Chen Yadong, Li Yongming, Peng Yu, Zhang Dingyuan, Ye Jiandu, Jiang Youshi
State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu 610500, China.
ACS Omega. 2024 Apr 26;9(18):19992-20002. doi: 10.1021/acsomega.3c10034. eCollection 2024 May 7.
The technology of water plugging and increasing production in high water cut reservoirs of low permeability is a common problem in the industry. Epoxy resin, displaying excellent mechanical properties and adherent performance, can easily inject a tiny crack, forming a long-term blocking barrier. This study aimed to investigate an easily injectable degradable epoxy resin sealing material. The injectable performance, long-term stability, and mechanical and plugging properties were comparatively analyzed in the fractured core, and the degradable performance was discussed in the degrading solution. The result showed that the range of ( is the ratio of EOG and MHHPA) from 1 to 1.1 and the mass fraction range of EMI from 0.01 to 4 wt % are the optimal formulations (EOGM). The curing time from 1 to 12 h could be regulated by adjusting the dosage of EMI, as well as the strength being more than 60 MPa. The plugging agent's initial viscosity is lower than 100 MPa s at 20 °C and injecting pressure is lower than 0.1 MPa. After curing for 24 h, compressive strength was more than 72.76 MPa, 3.6 times higher than that of cement, and the adhesion strength was 4.41 MPa when the contact area was 75.93 cm. Breakthrough pressures for sealing 1-5 mm fractures were all more than 10 MPa, and the breakthrough pressure for 1 mm crack even reached 29.4 MPa. Epoxy resin/acid anhydride system could be degraded in a mixed solution of phenol-potassium salt-heavy aromatics within 7 days at 60-100 °C, which reduced the plugging well risk of the epoxy resin plugging agent. These results suggest that an epoxy resin/acid anhydride plugging agent can be employed effectively and safely for the injection of tiny cracks, which is of great engineering significance.
低渗透高含水油藏堵水增产技术是行业内的一个常见问题。环氧树脂具有优异的机械性能和附着性能，能够轻松注入微小裂缝，形成长期封堵屏障。本研究旨在探究一种易于注入的可降解环氧树脂密封材料。在岩心裂缝中对其可注入性能、长期稳定性以及力学和封堵性能进行了对比分析，并在降解溶液中探讨了其降解性能。结果表明，EOG与MHHPA的比例（ ）在1至1.1之间以及EMI的质量分数范围在0.01至4 wt%是最佳配方（EOGM）。通过调整EMI的用量可将固化时间控制在1至12小时，强度超过60 MPa。封堵剂在20℃时的初始粘度低于100 MPa·s，注入压力低于0.1 MPa。固化24小时后，抗压强度超过72.76 MPa，是水泥的3.6倍，当接触面积为75.93 cm时，粘附强度为4.41 MPa。封堵1 - 5 mm裂缝的突破压力均超过10 MPa，1 mm裂缝的突破压力甚至达到29.4 MPa。环氧树脂/酸酐体系在60 - 100℃下于苯酚 - 钾盐 - 重芳烃混合溶液中7天内可降解，降低了环氧树脂封堵剂的堵井风险。这些结果表明，环氧树脂/酸酐封堵剂可有效且安全地用于注入微小裂缝，具有重要的工程意义。
