地质学报2025，Vol.99Issue(4)：1369-1380,12.DOI:10.19762/j.cnki.dizhixuebao.2023191
海相页岩顺层裂缝充填脉体生长模式及其地质意义
Growth model and geological significance of bedding-parallel fracture veins in marine shale:A case study of the Wufeng-Longmaxi formations shale in southern Sichuan basin
摘要
Abstract
Bedding-parallel fractures are widely developed in organic-rich shale,which are important reservoir space and lateral migration channel of shale gas,affecting the migration,enrichment,preservation of shale gas and the fracturing effect of reservoir.However,due to the complex formation mechanism of bedding-parallel fractures,it is difficult to accurately evaluate their impact on shale gas.This study takes the shale from the Wufeng-Longmaxi formations in the southern Sichuan basin as an example.Based on field,core,thin section,and scanning electron microscopy data,the macroscopic characteristics of bedding-parallel fractures and the microstructure characteristics of filling veins were studied,and the formation mechanism of bedding-parallel fractures was analyzed.Bedding-parallel fractures of the Wufeng-Longmaxi formations in the southern Sichuan basin are well-developed,mostly filled with striped calcite and quartz minerals.Bedding-parallel fractures contain three important microstructures,namely crack-seal bands,inclusion trails,and elongate crystals.The number of crack-seal bands can indicate the times of fracture opening.The inclusion trails can track the opening trajectory of fracture.According to the different driving forces of fracture opening during the formation of veins,bedding-parallel fracture veins can be divided into three types:fluid overpressure type,tectonic compression type,and tectonic-fluid overpressure type.During the growth of bedding fractures,they can serve as lateral migration channels for shale gas,which is helpful for the migration of shale gas to higher parts of the structure.The contact surface between the vein and the host rock is a mechanical weak surface which have a significant impact on the hydraulic fracturing effect.关键词
顺层裂缝脉体/张开-愈合条带/包裹体痕迹/页岩/四川盆地/龙马溪组Key words
bedding-parallel fracture vein/crack-seal band/inclusion trail/shale/Sichuan basin/Longmaxi Formation引用本文复制引用
田鹤,李彦佑,杨雪,李度,李跃纲,曾联波,李虹,陈丽清,伍秋姿,殷樱子,朱逸青,徐亮..海相页岩顺层裂缝充填脉体生长模式及其地质意义[J].地质学报,2025,99(4):1369-1380,12.基金项目
本文为中石油股份公司科技专项(编号2023ZZ21)和西南油气田公司科技项目(编号20220304-03)联合资助的成果. （编号2023ZZ21）
