Use of Hydraulic Fracturing Equipment for Formation Sand Control

Beginning early in the history of producing oil from subsurface strata, the industry has been constantly searching for efficient economical means of controlling the movement of unconsolidated formations into the wellbore. During the past 25 years, numerous investigations of various gravel screening media and their characteristics have been very satisfactorily carried out, demonstrating to the industry that sand or gravel properly selected and placed can effect formation sand control and not damage productivity. In the past years the use of gravel in wellbores for this purpose has met with varying success. Gravel or sand size selection for various formation conditions has been previously investigated. Early research and field applications of a gravel screening medium to unconsolidated oil-bearing sands were confined to only the problem of controlling the movement of these sands into the wellbore. It was early recognized that the more firmly such a screening medium could be placed against a producing formation, the more successful the pack would be in controlling movement. A satisfactory method and equipment for placing the packing material under pressure has long been desired. The mechanics of strata penetrated by wellbores have been under study for many years. Some of the developed theories vary even with ideal matrix. The unconsolidated oil-bearing sands conform to mechanical patterns that are even more highly controversial. The most common effect of stresses within these formations is movement of the formation particles. Secondary, but notable, is the usual rapid production decline in some of them. Theory and Practice Placing packing media against and into unconsolidated oil-bearing sands with pressure, allowing the carrying fluid to be absorbed by the formation being treated, appears to offer many advantages. This pressure technique can often effect a tight full pack which cannot always be realized with washdown methods where forces exercised are only equal to the weight of the packing medium.