Methods of drilling well bores using invertible oil external-water internal drilling fluids
AssigneeHalliburton Energy Services, Inc.
InventorsRobert S. Taylor, Suzanne Arnold, Tommy R. Gardner, Karen L. King
Life of this patent
Estimating the term…
Abstract
Methods of drilling well bores using an invertible oil external-water internal emulsion drilling fluid and then inverting the drilling fluid to a water external-oil internal emulsion are provided. The methods basically comprise the steps of contacting the oil external-water internal emulsion with an aqueous acid solution containing an anionic sulfonate surfactant for preventing aqueous acid solution-crude oil emulsions and crude oil sludging and a chemical for preventing the anionic sulfonate surfactant from reacting with the emulsifier in the oil external-water internal emulsion.
Claims20
In a method of drilling a well bore penetrating one or more crude oil producing zones using an invertible oil external-water internal emulsion drilling fluid stabilized with a nonionic emulsifier and then inverting the drilling fluid to a water external-oil internal emulsion by contact with an aqueous acid solution, the improvement which comprises the steps of:
- (a) contacting said oil external-water internal emulsion with an aqueous acid solution to invert said emulsion comprised of water, an acid, an anionic sulfonate surfactant for preventing the formation of aqueous acid solution-crude oil emulsions and crude oil sludging and a chemical for preventing said anionic sulfonate surfactant from reacting with said nonionic emulsifier after said emulsifier is made cationic by said acid;
- and then
- (b) removing said inverted water external-oil internal emulsion from said well bore.
An improved method of drilling a well bore penetrating one or more crude oil producing zones using an invertible oil external-water internal emulsion drilling fluid stabilized with a nonionic amine emulsifier and then inverting the drilling fluid to a water external-oil internal emulsion, comprising the steps of:
- (a) drilling said well bore using said oil external-water internal emulsion drilling fluid;
- (b) preparing an aqueous acid solution comprised of water, hydrochloric acid, an anionic sulfonate surfactant for preventing the formation of aqueous acid solution-crude oil emulsions and crude oil sludging and a chemical for preventing said anionic sulfonate surfactant from reacting with said nonionic amine emulsifier;
- (c) contacting said oil external-water internal emulsion with said aqueous acid solution to thereby invert said emulsion;
- and
- (d) removing said inverted water external-oil internal emulsion from said well bore.
Dependencies are inferred from the claim text.