古地理学报2025，Vol.27Issue(3)：714-730,17.DOI:10.7605/gdlxb.2025.02.007
海相富有机质页岩储集层特征、成因类型和机制:以川南长宁五峰组—龙马溪组为例
Characteristics,genetic types and mechanisms of marine organic-rich shale reservoirs:a case study of the Wufeng-Longmaxi Formations in Changning area,southern Sichuan Basin
摘要
Abstract
This study investigates the genetic mechanisms of marine organic-rich shale reservoirs through an integrated analysis of mineral composition,total organic carbon(TOC),porosity,gas content,and sedimentary paleogeomorphology in the Upper Ordovician Wufeng Formation(O3w)to Lower Silurian Longmaxi Formation(S1l1)within the Changning area,southern Sichuan Basin.The results show that:(Ⅰ)Carbonate minerals and siliceous minerals are mainly developed in the O3w,and the TOC,porosity and gas content of the shale are relatively poor;The shale in the bottom of S1l11 is dominated by siliceous minerals,and its TOC,porosity and gas content are the best.The upper S1l11 is dominated by clay minerals,and its TOC,porosity and gas content are poor.(Ⅱ)Marine shale reservoirs of O3w and S1l11 can be divided into three categories:matrix-porosity reservoirs(dominant in O3w,avg.porosity 3.1％),clay-fracture re-servoirs(prevalent in lower S1l11,avg.porosity 5.8％)and organic-porosity reservoirs(characteristic of upper S1l11,avg.porosity 2.3％).Organic-porosity reservoirs represent the optimal marine shale gas reser-voirs,characterized by high porosity and excellent gas-bearing capacity.(Ⅲ)The pre-depositional paleo-geomorphic pattern of the Longmaxi Formation is drawn based on the bottom interface of the lower Permian Liangshan Formation by the residual thickness and compensation thickness impression method.The compara-tive study of reservoir characteristics and paleogeomorphic pattern in the bottom of S1l11 proves that the pa-leouplift controls the high-quality source rocks,the slope area controls the high-quality reservoirs,and the distribution of brittle minerals is controlled jointly by the paleouplift and terrigenous input.Comprehensive analysis shows that the high quality shale gas reservoir mainly develops in the paleogeomorphic slope area.This systematic approach advances exploration strategies for marine shale reservoirs and enhances theoretical understanding of shale gas enrichment mechanisms in southern China.关键词
富有机质页岩/储集层特征/成因类型/成因机制/古地貌/奥陶系/四川盆地Key words
organic-rich shale/reservoir characteristics/genetic types/genetic mechanism/palaeogeomorphology/Ordovician/Sichuan Basin分类
能源科技引用本文复制引用
廖崇杰,陈雷,古志斌,刘丙晓,杨莉,谭秀成,熊敏,曹剑..海相富有机质页岩储集层特征、成因类型和机制:以川南长宁五峰组—龙马溪组为例[J].古地理学报,2025,27(3):714-730,17.基金项目
国家自然科学基金项目(编号:42372173)资助.Financially supported by the National Natural Science Foundation of China(No.42372173) （编号:42372173）
