无黏土水基钻井液用超支化聚合物降滤失剂的合成及性能评价

Synthesis and Performance Evaluation of Clay-free Water-based Drilling Fluid with Hyperbranched Polymer Filtrate Reducer

在高温条件下,聚丙烯酰胺类降滤失剂分子易发生降解,导致降滤失效果大幅下降。为此,通过超支化单体季戊四醇三烯丙基醚(APE)与2-丙烯酰胺-2-甲基丙磺酸(AMPS)、丙烯酰胺(AM)、对苯乙烯磺酸钠(SSS)共聚合成了一种耐高温的超支化聚合物降滤失剂JHPAS,以JHPAS为基础配制了一种新型的无黏土水基钻井液,分析其降滤失机理,评价其在高温、高盐条件下的流变性能和降滤失性能。结果表明:JHPAS具有很好的热稳定性,在水溶液中可形成网络结构,在无黏土水基钻井液中吸附于超细CaCO 3表面形成致密滤饼,并堵塞滤饼上的孔隙,进一步降低钻井液滤失量;构筑的无黏土水基钻井液在200℃老化16 h、饱和氯化钠盐水的条件下仍具有稳定的流变性和良好的降滤失性能,API滤失量和高温高压滤失量分别为5.5 mL和7.6 mL。研究成果有助于推动超支化聚合物在深层、超深层油藏钻井液中的研究与应用。

Under high temperature conditions,the degradation of polyacrylamide filtrate reducer molecules leads to a significant decrease in filtrate reduction efficiency.To address this issue,a high temperature resistant hyperbranched polymer filtrate reducer(JHPAS)was synthesized through copolymerization of hyperbranched monomer allyl pentaerythritol(APE)with 2-acrylamido-2-methylpropane sulfonic acid(AMPS),acrylamide(AM),and sodium styrene sulfonate(SSS).A novel clay-free water-based drilling fluid was formulated using JHPAS,and its filtrate reduction mechanism was analyzed.The rheological properties and filtrate performance under high temperature and high salt conditions were evaluated.The results demonstrate that JHPAS exhibits excellent thermal stability and has the ability to create a network structure in an aqueous solution.It adsorbs onto the surface of superfine CaCO 3,forming a compact filter cake in clay-free water-based drilling fluid,effectively plugging the pores on the filter cake and consequently reducing the filtrate loss of drilling fluid.The developed clay-free water-based drilling fluid maintains consistent rheological properties and demonstrates effective filtrate loss reduction even after exposure to 200℃aging for 16 hours and saturated sodium chloride brine.The API filtrate loss and high-temperature,high-pressure filtrate loss are measured at 5.5 mL and 7.6 mL,respectively.These research findings contribute to advancing the exploration and utilization of hyperbranched polymers in drilling fluids for in deep and ultra-deep reservoirs.