Abstract: Disclosed is a method of generating microbubbles in oleaginous liquids which comprises adding a silicone oil to the oleaginous liquid and thereafter subjecting the liquid to mechanical forces in the presence of a gas. Also disclosed are oil base well drilling and servicing fluids having a low shear rate viscosity as measured with a Brookfield Viscometer at 0.5 rpm of at least 10,000 centipoise and having incorporated therein microbubbles generated by the disclosed method, and a method of drilling a well wherein there is circulated within the wellbore during drilling the oil base, microbubble-containing fluid disclosed.