抗高温高钙梳型降滤失剂的制备与应用

选择几种不同的单体，按照一定配比，优选最佳方案合成梳型聚合物降滤失剂WA-1，并通过对比实验对其进行性能评价。选用2-丙烯酰胺基-2-甲基丙磺酸（AMPS）、二甲基二烯丙基氯化铵（DMDAAC）、N-乙烯基吡咯烷酮（NVP）和N,N-二甲基丙烯酰胺（DMAA）为单体，合成质量配比AMPS∶DMDAAC∶NVP∶DMAA=5∶3∶1∶1,总单体浓度19.8%，加0.2%过硫酸钾作为引发剂，反应温度为60 ℃，反应时间共5 h，pH值为7。性能评价结果表明，WA-1可抗温180 ℃，具有良好的流变性和降滤失性，抗钙性能良好；含2%CaCl₂的基浆中加2%WA-1，在180 ℃老化16 h后，中压滤失量为11.2 mL，降滤失效果优于线性聚合物。对WA-1进行红外光谱表征、热重量分析、钻井液Zeta电位和粒径分布分析，结果表明，WA-1作为梳型聚合物降滤失剂，能够抗高温高钙，提高钻井液的稳定性，具备独特的性能优势。 

Development and Application of Comb-like Polymer Filter Loss Reducer with High Temperature and High Calcium Contamination Resistance

A comb polymer filter loss reducer, WA-1, was synthesized with different monomers in a specific ratio. Comparative experiments were designed, and the optimum reaction program selected for the synthesis reaction. Monomers used in the synthesis of WA-1 included 2-acrylamido-2-methylpropanesulfonic acid (AMPS), dimethyl diallyl ammonium chloride (DMDAAC), N-vinyl pyrrolidone (NVP) and N, N-dimethyl acrylamide (DMAA) in a mass ratio of AMPS∶DMDAAC∶NVP∶DMAA = 5∶3∶1∶1. The total concentration of the monomers was 19.8%. Potassium persulphate of 2‰ was used as the reaction initiator. The monomers were allowed to react for 5 hours at 60 ℃ and pH of 7. Evaluation of the final product has shown that WA-1 can be used at temperatures up to 180 ℃. Drilling fluids treated with WA-1 have good rheology, filtration property and calcium contamination resistance. In laboratory experiment, a base mud containing 2%CaCl₂ was treated with 2%WA-1. The mud was aged at 180 ℃ for 16 hours and then tested. The API filtration rate of the mud was 11.2 mL, which was less than the filtration rate of the mud treated with linear polymers. Infrared spectroscopy characterization, thermogravimetric analysis, Zeta-potential measurement and particle size distribution analysis of drilling fluids treated with WA-1 have shown that, as a comb polymer filter loss reducer, WA-1 is able to resist the adverse effects of high temperature and high calcium, and to improve the stability of drilling fluids.