| 摘要 |
A novel buffered gelling/foaming agent and resulting gelled aqueous inorganic acid solution involving a N,N-bis (2-hydroxyethyl) fatty amine acetic acid salt (e.g., N,N-bis (2-hydroxyethyl) tallow ammonium acetate); alkali metal acetate; and acetic acid buffered system. The buffered gelling/foaming agent compositions exhibit pragmatic advantages in preparation, handling and use particularly at low temperatures because of low pour points (e.g., 5 DEG -10 DEG F.). Furthermore, the buffered gelling agent more efficiently utilizes the active ingredients in terms of desired viscosity rise as a function of concentration. The resulting gelled aqueous inorganic acid solutions using the buffered gelling agent exhibit a novel viscosity rise and calcium ion viscosity contribution as the concentrated acid is partially spent (i.e., approaches 12%), yet the totally spent acid returns to a nominal viscosity and is a foaming medium. As such, the novel buffered gelling agent and resulting gelled acid solutions are useful in acidizing and fracturing subterranean formations.
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