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High temperature set retarded well cement compositions and methods

  • US 4,997,487 A
  • Filed: 03/07/1990
  • Issued: 03/05/1991
  • Est. Priority Date: 03/07/1990
  • Status: Expired due to Fees
First Claim
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1. A set retarded cement composition which is substantially non-thinning at high temperatures comprising:

  • hydraulic cement;

    sufficient water to form a pumpable slurry;

    a set retarder comprising at least one member selected from the group consisting of a copolymer of 2-acrylamido, 2-methylpropane sulfonic acid (AMPS) and acrylic acid having an average molecular weight below about 5000 and comprising from about 40 to about 60 mole percent AMPS, said copolymer being present in an amount in the range of from about 0.1 to about 5% by weight of cement, lignosulfonates present in an amount in the range of from about 0.1 to about 5% by weight of cement, borates present in an amount in the range of from about 0.2 to about 5% by weight of cement and organic acids present in an amount of from about 0.2 to about 5% by weight of cement; and

    a galactomannan gum which has been treated with a hydrophobing agent selected from the group consisting of potassium pyroantimonate present on the gum in an amount of from about 0.001 to about 0.3 percent by weight of the gum and compounds capable of liberating borate ions when added to water present on the gum in an amount of from about 0.5 to about 1.0 percent by weight of the gum.whereby the hydration rate of said gum is retarded at temperatures below about 120 degrees F. and at pH levels above about 10, but the hydration rate increases at temperatures above about 120 degrees F., said treated gum being present in said composition in an amount of at least about 0.5% by weight of cement.

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