层内非均质性下聚合物驱对油田开发影响

Effect of polymer flooding on oil field developmentunder intra-layer heterogeneity

为明晰层内非均质性控制条件下,聚合物驱对海上油田剩余油分布及开发特征的影响,根据相似原理,参照油田实际储层和流体特征参数,开展了不同非均质性下的水驱和聚合物驱室内模拟实验。实验结果表明:水驱过程中无水采收期长短与非均质程度成反比,当非均质性较强时,低渗层剩余油富集,变异系数与水驱采收率成反比;相比于水驱开发方式,聚合物驱能够有效抑制高渗层中窜流现象,有效扩大波及体积,不同非均质性模型实施早期注聚后,同期采油速度显著提高,最终采收率较水驱采收率提高13.01%~16.69%,聚驱采收率与渗透率级差成反比;对于非均质性较强储层,聚驱后低渗层仍有大量剩余油富集,可布置调整井进行挖潜;对于非均质性较弱储层,采取调堵结合的策略,充分动用剩余油。通过实施针对性调整挖潜措施,明显改善了油田聚驱开发效果,能够为海上同类油田开发提供借鉴。

This paper is presented to clarify the influence of polymer flooding on the remaining oil distribution and development characteristics of offshore oilfield under the control of intra-layer heterogeneity.According to the principle of similarity and referring to the actual reservoir and fluid characteristic parameters of the oilfield,laboratory simulation experiments of water flooding and polymer flooding under different heterogeneity are carried out.The experimental results show that the length of anhydrous recovery period is inversely proportional to the degree of heterogeneity in the process of water flooding.When the heterogeneity is strong,the remaining oil in the low permeability layer is enriched,and the coefficient of variation is inversely proportional to the water flooding recovery.Compared with the water flooding development mode,polymer flooding can effectively inhibit the channeling effect in the high permeability layer,and effectively expand the spread volume.The oil recovery rate of different heterogeneity models during the same period can be increased,the final recovery rate can be increased by 13.01%~16.69%compared with water flooding.The recovery rate of polymer flooding is inversely proportional to the permeability grade.For the strong heterogeneous reservoir,there is still a lot of remaining oil in the low permeable layer after polymer flooding,so the strategy of tapping the adjusted well should be adopted.For the weak heterogeneous reservoir,the combination of regulation and plugging is adopted to change the direction of the main flow line.Through the implementation of targeted adjustment and potential tapping measures,the polymer flooding development effect of the oil field is obviously improved,which provides reference for offshore oil fields development of the same nature.