油藏非均质性对聚合物驱开发效果的影响

Impact of plane heterogeneity of oil reservoir on development effect of polymer flooding

聚合物驱是水驱后进一步提高原油采收率的三次采油技术,在不同类型油藏中均取得了较好的应用效果。聚合物驱开发过程中,油藏非均质性对聚合物驱的驱替效果有较大影响。基于油藏沉积微相展布形态,归纳出储层渗透率平面非均质性、厚度平面非均质性和几何形态非均质性等3类油藏非均质性。应用油藏数值模拟方法建立3类多个理论地质油藏模型,并且在每一类模型具有相同的生产约束条件下,研究了油藏非均质性对聚合物驱不同注采井网驱替效果的影响。研究结果表明,同一模型在相同工作制度和不同注采方式下,初期产油量和累积产油量存在较大差别。对于储层厚度平面非均质性油藏,厚注薄采的聚合物驱开发效果优于厚采薄注;对于渗透率平面非均质性油藏,高注低采的聚合物驱开发效果优于高采低注;对于几何形态的非均质性油藏,宽采窄注的聚合物驱开发效果优于宽注窄采。因此,合理地部署注采井网能有效地提高油藏聚合物驱的开发效果。

Polymer flooding is a tertiary oil recovery technique for EOR after water flooding,which has been applied in different types of oil reservoirs achieving good results. The polymer flooding effect would be affected a lot due to plane heterogeneity in the development. Three kinds of heterogeneous models including permeability,thickness and geometry form were proposed based on the distribution characteristics of the sedimentary micro-facie of certain reservoir. Three types of theoretical reservoir simulation models were built by applying the method of reservoir numerical simulation. The polymer flooding effect of different injection-production patterns was studied under the production conditions of each model. The research result shows that cumulative oil production and initial daily oil production were different at distinct injection-production pattern at the same working system. For the thickness heterogeneity reservoir,the reservoir with injector located in thicker layer and producer located in thinner layer has a better development effect than the contrary pattern. For the permeability heterogeneity reservoir,the reservoir with injector located in higher permeability and producer located in lower permeability has a better development effect than the contrary pattern. For the geometry form heterogeneity reservoir,the reservoir with injector located in narrow zone and producer located in wide zone has a better development effect than the contrary pattern.Injection-production pattern should be optimized to improve development effect of the polymer flooding.