Chemistry and Technology of Fuels and Oils ( IF 0.6 ) Pub Date : 2021-04-04 , DOI: 10.1007/s10553-021-01229-8 Junwei Fang , Yujing Luo , Shuanggui Li , Mingyi Deng , Gang Xie
In the development of shale gas, it is important to ensure the stability of the borehole wall. The stability of the borehole wall depends on the plugging ability of the drilling fluid, while the stabilizing ability of the drilling fluid is provided by adding the plugging agent to the fluid. Conventional plugging agents are characterized by a relatively high volume and do not allow one to effectively plug micropores and microcracks in shale rock. In this work, the PMMA-St copolymer was synthesized by emulsion polymerization of methyl methacrylate and styrene. The characteristics of the PMMA-St copolymer were studied by FT-IR, TGA, and phase analysis optical scanning methods. The results show that the size of PMMA-St nanoparticles ranges from 34 to 58 nm, and the average diameter is about 40.6 nm. The decomposition temperature of PMMA-St nanoparticles is 374.8°C, which indicates the good thermal stability of the copolymer. The PMMA-St nanoparticles have little affect on the rheological properties of water-based drilling fluids. The mud cake simulation method was used to evaluate the plugging performance of PMMA-St nanoparticles. The permeability of mud cake is 2.24 × 10-5 m2, which is close to the permeability of shale formation. When 0.5 wt % of the PMMA-St copolymer is added to the solution, the blocking rate is 70.27%. With increase in PMMA-St concentration, the blocking rate of the mud cake increases. The best stabilizing effect is achieved when the PMMA-St copolymer concentration is 1.0%. The results of the core experiments are consistent with the mud cake simulation, which indicates the excellent sealing ability of the PMMA-St copolymer. Therefore, PMMA-St nanoparticles can be effectively used as a plugging agent to ensure borehole stability in the shale formation.
中文翻译:
聚甲基丙烯酸甲酯和苯乙烯的共聚物在水基钻井液中作为堵漏剂的有效性
在页岩气的开发中,重要的是确保井眼壁的稳定性。钻孔壁的稳定性取决于钻井液的堵塞能力,而钻井液的稳定能力是通过向流体中添加堵塞剂来提供的。常规的堵漏剂的特征在于相对较高的体积,并且不允许人们有效地堵住页岩中的微孔和微裂缝。在这项工作中,PMMA-St共聚物是通过甲基丙烯酸甲酯和苯乙烯的乳液聚合而合成的。通过FT-IR,TGA和相分析光学扫描方法研究了PMMA-St共聚物的特性。结果表明,PMMA-St纳米颗粒的尺寸为34-58nm,平均直径为约40.6nm。PMMA-St纳米颗粒的分解温度为374.8℃,表明该共聚物具有良好的热稳定性。PMMA-St纳米颗粒对水基钻井液的流变特性影响很小。用泥饼模拟方法评价了PMMA-St纳米颗粒的堵漏性能。泥饼的渗透率为2.24×10-5 m 2,接近页岩形成的渗透率。当将0.5重量%的PMMA-St共聚物添加到溶液中时,封端率是70.27%。随着PMMA-St浓度的增加,泥饼的堵塞率增加。当PMMA-St共聚物的浓度为1.0%时,可获得最佳的稳定效果。核心实验的结果与泥饼模拟结果吻合,表明了PMMA-St共聚物具有出色的密封性能。因此,PMMA-St纳米颗粒可以有效地用作堵漏剂,以确保页岩地层中的井眼稳定性。