| 摘要 |
1498472 Fracturing underground formations DOW CHEMICAL CO and SCIENTIFIC SOFTWARE CORP 6 Oct 1975 [17 Oct 1974] 40800/75 Heading E1F A stable foam comprising a mixed dispersion of a liquid base, a surfactant, a propping agent and a gas is injected into a subterranean formation to initially fracture the formation or to extend a fracture in the formation, the foam having a Mitchell quality as derived by the formula ftp=Vsg/Vf, where #tp is the Mitchell quality, Vsg is the volume of saturated gas and Vf is the volume of foam, at the temperature and the breakdown pressure of the formation or the fracture extension pressure of the formation of between 0.5236 and 0.9999. Preferably the liquid base is oil, water or an acid, the gas is air, nitrogen, carbon dioxide or hydrocarbons, the surfactant is an anionic, cationic or non- ionic surfactant, and the propping agent is sand, glass beads, aluminium pellets &c walnut shells. Other formation treating agents may be included e.g. KCL, hydroxy alumina, iron chelating agents, HCL, HF, CH 3 COOH, non- emulsifying agents, gels, or active gaseous materials (CO 2 , Cl 2 or O 2 ).
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