致密砂岩油藏注采开发流固耦合数值模拟

摘要

In order to determine the deformation pattern of pore-fracture medium during injection and production process of tight sandstone reservoirs and the effect of fluid-solid coupling on the production performance of tight sandstone reservoirs, a dynamic model is built for physical parameters of pore-fracture medium based on the deformation process between matrix and fractures during injection and production process of tight sandstone reservoirs.In combination with multiphase filtration model and geomechanical model, this model forms a fluid-solid coupling mathematical model, which is solved with iteration method.Fluid-solid coupling in the reservoir is investigated by numerical simulation of the injection-production process of a typical tight oil block in Middle Sichuan.The results show that during the injection-production process of tight sandstone reservoirs, matrix near injection wells swells, fractures open and physical properties improve significantly, while near production wells, matrix shrinks, fractures close and physical properties gradually decease, indicating the bad influence of fluid-solid coupling on productivity index.The research provides guidance for the efficient development of tight sandstone reservoirs.%为揭示致密砂岩油藏在注水与采油过程中孔缝介质的变形规律,研究流固耦合作用对致密砂岩油藏生产动态的影响,基于致密砂岩油藏注采过程中基质与裂缝的变形作用过程,建立了孔缝介质物性参数动态模型,与多相渗流模型及地质力学模型共同组成了致密砂岩油藏流固耦合数学模型,采用迭代方法对耦合模型进行了求解.通过对川中典型致密油区块多井注采过程的数值模拟,研究了储层的流固耦合作用.研究结果表明:致密砂岩油藏注采过程中,注水井附近基质膨胀,裂缝开启,物性显著增加;采油井附近基质收缩,裂缝闭合,物性逐渐减小,说明流固耦合作用对产能指标造成不利影响.该研究为致密砂岩油藏的高效开发提供了借鉴.