复杂断块油砂体剩余油分布半定量评价技术

Semi-quantitative Evaluation on Remaining Oil Distribution in Oil-sand Body of Complex Fault-block Reservoirs

复杂断块油藏由于断层的切割作用,断块小,形态各异,油水关系复杂。经过长期注水开发后,进入中高-高含水开发阶段,剩余油在空间上分布十分复杂,挖潜难度越来越大。断块油藏的复杂性,给储层建模带来很大的困难,数值模拟工作难度大,精确度低,难以准确描述剩余油分布。提出了基于油砂体的剩余油定性到半定量评价技术,为复杂断块油砂体剩余油预测提供了新的技术手段。该方法是在小层油砂体图编制和油砂体储量评价基础上,对油井采出量和水井注入量进行劈分,将采出量和注入量落实到油砂体,以此为基础对油砂体的注采状况进行分析,明确油砂体的采出程度、总体水淹程度,确定油砂体内部水淹差异状况,编制油砂体水淹图,半定量表征水淹特征,定性-半定量指出油砂体内剩余潜力的纵向和平面分布,为油田进行下步综合治理提供依据。

Fault blocks were small and had different shapes,and oil-water relationship was very complex because of the segmentation of faults in complex fault-block reservoirs.After secular water-injection development at medium-high and high water cut stage,remaining oil distribution was complex in space,it was more difficult for tapping the potential.For the complex property of fault-block reservoirs,the reservoir numerical simulation was very difficult with low simulation accuracy,so it was hard for precisely describing the distribution of remaining oil.Qualitative to semi-quantitative assessment technique of remaining oil evaluation was proposed based on oil sand body,it provided a new technology for forecasting remaining oil distribution of oil sand body in complex fault-block reservoirs.On the base of preparing oil sand body diagram and evaluating oil sand body reserves,the production of oil well and water-injection rate are separated and the production and injection rate of oil sand body are calculated.After confirming recovery percent and water-out degree,water-out diagrams of oil sand body are drawn for semi-quantitatively describing water-out feature and qualitative and semi-quantitatively pointing out the distribution of remaining oil potential.It provides a basis for accurate description of remaining oil distribution for next reservoir development.