Fracturing method for stmulation of wells.

摘要

A method of fracturing a subterranean formation with a stabilised foamed fracturing fluid comprising from about 30 percent to in excess of about 95 percent by volume of carbon dioxide, with the remainder comprising a substantially anhydrous liquid and a selected surfactant. The foam is formed in situ by injection of a stabilised liquid-liquid emulsion containing liquid carbon dioxide into a well bore penetrating the formation. The temperature and pressure of the emulsion is controlled to maintain the carbon dioxide in the liquid phase during injection into the well bore. Thereafter, the carbon dioxide is heated by the subterranean formation to a temperature above about 88°F (31°C) at which time the stabilised emulsion spontaneously forms a high quality stabilised foam.