鄂尔多斯盆地延安地区山西组泥页岩孔隙表征

Pore characterization of shale in Shanxi Formation, Yan'an area, Ordos Basin

王子龙 郭少斌

WANG Zilong GUO Shaobin

中国地质大学(北京) 能源学院, 北京 100083

School of Energy, China University of Geosciences, Beijing 100083, China

以鄂尔多斯盆地延安地区上古生界二叠系山西组泥页岩储层为研究对象，通过核磁共振、扫描电镜、高压压汞、氮气吸附以及二氧化碳吸附等实验，对泥页岩储层进行了详细的全孔隙表征。研究区山西组主要发育粒间孔、粒内孔、裂缝及有机质孔四类孔隙类型，以粒内孔和有机质孔居多。核磁共振T2谱曲线多以单峰分布，离心后曲线几乎无变化，说明样品中含有较多的纳米级孔隙，并且连通性较差。高压压汞、氮气吸附、二氧化碳吸附实验表明，孔隙体积以中孔和宏孔为主，二者占孔总体积的85%左右，微孔仅占总孔体积的15%；而比表面积主要由微孔和中孔提供，微孔占总比表面积的51.94%，中孔占47.98%，二者占总比表面积的99%以上，宏孔可以忽略不计；样品孔隙形态以两端开孔或狭缝型的平行板孔为主。

The shale reservoirs in the Upper Paleozoic Shanxi Formation in the Yan'an area of the Ordos Basin were studied. The whole porosity of the shale was characterized in detail using NMR, SEM, high pressure mercury intrusion, nitrogen adsorption and carbon dioxide adsorption. The Shanxi Formation in the Yan'an area mainly developed four types of porosity, i.e. fractures, intergranular, intragranular pores, and organic pores, with intragranular and organic pores in the majority. The T2 NMR curves are mostly single-peaked and almost unchanged after centrifugation, indicating that the samples are dominated by nano pores with poor connectivity. High pressure mercury intrusion, nitrogen adsorption and carbon dioxide adsorption experiments showed that the pore volume is mainly meso pores and macro pores, accounting for about 85% of the total pore volume, while micro pores only account for 15% of the total pore volume. The specific surface area is mainly provided by micro pores and meso pores, with micro pores accounting for 52% of the total specific surface area, followed by meso pores accounting for 48%. Macro pores can be neglected when the surface area is more than 99%. The pore morphology of the samples is mainly parallel plate pores with openings or slits at both ends.

国家科技重大专项“不同类型页岩气生成机理与富集规律研究”（2016ZX05034-001）资助。

https://doi.org/10.11781/sysydz201901099