Texaco Inc.

Ricardo L Cardenas

Joseph T Carlin

Kenoth H Flournoy

Jim Maddox, Jr

Bobby G Harnsberger

Robert B Alston

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Our invention concerns a method for treating a well completed in a subterranean petroleum-containing formation which will improve the rate at which steam can be injected into the formation for a steam push-pull or steam drive oil recovery method. This preconditioning process is applied to formations exhibiting very limited steam receptivity because the formation contains high oil viscosity and has high oil saturation and is completely liquid filled. The method involves injecting a mixture of a non-condensable oil-insoluble gas such as nitrogen and an oil soluble gas such as carbon dioxide all in the gaseous phase into the formation at a controlled rate which will avoid permanently fracturing the formation and also avoid the immediate formation of an oil bank due to dissolution of the injected oil soluble gaseous fluid into the oil. Ideally by controlling the injection rate, the gaseous mixture first displaces water from the flow channels and then carbon dioxide slowly dissolves in the oil while nitrogen remains in the flow channels. Steam injection can then be applied to the formation without the previously experienced loss in steam injectivity.

Viscous oil recovery method

Many petroleum formations contain water having high salinity and/or high concentrations of divalent ions such as calcium or magnesium dissolved therein, and are additionally at temperature from about 70.degree. F. to about 300.degree. F. Most surfactants and polymers suitable for use in fluids or emulsions used in oil recovery operations are either ineffective in high salinity or high hardness waters, or cannot tolerate the higher temperatures encountered in many such formations. A water-external phase, viscous emulsion containing a water soluble and/or dispersible alkylpolyalkoxyalkylene sulfonate or alkylarylpolyalkoxyalkylene sulfonate and as a phase stabilizing additive, a water dispersable and/or soluble petroleum sulfonate, is an effective fluid for flooding oil formations containing brine whose salinity is from 70,000 to 220,000 parts per million total dissolved solids and also having temperatures as high as 300.degree. F. The emulsion is phase stable over a wide range of formation temperatures and water salinities and hardness values.

Emulsion oil recovery process usable in high temperature, high salinity

An oil recovery process comprising injecting a fatty alcohol into the oil phase of the reservoir followed by the injection of a soap which effectively emulsifies the oil-fatty alcohol mixture followed by further water injection to displace and produce the emulsified oil.

Oil recovery process: injection of fatty alcohol followed by soap

A method for transporting viscous hydrocarbons which involves introducing into a pipeline or well-bore with the viscous hydrocarbons a solution containing (1) an anionic surfactant such as sodium tridecyl sulfate, sodium oleate, etc., or an oxyalkylated anionic surfactant of the sulfonate or sulfate type, and mixtures of the surfactants mentioned and (2) an alkalinity agent such as sodium hydroxide, thereby forming a low viscosity, salt-tolerant, oil-in-water emulsion. Optionally, the solution may contain a small amount of a guanidine salt or a water-soluble oxyalkylated, nitrogen-containing aromatic compound such as ethoxylated-8-hydroxy quinoline.

Oil-in-water emulsion

Solution for transporting hydrocarbons in a pipeline

Pipeline method for transporting viscous hydrocarbons

A method of transporting viscous hydrocarbons which involves introducing into a pipeline or well-bore with the viscous hydrocarbons a solution containing an anionic surfactant or soap such as sodium tridecyl sulfate or sodium oleate together with a guanidine salt and optionally with an alkalinity agent and/or a nonionic surfactant such as a polyethoxylated alcohol thereby forming a low viscosity salt tolerant oil-in-water emulsion.

Pipeline transportation of viscous hydrocarbons

Surfactant flooding is frequently ineffective for recovering highly asphaltic petroleum because the asphaltic constituents of the petroleum have a strong affinity for the mineral surfaces such as sand grains present in the subterranean formation, and so are inefficiently displaced by passage of a surfactant containing solution through the pore spaces of the formation. Surfactant flooding is effective for asphaltic crudes if an effective solvent for the asphaltic petroleum which has a moderate water solubility is included in the preflush solution which preceded the surfactant solution or in the surfactant solution itself. Effective materials include quinoline and crude coal tar bases which contain substantial amounts of quinoline.

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Houston, TX, United States of America

Ricardo L Cardenas