鄂尔多斯盆地延长地区山西组页岩储层特征及影响因素

利用氩离子抛光片进行SEM观测，从微观尺度分析了鄂尔多斯盆地延长地区山西组页岩储层中的储集空间类型及其对应孔径发育情况；采用氦气膨胀法、压汞法、低压氮气吸附、二氧化碳吸附、核磁共振等定量化的测试手段，利用全孔径孔隙结构定量表征方法，对该储层物性和孔隙结构进行了测试分析，确定了不同岩石类型的孔隙结构特征；进一步结合储层的岩石矿物学特征和地化特征，从不同尺度讨论了影响山西组储层孔隙发育和保存的各种地质因素。结果显示：山西组泥页岩层系中不同类型岩石的孔隙类型、孔径和孔隙度等均存在差异，同一类型岩石中不同类型孔隙的孔径及发育特征也有所不同。粉砂质页岩有机质含量（沥青含量）是决定其孔隙度和中大孔发育的决定性因素。在低TOC页岩中，石英长石含量是影响孔隙度的最主要的因素，呈正相关性。有机质含量对于高TOC黏土质页岩孔隙度具有正向的影响，而刚性颗粒粒径和黏土矿物含量则表现出明显的负向影响。

Reservoir porosity characteristics and controls of the Shanxi Formation shale reservoir,Yanchang area,Ordos Basin

The micro-scale shale reservoir porosity type and the corresponding pore size distribution of the Shanxi Formation in the Yanchang exploration area of the Ordos Basin were analyzed using argon ion polished sections for SEM observation. Helium gas expansion, mercury injection, low pressure nitrogen adsorption, carbon dioxide adsorption, nuclear magnetic resonance (NMR) tests and full pore-size quantitative characterization were applied to study the reservoir physical properties and the pore structure of various rock types. Various geological factors influencing the reservoir pore development and preservation of the Shanxi Formation were discussed from different aspects combined with the mineralogical and geochemical characteristics of reservoir rocks. Results showed that there were differences in pore types, pore sizes and porosity of different rock types of the Shanxi mud shale formation, and there were differences in pore size and development characteristics of different pore types of the same rock type. The organic matter content (asphalt content) of silty shale was decisive for porosity and middle-large pore development. In low TOC shale, quartz feldspar content is a main factor that affects porosity, showing a positive correlation. Organic matter content has a positive influence on the porosity of the high TOC argillaceous shale, while rigid particle size and argillaceous mineral content show a clear negative relationship.