“PRODUCTION”

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

Production Production is the is the operation that deals with:operation that deals with:– bringingbringing hydrocarbons hydrocarbons

to the surface to the surface

– preparing them for their preparing them for their trip to the refinery or trip to the refinery or processing plantprocessing plant

Production begins after Production begins after the well is drilled. the well is drilled.

PRODUCTION

The mixture of oil, gas and water from the well is The mixture of oil, gas and water from the well is separated on the surface. separated on the surface. The water is separated and the oil and gas are The water is separated and the oil and gas are treated, measured, and tested. treated, measured, and tested.

PRODUCTION

Production operations Production operations include:include:

- bringing the oil and - bringing the oil and gas to the surface,gas to the surface,

- maintaining - maintaining production, production,

- purifying, - purifying, measuring, testing.measuring, testing.

After a well is drilled, the After a well is drilled, the operating company considers operating company considers all the data obtained from the all the data obtained from the various tests run on the various tests run on the formation of interest and a formation of interest and a decision is made on whether:decision is made on whether:

to plug and abandon the to plug and abandon the well orwell or to set production casing to set production casing and complete the welland complete the well

PRODUCTION

If the decision is to abandon it, the hole is If the decision is to abandon it, the hole is considered to be considered to be “dry”“dry” not capable of not capable of producing oil or gas in commercial quantities, can producing oil or gas in commercial quantities, can not justify the expense of completing the well.not justify the expense of completing the well.

Therefore, several cement plugs will be set Therefore, several cement plugs will be set in the well to seal it off more or less permanently.in the well to seal it off more or less permanently.

If the operating company decides to set If the operating company decides to set production casingproduction casing Well CompletionWell Completion

PRODUCTION

Well completionWell completion allows the allows the flow of petroleum or natural flow of petroleum or natural gas out of the formation and gas out of the formation and up to the surface. up to the surface. ItIt includes includes;;

strengthening the well hole with strengthening the well hole with casing,casing,

evaluating the pressure and evaluating the pressure and temperature of the formationtemperature of the formation,,

installing the proper equipment installing the proper equipment to ensure an efficient flow of to ensure an efficient flow of oil oil and and natural gas out of the well. natural gas out of the well.

WELL COMPLETION

Installing casing in the well is Installing casing in the well is an important part of an important part of both both the the drilling and completion process.drilling and completion process.

WELL COMPLETION

Casing is usedCasing is used; ; --to strengthen the sides of the well to strengthen the sides of the well

hole,hole, --ensure that no oil or natural gas seeps ensure that no oil or natural gas seeps

out of the well hole as it is brought to the surfaceout of the well hole as it is brought to the surface --to keep other fluids or gases from to keep other fluids or gases from seeping into the formation through the well. seeping into the formation through the well.

Cement is then forced into the annulus btw the Cement is then forced into the annulus btw the casing and the borehole wall to prevent fluid casing and the borehole wall to prevent fluid movement between formations. movement between formations.

Some of the casing Some of the casing strings:strings: Drive or Structural CasingDrive or Structural Casing Conductor CasingConductor Casing Surface CasingSurface Casing Intermediate CasingIntermediate Casing Liner StringLiner String

Production CasingProduction Casing

WELL COMPLETION

The production casing or oil string is the final casing for The production casing or oil string is the final casing for most wells. It provides a conduit from the surface of the most wells. It provides a conduit from the surface of the well to the petroleum producing formation.well to the petroleum producing formation.

Casing must be perforated to allow liquids to flow into Casing must be perforated to allow liquids to flow into the well. This is a the well. This is a perforated completionperforated completion..

PERFORATING

The most common method of The most common method of perforatingperforating is is ususinging shaped-charged shaped-charged explosivesexplosives. .

A A perforating perforating gungun is lowered into the is lowered into the well opposite the producing zone on a well opposite the producing zone on a wire line& fired by electronic means wire line& fired by electronic means from the surface. After perforations are from the surface. After perforations are made, the tool is retrieved. made, the tool is retrieved.

Perforations are simply holes through Perforations are simply holes through the casing and cement, extending into the casing and cement, extending into the formation. the formation.

The well is not produced through the casing. A small The well is not produced through the casing. A small diameter pipe, called diameter pipe, called tubingtubing, is used to transmit oil or gas , is used to transmit oil or gas to the surface.to the surface.

WELL COMPLETION

A device called A device called packerpacker that that fits around the tubing is fits around the tubing is lowered just above the lowered just above the producing zone. producing zone.

It expands and seals off the It expands and seals off the space between the tubing and space between the tubing and the casing, forcing the the casing, forcing the produced fluids to enter the produced fluids to enter the tubing to the surface. tubing to the surface.

WELL COMPLETION

When casing is set, cemented and perforated and When casing is set, cemented and perforated and when the tubing string is run then a collection of valves, when the tubing string is run then a collection of valves, called called Christmas treeChristmas tree is installed on the surface at the is installed on the surface at the top of the casing. top of the casing.

It contains tubes and valves It contains tubes and valves that control the flow of that control the flow of hydrocarbons and other fluids hydrocarbons and other fluids out of the well.out of the well.

Usually, once the Christmas Usually, once the Christmas tree is installed, the well can tree is installed, the well can truly be said to be complete.truly be said to be complete.

RESERVOIR DRIVE MECHANISMS

After the well has been completed, the hydrocarbons After the well has been completed, the hydrocarbons

flow from the reservoir to the surface.flow from the reservoir to the surface. This first period in This first period in

the producing life of a reservoir is called the producing life of a reservoir is called primary recoveryprimary recovery or or primary productionprimary production. .

During this stage, natural energy in the reservoir often During this stage, natural energy in the reservoir often displaces the hydrocarbons from the pores of a formation displaces the hydrocarbons from the pores of a formation and drives it toward the wells and up to the surface. and drives it toward the wells and up to the surface.

RESERVOIR DRIVE MECHANISMS

In order of importance, the three natural forces that move the fluids in In order of importance, the three natural forces that move the fluids in

a reservoir area reservoir are;;

water drivewater drive - -when there is enough energy available from free when there is enough energy available from free water in the reservoir water in the reservoir

gas drivegas drive --dissolved-gas drivedissolved-gas drive

(Some(Some hydrocarbons in the oil hydrocarbons in the oil become gaseous whenbecome gaseous when the well releases pressure from the reservoirthe well releases pressure from the reservoir.).)

--gas-cap drivegas-cap drive

(Gas(Gas forms a cap on top of the oil forms a cap on top of the oil. . When theWhen there isre is an an escape route for the oil in the reservoir, the pressure of escape route for the oil in the reservoir, the pressure of the gas cap the gas cap pushes the oilpushes the oil.).)

gravity drainagegravity drainage- - (G(Gravity causes oil to migrate upward,ravity causes oil to migrate upward, because because water is heavier than oilwater is heavier than oil.) .)

RESERVOIR DRIVE MECHANISMS

GGas-cap driveas-cap drive reservoir reservoir WaterWater drive drive reservoir

ARTIFICIAL LIFT

When pressures in the oil When pressures in the oil reservoir have fallen to the reservoir have fallen to the point where a well will not be point where a well will not be produced by natural energy, produced by natural energy, some method of some method of artificial liftartificial lift

must be used.must be used.

Artificial lift uses Artificial lift uses oil well oil well pumpspumps and and high pressure gashigh pressure gas to lift the oil from the reservoir.to lift the oil from the reservoir.

The most common method of The most common method of pumping oil in land-based pumping oil in land-based wells is wells is beam pumpingbeam pumping.  . 

The beam pumping creates The beam pumping creates an up-and-down motion to a an up-and-down motion to a string of rods called string of rods called sucker sucker rodsrods.  . 

The top of the sucker rod The top of the sucker rod string hangs down inside the string hangs down inside the tubing.  A sucker rod pump is tubing.  A sucker rod pump is located near the bottom of located near the bottom of the well. the well. 

ARTIFICIAL LIFT

WELL STIMULATION

Sometimes, petroleum exists in a formation but it is Sometimes, petroleum exists in a formation but it is unable to flow readily into the well, because the unable to flow readily into the well, because the formation has very low permeability. formation has very low permeability.

If the formation is composed of rocks that dissolve If the formation is composed of rocks that dissolve by acidby acidss, such as limestone or dolomite, then a , such as limestone or dolomite, then a

technique known as technique known as acidizingacidizing may be required. may be required.

AcidizingAcidizing a well consists of injecting acid (usually a well consists of injecting acid (usually hydrochloric acid) into the well. In limestone or hydrochloric acid) into the well. In limestone or carbonate formations, the acid dissolves portions of the carbonate formations, the acid dissolves portions of the rock in the formation, opening up spaces to allow for rock in the formation, opening up spaces to allow for the flow of petroleum. the flow of petroleum.

WELL STIMULATION

When sandstone rock contain oil or gas in commercial When sandstone rock contain oil or gas in commercial quantities but the permeability is too low to permit good quantities but the permeability is too low to permit good recovery, a process called recovery, a process called fracturingfracturing may be used to may be used to

increase permeability to a practical level.increase permeability to a practical level.

Fracturing Fracturing consists of injecting a fluid down the well consists of injecting a fluid down the well and into the formation under great pressure. Pumping and into the formation under great pressure. Pumping continues until the formation literally cracks open. continues until the formation literally cracks open.

In addition to the fluid being injected, 'propping In addition to the fluid being injected, 'propping agents' are also used to prop open the newly widened agents' are also used to prop open the newly widened fissures in the formation. fissures in the formation. Hydraulic fracturingHydraulic fracturing involves involves the injection of water into the formation. the injection of water into the formation.

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