Drilling fluid with self-adjusted alkalinity
AssigneeBaker Hughes Oilfied Operations LLC
InventorHelmuth Sarmiento Klapper
Life of this patent
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Abstract
The aqueous phase of a drilling fluid can be provided with self-adjusting alkalinity by introducing a buffering system, where the buffering system includes a buffering agent, an acid or a base, and an inorganic salt, and where the pH of the aqueous phase is in the range of from about 8 to about 12. In one non-limiting embodiment, the pH does not vary by more than about 0.5 pH units after a variation in temperature of the drilling fluid of at least about 175° C. for at least about 200 hours.
Claims12
A method for modifying a drilling fluid to have self-adjusted alkalinity, where the drilling fluid has an aqueous phase, the method comprising:
- producing a buffering system, wherein the step of producing the buffering system comprises the steps of:
- providing a buffering agent, wherein the buffering agent is N-cyclohexyl-2-aminoethanesulfonic acid;
- providing a pH-modifying agent;
- and
- combining between about 0.0125 M and about 0.04 M buffering agent with between about 0.0005 M and about 0.05 M pH-modifying agent;
- and
- combining the buffering system with the aqueous phase of the drilling fluid.
A drilling fluid comprising:
- a buffering system, wherein the buffering system comprises:
- between about 0.0125 M and about 0.04 M buffering agent, wherein the buffering agent is N-cyclohexyl-2-aminoethanesulfonic acid;
- and
- between about 0.0005 M and about 0.05 M pH-modifying agent;
- and
- an aqueous phase having a pH range of between about 8 and 12;
- and
- wherein the buffering system combines with the aqueous phase to stabilize the pH of the aqueous phase.
A method for modifying a drilling fluid to have self-adjusted alkalinity, where the drilling fluid has an aqueous phase, the method comprising:
- producing a buffering system, wherein the step of producing the buffering system comprises the steps of:
- providing a buffering agent, wherein the buffering agent is N-cyclohexyl-2-aminoethanesulfonic acid;
- providing a pH-modifying agent;
- and
- combining between about 0.0125 M and about 0.04 M buffering agent with between about 0.0005 M and about 0.05 M pH-modifying agent;
- and
- combining the buffering system with the aqueous phase of the drilling fluid, wherein the aqueous phase has a pH range of between about 8 and 12.
Dependencies are inferred from the claim text.