Slag-based well cementing compositions and methods
AssigneeBJ Services Company
InventorsDan T. Mueller, Jimmy P. Dickerson
Life of this patent
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Abstract
By the addition of wollastonite to slag based cements, such as those formed when converting drilling fluids to cementitious materials in oil and gas well applications, the flexural strength of the cementitious material is improved. The method involves forming a pumpable slurry of drilling fluid, blast furnace slag and the fibrous mineral, wollastonite. The slurry is then activated by the addition of such activators as sodium hydroxide and soda ash and is pumped into the well bore to a desired location and is allowed to solidify.
Claims12
A method of cementing a well borehole of an oil or gas well, the method comprising the steps of:
- forming a pumpable slurry by mixing together a slag based cementitious material of a type suitable for cementing subterranean formations for oil and gas wells, a silicate mineral having a fibrous, crystalline structure and a sufficient amount of water, the mineral being selected from a group consisting of wollastonite, sillimanite, sepiolite and pyrophyllite;
- pumping the slurry into a preselected location within the borehole of the well;
- and then
- allowing the slurry to solidify within the borehole.
A method of cementing a well borehole of an oil or gas well by solidifying an aqueous drilling fluid within the borehole, the method comprising the steps of:
- forming a pumpable slurry by mixing the drilling fluid with blast furnace slag, a silicate mineral having a fibrous, crystalline structure and a sufficient amount of water, the silicate mineral being selected from a group consisting of wollastonite, sillimanite, sepiolite and pyrophyllite;
- activating the slurry;
- pumping the activated slurry into a preselected location within the borehole of the well;
- and
- allowing the slurry to solidify.
A composition for cementing a well borehole, the composition comprising:
- an aqueous drilling fluid;
- a hydraulically active blast furnace slag for converting the drilling fluid into a cementitious material;
- a silicate mineral having a fibrous, crystalline structure which is capable of reducing the brittleness of the cement composition once the composition has solidified, the mineral being selected from a group consisting of wollastonite, sillimanite, sepiolite and pyrophyllite;
- and
- water.
Dependencies are inferred from the claim text.