Methods and compositions for sealing subterranean zones
AssigneeHalliburton Energy Services, Inc.
InventorsJiten Chatterji, Lewis R. Norman, David D. Onan, Bobby J. King, Roger S. Cromwell
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Abstract
The present invention provides methods and compositions for sealing subterranean zones. The methods of the invention basically comprise the steps of preparing a sealing composition comprised of an aqueous alkali metal silicate solution, a gelling agent and a delayed acid activator for causing the composition to set into a rigid mass, placing the sealing composition in said subterranean zone and allowing the sealing composition to set into a rigid sealing mass therein.
Claims28
A method of sealing a subterranean zone penetrated by a well bore comprising the steps of:
- (a) preparing a sealing composition comprised of an aqueous alkali metal silicate solution, a gelling agent selected from the group consisting of polyacrylate and polymethylacrylate for increasing the viscosity of said solution and a delayed activator for polymerizing or cross-linking said alkali metal silicate and causing said composition to set into a rigid sealing mass;
- (b) placing said sealing composition into said subterranean zone by way of said well bore;
- and
- (c) allowing said sealing composition to set into a rigid sealing mass therein.
The method of claim 4 wherein said gelling agent is cross-linked polyacrylate present in said composition in an amount in the range of from about 0.5% to about 3% by weight of said aqueous alkali metal silicate solution therein.
A method of sealing a subterranean zone penetrated by a well bore comprising the steps of:
- (a) preparing a pumpable sealing composition comprised of an aqueous sodium silicate solution, a cross-linked polyacrylate gelling agent present in said composition in an amount of about 1% by weight of said sodium silicate solution therein and a delayed acid polymerization activator for polymerizing said sodium silicate and causing said composition to set into a rigid mass, said delayed acid polymerization activator being comprised of a trimethyl citrate ester or an acid selected from the group consisting of citric acid and tartaric acid having a temporary coating thereon selected from the group consisting of polymers, elastomers and waxes which degenerate with time or temperature or both and being present in said composition in an amount of about 1% by weight of said sodium silicate solution therein;
- (b) pumping said sealing composition into said subterranean zone to be sealed by way of said well bore;
- and
- (c) allowing said sealing composition to set into a rigid sealing mass therein.
A sealing composition comprising:
- (a) an aqueous alkali metal silicate solution;
- (b) a gelling agent selected from the group consisting of polyacrylate and polymethylacrylate for increasing the viscosity of said solution present in said composition in an amount in the range of from about 0.5% to about 3% by weight of said alkali metal silicate solution therein;
- and
- (c) a delayed activator for polymerizing or cross-linking said alkali metal silicate and causing said composition to set into a rigid mass present in said composition in an amount in the range of from about 1% to about 5% by weight of said alkali metal silicate solution therein.
Dependencies are inferred from the claim text.