沉积学报2025，Vol.43Issue(4)：1233-1250,18.DOI:10.14027/j.issn.1000-0550.2024.079
鄂尔多斯盆地乌拉力克组页岩孔隙空间影响因素及其页岩气地质意义
Factors Influencing Pore Space in Wulalike Formation Shale,Ordos Basin:Geological significance for shale gas
摘要
Abstract
[Objective]Investigating the coupling relationships between the differential characteristics of marine shale pore spaces and lithofacies,material composition,pore structure,as well as their implications for shale gas en-richment patterns,is crucial for evaluating the gas-bearing potential of the Wulalike Formation shale in the western Ordos Basin.[Methods]Taking the Wulalike Formation shale in the western Ordos Basin as the research object,and based on the classification of typical shale lithofacies,this study analyzed the influence of material composition,siliceous genesis,and pore structure on shale pore space through microscopy and scanning electron microscopy obser-vations,helium porosity,pulse permeability,nuclear magnetic resonance,nitrogen and carbon dioxide adsorption,and methane isothermal adsorption tests.The vertical enrichment intervals of shale gas were also investigated.[Results]In the study area,the porosity of the Wulalike Formation shale shows an increasing trend from the bottom to the top,with no significant correlation between porosity and permeability.Unlike the Longmaxi Formation shale,the target shale interval is generally characterized by high biogenic silica content and low total organic carbon(TOC).The biogenic silica primarily occupies medium-small pores.[Conclusions]The relatively poor hydrocarbon genera-tion capacity limits hydrocarbon accumulation in the Wulalike Formation shale.Biogenic silica acts primarily as ce-mentation reducing porosity rather than framework support enhancing porosity.The upper section of the target layer is predominantly mixed shale.Although it exhibits high clastic content and high porosity,it suffers from low TOC con-tent and poor hydrocarbon generation and expulsion capacity.Transitioning towards the bottom,it changes to biogen-ic silica-rich shale.Although this section has a relatively higher TOC content,the cementation effect of biogenic sili-ca adversely affects reservoir properties.Integrating the characteristics of pore space,it is suggested that the interbed-ded intervals of multiple shale lithofacies located above the zones where biogenic silica-rich shale develops are expect-ed to indicate potential shale gas enrichment zones even within the low TOC background.关键词
鄂尔多斯盆地/乌拉力克组/孔隙空间/页岩气/差异富集Key words
Ordos Basin/Wulalike Formation/pore space/shale gas/differential enrichment分类
天文与地球科学引用本文复制引用
刘刚,黄何鑫,吴越,侯芳,赵帮胜,张艳妮,吴小力,刘齐,马亚轩..鄂尔多斯盆地乌拉力克组页岩孔隙空间影响因素及其页岩气地质意义[J].沉积学报,2025,43(4):1233-1250,18.基金项目
国家自然科学基金项目(42302157) （42302157）
中央高校基本科研业务费专项资金项目(300102262903,300102262901)National Natural Science Foundation of China,No.42302157 （300102262903,300102262901）
Special Fund Project for Basic Research Business Expenses of Central Universities,No.300102262903,300102262901 （）
