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Title: Method for controlling lost circulation of drilling fluids with hydrocarbon absorbent polymers

Patent ·
OSTI ID:6841209

A method is described of reducing lost circulation of drilling fluids in a borehole penetrating an underground formation, comprising: injecting a discrete slug of an aqueous fluid into a borehole, the aqueous fluid having dispersed therein a hydrocarbon absorbent polymer which expands upon absorbing a hydrocarbon. The polymer is dispersed in the aqueous fluid in proportions sufficient to seal off a lost circulation zone upon contact with a hydrocarbon; the hydrocarbon absorbent polymer selected from the group consisting of polymers and copolymers of styrenes and substituted styrenes, copolymers of vinyl chloride and vinyl acetate, polymers and copolymers of vinylidene chloride and acrylonitrile, polymers of methylmethacrylate and ethylacrylate, copolymers of styrene and divinylbenzene containing up to about 10 wt% of divinylbenzene, polymers and copolymers of alkylstyrenes, natural rubbers, and synthetic rubbers; forcing the aqueous polymer slug into a lost circulation zone; contacting the aqueous polymer slug with a hydrocarbon to allow the hydrocarbon absorbent polymer to absorb hydrocarbon and expand in the formation and borehole; and circulating undesired compounds out of the borehole.

Assignee:
Texaco, Inc., White Plains, NY
Patent Number(s):
US 4633950
OSTI ID:
6841209
Resource Relation:
Patent File Date: Filed date 28 May 1985
Country of Publication:
United States
Language:
English