复杂断块油藏砂体连通性对水驱效果的影响

Influence of Sandbody Connectivity in Complex Fault Block Reservoirs on Water Flooding Effect

复杂断块油藏沉积环境变化快,储层的非均质强,砂体连通性是其主要影响因素之一。基于实际油藏砂体连通方式,归纳出表征砂体连通状况的3种概念模型,依据砂体垂向连通和侧向连通程度建立相应的地质模型,采用数值模拟方法建立多个水驱单元理论模型,以累计产油量、注入量、地层压力和含油饱和度流线形态特征作为评价指标,分析得出对于砂体连通形式A和B,连通系数越大,日产油量和累计产油量越高,压力传播越快;对于砂体连通形式C,垂向渗透率大小对水驱开发效果影响较大,垂向渗透性较小时,不同连通系数下水驱开发效果差别越明显。因此,在不同连通程度下,油藏的水驱开发效果存在较大差异,该研究对复杂断块油藏后期剩余油挖潜具有一定的指导意义。

Complex fault block reservoirs are characterized by fast changing sedimentary environments and strong servoir heterogeneity, and the connectivity of sandbody is one of the main influential factors. In this paper, three conceptual models characterizing the connectivity of sandbody were summarized based on the connection patterns of actual sandbodies in oil reservoirs. Then, the corresponding geologic models were established according to vertical and lateral connection degree of sandbodies. The theoretical model of multiple water flooding units was developed by means of numerical simulation. The corresponding sandbody connection patterns A and B were established with the streamline morphological characteristics of oil saturation, cumulative oil production, injection rate and reservoir pressure as the evaluation indicators. In these two patterns, daily oil production, cumulative oil production and pressure propagation velocity increase with the increasing of connectivity factor. In sandbody connection pattern C, water flooding development effects are more affected by vertical permeability. When the vertical permeability is low- er, water flooding development effects corresponding to different connectivity factors are more different. To sum up, water flooding development effects of oll reservoirs vary largely with the connection degrees. The research results can be used as the reference for tapping the potential of remaining oil in complex fault block reservoirs in the late devel- opment stage.