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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

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.

대표청구항 ▼

A method of plugging the perforations in a casing which has been set in a wellbore which penetrates a subterranean formation comprising: (a) flowing down said casing a wellbore fluid having dispersed therein a plurality of ball sealers, said ball sealers being sized to seal said perforations and bei

A method of plugging the perforations in a casing which has been set in a wellbore which penetrates a subterranean formation comprising: (a) flowing down said casing a wellbore fluid having dispersed therein a plurality of ball sealers, said ball sealers being sized to seal said perforations and being comprised of a polyester polymer which is substantially insoluble in said wellbore fluid and degradable in the presence of water at the formation temperature to oligomers which are at least partially soluble in a formation fluid, and (b) continuing the flow of said wellbore fluid until at least a portion of said perforations are sealed by said ball sealers.