Earth boring – well treating – and oil field chemistry – Earth boring – Contains organic component
Patent
1995-06-12
1998-01-20
Gibson, Sharon
Earth boring, well treating, and oil field chemistry
Earth boring
Contains organic component
507925, C09K 700
Patent
active
057101078
DESCRIPTION:
BRIEF SUMMARY
This application is a 371 of PCT/US93/1089 filed Nov. 9, 1993.
FIELD OF THE INVENTION
The invention relates to drilling, workover, completion, and well servicing fluids and methods to improve the same.
BACKGROUND OF THE INVENTION
In the art of drilling wells to tap subterranean deposits of fluids such as oil and/or gas, especially when drilling by the rotary method employing a rotary bit and drill stem, a drilling fluid, usually a compounded fluid made to predetermined physical and chemical properties, is circulated to the bottom of the bore hole, and then back up said bore hole to the surface by passage through the annular space between said drill stem and the wall of said bore hole (or between said drill stem and the wall of the casing where casing has been put in place).
The drilling fluid must act as a liquid medium of controlled viscosity for removing cuttings from the bore hole; it must prevent excessive amounts of fluid from flowing from the bore hole into surrounding formations by depositing on the wall of the hole a thin but substantially impervious filter cake; it must possess a gel structure of sufficient strength to hold in suspension solids, particularly during any time the fluid is not circulating; it must serve as a weighting material exerting sufficient pressure to counterbalance any pressure exerted by water, gas, oil, or other fluid from a penetrated formation and to prevent caving or other intrusion into the drill hole. The drilling fluid must also serve as a lubricant for the bearings of the drill bit and the cutting surface of the bit teeth, and to reduce frictional forces on the drill pipe.
The science and technology of drilling fluids and methods of drilling, working over, completing, and servicing oil and/or gas wells has been extensively investigated for over sixty years. Materials and methods are known to increase the yield point or gel strength, to decrease the fluid loss, and to decrease the coefficient of friction of aqueous base drilling fluids, and to decrease the swelling of shales contacted by the drilling fluids.
While the systems developed thus far show improvement over the older aqueous base fluids, they are sometimes inadequate when difficult shale formations are encountered. Operators are, therefore, forced to revert to hydrocarbon-containing fluids. It is desirable to provide biodegradable additives for aqueous base fluids that would minimize or completely avoid the need for oil base systems when drilling problem shale formations.
SUMMARY OF THE INVENTION
The present invention is based on the discovery that a biodegradable water soluble alkyl glycoside, when added to an aqueous base drilling fluid, will increase the yield point and/or gel strength of the drilling fluid, decrease the fluid loss of the drilling fluid, decrease the coefficient of friction of the drilling fluid, and/or decrease the aqueous activity and thus the swelling of shales contacted by the drilling fluid, depending upon the concentration of the alkyl glycoside incorporated into the fluid.
Thus it is an object of this invention to provide a method of (a) increasing the yield point or gel strength of an aqueous base drilling fluid, (b) decreasing the fluid loss of an aqueous base drilling fluid, (c) decreasing the coefficient of friction of all aqueous base drilling fluid, (d) and/or decreasing the aqueous activity of an aqueous base drilling fluid and thus decreasing the swelling of shales contacted by an aqueous base drilling fluid, which comprises adding to the fluid an amount of alkyl glycoside sufficient to effect such increase or decrease.
It is another object of this invention to provide aqueous based fluids containing a water soluble alkyl glycoside in an amount which is sufficient to either (a) increase the yield point or gel strength of the fluid, (b) decrease the fluid loss of the fluid, (c) decrease the coefficient of friction of the fluid, and/or (d) decrease the aqueous activity of the fluid and thereby decrease the swelling of shales contacted by the fluid.
In its broadest: as
REFERENCES:
patent: 3936300 (1976-02-01), Cardone
patent: 4528106 (1985-07-01), Grolitzer
patent: 4687843 (1987-08-01), Smolin et al.
patent: 5403820 (1995-04-01), Walker
patent: 5479987 (1996-01-01), Hale
patent: 5494120 (1996-02-01), Hale et al.
patent: 5602082 (1997-02-01), Hale et al.
Fee Valerie
Gibson Sharon
House Roy F.
O'Brien-Goins-Simpson & Associates
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