the cement
slurry displaces the existing mud in the annulus, when adequate cement has
been pumped a second plug called seal plug is then inserted. This seal plug
serves the separate the cement slurry from the fresh mud that follows. Finally the