Exxon Production Research Company

Michael M Epstein

Claude E Cooke, Jr

Richard G Sinclair

Steven R Erbstoesser

Plugging perforations in casing in a wellbore penetrating a subterranean formation using degradale ball sealers. The ball sealer used is composed of a polyester polymer which is substantially insoluble in the wellbore fluid. The polymer degrades in the presence of water at an elevated temperature to form small molecules which are soluble in a fluid in the subterranean formation. After the polymer degrades, the flow through the perforation returns to substantially its initial value.

Use of degradable ball sealers to seal casing perforations in well

The present invention relates generally to the composition and method for reducing the permeability of subterranean formations penetrated by a wellbore. The composition of the present invention comprises a wellbore fluid having dispersed therein a fluid loss control agent comprising a polyester polymer which is substantially insoluble in the wellbore fluid. The polymer degrades in the presence of water at an elevated temperature to form small molecules which are soluble in a fluid in the subterranean formation. The method of the present invention comprises reducing the permeability of subterranean formations penetrated by a wellbore by placing the composition of the present invention down the wellbore.

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Columbus, OH, United States of America

Michael M Epstein