页岩气储层微观导电机理及导电模型研究

Macroscopic physical response of reservoir rock (such as electrical properties) is the result of the combined effects of a variety of micro-factors. Understanding the microscopic conductive mechanism and construct a conductivity model of shale rocks plays an important role on shale gas logging evaluation and identification. Shale rocks have the properties of low porosity and permeability, complex pore structure and mineral composition, thus conventional petrophysical experiments are difficult to reveal the relationship between formation conductivity and micro-factors, such as pore type, conductive mineral, clay and kerogen, those characteristics cause the difficulty of shale gas logging evaluation and identification. In this study, the digital rock models of shale gas reservoirs are constructed based on numerical construction method, supplemented by experimental construction method. Lattice Boltzmann method is used to simulate the distribution of fluid in the pores of different wettability. Finite element method is used to study the effect of pore type, conductive mineral, clay, kerogen on the electrical properties of shale rock and reveal the microscopic conductive mechanism and construct a conductivity model of shale rocks. The results will deepen shale gas reservoirs microscopic conductive mechanism understanding and lay foundation for shale gas log interpretation and evaluation.

储层岩石的宏观物理响应（如岩电特性）是各种微观因素综合作用的结果，探明页岩气储层微观导电机理，构建泥页岩导电模型对页岩气储层测井识别与评价具有重要作用。页岩气储层低孔低渗，孔隙结构复杂，矿物组成多样，常规岩石物理实验难以揭示页岩气储层导电性与孔隙类型及导电矿物、粘土矿物、干酪根等微观因素的关系，导致页岩气储层测井评价与识别困难。本研究拟采用“实验手段为辅，数值构建方法为主”的思路构建泥页岩数字岩心，利用格子玻尔兹曼算法模拟流体在不同润湿性孔隙中的分布，随后用有限元数值模拟算法研究孔隙类型、导电矿物、粘土矿物、干酪根等微观因素对页岩气储层电性的影响，探讨泥页岩储层电性微观响应机理，构建泥页岩导电模型。研究结果将加深对泥页岩储层微观导电机理的认识，为页岩气储层测井解释与评价奠定基础。

储层岩石的宏观物理响应（如岩电特性）是各种微观因素综合作用的结果，探明页岩气储层微观导电机理，构建泥页岩导电模型对页岩气储层测井识别与评价具有重要作用。页岩气储层低孔低渗，孔隙结构复杂，矿物组成多样，常规岩石物理实验难以揭示页岩气储层导电性与孔隙类型及导电矿物、粘土矿物、干酪根等微观因素的关系，导致页岩气储层测井评价与识别困难。本研究拟采用聚焦离子束-扫描电镜（FIB-SEM）技术构建泥页岩数字岩心，系统完成了FIB-SEM数字图像的处理，利用格子玻尔兹曼算法模拟流体在不同润湿性孔隙中的分布，随后用有限元数值模拟算法研究孔隙类型、导电矿物、粘土矿物、干酪根等微观因素对页岩气储层电性的影响，探讨泥页岩储层电性微观响应机理，构建泥页岩导电模型，将饱和度模型计算结果与实验结果进行了对比，具有较好地一致性，验证了模型的准确性。研究结果将加深对泥页岩储层微观导电机理的认识，为页岩气储层测井解释与评价奠定基础。