EPOXY ACID BASED BIODEGRADABLE SET RETARDER FOR A CEMENT COMPOSITION

摘要

Compositions and methods according to the invention are directed to a cement composition for use in a subterranean formation. The cement composition 5 comprises: (A) cement; (B) water; and (C) a polymer, wherein the polymer; (i) com prises a monomer or monomers selected from the group consisting of epoxysuccinic acid, a substituted epoxysuccinic acid, and an alkali metal salt, alkaline earth metal salt, or ammonium salt of any of the foregoing, and any combination of any of the foregoing; (ii) has the following characteristics: (a) is water soluble; and (b) is 10 biodegradable; and (iii) is capable of providing; (a) a thickening time of at least 2 hours for a test composition at a temperature of 190 'F and a pressure of 5,160 psi; and (b) an initial setting time of less than 24 hours for the test composition at a temperature of 217 'F and a pressure of 3,000 psi, wherein the test composition consists of 860 grams of Class-H Portland cement, 325 grams of deionized water, 15 and 0,4% by weight of the cement of the polymer. The method comprises the steps of: (A) introducing the cement composition into the subterranean formation; and (B) allowing the cement composition to set after introduction into the subterranean formation. 11/04/13,dh-20762 - abstract - cdm.docx,2 WO 2011/104503 PCT/GB2011/000247 Thickening Time versus Temperature 150 200 250 300 Temperature (F)