Liu Bin, Wang Yanling, Liang Lei, Zeng Yijin
School of Petroleum Engineering, China University of Petroleum (East China) Qingdao 266580 China
Sinopec Petroleum Exploration and Development Research Institute Beijing 10083 China
RSC Adv. 2021 May 11;11(28):17197-17205. doi: 10.1039/d1ra02069b. eCollection 2021 May 6.
Supercritical carbon dioxide (SC-CO) fracturing technology has the characteristics of a large amount of fixed CO and anhydrous fracturing. It has great application potential for developing unconventional oil and gas resources and mitigating the greenhouse effect. However, the low viscosity of SC-CO limits the development of this technology. In this work, HS series thickeners were prepared a ring-opening polymerization and hydrosilylation reaction by a molecular simulation-aided design method. The simulation results of cohesive energy density, interaction energy, and radial distribution function are consistent with the visualization experimental results, which proves that HS (hyperbranched siloxane) series thickeners have excellent solubility in SC-CO. HS-3 is the best thickener in the HS series. At 305.15 K and 10 MPa, 5 wt% HS-3 (60 s) increases the viscosity of SC-CO by 151 times, and the apparent viscosity is 3.024 mPa s. The apparent viscosity of SC-CO was positively correlated with the pressure and concentration but negatively correlated with the temperature and shear rate. The results indicate that it is feasible to introduce an aliphatic group and polysiloxane into a SC-CO thickener by hydrosilylation.
超临界二氧化碳（SC-CO）压裂技术具有大量固定二氧化碳和无水压裂的特点。它在开发非常规油气资源和缓解温室效应方面具有巨大的应用潜力。然而，SC-CO的低粘度限制了该技术的发展。在这项工作中，通过分子模拟辅助设计方法，利用开环聚合和硅氢加成反应制备了HS系列增稠剂。内聚能密度、相互作用能和径向分布函数的模拟结果与可视化实验结果一致，这证明了HS（超支化硅氧烷）系列增稠剂在SC-CO中具有优异的溶解性。HS-3是HS系列中最佳的增稠剂。在305.15 K和10 MPa条件下，5 wt%的HS-3（60 s）可使SC-CO的粘度提高151倍，表观粘度为3.024 mPa·s。SC-CO的表观粘度与压力和浓度呈正相关，但与温度和剪切速率呈负相关。结果表明，通过硅氢加成将脂肪族基团和聚硅氧烷引入SC-CO增稠剂是可行的。
