基于损伤力学的裂缝性储层流固耦合数值模拟

为了研究裂缝性储层裂缝的变形规律以及其对生产动态的影响,采用塑性损伤模型和双重孔隙介质模型相结合的流固耦合数值模拟方法,模拟了裂缝性储层注采过程中的裂缝和产量变化.采用迭代耦合方法模拟流体渗流与裂缝变形的耦合力学行为,并使用损伤变量从数学上表征储层裂缝的渗透率.分析了裂缝性储层开采时的损伤演化,获得了裂缝渗透率和地层压力的分布变化.结果表明,开采过程中地层裂缝逐渐闭合且渗透率降低,对产量造成不利影响.裂缝渗透率降低是导致地层产量下降的重要因素,裂缝性储层数值模拟时应考虑裂缝渗透率变化对生产带来的影响.

Numerical simulation for fluid-solid coupling based on damage mechanics in fractured reservoir

In order to study the deformation rule of fracture and its influence on the production performance of fractured reservoir, the changes of fracture and oil yield during the injection and production process of fractured reservoir were simulated by a numerical simulation method for the fluid-solid coupling under a model combining plastic damage and dual porosity medium. An iterative coupling method was adopted to simulate the coupling mechanical behavior of fluid flow and fracture deformation. The fracture permeability in the reservoir was mathematically expressed with the damage varibles. In addition, the damage evolution of fractured reservoir during the production was analyzed, and the distribution changes of both fracture permeability and stratum pressure were attained. The results suggest that the stratum fractures gradually close and the permeability decreases during the production process, which can bring negative influence on the oil yield. The decline of fracture permeability is a main factor for the drop of oil yield in the stratum. The influence of fracture permeability variation on the production should be considered in the numerical simulation of fractured reservoir.