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US 5,343,951 AGranted
Drilling and cementing slim hole wells
AssigneeShell Oil Company
InventorsKenneth M. Cowan, Arthur H. Hale
Life of this patent
Estimating the term…
Abstract
A slim hole well is drilled using a drilling fluid comprising blast furnace slag and water which drilling fluid is circulated during the drilling to lay down a filter cake. Thereafter, an activator is added and generally, an alkaline material and additional blast furnace slag, to produce a cementitious slurry which is passed down a casing and up into an annulus to effect primary cementing.
Claims17
A method comprising:
- drilling a slim hole wellbore with a drill string comprising a drill pipe utilizing a drilling fluid comprising granulated water-quenched blast furnace slag and water;
- circulating said drilling fluid down said drill pipe and up an annulus between said drill pipe and walls of said wellbore, thus laying down a filter cake on said walls of said wellbore during said drilling;
- withdrawing said drill string and inserting a casing, thus creating an annulus having a dimension between 0.1 and 1.25 inches between said casing and said walls of said wellbore;
- adding an activator to said drilling fluid to produce a cementitious slurry;
- and
- circulating said cementitious slurry down said casing and up into said annulus between said casing and said walls of said wellbore.
3 more elements
A method for drilling a slim hole well comprising:
- drilling a borehole with a rotary drill comprising a drill pipe and a bit;
- utilizing a drilling fluid comprising 20-50 lbs/bbl of granulated water-quenched blast furnace slag, clay, starch, partially hydrolyzed polyacrylamide, and barite;
- circulating said drilling fluid down said drill pipe and up an annulus between said pipe and the walls of said borehole thus laying down a filter cake on said walls of said borehole;
- withdrawing said rotary drill and inserting a casing, thus creating an annulus between said casing and said walls of said borehole having a dimension between 0.1 and 1.25 inches;
- adding blast furnace slag, a lignosulfonate thinner, and an activator comprising a mixture of caustic soda and soda ash to said drilling fluid to produce a cementitious slurry having a total amount of blast furnace slag within the range of 100 to 500 lbs/bbl;
- and
- passing said cementitious slurry down through said casing and up into said annulus formed by said casing and said walls of said borehole.
4 more elements
Dependencies are inferred from the claim text.