古地理学报2025，Vol.27Issue(5)：1119-1136,18.DOI:10.7605/gdlxb.2025.067
四川盆地高石梯地区龙王庙组准层序微相组合及其孔隙成因差异性分析
Microfacies assemblages within parasequence stratigraphy and their differences in pore genesis of the Cambrian Longwangmiao Formation in Gaoshiti area,Sichuan Basin
摘要
Abstract
The Cambrian Longwangmiao Formation in the Gaoshti area of the Sichuan Basin is abundant in natural gas resources.However,studies on pore diversity among different beach bodies are still insufficient.Based on core observations and thin-section analysis,four distinct microfacies assemblages within the parasequences of the Longwangmiao Formation have been identified.These assemblages exhibit significant differences in diagenetic processes at various stages,particularly in the upper sections of each microfacies:(1)The sandstone shoal-oolitic shoal primarily develops intergranular dissolution pores due to meteoric freshwater dissolution,with porosity ranging from 2％to 6％.(2)The intershoal sea-sandstone shoal experiences both meteoric freshwater dissolution and dissolution during medium-deep burial stages,as well as extensive cementation,resulting in intergranular dissolution pores with porosity ranging from 1.5％to 5％.(3)The sandstone shoal-dolomite flat is influenced by meteoric freshwater dissolution,dissolution during medium-deep burial stages,and recrystallization,leading to the development of intergranular pores,intragranular dissolution pores,and intercrystalline dissolution pores with distinct pore size differentiation,exhibiting porosity ranging from 2％to 8％.(4)The medium-high energy sandstone shoal shows a strong correlation between burial dissolution intensity and late-stage cementation,resulting in intergranular dissolution pores with significant pore size variation,with porosity ranging from 1.4％to 5.8％.Therefore,the porosity of the four types of microfacies assemblages,ranked from highest to lowest,is as follows:sandstone shoal-dolomite flat(2％～8％),sandstone shoal-oolitic shoal(2％～6％),medium-high energy sandstone shoal(1.4％～5.8％),and intershoal sea-sandstone shoal(1.5％～5％).This study provides valuable insights into the types and evolutionary characteristics of secondary pores in rocks within the parasequences,which is crucial for evaluating the differences in various reservoir types.关键词
四川盆地/高石梯地区/龙王庙组/准层序/微相组合/成岩作用/孔隙成因Key words
Sichuan Basin/Gaoshiti area/Longwangmiao Formation/parasequence/microfacies assemblage/diagenesis/pore genesis分类
天文与地球科学引用本文复制引用
屈海洲,田伟,杨东凡,周刚,陈洋,张兴宇,何溥为,张云峰..四川盆地高石梯地区龙王庙组准层序微相组合及其孔隙成因差异性分析[J].古地理学报,2025,27(5):1119-1136,18.基金项目
国家自然科学基金项目(编号:41702163,42272181,42472174),中国石油—西南石油大学创新联合体科技合作项目(编号:2020CX010301)联合资助.[Co-funded by the National Natural Science Foundation of China(Nos.41702163,42272181,42472174),and Science and Technology Cooperation Project of the CNPC-SWPU Inno-vation Alliance(No.2020CX010301)] （编号:41702163,42272181,42472174）
