基于应力敏感与基质收缩效应的低渗油藏数值模拟方法及应用

Numerical Modeling Method of Low-permeability Reservoir Based on Stress Sensitivity and Matrix Shrinkage Effect and Its Application

低渗透油藏开发往往仅考虑应力敏感效应而忽略基质孔隙收缩效应的影响,导致储层渗流能力和产能评价结果误差较大。针对上述问题,运用油藏工程方法,建立了考虑应力敏感和基质收缩双重效应影响的数学模型,结合基于分形理论的渗透率演化模型,探讨其在安塞油田预测生产动态的可行性。研究表明:在低于5 MPa的有效应力下,若忽视基质收缩效应会低估储层渗透率,影响开发方案的后期调整;文中建立的理论模型与实际生产数据匹配性达到92%,说明该模型可较好地预测研究区油井生产动态。研究成果对长庆油田类似低渗透油藏开发后期挖潜调整具有重要指导意义。

In low-permeability reservoirs,stress sensitivity effect is often considered while matrix pore shrinkage effect is ignored,resulting in great errors in the evaluation results of reservoir permeability and productivity.To address the above problems,a mathematical model considering the effects of both stress sensitivity and matrix shrinkage was established with reservoir engineering methods,to explore its feasibility in predicting production performance in the Ansai Oilfield,in combination with a permeability evolution model based on fractal theory.The study showed that under the effective stress below 5 MPa,if the matrix shrinkage effect was ignored,the reservoir permeability was underestimated,which affected the later adjustment of the development plan;the theoretical model established in this paper matched the actual production data by 92%,indicating that the model can better predict the production performance of oil wells in the study area.The study results can be used as an important reference for the late tapping potential and adjustment of similar low-permeability reservoirs in Changqing Oilfield.