基于SEM、NMR和X-CT的页岩储层孔隙结构综合研究

运用扫描电镜、核磁共振和计算机断层扫描3种孔隙结构研究方法对页岩进行了实验分析。研究结果表明：(1)扫描电镜对于页岩样品的局部观察能力较强，能够直观地反映页岩样品的微观孔隙类型和形态等信息，经氩离子抛光后还可观察到样品的有机质纳米级孔隙，但扫描电镜对样品的总体情况反映能力不够完善；(2)核磁共振受岩石骨架的影响小，可以更精确地测定页岩的孔隙度，进行孔隙大小分布、孔隙连通性和可动流体分析，得到样品的总体特征，但对样品细节的反映较欠缺；(3)CT扫描能够定量分析页岩组分，通过三维重构技术建立页岩样品孔隙和高密度物质分布状况的三维模型，从宏观角度反映孔隙的形态和空间配置特征，其主要不足在于三维重构时CT数阀值的选择对结果具有一定影响。综合运用3种方法，才能更准确地对页岩储层孔隙结构进行研究，以得到更加完善的储层孔隙结构资料。

Comprehensive Study on Pore Structures of Shale Reservoirs Based on SEM,NMR and X-CT

Three types of pore-structure study methods including scanning electron microscope(SEM), nuclear magnetic resonance(NMR) and computer tomography(CT) scanning were used to analyze the shale. The research results show the following aspects: (1)SEM has a good ability of observation for the partial of shale and can directly reflect the information such as types, shapes of micro pores of shales; after argon-ion milling, nano-size pores are able to be observed; combined with ImageJ, the plane porosity can be obtained. But SEM cannot reflect the overall characteristics of samples very well. (2)The rock matrix makes little influence on NRM, so NMR can determine porosity and more accurately analyze the pore size distribution, pore connectivity and movable fluid saturation of shale. Through NMR, the overall characteristics of the samples can be gotten, but the details are not involved. (3)CT scanning is capable to do quantitative analysis for the shale component and to build a 3D model which shows the distribution of pores and high density matters in the shale by the 3D reconstruction technique, so macroscopic observation for the shape and spatial allocation of pores is available. One disadvantage of CT scanning is that the threshold choice has an influence on results of 3D reconstruction. Only with the comprehensive use of these three methods, can a more accurate analysis on the pore structure of shale reservoirs be done, as a result, a more perfect data of pore structures can be gotten.