Well fluid for in-situ borehole repair
AssigneeShell Oil Company
InventorsJames J. W. Nahm, Reece E. Wyant
Life of this patent
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Abstract
A method for consolidating incompetent formations penetrated by a borehole using drilling fluids. The method uses a water-based drilling fluid the solids contents of which includes microfine-ground blast furnace slag. This provides a fluid that will penetrate the incompetent formation and harden in place to consolidate the formation. Subsequent cementing with a cementitious slurry comprising water, activator and normally-ground blast furnace slag results in a compatible cement which will adhere to filter cake from the drilling.
Claims18
A method for consolidating a formation penetrated by a borehole, comprising:
- drilling the borehole using an aqueous drilling fluid comprising microfine-ground blast furnace slag;
- applying sufficient hydraulic pressure to force said drilling fluid to flow into said formation and lay down a filter cake on the borehole walls;
- and
- contacting said filter cake with an activator which is added to said drilling fluid.
A method for consolidating a formation penetrated by a borehole, comprising:
- drilling the borehole using an aqueous drilling fluid comprising microfine-ground blast furnace slag and an activator;
- and
- applying sufficient hydraulic pressure to force said drilling fluid to flow into said formation and lay down a self-setting filter cake on the borehole walls.
A method for drilling and cementing a well, comprising:
- drilling a borehole in a subterranean formation using an aqueous drilling fluid comprising microfine ground blast furnace slag under sufficient pressure to cause flow of said drilling fluid into said formation;
- thereafter inserting a casing into said borehole;
- and
- thereafter passing a cementitious slurry comprising water, normally ground blast furnace slag and an activator into the annulus between said casing and said borehole.
A method for drilling and cementing a well, comprising:
- drilling a borehole in a subterranean formation using an aqueous drilling fluid comprising microfine-ground blast furnace slag under sufficient pressure to cause flow of said drilling fluid into said formation;
- thereafter inserting a casing into said borehole;
- and
- thereafter passing a cementitious slurry comprising water and normally-ground blast furnace slag into the annulus between said casing and said borehole.
Dependencies are inferred from the claim text.