| 摘要 |
<p>Wells of subterranean formations containing hydrocarbons are stimulated by the injection of a crosslinked acid polysccharide. The crosslinked acid polysaccharide is a gel formed from a hydrated polysaccharide sol containing hydrochloric acid and having a pH of less than one to which a water hydrolyzable polyvalent metal salt is added to cause the crosslinking. The metal salt is zirconium, titanium or hafnium. The crosslinked acid polymer contains from about 30 to about 120 pounds polysaccharide per 1,000 gallons acid (about 3.6 to about 14.4 kilograms per 1,000 liters acid) and from about 3 to about 28 weight percent hydrochloric acid. The crosslinked acid polymer retards the chemical reactivity of the hydrochloric acid thereby allowing the acid to deeply penetrate the formation before the activity of the acid is spent, After its injection, the crosslinked acid polymer breaks down as a result of time and the temperature of the reservoir into a less viscous fluid allowing the acid to react with the formation.</p> |
