海相油气地质2025，Vol.30Issue(6)：563-574,12.DOI:10.3969/j.issn.1672-9854.2025.06.003
开江—梁平海槽二叠系吴家坪组页岩孔隙非均质性及地质意义
Heterogeneity and geological significance of shale pores of the Permian Wujiaping Formation in Kaijiang-Liangping Trough,Sichuan Basin
摘要
Abstract
Taking the marine shale of the Permian Wujiaping Formation in the Kaijiang-Liangping Trough,Sichuan Basin as the research object,this study quantitatively characterizes the pore structure characteristics of different shale lithofacies through experimental analyses such as X-ray diffraction(XRD),gas adsorption,and high-pressure mercury intrusion(HPMI).Based on equations like V-S and FHH,the fractal dimensions of shale pores are calculated to reveal the pore heterogeneity characteristics of shale reservoirs.Furthermore,the influencing factors and geological significance of pore development heterogeneity in different lithofacies are clarified.The results show that:(1)The lower part of the Wujiaping Formation consists of argillaceous shale,which transitions upward into mixed shale and eventually evolves into siliceous shale in the upper section.Correspondingly,the dominant pore types shift progressively from clay mineral intercrystalline pores to dissolution pores,brittle mineral intercrystalline pores,and organic matter pores.(2)The pores of siliceous shale are dominated by nanoscale organic pores,and their development characteristics are controlled by the distribution morphology and abundance differences of organic matter,showing significant heterogeneity.This results in the highest fractal dimension of micropores in siliceous shales.The mixed shale primarily contains mesopore-scale intercrystalline and dissolution pores,with pore development strongly influenced by diagenetic processes and exhibiting a discrete distribution,leading to the highest fractal dimension of mesopores in this lithofacies.Clay minerals are prone to deformation due to compaction,which makes argillaceous shale highly heterogeneous at the macropore-scale.(3)The TOC content has the greatest influence on the mesopore fractal dimension of siliceous shale,while the macropore fractal dimension increases with the increase of clay mineral content.Comprehensive analysis suggests that highly to moderately organic-rich siliceous shale has the highest overall fractal dimension and strongest adsorption effect on shale gas,making it the dominant lithofacies of the Wujiaping Formation in the Kaijiang-Liangping Trough.关键词
页岩/孔隙结构/非均质性/分形维数/吴家坪组/开江—梁平海槽Key words
shale/pore structure/heterogeneity/fractal dimension/Wujiaping Formation/Kaijiang-Liangping Trough分类
能源科技引用本文复制引用
袁乐欣,徐志明,孙豪飞,路俊刚,尹相东..开江—梁平海槽二叠系吴家坪组页岩孔隙非均质性及地质意义[J].海相油气地质,2025,30(6):563-574,12.基金项目
本文受国家自然科学基金项目"烃源岩早期产物对致密油充注聚集的控制机理研究"(编号:42072185)资助 （编号:42072185）
