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gas migration in oil industry

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Reband Hawlery
Reband Hawlery

Gas migration is a common problem in the petroleum industry where gas invades from high pressure zones into lower pressure zones like wellbores, potentially causing blowouts. It occurs when the hydrostatic pressure decreases below the formation gas pressure after cementing. Proper density control of drilling mud and cement slurry can prevent gas migration by maintaining pressure between pore and fracturing pressures. Surfactants and additives like bentonite can also help prevent gas from seeping into wellbores. Setting casing packers is another physical method used to impede gas migration.

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Name: Reband Azad Raza Petroleum Engineering Department/ Drilling Engineering II Date: 23 03 2016 (Is gas migration problem in petroleum industry?) petroleum industry looking forward to be safe and reliable industry, one of most common problems petroleum industry faced since it’s development it’s (gas migration) Gas migration also called gas communication or gas leakage (Carter and Slagle, 1970) gas migration is the most frequent, and no doubt the most critical and dangerous (faul, 10 Dec 1984) , as the beginning of industry the gas migration wasn’t detectable due to complex of reservoir and inefficient technology, Gas migration is most common drilling problems, it’s occurs when gas invasion migrate from High pressure zone[formation] to lower pressure zone[wellbore],the gas migration can cause the well severity problems like blowout when the well all in lost due to imbalanced pressure all and when it’s cement running or while drilling running on, the detecting gas migration down hole it’s not such easy way to try, the detection always running on the well’s surface by checking the pressure regulators and well control monitors or by increase Flow rate or increase in mud pits and having flow while Mud Pumps shut down, there are several cause and predictable ways to prevent gas migration, one of such factors is [density],Controlling density immediately after cementing it’s so similar to well control after drilling, if the [hydrostatic pressure] decrease below the formation gas pressure will cause [gas kick], must assure that the pressure at critical zones is maintained between the pore and the fracturing pressure at all times during, and immediately after, the cement job (Parcevaux, Step 6 1984), density must be carefully and correctly to be designed to prevent gas flow during cement displacement (Bonett, Spring 1996), although the design must care of danger of losing circulation, any density went wrong made while mixing a slurry on the surface may causes
large changes in slurry properties ,that is why now modern mixing cement systems will offers accurate density control, and the Mud can be a good character For preventing gas migration, There is no easy path for gas if good mud exists in the well bore, drawn water from [Mud cake] to surface of [cement sheath], this can causes of cracking in the mud cake which is causes the best route for gas migration, for example if thick mud cake dehydrates by 14 % it will make (0.195 mm cracks) in the mud cake at the sidewall of the well bore (NELSON, 1990), and another threat it’s while when the cement slurry begins to set, the hydrostatic pressure quickly approaches zero (Levine .D, 1979), due to separation of both of fluids and pore from connecting each other that makes to separate system , because the fluids in the wellbore cannot have force on the well bore’s wall that why hydrostatic approach to zero, one of the solutions it’s using surfactants with cement slurry, the surfactants will enter gas zones to become a foam, and by using a [bentonite][sulphate salts] to control Gel-strength of cement to prevent Gas sneak, there is also a physical ways to prevent Gas migration, by setting a Casing Packers. References Bonett,A.,Spring1996. Oil FieldReview. Schlumbeger[online], p.4. Carter andSlagle,1970. A Studyof CompletionPractices. SPE764, p. 5. faul,s.,10 Dec 1984. AnnularGas FlowTheoryandPrevention. Oil&gasJ, pp.84-112. Levine .D,T. ..,1979. AnnularGasFlowAfterCementing:A Look;it Practical Solutions, s.l.:paperspe 8255. NELSON,E. B., 1990. Well Cemening. Saint-Etienne,France:Elisiver. Parcevaux,D.a., Step6 1984. Mechanismsof GasChanneling During Primary Cementation-Methods forPrevention and Repair. newyork:ChemischeProdukteinderErdolgewinnung,Clausthal-Zellerfeld.

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gas migration in oil industry

  • 1. Name: Reband Azad Raza Petroleum Engineering Department/ Drilling Engineering II Date: 23 03 2016 (Is gas migration problem in petroleum industry?) petroleum industry looking forward to be safe and reliable industry, one of most common problems petroleum industry faced since it’s development it’s (gas migration) Gas migration also called gas communication or gas leakage (Carter and Slagle, 1970) gas migration is the most frequent, and no doubt the most critical and dangerous (faul, 10 Dec 1984) , as the beginning of industry the gas migration wasn’t detectable due to complex of reservoir and inefficient technology, Gas migration is most common drilling problems, it’s occurs when gas invasion migrate from High pressure zone[formation] to lower pressure zone[wellbore],the gas migration can cause the well severity problems like blowout when the well all in lost due to imbalanced pressure all and when it’s cement running or while drilling running on, the detecting gas migration down hole it’s not such easy way to try, the detection always running on the well’s surface by checking the pressure regulators and well control monitors or by increase Flow rate or increase in mud pits and having flow while Mud Pumps shut down, there are several cause and predictable ways to prevent gas migration, one of such factors is [density],Controlling density immediately after cementing it’s so similar to well control after drilling, if the [hydrostatic pressure] decrease below the formation gas pressure will cause [gas kick], must assure that the pressure at critical zones is maintained between the pore and the fracturing pressure at all times during, and immediately after, the cement job (Parcevaux, Step 6 1984), density must be carefully and correctly to be designed to prevent gas flow during cement displacement (Bonett, Spring 1996), although the design must care of danger of losing circulation, any density went wrong made while mixing a slurry on the surface may causes
  • 2. large changes in slurry properties ,that is why now modern mixing cement systems will offers accurate density control, and the Mud can be a good character For preventing gas migration, There is no easy path for gas if good mud exists in the well bore, drawn water from [Mud cake] to surface of [cement sheath], this can causes of cracking in the mud cake which is causes the best route for gas migration, for example if thick mud cake dehydrates by 14 % it will make (0.195 mm cracks) in the mud cake at the sidewall of the well bore (NELSON, 1990), and another threat it’s while when the cement slurry begins to set, the hydrostatic pressure quickly approaches zero (Levine .D, 1979), due to separation of both of fluids and pore from connecting each other that makes to separate system , because the fluids in the wellbore cannot have force on the well bore’s wall that why hydrostatic approach to zero, one of the solutions it’s using surfactants with cement slurry, the surfactants will enter gas zones to become a foam, and by using a [bentonite][sulphate salts] to control Gel-strength of cement to prevent Gas sneak, there is also a physical ways to prevent Gas migration, by setting a Casing Packers. References Bonett,A.,Spring1996. Oil FieldReview. Schlumbeger[online], p.4. Carter andSlagle,1970. A Studyof CompletionPractices. SPE764, p. 5. faul,s.,10 Dec 1984. AnnularGas FlowTheoryandPrevention. Oil&gasJ, pp.84-112. Levine .D,T. ..,1979. AnnularGasFlowAfterCementing:A Look;it Practical Solutions, s.l.:paperspe 8255. NELSON,E. B., 1990. Well Cemening. Saint-Etienne,France:Elisiver. Parcevaux,D.a., Step6 1984. Mechanismsof GasChanneling During Primary Cementation-Methods forPrevention and Repair. newyork:ChemischeProdukteinderErdolgewinnung,Clausthal-Zellerfeld.