天然气勘探与开发2025，Vol.48Issue(6)：1-16,16.DOI:10.12055/gaskk.issn.1673-3177.2025.06.001
川中地区二叠系茅口组白云岩储层特征及成因机制
Characteristics and genetic mechanism of dolomite reservoirs in the Permian Maokou Formation,central Sichuan Basin
摘要
Abstract
The dolomite reservoirs of the Middle Permian Maokou Formation in the central Sichuan Basin are complex in genesis and unclear in key controlling factors,thereby restricting their exploration evaluation.To reveal its reservoir development mechanism,a comprehensive study was systematically conducted on the petrological characteristics of dolomite,the evolution of reservoir spaces,and multi-stage dolomitization processes according to the latest core data,employing methods such as core observation,thin-section identification,cathodoluminescence,and LA-ICP-MS geochemical analysis.The following results are obtained.First,the Maokou reservoirs in the study area are dominated by granular dolomite,followed by bioclastic dolomite and saddle dolomite.They are primarily porous-cavity reservoirs with the storage space consisting of intercrystalline pores,intercrystalline dissolution pores,and secondary cavities.High-quality intervals are concentrated in the middle to upper parts of Mao 2 Member,with net thicknesses reaching tens of meters.Second,the reservoir evolution is controlled by the synergy of dolomitization processes in three phases:(1)the contemporaneous-penecontemporaneous dolomitization,which kept the primary pores preserved;(2)the burial dolomitization,which generated abundant intercrystalline pore system,creating a precursor framework for later dissolution porosity;and(3)the tectonic-hydrothermal dolomitization,which exhibited dual effects of dissolution improvement and pore connectivity,except for the possible destruction of partial pores due to the filling by precipitated saddle dolomite.It is concluded that the burial granular dolomitization served as the key genetic mechanism of the Maokou reservoirs in the study area,and the later hydrothermal dissolution and tectonic rupture modified the reservoirs to improve their properties,regardless of the varying reworking intensity across areas.Specifically,the Moxi-Longnvsi area is more strongly influenced by tectonic-hydrothermal dissolution,resulting in a reservoir dominated by porous-cavity dolomite,while in the northern slope area,such process was relatively weaker,leading to the dominance of porous dolomite reservoirs.关键词
四川盆地中部/川中地区/二叠系中统茅口组/白云岩/储层特征/成因机制Key words
Central Sichuan Basin/Middle Permian Maokou Formation/Dolomite/Reservoir characteristics/Genetic mechanism分类
能源科技引用本文复制引用
肖钦仁,叶子旭,王佳琪,袁海锋,李天军,陈聪,匡明志,谌辰,王涛,弓永铭,许文龙..川中地区二叠系茅口组白云岩储层特征及成因机制[J].天然气勘探与开发,2025,48(6):1-16,16.基金项目
国家自然科学基金项目"川中安岳气田寒武系龙王庙组储层多期自生石英的地球化学演化及其流体历史重建"(编号:41872130). （编号:41872130）
