基于三维数字岩心的碳酸盐岩电阻率数值模拟研究

项目名称： 基于三维数字岩心的碳酸盐岩电阻率数值模拟研究

项目编号： No.41204084

项目类型： 青年科学基金项目

立项/批准年度： 2013

项目学科： 地球物理学和空间物理学

项目作者： 刘学锋

作者单位： 中国石油大学（华东）

项目金额： 25万元

中文摘要： 碳酸盐岩的非均质性和各向异性导致经典的饱和度评价模型-阿尔奇公式不能直接应用。裂缝、孔洞发育段岩心破损严重，仅采用岩电实验难以研究其导电机理。首先，采用X射线CT建立岩心低分辨率三维图像，反映裂缝和孔洞信息。以高分辨率扫描电镜图像为基础，采用多点地质统计学重构基质孔隙的三维结构。通过尺度融合建立双孔隙三维数字岩心，并结合岩电实验结果，分析孔隙结构对岩石电阻率的影响规律。然后，采用数值模拟算法计算岩石电阻率，并与实验结果比较，验证算法的准确性。最后，从X射线CT建立的三维数字岩心中提取裂缝和孔洞的特征信息，随机生成具有不同裂缝孔隙度、孔洞孔隙度、基质孔隙度、裂缝倾角、润湿性等参数的双孔隙三维数字岩心。采用数值模拟方法研究孔隙结构对碳酸盐岩岩电参数的影响规律，分析不同孔隙系统的电阻率耦合关系。本研究将三维数字岩心技术拓展至非均质的碳酸盐岩储层，进而揭示其导电机理，有助于改进储层饱和度评价。

中文关键词： 数字岩心；电阻率；碳酸盐岩；数值模拟；

英文摘要： Archie equations have been widely applied in the evaluation of water saturation of homogeneous clastic. However, they are no more applicable for carbonate formation because of its heterogeneity and anisotropy. Carbonate resistivity experiments are not sufficient to investigate conductive mechanisms because the cores from fracture and vug interval are easily broken. Firstly, 3-D images with low resolution obtained by X-ray CT are used to gather the information of vug and fracture. 3-D structures of matrix pore are reconstructed by multi-points geostatistics (MPS) from 2-D SEM images of rock with high resolution. 3-D digital core with dual pore system is built by multi scale fusion. The effects of pore structure on carbonate resistivity are analyzed qualitatively based on 3-D digital cores and experimental results of resistivity. Secondly, the resistivities of carbonate are calculated by the finite element method and mathematical morphology and the algorithm is thus validated by comparing the measured resistivities with simulated results. Finally, the characteristic information of fractures and vugs are obtained from 3-D digital cores derived from X-ray CT experiments. The 3-D digital cores with dual pore systerm are synthesized by stochastic method, where fracture porosity, vuggy porosity, matrix porosity, fractu

英文关键词： Digital Rock；Resistivity；Carbonate；Numerical simulation；