Study and Application of a High Temperature Retarding Agent for Well Cementing

At temperatures between 130 ℃ and 150 ℃, a cement slurry treated with the commonly used retarding agent AMPS/IA has a thickening time that is longer than the thickening time at lower temperatures. This is an abnormal phenomenon that is risky to the well cementing operation and negatively affects the quality of cementing jobs. In laboratory experiment, AMPS and IA were reacted with each other through radical solution copolymerization. During the copolymerization, EDTA-2Na (disodium ethylene-diamine tetra-acetic acid) and CTAC (cetyl trimethyl ammonium chloride) were added to compound with the copolymerization product. The final product of the copolymerization, BH-R103L, is a retarding agent which can be used to prevent the abnormal thickening time. Comprehensive evaluation of the retarding agent BH-R103L revealed that it has reliable high temperature resistance and gel strength adjustment property. A cement slurry treated with BH-R103L has a thickening time that is adjustable between 120 ℃ and 150 ℃. At 150 ℃, a cement slurry treated with 2% (BWOC) BH-R103L has a thickening time longer than 300 min, and the thickening time has a linear relationship with the concentration of BH-R103L in the cement slurry. Using BH-R103L, the abnormal thickening time is eliminated, the cement slurry has a low initial consistency, the temperature and concentration sensitivity become low, and the thickening timeline becomes normal. BH-R103L has good compatibility with high temperature filter loss reducers such as AMPS, and can be used to inhibit “soft core” phenomenon of a cement slurry at elevated temperatures. Cured at 60 ℃, the set cement has a strength that develops very fast, other general properties of the set cement all satisfy the needs of well cementing operation. BH-R103L has been used in the cementing operation on the 203H153 platform in Luzhou block, Sichuan Province, sonic logging results showed that the cementing job quality met the designed requirements.