页岩储层多尺度数字岩心和孔缝网络模型升级方法研究

Nano-micro pore and micro-fractures are developed in shale formation, the storage space size distributes from 1nm to 1mm, which crosses six orders of magnitude and could not be described by the single scale digital rock analysis technology. Due to the multi-scale storage space characteristics in shale formation, low resolution micro-CT is used to capture micro-fracture characteristics, micro-fracture network is extracted and analyzed quantitatively. Then, high resolution micro-CT and FIB-SEM are used to construct micro pore digital rock and nano pore digital rock respectively, and the corresponding pore networks are extracted. Based on nano-micro pore conductivity equation and matrix pore – micro fracture conductivity equation, the multi-scale digital rock and pore network upscaling method is proposed to construct multi-scale digital rock and pore network in shale formation, and calculate multi-scale pore – micro-fracture petrophysical and flow parameters accurately, this method is verified with comparison of several parameters which could be measured by lab measurements. This project could build the research platform for matrix pore - micro-fracture study, reveal multi-scale storage structure and flow characteristics in shale formation, and guide the shale oil/gas exploration and development plan.

页岩储层发育微纳米孔隙和微裂缝，尺度从1nm~1mm，单一尺度的数字岩心分析技术不足以描述页岩储集空间6个数量级的多尺度特征。针对页岩储层储集空间的多尺度特征，基于低精度微米CT扫描识别表征页岩岩心微裂缝，提取微裂缝网络进行定量分析；基于高精度微米CT和聚焦离子束扫描电镜(FIB-SEM)分别构建微米孔隙数字岩心和纳米孔隙数字岩心，并提取相应的孔隙网络模型；在此基础上，基于微纳米孔隙传导方程和基岩孔隙-微裂缝传导方程，提出页岩多尺度数字岩心和孔隙网络模型的整合升级方法，构建页岩基岩孔隙-微裂缝多尺度网络模型，在岩心尺度上精确计算页岩多尺度孔隙-微裂缝的物性参数和渗流参数，并通过室内实验能够获取的部分页岩物性参数对比验证该整合方法的正确性，建立页岩岩心基岩孔隙-微裂缝多尺度特征的研究平台，揭示页岩岩心的多尺度储集空间结构特征和渗流规律，指导页岩油气勘探和开发方案的制定。

页岩储层发育微纳米孔隙和微裂缝，尺度从1nm~1mm，单一尺度的数字岩心分析技术不足以描述页岩储集空间6个数量级的多尺度特征。针对页岩储层储集空间的多尺度特征，基于低精度微米CT扫描，获取反映页岩天然微裂缝特征的三维扫描图像数据体，进而识别表征微裂缝，提取微裂缝网络，对微裂缝的结构特征进行定量描述。基于高精度微米CT和聚焦离子束扫描电镜，获取反映页岩微米尺度和纳米尺度孔隙特征的三维扫描图像数据体，分别构建微米孔隙数字岩心和纳米孔隙数字岩心，并提取三维微米孔隙网络模型和纳米孔隙网络模型，基于微纳米孔隙传导方程，将纳米孔隙网络模型中的纳米孔隙传导特性整合到微米孔隙网络模型中的基质相中，构建出页岩基岩微纳米多尺度孔隙网络模型。在此基础上，基于微纳米孔隙传导方程和基岩孔隙-微裂缝传导方程，提出页岩多尺度整合升级方法，构建页岩基岩孔隙-微裂缝多尺度网络模型，在岩心尺度上精确计算页岩多尺度孔隙-微裂缝的物性参数和渗流参数，并通过室内实验能够获取的部分页岩物性参数对比验证该整合方法的正确性，建立页岩岩心基岩孔隙-微裂缝多尺度特征的研究平台，揭示页岩岩心的多尺度储集空间结构特征和渗流规律，指导页岩油气勘探和开发方案的制定。