新型耐高温油井水泥降失水剂的合成及性能研究

Synthesis and Performance of a New Fluid Loss Additive for Cement Slurry with High Temperature Resistance

为提高普通油井水泥降失水剂的抗温性能,以2-丙烯酰胺基-2-甲基丙磺酸(AMPS)、丙烯酰胺(AM)、丙烯酸(AA)和N-乙烯基吡咯烷酮(NVP)为原料,合成了AMPS/AM/AA/NVP四元共聚物耐高温油井水泥降失水剂,研究了反应单体浓度、单体配比、引发剂浓度等因素对降失水剂性能的影响,考察了降失水剂的耐温耐盐性及其对水泥浆性能的影响。结果表明,降失水剂的最佳合成条件为:单体加量15%,单体组成为:60%AMPS、20%AM、15%AA、5%NVP,引发剂、交联剂(N,N-亚甲基双丙烯酰胺)和分子量调节剂(甲基丙烯磺酸钠)加量分别为单体总量的1%、0.15%和0.8%,pH=7,反应温度60℃,反应时间4 h。该降失水剂具有优良的耐温耐盐性能,耐温可达180℃,在36%NaCl溶液中添加3%降失水剂即可使水泥浆API失水量降至46 mL。在180℃、降失水剂掺量为4%时,水泥浆API失水量为48 mL、稠化时间为308 min、水泥石抗压强度为32.5 MPa,满足高温条件下的固井施工要求。

In order to improve the temperature resistance of common oil well cement fluid loss additive, a new quadripolymer fluid loss additive for high temperature cement slurry was synthesized by 2-acrylamide-2-methyl propane sulfonic acid （AMPS） , acrylamide （AM）, acrylic acid （AA） and N-vinyl pyrrolidone （NVP）. The effect of monomer concentration, monomer ratio and initiator concentration on the performance of fluid loss additive was studied. The temperature-resistance and salt-resistance properties of fluid loss additive and the effect on the performance of cement slurry system were investigated. The results showed that the optimum synthesis condition of fluid loss additive was obtained as follows： 15% monomers dosage, monomer composition： 60% AMPS, 20% AM, 15% AA and 5% NVP, initiator, crosslinking agent （N, N-methylenebis acrylamide） and molecular weight regulator （sodium methallyl sulfonate） dosage of 1%, 0.15% and 0.8% in terms of total monomer mass respectively, 7 pH value, 60℃ reaction temperature, 4 hrs reaction time. The fluid loss additive had good temperature and salt resistance property, the temperature-resistance capacity was up to 180℃. The API water loss of cement slurry system including 3% fluid loss additive and 36% NaCl could be decreased to 46 mL. At 180℃, the API water loss of cement slurry system including 4% fluid loss additive was 48 mL, thicken time was 308 minutes and compressive strength of cement stone was 32.5 MPa. The AMPS/AM/AA/NVP quadripolymer fluid loss additive satisfied the cementing operation requirements at high temperature.