Aqueous drilling fluids and additives therefor

An aqueous drilling fluid comprising water, clay and a friction reducing composition which is stable in said drilling fluid at temperatures above about 150.degree. F, is stable in the presence of drilling fluid additives and contaminants and which substantially reduces foaming and drag comprising a mixture of up to 95% by weight of at least one linear alkyl alcohol having about three to eight carbon atoms per molecule with an ester of an acid and an oxazolidine derivative, said ester consisting essentially of a derivative represented by the formula:

• ##STR7## wherein n is a whole integer in the range of about 8 to 16, wherein said ester is present in an amount of about 0.2-5 pounds per barrel of said drilling fluid.

A method of drilling a well penetrating a subterranean formation using an aqueous drilling fluid comprising water and clay, said method comprising rotating a bit in contact with the bottom of said said well and attached to the lower end of a hollow drill pipe extending from the bottom of said well to the surface while circulating an aqueous drilling fluid comprising water, clay and an effective amount of a friction reducing composition downwardly through the drill pipe and upwardly through the annulus of said well, said friction reducing composition comprising an ester of an acid and an oxazolidine derivative, said ester consisting essentially of a derivative represented by the following formula:

• ##STR8## wherein n is an integer in the range of about 8-16.