合水地区长7致密砂岩储层微观孔喉结构分形特征

Fractal characteristics of microscopic pore?鄄throat structures of Chang 7 tight sandstone reservoirs, Heshui area, Ordos Basin

谢启超 冯波 宋鹏 刘广峰 刘建 张腾换3

中国石油长庆油田分公司勘探开发研究院，陕西 西安 710018 低渗透油气田勘探开发国家工程实验室，陕西 西安 710018 中国石油大学（北京）油气资源与探测国家重点实验室，北京 102249

Exploration and Development Research Institute, Changqing Oilfield Company, Petrochina, Xi′an 710018, China National Engineering Laboratory for Exploration and Development of Low?鄄Permeability Oil & Gas Fields, Xi′an 710018, China State Key Laboratory of Petroleum Resource and Prospecting, China University of Petroleum, Beijing 102249, China)

致密砂岩油藏储量丰富，前景广阔，但开发过程中存在许多问题；因此，开展致密储层微观孔喉结构的研究具有重要意义。针对鄂尔多斯盆地合水地区长7致密砂岩储层，在开展18块岩心高压压汞实验的基础上，研究了致密储层的微观孔喉结构及其分形特征。研究发现，合水地区长7储层的喉道半径主要分布在10-2~100 μm，岩石孔喉结构存在两段分形和三段分形特征。储层物性与总分形维数无明显相关性，但储层孔喉特征参数与总分形维数存在一定相关性，表明了研究区孔喉结构的复杂性，可以用分形维数表征孔喉结构的非均质性。

Tight sandstone reservoirs are rich in reserves and have broad prospects, but there are many problems in the development process. Therefore, it is of great significance to carry out research on the microscopic pore throat structure of tight oil. In this paper, based on the 18 high?鄄pressure mercury intrusion experiments conducted in the Chang 7 tight sandstone reservoir in Heshui area of Ordos Basin, the fractal characteristics of the microscopic pore throat structure of the tight reservoir were studied. The study found that the throat radius in this area is mainly between 0.010￣1.000 μm, and there are two fractal and three?鄄stage fractal features in the pore throat structure in Heshui Chang 7 Formation. There is no obvious correlation between fractal dimension and reservoir physical properties but a certain correlation between the fractal dimension and structural parameters of the pore throat is existed, indicating the complexity of the pore?鄄throat structure in this area and the fractal dimension can be used to characterize the heterogeneity of the micro pore throat structure of the reservoir.

10.6056/dkyqt201902017