高温高盐油藏泡沫凝胶复合封窜体系的制备与评价

PREPARATION AND EVALUTION OF FOAM GEL COMPOUND CHANNELING SYSTEM FOR HIGH TEMPERATURE AND HIGH SALT RESERVOIR

为了改善高温高盐油藏部分油井水窜频发等问题,在聚合物溶液中加入交联剂和起泡剂等,制得泡沫凝胶复合封窜体系。通过光学显微镜和环境扫描电镜分析其稳定性机理,并通过室内驱替实验评价其封堵性能。结果表明,聚合物在成胶后形成的三维网状结构,增加了液相黏度及液膜厚度,阻碍气泡间的传质过程,大幅度降低泡沫的析液速率,进而提高泡沫的稳定性。室内驱替实验结果表明,在高温(150℃)、高盐(99.99 g/L)条件下注入0.5 PV泡沫凝胶体系封堵率可达97%以上,并且,随着渗透率降低,泡沫凝胶体系的封堵能力越好;泡沫凝胶体系具有较好的剖面改善能力,有效封堵高渗、启动低渗;此外,在注入0.5 PV泡沫凝胶体系后,可提高原油采收率16%以上,表明泡沫凝胶体系具有较好的提高采收率能力。

In order to solve the problem of frequent water channeling in some oil wells in high temperature and high salt reservoir,the foam gel compound sealing channeling system was prepared by adding crosslinking agent and foaming agent into polymer solution.Its stability mechanism was analyzed by optical microscope and environmental scanning electron microscope,and its plugging performance was evaluated by laboratory displacement experiment.The results show that the three-dimensional network structure formed by the polymer after gelation increases the viscosity of the liquid phase and the thickness of the liquid film,hinders the mass transfer process between bubbles,and greatly reduces the liquid separation rate of the foam,and thereby improves the stability of the foam.The results of indoor flooding experiments show that the plugging rate of 0.5 PV foam gel system can reach more than 97%under the conditions of high temperature(150℃)and high salt(99.99 g/L),and as the permeability decreases,the better the plugging ability of the foam gel system;Foam gel system has good profile improvement ability,effectively plugging high permeability and starting low permeability;In addition,after the injection of 0.5 PV foam gel system,the oil recovery rate can be increased by more than 16%,indicating that the foam gel system has a better ability to increase oil recovery.