非均质变异系数对聚合物驱各小层驱油效果及特征的影响

The Influence of Heterogeneity Variation Coefficient on Polymer Flooding Displacement Effect and Characteristic of Small Layers

刘 露 孙长红 李华斌 何荣华 牛忠晓

LIU Lu SUN Chang-Hong LI Hua-Bin HE Rong-Hua NIU Zhong-Xiao

利用数值模拟技术研究油层非均质变异系数（Vk）对各单层聚合物驱油效果的影响。结果表明，在同一Vk下，特别是Vk≥0.3时，高渗透率层位的最终采出程度高（61%～62%），聚合物驱采收率增幅低（5%OOIP～15%OOIP）。当Vk为0～0.3即油层相对均质时，由于水驱波及效率高，各小层的最终采出程度基本相同，约为62%。随着Vk的增大，高渗透率层（第6、7小层）采收率增幅分别从15.71%OOIP和16.27%OOIP降至13.78%OOIP和 6.47%OOIP；中高渗透率层（第4、5小层）采收率增幅保持上升趋势，从14.68%OOIP和15.14%OOIP分别增至30.35%OOIP和23.52%OOIP；中低渗透率层（第1、2、3小层）的则先增加后降低。当全区综合含水98%时，总是高渗层进入的聚合物溶液多，含水率高；低渗层进入的聚合物溶液少，含水率低。剩余油主要存在于渗透率相对较低层（第1~4层）。第2~4层进入的聚合物溶液分别占该小层孔隙体积的17%、22%和28%，占全区注入量的5%、7%和10%。第2~4小层是该方案条件下，聚合物驱提高采收率的主要贡献层位。

The effect of heterogeneity variation coefficient of reservoir （Vk）on polymer displacement effect and dynamic characteristics of every thin stratum was investigated by numerical simulation technology. The results indicated that when Vk was the same, especially Vk≥0.3，the ultimate recovery degree of high permeability stratum was high（61%～62%）and the recovery ratio increment of polymer flooding was low（5%OOIP～15%OOIP）. The final recovery degree of each small stratum was about 62% when the reservoir was relatively homogeneous (Vk=0~0.3), which had high efficiency by water flooding. With increasing Vk, the recovery ratio increment of high permeability zone (6, 7 single layer) reduced from15.71%OOIP and 16.27%OOIP to 13.78%OOIP and 6.47%OOIP respectively, that of middle-high permeability layer (4, 5 single layer) increased from 14.68%OOIP and 15.14%OOIP to 30.35%OOIP and 23.52%OOIP, and that of middle-low permeability layer (1—3 single layer) increased first and then reduced. When the water cut was of 98%, the high permeability layer input polymer solution more and the water cut was high, the low permeability layer input polymer solution less and the water cut was low. Remaining oil mainly existed in relatively lower permeability layer (1—4 single layer). The quantity of polymer solution pouring into 2—4 single layer was of 17%, 22% and 28% accounting for the small layer pore volume, and 5%, 7% and 10% accounting for the injection amount. 2—4 single layers were the main contribution horizon which improved oil recovery by polymer flooding on the scheme conditions.