化学驱是注水油田提高最终采收率的重要技术措施,聚合物分子量确定及浓度优化是油田化学驱方案优化设计的重要内容。针对如何确定聚合物分子量及浓度问题,分别进行了理论计算和天然岩心注入性评价实验。结果表明:理论计算可以快速确定与渗透率对应的聚合物分子量技术界限及适用的浓度范围;注入性评价实验能同时确定聚合物分子量和浓度与储层匹配的临界值,分子量的确定结果与理论计算结果基本一致,结果更接近真实情况;聚合物分子量可采用理论计算结合注入性评价实验确定,聚合物浓度可采用黏度比法结合注入性评价实验确定,同时考虑注入过程各节点黏损;不同物性条件的油藏需要开展有针对性的注入性实验确定聚合物参数。因此采用注入性实验并结合理论计算是确定聚合物参数的有效方法,研究结果可以为化学驱方案设计提供参考。

Chemical flooding is an important technical measure to improve ultimate recovery in water flooding oilfield, and the molecular weight and concentration of polymer are important contents in the design of chemical flooding formula.Aiming at how to determine molecular weight and concentration of polymer, theoretical calculation and injection evaluation experiments in natural cores are carried outand the results indicate that the technical limits of molecular weight of polymer and applicable concentration range corresponding to the permeability of rock can be calculated rapidly by theoretical method.The critical value of molecular weight and concentration matching reservoirs can be determined simultaneously in injection evaluation experiments.The critical value of molecular weight determined by injection method, which represents the reality in reservoir, is basically the same as that of theoretical calculation.The polymer molecular weight can be determined by theoretical calculation and injection method,and the polymer solution concentration can be determined by viscosity ratio and injection method.At the same time, the viscosity loss of polymer solution in the course of injection should be considered.The targeting injection experiment is needed in different reservoir with different physical properties to determine polymer parameters.So using injection experiment with theoretical calculation is an effective method to determine polymer parameter, and the result can provide reference for the design of chemical flooding schemes.