| 摘要 |
<p>A cement composition for use in an oil or gas well, the cement composition comprises: a calcium aluminate cement; water; an organic acid; and a polymeric mixture comprising: (A) water; (B) citric acid; (C) a first polymer, wherein the first polymer: (i) comprises a cellulose backbone and carboxymethyl functional groups: 10 and (ii) has a molecular weight of less than 100,000; and (D) a second polymer. wherein the second polymer: (i) comprises a lignosulfonate; and (ii) has a molecular weight of less than 100,000, wherein a test composition consisting essentially of: the cement; the water; the organic acid; and the polymeric mixture, and in the same proportions as in the cement composition has a thickening time of at least 5 hours at 15 a temperature of 300 °F (148.9 °C) and a pressure of 10,000 psi (68.9 MPa).</p> |
