基于沉积特征和冲刷程度的注采优化研究

Study on injection-production optimization based on sedimentary characteristics and scour degree

为了提升BS窄条带稠油油藏注水开发效果,针对高含水阶段局部注水突进严重、不同区域注采优化措施增油效果差异变大的问题,从研究砂体沉积微相入手,系统分析了分流河道与河坝复合砂体沉积韵律及展布特征;根据动静态参数及测试资料,建立了表征砂体水洗差异的储量冲刷程度与表征储层物性变化特征的渗透率时变系数的关系图版,提高了判定任意时刻储层任意位置渗透率动态变化的准确性。研究表明,随着注入水持续冲刷,分流河道中部储层渗透率增大,河道边部储层渗透率减小;河坝复合砂体主干河道渗透率有一定增大,但增幅较小;河坝复合砂体主体部位渗透率有一定减小,坝缘渗透率有明显降低。提出了“两变化、三加强、两控制”的控水增油调整措施策略。现场实施注采优化措施84井次,累增油19.6×10^(4)m^(3),油田含水率下降0.9%,取得了较好的控水增油效果。研究结果可为类似窄条带稠油油藏高含水期提升开发效果提供参考。

In order to improve the effect of water control and oil stability of BS narrow strip sand body, starting from the study on sedimentary microfacies of sand body, the rhythm and distribution characteristic parameters of distributary channel and river bar composite sand body are systematically analyzed. Based on the dynamic and static parameters and test data, the relationship between the degree of reservoir flushing, which characterizes the difference of sand washes, and the time-varying coefficient of permeability, which characterizes the physical properties of the reservoir, was established to improve the accuracy of determining the dynamic change of permeability at any location in the reservoir at any time. The results show that with continuous scouring, the permeability of the middle part of the distributary channel increases further and the permeability of edge of the distributary channel decreases. The permeability of the main channel of the river bar composite sand body is increased to some extent, but the amplitude is small. The permeability of the main part of the river bar composite sand body is decreased to some extent, and the permeability of the dam edge is obviously weakened. According to the change characteristics, the injection and production optimization adjustment strategy of “two changes, three strengthening and two controls” was put forward, which guided the implementation of the injection and production optimization measures for 84 Wells. The accumulative oil increase was 19.6×10^(4) m^(3), and the water cut rate in the oilfield decreased by 0.9 %, which provided a reference for the stable production of oilfields of the same nature in high water cut period.