Abstract: The invention provides for either (a) increasing the yield point or gel strength of an aqueous based drilling fluid; (b) decreasing the fluid loss of an aqueous based drilling fluid; (c) decreasing the coefficient of friction of an aqueous based drilling fluid; or (d) decreasing the aqueous activity of an aqueous based fluid drilling fluid thus decreasing the swelling of shales contacted by an aqueous based fluid, the methods comprises adding to the drilling fluid an amount of an alkyl glycoside, preferably methyl glucoside, sufficient to effect such increase or decrease. The invention also provide for aqueous based completion fluids, workover fluids, and well working fluids containing an alkyl glucoside solubilized in the aqueous phase of said fluids.

Abstract: The invention provides a water base drilling fluid having decreased swelling effect on hydratable shales contacted by the drilling fluid wherein the aqueous phase contains an alkyl glucoside solubilized therein. Another embodiment of the invention provides an aqueous solution for addition to drilling fluids to decrease the swelling of hydratable shales contacted by the drilling fluid, the solution comprising an aqueous phase having dissolved (solubilized) therein from about 50% to about 85% by weight methyl glucoside and at least about 2% by weight of an alkali metal hydroxide.

Abstract: Disclosed are invert oil emulsion drilling fluids containing a non-toxic, biodegradable oil having a viscosity at 25.degree. C. of less than 1.5 centipoise, a flash point of at least 60.degree. C., an aniline point of at least 80.degree. C., and a content of aromatic hydrocarbons of less than 1% by volume. These drilling fluids have a low viscosity at the high shear rates imparted to a drilling fluid at the bit during drilling. This low bit viscosity provides for faster penetration rates. Such drilling fluids containing a temperature stabilizing additive exhibit superior thermal stability.