Process for secondary recovery of hydrocarbons
AssigneeTexaco Development Corporation
InventorsDavid R. McCoy, Carter G. Naylor
Life of this patent
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Abstract
Hydrocarbons are recovered from a subterranean hydrocarbon-bearing formation penetrated by an injection well and a production well by displacing hydrocarbons toward the production well using a drive fluid such as water containing dissolved therein: (a) a small amount of a nonionic surfactant of the formula RO(CH.sub.2 CH(OH)CH.sub.2 O).sub.m (CH.sub.2 CH.sub.2 O).sub.n H where R is alkyl or alkylaryl, n is an integer of from 1 to about 20 and m> 1, and (b) a small amount of an anionic sulfonate or sulfate surfactant. Optionally the drive fluid may be saturated with natural gas and/or carbon dioxide at the injection pressure. A polymeric thickening agent also may be included in the drive fluid, if desired.
Claims11
A process for recovering hydrocarbons from a subterranean hydrocarbon-bearing formation penetrated by an injection well and a production well which comprises:
- (A) injecting into the formation via an injection well a drive fluid comprising water having dissolved therein:
- (a) from 0.05 to about 6.0 weight percent of a nonionic surfactant of the formula:
- RO(CH.sub.2 CH(OH)CH.sub.2 O).sub.m (CH.sub.2 CH.sub.2 O).sub.n H,
- wherein R is selected from the group consisting of alkyl of from 8 to about 20 carbon atoms and ##STR13## wherein R.sub.a is branched or linear alkyl of from 6 to about 18 carbon atoms, wherein m is an integer of from 1 to about 20 and n is an integer of from 2 to about 20, and
- (b) about 0.03 to about 5 weight percent of a surfactant selected from the group consisting of an anionic sulfonate and an anionic sulfate surfactant,
- (B) forcing the said fluid through the formation, and
- (C) recovering hydrocarbons through the production well.
Dependencies are inferred from the claim text.