岩石塑性对超深储层裂缝闭合的影响研究

为了分析岩石塑性对生产过程中裂缝闭合的影响,在Herz接触模型基础上,采用Drucker-Prager屈服准则,建立了弹塑性裂缝闭合模型,分析了不同地应力和岩石塑性参数对裂缝闭合行为的影响。结果表明:弹性模量、硬化参数和粘聚力是影响塑性裂缝闭合的关键因素。粘聚力越大,初始屈服应力就越大。硬化参数与弹性模量的比值越大,后继屈服应力越大,裂缝闭合塑性效应越弱。另外,地应力对裂缝闭合也有较大的影响,在裂缝面法向上的正应力越大,裂缝闭合塑性效应系数越高。

Research on the Influence of Rock Plasticity on Fracture Closure in Ultra Deep Reservoirs

In order to analyze the impact of rock plasticity on crack closure during production, an elastic-plastic crack closure model was established using the Drucker Prager yield criterion based on the Herz contact model. The effects of different in-situ stresses and rock plasticity parameters on the crack closure behavior were analyzed. The results indicate that the elastic modulus, hardening parameters, and cohesion are key factors affecting the plastic crack closure. The greater the cohesion, the greater the initial yield stress. The larger the ratio of hardening parameters to the elastic modulus is the greater the subsequent yield stress, and the weaker the plastic effect of crack closure. In addition, the in-situ stress also has a significant impact on crack closure. The higher the normal stress in the normal direction of the crack surface, the higher the plastic effect coefficient of crack closure.