COMPOSITIONS AND METHODS FOR REDUCING LOST CIRCULATION

摘要

Fluid compositions comprising an aqueous base fluid, one or more fibers and one or more swellable polymers are useful for curing lost circulation in subterranean wells. One method for applying the fluid composition comprises circulating a drilling fluid in a wellbore, encountering a region in the wellbore from which drilling fluid escapes into a surrounding formation, preparing the composition, placing the composition in the wellbore adjacent to the region from which drilling fluid escapes, allowing the fibers to penetrate formation openings and form a bridge, and introducing an activation fluid that causes the swellable polymers to expand, thereby forming a plug.