鄂尔多斯盆地姬塬地区长8低渗透砂岩储层微观孔隙结构特征研究

摘要

以常规压汞、铸体图像、扫描电镜和薄片观察为基础，结合恒速压汞测试，对鄂尔多斯盆地姬塬地区长8低渗透砂岩储层微观孔隙结构特征进行研究。结果表明，姬塬地区长8储层孔隙类型多样，以残余粒间孔为主，孔隙结构可划分为4种类型。恒速压汞测试表明，姬塬长8储层为大孔细喉型。与特低渗透储层相比，超低渗透储层喉道分布范围更集中，小喉道所占比例更大，孔喉半径比分布范围更宽。特低、超低渗透储层差异主要体现在喉道的大小和分布上，喉道控制储层品质及渗流能力。在低渗透砂岩储层的开发中应尤其注重孔喉间的配置关系。%The microscopic pore structure of Chang 8 low-permeability sandstone reservoirs of the Yanchang Forma-tion in the Ordos Basin Jiyuan Area is thoroughly analyzed and investigated by using constant-speed mercury intrusion technology,combined with conventional constant-pressure mercury injection,cast image,scanning electron microscopy and slice observation.The result shows Chang 8 reservoirs has various pore type and the main type is residual intergranu-lar pore , the pore structure is divided into four categories. The reservoirs type of Chang 8 in Jiyuan Area is mainly large scale pore with thin throat.Compared with ultra-low permeability reservoirs,the throat distribution of super-low perme-able reservoirs is more concentrated,it has more narrow throat, the rang of pore-throat ratio is wider. The differences of pore throat characteristics between ultra-low and super-low permeable reservoirs mainly lay in throats, throats control the quality of reservoirs and its percolation capacity.In the process of low-permeability sandstone reservoirs develop-ment, we should pay more attention to the allocation relation between pore and throat.