致密砂岩储层微观孔隙结构特征分析——以鄂尔多斯盆地姬塬长7致密储层为例

The Characteristics of Microscopic Pore Structure——In Case of Chang7 Tight Sandstone Reservoir in Jiyuan Area of Ordos Basin

新安边致密油藏的发现表明鄂尔多斯盆地西部具有巨大的勘探潜力。通过铸体薄片、扫描电镜、常规压汞和恒速压汞,对鄂尔多斯盆地西部的姬塬地区长7致密砂岩储层微观孔隙结构进行分析,结果表明孔隙类型以粒间孔和长石溶孔为主,喉道以弯片状喉道为主,压汞曲线排驱压力高,中值压力中等,孔喉分选性差,孔隙半径和喉道半径狭小。常规压汞参数中分选系数、中值半径、排驱压力、退汞效率和物性相关性较好。

With the discovery of chang7 tight sandstone reservoir,the western of Ordos Basin has large exploration potential.This article researches the microscopic pore structure of Chang7 tight sandstone reservoir of Jiyuan Oilfield in Ordos Basin,by casting thin sections,SEM,conventional Hg injection technique and rate-controlled mercury penetration.Results show that the main types of pores in research area are feldspar dissolution pore and intergranular pore,and the types of throat are mainly tortuous sheet shape.The intrusive mercury curves indicate that the expulsion pressure is relatively high,and median value pressure is medium.The sorting feature of pore and throat is low,pore radius and throat radius of reservoir is narrow.In conventional Hg injection parameters,sorting feature,median radius,expulsion pressure,efficiency of mercury withdrawal,has obvious correlation with physical property.