An Overview of Surfactant Applications in Drilling Fluids for the Petroleum Industry

ABSTRACT Surfactants are increasingly being used in an ever-expanding variety of applications for drilling fluids. In oil-based drilling fluids, the most well-known applications of surfactants are as emulsifiers and wetting agents. In water-based drilling fluids, there is a continually-growing variety of applications that include: oil-in-water emulsification in base fluid formulations;shale-swelling inhibitors to prevent wellbore instabilities;detergency to prevent cuttings sticking to drill bit (adhesion of clay to metal parts);prevention of differential sticking;dispersants to inhibit flocculation of clay particles;foaming additives, to generate high gas/water ratio foam used as drilling fluids for low-pressure reservoirs and hard-rock drilling;defoaming additives to eliminate undesirable foam in water-based fluids;surfactant-polymer complexes for enhanced properties in fluids for low-pressure reservoirs. This review describes historical and modern applications of surfactant technology in drilling fluids, and the impact of those molecules on drilling operations. Proper selection and application of surfactants in drilling fluids have a significant economic impact, in terms of reducing the amount of lost time and potential trouble, and have a direct consequence on overall drilling performance and results.