Water and Oil Base Fluid Retention in Low Permeability Porous Media - an Update

Phase trapping refers to the temporary or permanent trapping of oil or water based fluids introduced into a porous media during drilling or completion operations which result in a reduction in the effective permeability to the desired producing or injected phase. This problem has emerged in recent years as a major mechanism of formation damage, most notably in low permeability gas producing formations. This paper reviews the current state of the art with respect to new technology which is being used to identify formations that are particularly susceptible to this mode of formation damage, as well as describing some of the most current technology being used to avoid and remove these problems. This includes the use of various types of new non-alcohol based surface tension reducing agents, foamed fluids and other surfactants, transient wettability modifying agents, oil based fluids, as well as CO 2 or nitrogen based fracturing technology. The potential advantages of some of these new technologies and where they have the greatest degree of potential application are discussed .