3. Primary Recovery
• Drilling- The oil well is created by
drilling a hole into the earth with an
oil rig. A steel pipe (casing) is placed
in the hole, to provide structural
integrity to the newly drilled
wellbore. Holes are then made in
the base of the well to enable oil to
pass into the bore. Finally a
collection of valves called a
"Christmas Tree" is fitted to the top,
the valves regulating pressures and
controlling flows.
4. Grounds for Primary Recovery
• If the underground pressure in the oil
reservoir is sufficient, then this pressure
will force the oil to the surface. Gaseous
fuels, natural gas or water are usually
present, which also supply needed
underground pressure. In this situation, it
is sufficient to place a complex
arrangement of valves (the Christmas tree)
on the well head to connect the well to a
pipeline network for storage and
processing.
• Usually, about 20% of the oil in a reservoir
can be extracted using primary recovery
methods.
5. Secondary Recovery
• Secondary or enhanced oil recovery
(EOR) methods are needed because
only a small fraction of the oil in a
reservoir can be produced by primary
means (the reservoir's natural drives).
• Initial recovery ranges from only
about 5 per cent (Lloydminster-area
heavy oils) up to about 20 per cent
(better quality oils like those
produced in the province's southwest
and southeast). These methods must,
naturally, also be both economic and
effective, or companies may not
bother trying to coax more oil from
the reservoir.
• Over the lifetime of the well the
pressure will fall, and at some point
there will be insufficient underground
pressure to force the oil to the
surface. If economical, as often is, the
remaining oil in the well is extracted
6. • using secondary oil recovery methods (see:
energy balance and net energy gain).
• Secondary oil recovery uses various
techniques to aid in recovering oil from
depleted or low-pressure reservoirs.
Sometimes pumps, such as beam pumps
and electrical submersible pumps (ESPs),
are used to bring the oil to the surface.
Other secondary recovery techniques
increase the reservoir's pressure by water
injection, natural gas reinjection and gas
lift, which injects air, carbon dioxide or
some other gas into the reservoir.
• Together, primary and secondary recovery
generally allow 25% to 35% of the
reservoir's oil to be recovered.
7. Examples of Secondary Recovery
• Water Flooding: Water flooding is
utilized primarily as a secondary
recovery technique, where the primary
drive mechanism used to produce the
oil (dissolved gas) is depleted. Water is
recovered from the water table and
injected into the reservoir, displacing
the oil towards the target production
wells. Because of the limited amount
of dissolved gas remaining in solution,
pumps are used to bring the oil to
surface.
8. • Sand Franc (beam pump, electrical
submersible pump): Sand Fracas are used
where porosity development or
permeability is low (the formation is tight).
This treatment is done under high
pressure, the formation is fractured, and a
sand/gel mixture is pumped into the
fractures. Once the fractures are allowed
to settle, trapping the sand, the well is
produced with a significant increase in
production, because the pathways towards
the well-bore have been opened up.
Almost like changing a single lane highway
into a six lane highway
9. Tertiary Recovery
• Tertiary oil recovery reduces the oil's viscosity to increase oil production.
• Thermally enhanced oil recovery methods (TEOR) are tertiary recovery
techniques that heat the oil and make it easier to extract. Steam injection is
the most common form of TEOR, and is often done with a:
1) cogeneration plant. In this type of cogeneration plant, a gas turbine is
used to generate electricity and the waste heat is used to produce steam,
which is then injected into the reservoir. This form of recovery is used
extensively to increase oil production in the San Joaquin Valley, which has
very heavy oil, yet accounts for 10% of the United States' oil production.[citation
needed]
.
10. 2) In-situ burning is another form of TEOR, but
instead of steam, some of the oil is burned to
heat the surrounding oil. Occasionally,
detergents are also used to decrease oil
viscosity as a tertiary oil recovery method.
• 3) carbon dioxide flooding.
• Tertiary recovery allows another 5% to 15%
of the reservoir's oil to be recovered.
• Tertiary recovery begins when secondary oil
recovery isn't enough to continue adequate
production, but only when the oil can still be
extracted profitably. This depends on the cost
of the extraction method and the current
price of crude oil. When prices are high,
previously unprofitable wells are brought
back into production and when they are low,
production is curtailed
11. Other Tertiary Recovery Methods
• Cyclic Steam Stimulation
• This method, also known as the Huff
and Puff method, consists of 3 stages:
• 1)injection,
• 2)soaking
• 3) production.
• Steam is first injected into a well for a
certain amount of time to heat the oil
in the surrounding reservoir to a
temperature at which it flows. After it
is decided enough steam has been
injected, the steam is usually left to
"soak" for some time after (typically
not more than a few days). Then oil is
produced out of the same well, at first
by natural flow (since the steam
injection will have increased the
reservoir pressure) and then by
artificial lift. Production will decrease
as the oil cools down, and once
production reaches an economically
determined level the steps are
repeated again.
12. • The process can be quite effective,
especially in the first few cycles. However,
it is typically only able to recover
approximately 20% of the Original Oil in
Place (OOIP), compared to steam flooding
which has been reported to recover over
50% of OOIP. It is quite common for wells
to be produced in the cyclic steam manner
for a few cycles before being put on a
steam flooding regime with other wells.
• The mechanism was accidentally
discovered by Shell while it was doing a
steam flood in Venezuela and one of its
steam injectors blew out and ended up
producing oil at much higher rates than a
conventional production well in a similar
environment.
13. Steam Flooding
• Steam Flooding
• In a steam flood, sometimes known as a
steam drive, some wells are used as steam
injection wells and other wells are used for
oil production. Two mechanisms are at
work to improve the amount of oil
recovered. The first is to heat the oil to
higher temperatures and to thereby
decrease its viscosity so that it more easily
flows through the formation toward the
producing wells. A second mechanism is
the physical displacement employing in a
manner similar to water flooding, in which
oil is meant to be pushed to the production
wells. While more steam is needed for this
method than for the cyclic method, it is
typically more effective at recovering a
larger portion of the oil.
14. • A form of steam flooding that has become
popular in the Alberta tar sands is steam
assisted gravity drainage (SAGD), in which
two horizontal wells are drilled, one a few
meters above the other, and steam is
injected into the upper one. The intent is
to reduce the viscosity of the bitumen to
the point where gravity will pull it down
into the producing well.
15. polymer flooding
Description
Polymer augmented water flooding consists of
adding water soluble polymers to the water
before it is injected into the reservoir.
Mechanisms That Improve Recovery Efficiency
Mobility control (improves volumetric sweep
efficiency).
Limitations
High oil viscosities require a higher polymer
concentration. Results are normally better if
the polymer flood is started before the water-
oil ratio
becomes excessively high.
Clays increase polymer adsorption.
Some heterogeneity is acceptable, but avoid
extensive fractures. If fractures are present,
the cross linked or gelled polymer techniques
may be applicable.
16. Challenges
Lower infectivity than with water can adversely
affect oil production rates in the early stages
of the polymer flood.
Acryl amide-type polymers loose viscosity due
to sheer degradation, or it increases in
salinity and divalent ions.
Xanthus gum polymers cost more, are subject
to microbial degradation, and have a
greater potential for wellbore plugging.
Screening Parameters
Gravity >18º API
Viscosity <200 cp
Composition not critical
Oil saturation >10% PV mobile oil
Formation type sandstone/carbonate
Net thickness not critical
Average permeability >20 mad
Transmissibility not critical
Depth <9,000 feet
Temperature <225ºF
17. Microbial injection
Introduction
• Currently global energy production from
fossil fuels is about 80-90% with oil and
gas representing about 60 %
• During oil production, primary oil
recovery can account for between 30-40
% oil productions
• While additional 15-25% can be
recovered by secondary methods such as
water injection leaving behind about 35-
55 % of oil as residual oil in the
reservoirs
• This residual oil is usually the target of
many enhanced oil recovery technologies
and it amounts to about 2-4 trillion
barrels (Hall et al., 2003)
18. What is microbial enhanced oil recovery (MEOR)?
Use of microbes to improve oil recovery, established by Beckman 1926
How much additional oil can be produced? Up to 60% oil in place after primary
recovery
19. MEOR Mechanisms
Bioproduct Effect
Acids
Biomass
Gases (CO2, CH4, H2)
Solvents
Surface-active agents
Polymers
Modification of reservoir rock
Improvement of porosity and permeability
Reaction with calcareous rocks and CO2 production
Selective or non selective plugging
Emulsification through adherence to hydrocarbons
Modification of solid surfaces
Degradation and alteration of oil
Reduction of viscosity and oil pour point
Desulfurization of oil
Reservoir repressurization
Oil swelling
Viscosity reduction
Increase permeability due to solubilization of carbonate rocks by
CO2
Dissolving of oil
Lowering of interfacial tension
Emulsification
Mobility control
Selective and non-selective plugging
20. Microbial Enhanced Oil Recovery (MEOR)
Microbial Enhanced Oil Recovery (MEOR) is a technology using micro-organisms to
facilitate, increase or extend oil production from reservoir.
Average size of microbe is one micron, 10,000th of cm. More
than 27,000 species of bacteria have been identified.
The bacteria, which can be mobile or non-mobile, have three
basic shapes: round (cocas), rod (bacillus) and spiral (spiralled).
Microbes are the most primitive earth's single celled
organisms.
Their basic role in life is to recycle the components of living
organisms, converting them to the nutrient chemicals used by
plants in photosynthesis & chemosynthesis.
21. Enhanced Oil Recovery Research
Saskatchewan’s Heavy Oil Production
20.4 billion barrels currently in place
24. • A suite of projects to gain knowledge of
enhanced oil
recovery in light and tight oil reservoirs, and heavy
oil
• Considering the certainty of decline, these will
hopefully
provide solutions before solutions are even
required
• Projects designed to help us with water, be it
from an
environmental standpoint, or usage in water flood
25. CONCLUSION
According to production rates from graph of oil recovery methods
we can say that thermal method is more efficient than other
methods and chemical method is less efficient
26. REFERENCES
• Petroleum Technology Research Centre
Saskatchewan articles
• Dr. Maria Antoinette Baronet- fall 2001, class
notes Pete module-1
• Oil and Gas recovery by Squab
• Microbial oil recovery by I.A Jimson, Rudy S.N and
Sugared E.G
