Method of drilling and cementing a well using a drilling fluid convertible in place into a settable cement slurry

摘要

A method of drilling and cementing a well using a novel drilling fluid convertible in place by the extrinsic application of heat into a settable cement slurry and composition therefor. The novel drilling fluid comprises an aqueous drilling mud containing in intimate admixture therewith cement and a thermally deactivatable deflocculant which prevents the cement from setting while the fluid is being used as a drilling mud. The method comprises drilling a well with a rotary bit through which the novel drilling fluid is circulated; suspending a casing in the well; removing the fluid from inside the casing; and applying sufficient extrinsic heat to the fluid in place in the annulus of the well to deactivate the deflocculant, thereby converting the fluid in place into a settable cement slurry.