The usefulness of medium grade Indian bentonite clay for oil well drilling has been studied. The rheological properties of water bentonite system needed improvement to meet the desired results expected from a oil well drilling fluid. The effects of certain polymers like partially hydrolyzed polyacrylamide (PHPA), low viscosity sodium carboxy are studied. The impact of the favourable drilling fluid developed on the formation damage is also studied by using Ruska liquid permeameter.