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根据双河油田IV5-11层系的油藏特征,利用正交实验法,对聚合物质量浓度、表面活性剂种类及其质量分数进行筛选,得到了由质量浓度为1500mg/L的ZL-Ⅱ、质量分数为0.3%的QY-3组成的二元复合驱油体系及由质量浓度为1500mg/L的ZL-Ⅱ、质量分数为0.3%的QY-3和1.0%的Na2CO3组成的三元复合驱油体系,这2个体系均能与双河模拟油形成超低界面张力且粘度适中。利用均质与非均质人造岩心及微观非均质仿真模型,对所选复合驱油体系进行物理模拟驱油实验;并在模拟油藏具有代表性的3倍渗透率级差条件下,优选了三元复合驱油体系注入方式。实验结果表明,在均质条件下,三元复合驱油体系提高采收率程度明显高于二元复合驱油体系;在非均质条件下,随着非均质性的增强,三元复合驱油体系与二元复合驱油体系提高采收率的差距逐渐缩小,但前者始终高于后者;对于同一驱油体系,随着非均质性的增强,驱油效率先增大后减小,渗透率级差为3倍时的采收率最高。综合分析可知,三元复合驱油体系好于二元复合驱油体系,在其注入前后分别注入0.05倍孔隙体积交联聚合物保护段塞的注入方式,三元复合驱油体系提高采收率比不加保护段塞时提高了4%。
According to the reservoir characteristics of IV5 - 11 reservoir in Shuanghe Oilfield, orthogonal experiment was used to screen the polymer concentration, surfactant type and mass fraction, and the mass concentration of ZL - Ⅱ , A mass fraction of 0.3% QY-3 binary composite flooding system composed of a concentration of 1500mg / L of ZL-Ⅱ, a mass fraction of 0.3% QY-3 and 1.0% of the composition of ternary Na2CO3 Oil displacement system, these two systems can be formed with the Shuanghe simulation oil ultra-low interfacial tension and viscosity. Using homogeneous and heterogeneous artificial cores and microscopic heterogeneous simulation models, the physical simulation of oil displacement was carried out on the selected composite flooding system. And under the conditions of 3 times of permeability gradient representative of reservoir simulation, ASP flooding system injection method. The experimental results show that under the homogeneous conditions, the oil recovery of the ASP flooding system is obviously higher than that of the binary flooding system. Under heterogeneous conditions, with the increase of the heterogeneity, the ternary complex The difference between the flooding system and the binary composite flooding system to reduce oil recovery gradually decreases, but the former is always higher than the latter. For the same flooding system, the flooding efficiency first increases and then decreases with the increase of heterogeneity Small, permeability rate of 3 times the highest recovery. Comprehensive analysis shows that the ASP flooding system is better than the binary composite flooding system, injection of 0.05 times the pore-volume cross-linked polymer before and after injection of slug injection, ASP flooding system to improve oil recovery A 4% increase over unprotected slugs.