亲油水泥浆界面封隔性能评价研究

A Study on the Hydraulic Isolation Property of Cement-casing and Cement-formation Interfaces by Oleophilic Cement Slurry

黄盛 周灿 李早元 杨川 刘洋

HUANGSheng ZHOUCan LIZaoyuan YANGChuan LIUYang

油气藏地质及开发工程全国重点实验室·西南石油大学, 四川 成都 610500 西南石油大学石油与天然气工程学院, 四川 成都 610500 中国石油川庆钻探工程有限公司井下作业公司, 四川 成都 610052

National Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu, Sichuan 610500, China Petroleum Engineering School, Southwest Petroleum University, Chengdu, Sichuan 610500, China Downhole Operation Company, CCDC, Chengdu, Sichuan 610052, China

页岩气井油基钻井液条件下固井时，套管与井壁表面附着油膜或油基钻井液易导致水泥环界面封隔能力下降，形成窜流通道，影响后期增产改造作业。虽然前置液能有效提高界面润湿反转，但受用量、冲洗效率等因素限制，界面仍会出现油膜附着情况。为此，在水泥浆中加入亲油表面活性剂，制备形成亲油水泥浆，赋予水泥环亲油能力。采用接触角、剪切胶结强度、界面水力封隔测试等评价了亲油水泥石的亲油能力及界面封隔效果。研究发现，非极性溶剂在亲油水泥石表面接触角远低于常规水泥石表面，具备良好的亲油性能；亲油水泥石与含白油、油基钻井液的套管、页岩岩芯胶结后，一、二界面抗流体窜流压力分别提升500%和400%，胶结强度分别提高205%和122%；亲油表面活性剂的加入不会对水泥水化程度、水泥浆工程性能及水泥石力学性能产生负面影响。结果表明，亲油表面活性剂掺入后可有效提高水泥环与含油界面的封隔能力，具备提高油基钻井液条件下水泥环-套管-地层界面胶结与封隔性能的潜力。

When cementing with oil-based drilling fluid in shale gas wells, oil in casing and wellbore is easy to reduce the interface isolation performance and form channeling circulation channels, which will have a negative impact on subsequent production. Although the pre-fluid can effectively improve the interface wetting reversal, the oil film retention and adhesion will still occur due to the limitation of flushing efficiency. To this end, we add oil-wetting surfactants to cement slurry, and form oil-wetting cement slurry, giving cement oil-wetting ability. Contact angle, shear bonding strength and interfacial hydraulic isolation tests were used to evaluate the oil-wetting ability and interfacial isolation effect of the cement. It is found that the contact angle of non-polar solvent on the surface of oil-wetting cement is much lower than that on the surface of conventional cement, and the non-polar solvent has good oil-wetting performance. After oil-wet cement cementing with casing and shale core containing white oil and oil-base drilling fluid, the resistance to fluid cross-flow pressure of the cement-casing interface and cement-formation interface were increases by 5 times and 4 times, and the shear bonding strength increases by 205% and 122%, respectively. The addition of oil-wetting surfactant has no negative effect on the hydration degree of cement, mechanical properties of cement and basic engineering performance of cement stone. The results show that the addition of the oil-wetting surfactant can effectively improve the cement ring and oil-bearing interface, and has the potential to improve the cement sheath, casing and formation interface bonding and isolation performance under oil-based drilling fluid condition.

10.11885/j.issn.1674-5086.2021.10.03.01