I hope this presentation helps you to understand why sometimes it becomes a necessity that we use secondary cementing . You can also know the equipment used in secondary cementing process . Any questions contact me at karim.elfarash@std.suezuniv.edu.eg

3. •Kareem Hassan Ahmed Elfarash SEC 3
•Hossam Hamdy Abd Eltwab SEC 2
•Ahmed Gamal Ahmed Mohamed SEC 1
•Mohamed Adel Elsemary SEC 3

5. Secondary
Cementing
Plug-Back Cementing Squeeze Cementing

8. •It prevents damaging fluids from entering
a producing formation. High-pressure
from a squeeze job performed above the
pay zone may force cement or wellbore
fluids into a pay zone, causing damage
and loss of production.

9. •It isolates an upper zone by forming a new
bottom for the well from which formation tests
can be run. The plug eliminates the chances of
sticking your pipe below the testing assembly.
•It can be used to block off a problem area. For
example, a permanent cement plug can be
placed above a depleted zone without affecting
the producing zones above the plug.

11. •Circulation loss generally occurs in porous or
fractured formations, because drilling fluids
or cement slurries flow into the fractures.
•A cement plug is sometimes set during
drilling or cementing operations to stop lost
circulation.

12. •A cement plug helps combat this problem since
before the plug’s cement sets, it drifts into the
cavities to block them off.

13. •At times, you do not or cannot perform vertical
drilling. Perhaps an object is blocking the path
downwards (for example, a broken string of pipe), the
hole is deviated, or you want to drill toward a target
which is off to the side of the hole.
•Before directional drilling can be performed, you need
a seat or a bridge on which to set the tool. A cement
plug can be used for this purpose.

14. MECHANISMMECHANISM
• Directional drilling or whipstocking is done by
setting the plug, and then rotating the bit off
the plug in another direction.
• The cement plug is called a whipstock when
used in this way.

15. A whipstock plug provides a way to:A whipstock plug provides a way to:
• get around non-retrievable objects
• correct excessive vertical deviations
of the hole
• drill a relief well

17. •When a dry or depleted well is abandoned, a
portion of the casing that was left uncemented
may be pulled from the hole.
•This leaves freshwater zones unprotected. In
addition, highpressure zones may be
uncovered.
•This allows fluid to migrate to the surface, and
causes unfavorable surface conditions.

18. cement plugs are usually set:cement plugs are usually set:
• across and above potential oil and gas
producing zones
• above and below freshwater zones
• above and below the bottom of any casing left
in the hole
• at ground level .

20. Squeeze cementing is the process of
forcing a cement slurry through
perforations in the casing to a desired
location to provide a seal across an
undesired gap.

21. A series of decisions must be made to
determine :
•If a problem exists
•The magnitude of the problem
•If squeeze cementing will correct it
•The risk factors present
•If economics will support it.

22. During placement water is driven from the
slurry into a permeable formation to form a
cement filter-cake which hardens to form a
seal.

23. • It is a common misconception that the cement
actually penetrates the pores of the rock.
• As cement slurries have a mean particle size of
20-50 microns, it would require a formation
with a permeability of between 2-100 darcies
for the cement grains to penetrate the
formation.

24. The need for squeeze cementing can arise for a
variety of reasons during the drilling and
production phases.
Some of the most common reasons are asSome of the most common reasons are as
following:following:
• The repair of a faulty or inadequate primary cement job
• To shut-off the flow of unwanted water or gas
• The isolation of a zone prior to perforating for
production
• To abandon a non-productive or depleted zone
• To repair casing leaks.

25. The slurry is supjected to differential pressure
that allows the slurry to cover the defective
zone by the process of the liquid base filtering
into the formation
Thus squeeze cementing is divided into:Thus squeeze cementing is divided into:
LOW PRESSURE SQUEEZELOW PRESSURE SQUEEZE
HIGH PRESSURE SQUEEZEHIGH PRESSURE SQUEEZE

26. 1-LOW PRESSURE SQUEEZE
• Cement slurry is forced through the perforations at
pressures below the formation fracture pressure.
• The aim of this operation is to fill perforation
cavities and interconnected voids with dehydrated
cement.
• The volume of cement is small since no slurry is
actually pumped into the formation..

27. 2-HIGH PRESSURE SQUEEZE
In some instances a low pressure squeeze will
not accomplish the objective of the job due to:
• Channels behind the casing may not be
directly connected with the perforations
• Small cracks or microannuli may permit the
flow of gas but not of a cement slurry
• The impossibility of displacing plugging fluids

28. Mechanism
Placement of the cement slurry behind the
casing is accomplished by breaking down
formations at, or close to, the perforations.
Fluids ahead of the slurry are displaced into
the fractures, allowing cement to fill the
desired spaces.

29. 3-HESITATION SQUEEZE
Sometimes pumping is continuous but more commonly
it is on a stop and start basis
A small volume of slurry is pumped in and theA small volume of slurry is pumped in and the
corresponding pressure increase is notedcorresponding pressure increase is noted
Pumping is halted for a specific time and thePumping is halted for a specific time and the
pressure drop caused by the slurry is notedpressure drop caused by the slurry is noted
The cycle is repeatedThe cycle is repeated
In this way pumping is easier and there is more time for
cement cake to develope

32. This process is done using:
• Drill pipes alone
• Drill pipes with squeeze packer
• Drill pipe with cement retainer
• Retrievable or permanent bridge plug

34. DRILLABLE CEMENT RETAINER

35. Bridge plug

36. • The main objective of using a packer is to isolate
the casing and wellhead while high pressure is
applied downhole.
• The advantage of the retrievable packer is the
fact that it can be set and released many times.
• Retrievable squeeze packers can be either
compression set or tension set.

37. • Squeeze packers have a by-pass valve to
allow circulation of fluids while running in
and pulling out of the hole and also when
the packer has been set
• Drillable or retrievable bridge plugs can be
set to isolate the casing below the zone to
be treated.

38. DRILLABLE CEMENT RETAINER
• Cement retainers are drillable packers provided with
a two-way valve that prevents flow in either or both
directions.
• Drillable cement retainers run on wireline are used
instead of packers to prevent backflow when no
dehydration of cement is expected, or when high
negative differential pressures may disturb the
cement cake.

39. When cementing multiple zones the cement
retailer isolates the lower perforations and
subsequent zone squeezing can be carried out
without having to wait for the cement to set .
These retainers are also used for well
abandonment purposes .

40. BRADENHEAD PLACEMENT
METHOD
• This squeeze technique is the simplest of the squeeze
techniques and does not use a packer.
• It is to be only practised with the Low Pressure
Squeeze Technique.
• Open ended tubing is run to the desired depth, the
slurry is placed using the balanced plug method and
the string raised above the plug.
• The rams are closed and squeeze pressure applied

48. References
Well completion and
servicing
Cementing 1