Foamed Anhydrous Methanol Stimulation

Abstract

ABSTRACT Laboratory studies have indicated that foamed anhydrous methanol may be an effective stimulation technique for the sands and shales of the Appalachian Basin and the Eastern Overthrust Belt. These formations are characterized by low pressures, low permeabilities, and sensitivity to injected water. Conventional aqueous fracturing foams pumped into these formations result in fluid retention, clay swelling, and migration, along with capillary pore blockage. To forego such problems, some operators instead pump strictly nitrogen (N2) gas or liquid carbon dioxide (CO2) as the stimulation fluid. Such treatments minimize formation damage but are incapable of transporting appreciable quantities of proppant for the created fractures. Laboratory studies were conducted to determine a more effective stimulation fluid. Results indicate that foamed anhydrous methanol may be such a fluid because it is nonaqueous and capable of transporting proppant.