Artficial Lift Techniques - Oil Well

7/31/2019 Artficial Lift Techniques - Oil Well

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How Does Artificial Lift Work?

URL: http://www.rigzone.com/HowItWorks//insight.asp?i_id=315

Artificial lift is a process used on oil wells to increase pressure within the reservoir and encourage oil to thesurface. When the natural drive energy of the reservoir is not strong enough to push the oil to the surface,artificial lift is employed to recover more production.

While some wells contain enough pressure for oil to rise to the surface without stimulation, most don't,requiring artificial lift. In fact, 96% of the oil wells in the US require artificial lift from the very beginning.

Even those wells that initially posses natural flow to the surface, that pressure depletes over time, and artificiallift is then required. Therefore, artificial lift is generally performed on all wells at some time during theirproduction life.

Although there are several methods to achieve artificial lift, the two main categories of artificial lift includepumping systems and gas lifts.

Methods of Artificial Lift

The most common type of artificial lift pump system applied is beam pumping, which engages equipment onand below the surface to increase pressure and push oil to the surface. Consisting of a sucker rod string anda sucker rod pump, beam pumps are the familiar jack pumps seen on onshore oil wells.

Beam PumpSource: Calsac Corporation

Above the surface, the beam pumping system rocks back and forth. This is connected to a string of rodscalled the sucker rods, which plunge down into the wellbore. The sucker rods are connected to the sucker rodpump, which is installed as a part of the tubing string near the bottom of the well. As the beam pumpingsystem rocks back and forth, this operates the rod string, sucker rod and sucker rod pump, which workssimilarly to pistons inside a cylinder. The sucker rod pump lifts the oil from the reservoir through the well to thesurface.

Usually pumping about 20 times a minute, the pumping units are powered electronically or via gas engine,called a prime mover. In order for the beam system to work properly, a speed reducer is employed to ensurethe pump unit moves steadily, despite the 600 revolutions per minute the engine achieves.

Another artificial lift pumping system, hydraulic pumping equipment applies a downhole hydraulic pump,rather than sucker rods, which lift oil to the surface. Here, the production is forced against the pistons, causingpressure and the pistons to lift the fluids to the surface. Similar to the physics applied in waterwheels

powering old-fashion gristmills, the natural energy within the well is put to work to raise the production to thesurface.

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Hydraulic PumpSource: Schlumberger

Hydraulic pumps are generally composed of two pistons, one above the other, which are connected by a rodthat moves up and down within the pump. Both the surface hydraulic pumps and subsurface hydraulic pumpsare powered by power oil, or clean oil that has been previously lifted from the well. The surface pump sendsthe power oil through the tubing string to the subsurface hydraulic pump installed at the bottom of the tubingstring, the reservoir fluids are then sent up a second parallel tubing string to the surface.

Electric submersible pump systems employ a centrifugal pump below the level of the reservoir fluids.Connected to a long electric motor, the pump is composed of several impellers, or blades, that move the fluidswithin the well. The whole system is installed at the bottom of the tubing string. An electric cable runs thelength of the well, connecting the pump to a surface source of electricity.




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Electric Submersible PumpSource: Schlumberger

The electric submersible pump applies artificial lift by spinning the impellers on the pump shaft, puttingpressure on the surrounding fluids and forcing them to the surface. A mass producer, electric submersiblepumps can lift more than 25,000 barrels of fluids per day.

An emerging method of artificial lift, gas lift injects compressed gas into the well to reestablish pressure,making it produce. Even when a well is flowing without artificial lift, it many times is using a natural form of gaslift.




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Gas LiftSource: Tech Flo Consulting LLC

The injected gas reduces the pressure on the bottom of the well by decreasing the viscosity of the fluids in thewell. This, in turn, encourages the fluids to flow more easily to the surface. Typically, the gas that is injected isrecycled gas produced from the well.

With very few surface units, gas lift is the optimal choice for offshore applications. Occurring downhole, thecompressed gas is injected down the casing tubing annulus, entering the well at numerous entry points calledgas-lift valves. As the gas enters the tubing at these different stages, it forms bubbles, lightens the fluids andlowers the pressure.

In the US, the majority of wells, 82%, employ a beam pump. Ten percent use gas lift, 4% use electricsubmersible pumps, and 2% use hydraulic pumps.

SourcesOil & Gas Production

in Nontechnical LanguageOil and Gas:

The Production Story




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How Does Water Injection Work?


While primary production refers to oil that is recovered naturally from a producing well, Enhanced OilRecovery (EOR) improves the amount of oil recovered from a well by using some form of additionalengineering technique. Water injection, also known as waterflood, is a form of this secondary EOR productionprocess.

Baobab Subsea Production System

Used in onshore and offshore developments, water injection involves drilling injection wells into a reservoirand introducing water into that reservoir to encourage oil production. While the injected water helps toincrease depleted pressure within the reservoir, it also helps to move the oil in place.

Whether water injection occurs after production has already been depleted or before production from the

reservoir has been drained, waterflood sweeps remaining oil through the reservoir to production wells, whereit can be recovered.

Water Injection Methods

The water used for water injection is usually some sort of brine, but it can also be made up of other sourcesthat are treated. For example, in some reservoirs water is produced with the hydrocarbons, removed from theproduction and re-injected into the formation.

Enhanced Oil RecoverySource: Schlumberger

It is important that the water being injected works within the formation. Filtration and processing of the water

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that will be injected are sometimes necessary to ensure that no materials clog the well pores and that bacteriais not permitted to grow. In an effort to reduce any corrosion within the reservoir, oxygen is often removedfrom the water, as well.

While production wells can be converted into injection wells, water-injection wells are also drilled specificallyfor this purpose. Water is then pumped into the reservoir, or gravity can help to push the liquid into theformation. This solution positions water tanks on hills or somewhere above the well, and the water simply isfed into the wellbore.

There are a number of techniques for determining where the water-injection wells should be drilled, as well asestablished patterns for water-injection wells in relation to production wells. One popular pattern, called thefive-spot pattern, involves drilling four water-injection wells in a square around a production well. This isrepeated around each production well on the reservoir, resulting in four production wells surrounding eachwater-injection well, as well.

Other drilling techniques include the seven-spot pattern, which has six water-injection wells surrounding aproduction well, and the inverted seven-spot pattern, which describes six production wells surrounding onewater-injection well.

Also, wells can be drilled in line patterns, rather than spot patterns, where a direct line or staggered line of

production wells is followed by a similar line of water-injection wells, and so on. In an edge waterflood, water-injection wells are drilled along the outside borders of the field, and water is injected, with production flowingtoward the production wells in the center of the reservoir.

Improved Oil Recovery

Primary production usually only recovers some 30 to 35% of the oil in place. Although the effectiveness ofwater injection varies according to the formation characteristics, a waterflood can recover anywhere from 5%to 50% of the oil that is remaining in the reservoir, greatly enhancing the productivity and economics of thedevelopment.

WaterfloodingSource: Perisai Petroleum Teknology

This form of EOR is typically more productive when there are relatively small amounts of primary production,and the process becomes uneconomical when the water cut reaches the 90 to 99% level. Some waterfloods




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may take up to two years of injection before production is increased; and some reservoirs do not have theright characteristics, and water injection is not a viable option for increasing production from waning wells.(For example, water injection is never used on natural gas wells.)

Another form of water injection involves introducing heated water into the reservoir. This helps to make the oilmore fluid, especially in reservoirs that contain heavy oil. Also, the water can be treated with polymers toincrease the viscosity of the water and help to encourage oil movement within the reservoir.

SourcesNontechnical Guide to

Petroleum Geology etc...




8/23

How is Nitrogen Used in Oil and Gas Fields?


A colorless, odorless gas, Nitrogen is a non-hydrocarbon inert gas used for a variety of functions in thedrilling, workover and completion phases of oil and gas wells, as well as in pigging and purging pipelines.

Used both in onshore and offshore situations, applications for nitrogen include well stimulation, injection andpressure testing, Enhanced Oil Recovery (EOR), reservoir pressure maintenance, nitrogen floods and inertgas lift. Additionally, nitrogen can be used to help prevent flammable gases from igniting and protect tubularsfrom downhole corrosion.

Source: Generon

Used to support drilling operations, nitrogen can be utilized for instrument panel inerting, as well as flare gasinerting, and pressure systems purging and testing. Also, nitrogen can be supplied for the engine starters,controls, dry bulk transfer and hoisting systems. Providing a dry air supply, nitrogen can extend the life ofsome systems, as well as prevent breakdowns.

In workover and completion operations, nitrogen is an optimal choice to displace well fluids in order to initiateflow and clean wells because of its low density and high pressure characteristics. The high-pressure gas isalso used for production stimulation through hydraulic fracturing. Also, nitrogen is used for cementingoperations and controlling cement slurry weights.

Additionally, nitrogen is used to maintain pressure in reservoirs that have either been depleted ofhydrocarbons or experienced natural pressure reduction. Because nitrogen is immiscible (or does not mix)

with oil and water, a nitrogen injection program or nitrogen flood can be used to move missed pockets ofhydrocarbons from an injection well to a production well.

Nitrogen can also be used in pigging and purging a pipeline. For example, nitrogen can be used as the driverto push the pigs through the pipe. Nitrogen can also be used to purge the pipeline after pigging has beencompleted. In this case, the dry gas is run through the line without the pig to dry up any remaining water in thepipeline.

Also, nitrogen can be used in FPSOs and other situations where hydrocarbons are stored. In a process calledtank blanketing, nitrogen is applied to an empty storage facility, to increase safety and provide a buffer for theentering hydrocarbons.

How Does Nitrogen Generation Work?

Developed by Dow Chemical in the 1970s, nitrogen generation through hollow fiber membrane technologyhas progressed over the last several decades. Now, the technology offers onsite generation through various

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output and capacity generators. Achieving up to 99.9% purity levels, nitrogen generation has made a myriadof applications in the oil and gas field more economical.

Nitrogen Membrane ModuleSource: Generon

Nitrogen is produced through patented membrane filters. The process starts by atmospheric air being takeninto a rotary screw compressor. Here the air is compressed to a designated pressure and air flow. Then, thecompressed air is saturated with three to five parts per million of hydrocarbons and particulates. It is thenintroduced into the nitrogen generation system.

Source: Generon

The air then enters a pre-filtration system, composed of either a demister or cyclone-type water separator toremove up to 94% of free liquids.

Next, the air travels through two coalescing filters; the first is a 1.0 micron coalescing filter. And immediately,the air travels to a 0.01 micron coalescing filter. These filters remove 99.9999% of all contaminants from theair, which is still in a vapor state and saturated with water and hydrocarbons.

Ensuring the remaining contaminants are in a vapor state, the air is then heated, raising the dew point. The airnow enters an activated carbon vessel, where the hydrocarbons are absorbed.

From here, the air travels through to a 0.01 micron particulate filter, which makes the air stream a specificationof eight to ten parts per billion of contaminants. This guarantees a high-quality air is being supplied to themembrane modules.

Now, the air is fed to a dehydration membrane. Here, the water is removed from the recently cleansed air,

reaching dewpoints as low as negative 40 degrees Fahrenheit. The dry air is then introduced to the nitrogenmembranes.

In the nitrogen membranes, the oxygen is removed from the air, resulting in nitrogen at a purity level of 90 to




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99%. Because the nitrogen is supplied at a 70-degree Fahrenheit dewpoint, additional residual water vapor isthen removed.

Providing vast savings in comparison, onsite nitrogen generation is preferable over bulk nitrogen shipments.Furthermore, nitrogen can be created a various specifications for an assortment of uses.




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How Does Well Acidizing Work to Stimulate Production?


Stimulation is performed on a well to increase or restore production. Sometimes, a well initially exhibits lowpermeability, and stimulation is employed to commence production from the reservoir. Other times, stimulationis used to further encourage permeability and flow from an already existing well that has become under-productive.

A type of stimulation treatment, acidizing is performed below the reservoir fracture pressure in an effort torestore the natural permeability of the reservoir rock. Well acidizing is achieved by pumping acid into the wellto dissolve limestone, dolomite and calcite cement between the sediment grains of the reservoir rocks. Thereare two types of acid treatment: matrix acidizing and fracture acidizing.

Well AcidizingSource: MPG Petroleum

A matrix acid job is performed when acid is pumped into the well and into the pores of the reservoir rocks. Inthis form of acidization, the acids dissolve the sediments and mud solids that are inhibiting the permeability ofthe rock, enlarging the natural pores of the reservoir and stimulating flow of hydrocarbons.

While matrix acidizing is done at a low enough pressure to keep from fracturing the reservoir rock, fractureacidizing involves pumping highly pressurized acid into the well, physically fracturing the reservoir rock anddissolving the permeability inhibitive sediments. This type of acid job forms channels through which thehydrocarbons can flow.

There are different acids used to perform an acid job on wells. A common type of acid employed on wells tostimulate production is hydrochloric acids (HCI), which are useful in removing carbonate reservoirs, orlimestones and dolomites, from the rock. Also, HCI can be combined with a mud acid, or hydrofluoric acid(HF), and used to dissolve quartz, sand and clay from the reservoir rocks.

In order to protect the integrity of the already completed well, inhibitor additives are introduced to the well toprohibit the acid from breaking down the steel casing in the well. Also, a sequestering agent can be added toblock the formation of gels or precipitate of iron, which can clog the reservoir pores during an acid job.

After an acid job is performed, the used acid and sediments removed from the reservoir are washed out of thewell in a process called backflush.

For more information about reservoir stimulation, take a look at How Does Well Fracturing Work to StimulateProduction?

SourcesNontechnical Guide to

Petroleum GeologyOil & Gas


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Impermeable Pores in Tight Gas FormationSource: USGS, www.energy.usgs.gov

While a conventional gas formation can be relatively easily drilled and extracted from the ground unassisted,

tight gas requires more effort to pull it from the ground because of the extremely tight formation in which it islocated. In other words, the pores in the rock formation in which the gas is trapped are either irregularlydistributed or badly connected with overly narrow capillaries, lessening permeability -- or the ability of the gasto travel through the rock. Without secondary production methods, gas from a tight formation would flow atvery slow rates, making production uneconomical.

While conventional gas formations tend to be found in the younger Tertiary basins, tight gas formations aremuch older. Deposited some 248 million years ago, tight gas formations are typically found in Palaeozoicformations. Over time, the rock formations have been compacted and have undergone cementation andrecrystallisation, which all reduce the level of permeability in the rock.

Typical conventional natural gas deposits boast a permeability level of .01 to .5 darcy, but the formationstrapping tight gas reserves portray permeability levels of merely a fraction of that, measuring in the millidarcy

or microdarcy range.

In order to overcome the challenges that the tight formation presents, there are a number of additionalprocedures that can be enacted to help produce tight gas. Deviating drilling practices and more specificseismic data can help in tapping tight gas, as well as artificial stimulation, such as fracturing and acidizing.

Developing Tight Gas

One of the most important aspects of drilling for any petroleum is predetermining the success rate of theoperation. Operators do not just drill anywhere. Extensive seismic data is gathered and analyzed to determinewhere to drill and just what might be located below the earth's surface.

These seismic surveys can help to pinpoint the best areas to tap tight gas reserves. A survey might be able tolocate an area that portrays an improved porosity or permeability in the rock in which the gas is located.Should wells directly hit the best area to develop the reserve, costs of development can be minimized.

Most tight gas formations are found onshore, and land seismic techniques are undergoing transformations tobetter map out where drilling and development of these unconventional plays. Typical land seismic techniquesinclude exploding dynamite and vibroseis, or measuring vibrations produced by purpose-built trucks. Whilethese techniques can produce informational surveys, advancements in marine seismic technologies are nowbeing applied to land seismic surveys, enhancing the information available about the world below.

Not only providing operators with the best locations for drilling wells into tight gas formations, extensiveseismic surveys can help drilling engineers determine where and to what extent drilling directions should bedeviated.

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Directional DrillingSource: MacKenzie Gas Project, www.mackenziegasproject.com

While vertical wells may be easier and less expensive to drill, they are not the most conducive to developing

tight gas. In a tight gas formation, it is important to expose as much of the reservoir as possible, makinghorizontal and directional drilling a must. Here, the well can run along the formation, opening up moreopportunities for the natural gas to enter the wellbore.

A common technique for developing tight gas reserves includes drilling more wells. The more the formation istapped, the more the gas will be able to escape the formation. This can be achieved through drilling myriaddirectional wells from one location, lessening the operator's footprint and lowering costs.

Production Stimulation

After seismic data has illuminated the best well locations, and the wells have been drilled, productionstimulation is employed on tight gas reservoirs to promote a greater rate of flow. Production stimulation can beachieved on tight gas reservoirs through both fracturing and acidizing the wells.

Fracturing, also known as "fracing," a well involves breaking the rocks in the formation apart. Performed afterthe well has been drilled and completed, hydraulic fracturing is achieved by pumping the well full of frac fluidsunder high pressure to break the rocks in the reservoir apart and improve permeability, or the ability of the gasto flow through the formation.

Additionally, acidizing the well is employed to improve permeability and production rates of tight gasformations. Acidation involves pumping the well with acids that dissolve the limestone, dolomite and calcitecement between the sediment grains of the reservoir rocks. This form of production stimulation helps toreinvigorate permeability by reestablishing the natural fissures that were present in the formation beforecompaction and cementation.

Furthermore, deliquification of the tight gas wells can help to overcome some production challenges. In manytight gas formations, the reservoirs also contain small amounts of water. This water can collect and undermineproduction processes. Deliquification is achieved in this instance through artificial lift techniques, such asusing a beam pumping system to remove the water from the reservoir, although this has not proven the most




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effective way to overcome this challenge.

Engineers continue to develop new techniques and technologies to better produce tight gas. Through theirefforts, maybe one day, tight gas will no longer be considered an unconventional play.




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How Does Gas Injection Work?


Typically, a well will produce at its highest production rate at the beginning of the production cycle; and thenproduction will wane. In an effort to increase production from both oil and natural gas wells, secondaryproduction methods are employed. A type of Enhanced Oil Recovery (EOR), secondary production includeswater flooding and gas injection.

Secondary Production: Gas Injection

Secondary production methods are employed to increase production by boosting depleted pressure in aformation. As the oil or natural gas in a formation is produced, the hydrocarbons remaining in the reservoirmay become trapped because the pressure in the formation has lessened, making production either slowdramatically or stop altogether.

Gas Injection & Production WellSource: www.libyaninvestment.com

A form of secondary production, gas injection is used on a well to enhance waning pressure within theformation. Systematically spread throughout the field, gas-injection wells are used to inject gas and effectivelysweep the formation for remaining petroleum, boosting production.

Somewhat similar to water injection, or water flooding, gas injection is a pressure maintenance program thatcan be employed on a reservoir at the start of the production process or introduced after production hasalready started to lessen. Here, gas is injected into the gas cap of the formation, whereas in water injection,the water is injected directly into the production zone.

Cycling in a Natural Gas Reservoir

Sometimes known as cycling, gas injection can entail re-injection of produced natural gas. In this instance, asthe pressure drops in a natural gas field, the condensate separates from the dry gas in the reservoir. Thecondensate liquids block the pores within the reservoir, making extraction practically impossible.

Cycling is used to prevent the condensate from separating from the natural gas in the reservoir. In this

process, the natural gas liquids (condensate) are stripped from the gas on the surface after it has beenproduced from the reservoir, and the dry gas is then re-injected into the reservoir through injection wells.Again, this helps to maintain pressure in the reservoir while also preventing the separation within thehydrocarbon.

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Natural Gas Disposal Solution

Additionally, gas injection can serve as an economical way to dispose of uneconomical gas production on anoil reservoir. While in the past, low levels of natural gas that were produced from oil fields were flared orburned off, that practice is discouraged in some countries and against the law in others.

Flaring

Now, the low levels of natural gas that are produced from prolific oil fields are re-injected into the formation asform of disposal, as well as pressure maintenance. Here, produced wet gas from oil fields are stripped of theirnatural gas liquids, compressed and pumped into an injection well.

If the oil field is highly saturated, the natural gas is injected in the free gas cap; but if the oil field is under-saturated, the gas is injected directly into the oil reservoir.

Gas Injection, Gas Lift & Gas Miscible Process

Although the terms are sometimes interchanged, gas injection and gas lift are two separate processes thatare used to increase production. While gas injection is a secondary production method, gas lift is a type ofartificial lift.

Artificial lift is another way to increase production from a well by increasing pressure within the reservoir. Themain types of artificial lift include gas liftand pumping systems, such as beam pumps, hydraulic pumps andelectric submersible pumps.

While gas injection is achieved by injecting gas through its own injection well, gas lift occurs through theproduction wells. In gas lift, compressed gas is injected down the casing tubing annulus of a production well,entering the well at numerous entry points called gas-lift valves. As the gas enters the tubing at these differentstages, it forms bubbles, lightens the fluids and lowers the pressure, thus increasing the production rate of thewell.

Furthermore, a type of EOR employed on a well in the tertiary production process, a gas miscible process canbe used to increase production. The difference in this recovery method is that the gases introduced into thereservoir are not naturally occurring. In a gas miscible process, carbon dioxide, nitrogen and LPG are injectedinto the reservoir.


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What Is EOR, and How Does It Work?


Oil production is separated into three phases: primary, secondary and tertiary, which is also known asEnhanced Oil Recovery (EOR). Primary oil recovery is limited to hydrocarbons that naturally rise to thesurface, or those that use artificial lift devices, such as pump jacks. Secondary recovery employs water andgas injection, displacing the oil and driving it to the surface. According to the US Department of Energy,utilizing these two methods of production can leave up to 75% of the oil in the well.

The way to further increase oil production is through the tertiary recovery method or EOR. Although moreexpensive to employ on a field, EOR can increase production from a well to up to 75% recovery.

Enhanced Oil RecoverySource: Schlumberger

Used in fields that exhibit heavy oil, poor permeability and irregular faultlines, EOR entails changing the actualproperties of the hydrocarbons, which further distinguishes this phase of recovery from the secondaryrecovery method. While waterflooding and gas injection during the secondary recovery method are used topush the oil through the well, EOR applies steam or gas to change the makeup of the reservoir.

Whether it is used after both primary and secondary recovery have been exhausted or at the initial stage ofproduction, EOR restores formation pressure and enhances oil displacement in the reservoir.

There are three main types of EOR, including chemical flooding, gas injection and thermal recovery.Increasing the cost of development alongside the hydrocarbons brought to the surface, producers do not useEOR on all wells and reservoirs. The economics of the development equation must make sense. Therefore,each field must be heavily evaluated to determine which type of EOR will work best on the reservoir. This isdone through reservoir characterization, screening, scoping, and reservoir modeling and simulation.

Thermal Recovery

Thermal recovery introduces heat to the reservoir to reduce the viscosity of the oil. Many times, steam isapplied to the reservoir, thinning the oil and enhancing its ability to flow. First applied in Venezuela in the1960s, thermal recovery now accounts for more than 50% of applied EOR in the US.

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Thermal RecoverySource: Alberta Geological Survey

Chemical Injection

Chemical injection EOR helps to free trapped oil within the reservoir. This method introduces long-chainedmolecules called polymers into the reservoir to increase the efficiency of waterflooding or to boost theeffectiveness of surfactants, which are cleansers that help lower surface tension that inhibits the flow of oilthrough the reservoir. Less than 1% of all EOR methods presently utilized in the US consist of chemical

injections.

Gas Injection

Gas injection used as a tertiary method of recovery involves injecting natural gas, nitrogen or carbon dioxideinto the reservoir. The gases can either expand and push gases through the reservoir, or mix with or dissolvewithin the oil, decreasing viscosity and increasing flow.

Carbon Dioxide EORSource: Lawrence Livermore National Laboratory

Carbon dioxide EOR (CO2-EOR) is the method that is gaining the most popularity. While initial CO2-EOR




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developments used naturally occurring carbon dioxide deposits, technologies have been developed to injectCO2 created as byproducts from industrial purposes.

First employed in the US in the early 1970s in Texas, CO2-EOR is successfully used in Texas and NewMexico and is expected to become more widely spread in the future. Nearly half of the EOR employed in theUS is a form of gas injection.

Other EOR applications gaining acceptance are low-salinity water flooding, which is expected to increaseproduction by nearly 20%, and well stimulation, which is a relatively low-cost solution because it can beemployed to single wells (rather than the whole reservoir).

Offshore EOR Applications

Although EOR applications are predominantly employed onshore, technologies are being developed toexpand the reach of EOR to offshore applications. Challenges that presently exist for offshore EOR includeeconomics of the development; the weight, space and power limitations of retrofitting existing offshorefacilities; and fewer wells that are more widely spaced contributing to displacement, sweep and lag time.

Currently, the application of EOR is being considered for a number of offshore developments. With successfulsubsea processing and secondary recovery methods employed in offshore environments through water and

gas injection, the technologies to apply EOR methods is quickly nearing.

EOR in the US

The US Department of Energy estimates that currently there are 89 billion barrels of additional oil trapped inonshore reservoirs. This is in great contrast to the country's current domestic proven reserves, which isestimated at 21.9 billion barrels. The DOE stresses that much of this production could be tapped byimplementing EOR methods, namely the injection of carbon dioxide.

Area Focus for Potential EORSource: DOE

In fact, the governmental agency claims that the pervasive application of EOR technologies on US reservescould increase the country's oil recovery from approximately 30% to more than 60%. If this oil was added tothe US proven reserves, the country would rank fifth in the world for the size of its reserves.

If this oil could be recovered, the country's dependence on foreign oil would be greatly depreciated, an effortfor which the US has been striving. However, a wider application of EOR methods on US reservoirs requires amuch higher cost of production, and the price of oil must legitimize the investment.


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Artficial Lift Techniques - Oil Well

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