Effect Of Crack Geometry On Effective Physical Properties Of Shale Model

Fully understanding the physical properties and mechanical properties of the shale that stored unconventional oil and gas is of great significance for improving the quality of shale oil and gas exploitation,the development efficiency,as well as reducing the cost.The investigation of the effective electrical properties and mechanical properties for the anisotropic shale model with cracks is an important foundation of unconventional oil and gas exploration and logging interpretation.This thesis establishes idealized shale physical models for shale reservoir with thin-layered structure and cracked characteristics.The Finite Element Method(FEM)and anisotropic physical tensor analysis were used to simulate effective electrical parameter tensor and mechanical parameter tensor of the shale model with spherical cracked structure,needle cracked structure and sheet cracked structure.The effect of cracked structure with different shapes on effective electrical parameter tensor and mechanical parameter tensor was analyzed.The rule of effective electrical characteristics of shale models with different cracked structures with the rotation angle of fractures was summarized.Meanwhile,according to the derived mapping relationship between electricity and mechanics theory,the shale model with cracked structure was analyzed from different dimensions.The relationship between mechanical parameters and electrical parameters of shale models with different cracked structures was summarized.The result showed the existence of cracks is one of the reasons for the anisotropy of the electrical properties of the shale model;With the change in angle between cracks and shale,The effective electrical characteristic tensor of shale models with different morphological cracked structures shows different changes;Combining the theoretical mapping between electricity and mechanics,the influence of mechanical parameters on effective electrical parameters under different cracked structures is also different.These researches conducted for the effective electrical properties of shale model will provide valuable theoretical reference for the broadband electromagneticlogging method and potential benefit to the inversion of shale oil and gas.