Abstract: A drilling fluid comprises water and microbubbles in an amount to achieve a density of the fluid in the range of 4-6 pounds per gallon; the desired density is achieved, and the novel drilling fluid exists, at pressures in the range of 350-5000 pounds per square inch.

Abstract: Light weight drilling fluids are prepared by passing a gas and the drilling fluid through a cavitation device. Bubbles are finely divided into microbubbles, thereby reducing the density of the fluid. Low HLB surfactants, natural polymers, and ionic-charged polymers may be added to enhance the stability of the microbubble suspension.

Abstract: A substantially nonaqueous composition comprising a polyol and potassium formate is made by removing water from a mixture while heating. The polyol beneficially contains 3-50 hydroxyl groups and may be polyglycerin. The water removed may originate from a solution of one or more of the ingredients, from a condensation reaction of hydroxyl groups, and/or from an esterification reaction of hydroxyl groups on the polyol(s) and the formate groups. The composition is effective for treating shale formations in well drilling to reduce hydration and sloughing of the shale. If, in the course of treating shale formations, the polyol/potassium formate composition mixes with connate or other water, the water may be removed on returning the composition to the surface, and recycled.