共聚物钻井液降滤失剂的合成与性能评价

以丙烯酰胺(AM)、2-甲基-2-丙烯酰胺基丙磺酸(AMPS)、丙烯酸(AA)、甲基丙烯酰氧乙基三甲基氯化铵(DMC)为原料,采用氧化还原引发体系合成了一种四元共聚物水基钻井液降滤失剂。确定了最佳合成条件:单体配比为AM/AMPS/AA/DMC=55∶30∶10∶5(质量比),引发剂加量各为0.3%(单体浓度为1),单体总浓度为20%(质量分数),反应温度为50℃,溶液p H值为7,反应时间为4 h。对聚合物进行了红外表征,合成产品与设计结构一致。钻井液性能评价结果显示:淡水基浆中聚合物加量为0.7%时,常温中压滤失量为6.0 m L,经过180℃老化后,API滤失量为8.2 m L,高温高压滤失量为11.6 m L;聚合物加量为1.0%时的页岩相对回收率达到99.4%。说明AM/AMPS/AA/DMC聚合物降滤失能力强,且热稳定性和抑制性能好。

Synthesis and Evaluation of Copolymer Filter Loss Reducer

A quadripolymer filter loss reducer was synthesized using acrylamide (AM), 2-acrylamide-2-methyl propane sulfonic acid (AMPS), acrylic acid (AA) and dimethylaminoethyl methacrylatemethyl chloride (DMC) as raw materials through redox polymerization. The mass ratio of the four monomers is AM:AMPS:AA:DMC=55:30:10:5, the concentration of initiator 0.3% (taking the concentration of all monomers as 1), total concentration of monomers 20% (mass ratio), reaction temperature 50℃, pH of the solution 7, and reaction time 4 hours. Characterization of the molecular structure of the copolymer showed that the molecular structure was the same as design. Treatment of API standard water base mud with 0.7% copolymer reduced the API filter loss to 6.0 mL. After aging at 180℃, filter loss at 0.7 MPa was 8.2 mL, and 11.6 mL at 3.5 MPa. In hot rolling test, shale cuttings recovery of 99.4% was attained at copolymer concentration of 1.0%. These laboratory tests showed that the synthesized copolymer had good filter loss control capability, thermal stability and inhibitive capacity.