“RESERVOIR ENGINEERING”

“RESERVOIR ENGINEERING”

MIDDLE EAST TECHNICAL UNIVERSITYMIDDLE EAST TECHNICAL UNIVERSITY

Spring 2008Spring 2008

DepartmentDepartment of Petroleum and Natural Gas Engineeringof Petroleum and Natural Gas Engineering

Dr. Mahmut ParlaktunaRes. Assist. Sevtaç Bülbül

A A rreservoireservoir is formed of is formed of one (or more) subsurface one (or more) subsurface rock formations, rock formations, containing liquid and/ or containing liquid and/ or gaseous hydrocarbons, of gaseous hydrocarbons, of sedimentary origin.sedimentary origin.

The reservoir rock is The reservoir rock is porous porous and and permeable permeable and bounded by and bounded by impermeable barriers, impermeable barriers, which which traptrap hydrocarbons. hydrocarbons.

RESERVOIR ENGINEERING

A cross-section of a typical hydrocarbon reservoir

((R. Cosse, Basics of Reservoir R. Cosse, Basics of Reservoir Engineering, 1993Engineering, 1993))

RReservoir engineeringeservoir engineering is is concerned with: concerned with:

– producproducinging oil and gas oil and gas reservoirs in such a way that reservoirs in such a way that the the economic economic recovery is recovery is maximizedmaximized, , and and

– the rate at which the the rate at which the petroleum is produced is petroleum is produced is maximized. maximized.

RESERVOIR ENGINEERING

Reservoir engineerReservoir engineer deals with:deals with:

– Control of amount of gasControl of amount of gas & & water produced with oil water produced with oil

– Proper placement of wellsProper placement of wells

– Use of proper distance between wellsUse of proper distance between wells

– Injection of water or other fluids into the reservoir Injection of water or other fluids into the reservoir and many other means are used to help to and many other means are used to help to maximize the oil.maximize the oil.

RESERVOIR ENGINEERING

Image of the reservoir: Image of the reservoir: forms, boundaries, forms, boundaries, distribution and volumes of distribution and volumes of fluidsfluids

Well characteristics: Well characteristics: e.g.average permeabilitye.g.average permeability

Recovery mechanisms: Recovery mechanisms: natural drive, enhanced oil natural drive, enhanced oil recoveryrecovery

Reservoir Simulation: Reservoir Simulation: Integrating the reservoir data Integrating the reservoir data and flow lawsand flow laws computer computer models to predict the flow of models to predict the flow of fluids fluids

RESERVOIR ENGINEERING

(R. Cosse, Basics of Reservoir (R. Cosse, Basics of Reservoir Engineering, 1993)Engineering, 1993)

Reservoir Simulation

(R. Cosse, Basics of Reservoir (R. Cosse, Basics of Reservoir Engineering, 1993)Engineering, 1993)

After a well has used up the reservoir's After a well has used up the reservoir's natural natural drives drives and gas lift or pumps have recovered all the and gas lift or pumps have recovered all the hydrocarbons possible, statistics show that 25 to hydrocarbons possible, statistics show that 25 to 95% of the original oil in the reservoir may still be 95% of the original oil in the reservoir may still be there.there.

This amount of oil can be worth recovering if This amount of oil can be worth recovering if

prices are high enough. prices are high enough. 

Enhanced Oil Recovery (EOR)

Enhanced Oil RecoveryEnhanced Oil Recovery;;– is the recovery of oil from a reservoir using means is the recovery of oil from a reservoir using means

other than using the natural reservoir pressure.other than using the natural reservoir pressure.– generally results in increased amounts of generally results in increased amounts of produced produced

oiloil– Its purpose is not only to restore Its purpose is not only to restore formation

pressure, but also to improve oil displacement or pressure, but also to improve oil displacement or fluid flow in the reservoir.fluid flow in the reservoir.

Enhanced Oil Recovery (EOR)

Secondary recovery Secondary recovery processes generally useprocesses generally use;;– injection of water injection of water or or natural gas natural gas into the production reservoir to into the production reservoir to

replace or assist the natural reservoir drive or primary production.replace or assist the natural reservoir drive or primary production.

Enhanced Oil Recovery (EOR)

(www.bp.com)

Tertiary recovery Tertiary recovery methods methods are used are used where secondary recovery methods leave-off. where secondary recovery methods leave-off. TThree major categories; hree major categories;

Enhanced Oil Recovery (EOR)

(http://www.seed.slb.com/en/scictr/watch/climate_change/capture.htm)

1) Thermal displacement (steam injection, (steam injection, in-situin-situ combustioncombustion

2) Chemical displacement

((polymer injection, polymer injection, polymer flooding and caustic polymer flooding and caustic floodingflooding))

3) Miscible displacement –((hydrocarbon displacement, hydrocarbon displacement, COCO22 injection and inert gas injection and inert gas

(nitrogen) injection(nitrogen) injection

Oil and gas are not usually salable as they come Oil and gas are not usually salable as they come from the wellhead. from the wellhead.

Typically, a well stream is a high-velocity, turbulent, Typically, a well stream is a high-velocity, turbulent, constantly expanding mixture of hydrocarbon liquids constantly expanding mixture of hydrocarbon liquids and gases mixed with and gases mixed with – water and water vapor, water and water vapor, – solids such as sand and shale sediments, solids such as sand and shale sediments, – sometimes contaminants such as carbon dioxide and sometimes contaminants such as carbon dioxide and

hydrogen sulfide.hydrogen sulfide.   Several steps are necessary to get oil or gas ready Several steps are necessary to get oil or gas ready

to transport to its next stopto transport to its next stop

Surface Handling of Well Fluids

The well stream is first passed through a series of The well stream is first passed through a series of separating and treating devicesseparating and treating devices;;

– to remove the sediments and waterto remove the sediments and water– to separate the liquids from the gases, to separate the liquids from the gases, – to treat the emulsions for further removal of water, solids, to treat the emulsions for further removal of water, solids,

and undesirable contaminants. and undesirable contaminants.

The oil is then The oil is then stabilizedstabilized, , storedstored, and , and tested tested for for purity. The gas is tested for hydrocarbon content purity. The gas is tested for hydrocarbon content and impurities, and gas pressure is adjusted to and impurities, and gas pressure is adjusted to pipeline or other transport specifications.pipeline or other transport specifications.

Surface Handling of Well Fluids

Surface Handling of Well Fluids

At the wellhead, separators are used to separate the remaining gas in solution by or adjusting pressure in the separator. Water is separated due to the gravity difference. Crude oil is fed into crude oil line. Gas is flowed through the gas line.

Crude oil Crude oil is stored in large is stored in large tankstanks after produced. after produced.

NNatural gasatural gas;;– is liquified before storage. is liquified before storage. ((Liquefied natural gas Liquefied natural gas

or LNGor LNG)) – It is also stored in It is also stored in underground formationsunderground formations

((depleted gas reservoirs, aquifers, and salt depleted gas reservoirs, aquifers, and salt cavernscaverns))..

Natural gas is injected into suitable formations when Natural gas is injected into suitable formations when demand is low. Then it is produced when demand is demand is low. Then it is produced when demand is high.high.

Storage

CCrude oil rude oil taken from taken from oiloil fields fields is carried to refineries near the is carried to refineries near the big markets bybig markets by;;– PPipelineipeliness or or –TankerTankerss

depending upon whether it is depending upon whether it is being moved overland or by being moved overland or by water. water.

Railroad tank cars Railroad tank cars and even and even truckstrucks are sometimes used to are sometimes used to carry crude oil from the fields carry crude oil from the fields that cannot be reached by that cannot be reached by pipelines.pipelines.

Transportation

Natural GasNatural Gas is moved primarily by is moved primarily by pipelinepipelines.s. The gas transport system is therefore mostly on The gas transport system is therefore mostly on land, with collection systems, continent crossing land, with collection systems, continent crossing pipelines, and local distribution systems. pipelines, and local distribution systems. Liquefied natural gas (LNG) Liquefied natural gas (LNG) and liquid gas products and liquid gas products such as propane are moved by such as propane are moved by ship, barge, truck, rail and ship, barge, truck, rail and pipelinepipelines.s.Compressed natural gas Compressed natural gas (CNG)(CNG) can becan be transported by transported by tank truckstank trucks..

Transportation

Crude oil is often a dark, sticky liquid that cannot be Crude oil is often a dark, sticky liquid that cannot be used without changing it. used without changing it. An An oil refinery oil refinery is an industrial is an industrial processprocess plant where plant where cruide oil cruide oil is processed and refined into more useful is processed and refined into more useful petroleum products petroleum products such as such as gasolinegasoline, , diesel fueldiesel fuel, , asphalt baseasphalt base, , heating oil heating oil and and liquefied petroleum gas liquefied petroleum gas (LPG).(LPG).

Refining

The first part of refining The first part of refining crude oil is to heat it until crude oil is to heat it until it boils. The boiling liquid it boils. The boiling liquid is separated into different is separated into different liquids and gases in a liquids and gases in a distillation column. distillation column.

THANKS FOR LISTENING.