abstract |
A method of fracturing a subterranean formation with a stabilized foamed fracturing fluid comprising from about 50 percent to in excess of about 96 percent by volume of carbon dioxide with the remainder comprising an aqueous liquid and a selected surfactant. The foam is formed in situ by injection of a stabilized 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 DEG F. at which time the stabilized emulsion spontaneously forms a high quality stabilized foam. |