海相油气地质2024，Vol.29Issue(2)：136-146,11.DOI:10.3969/j.issn.1672-9854.2024.02.003
四川盆地中部合川—潼南地区茅二下亚段白云岩储层特征及成储机制
Characteristics and formation mechanism of dolomite reservoirs in the lower submember of Maokou Member 2 in Hechuan-Tongnan area,central Sichuan Basin
摘要
Abstract
The Middle Permian Maokou Formation is an important stratigraphic series for increasing reserves and production in Sichuan Basin.The preliminary exploration mainly focused on the limestone fissure type reservoirs related to the weathered crust at the top of the Maokou Formation.In recent years,with the breakthrough of a series of high-yield wells in the central Sichuan region,the significant exploration potential in dolomite of the Maokou Member 2 has been demonstrated,including the intraplatform shoal dolomite reservoir of the lower member of Permian Maokou Member 2 in Hechuan-Tongnan area,while the strong reservoir heterogeneity restricts the further exploration.Based on core and thin section observation,physical property experiments and geochemical analysis,the basic characteristics of dolomite reservoir of the lower submember of Maokou Member 2 in Hechuan-Tongnan area are systematically analyzed,and the genesis and formation mechanism of dolomite reservoir are discussed.The results show that the dolomite reservoir of lower submember of Maokou Member 2 consists of pinhole dolomite and vuggy dolomite,and the reservoir space is characterized by intercrystal(dissolved)pore,karst cave and fracture as the main seepage channel.The reservoir type is mainly fracture-vuggy reservoir,and secondly fracture-pore reservoir.The average porosity and permeability of pinhole dolomite of the full diameter sample are 2.50%and 0.806×10-3 μm2,and these of vuggy dolomite are 4.32%and 1.047×10-3 μm2.Combined with previous sedimentation and diagenesis research,it is considered that the high energy shoal facies is material base for reservoir development and multi-stage karstification is the key for the formation of high quality reservoir.Penecontemporaneous dolomitization is the key to reservoir space preservation by enhancing the compaction resistance of rocks.The late hydrothermal dolomitization of Maokou Formation related with the Dongwu Movement(Emei taphrogenesis in the upper-Yangtze region)in the late Middle Permian is dominated by cementing and filling early pores,which reduces the reservoir performance of dolomite.This study provides a basis for predicting the distribution zone of high-quality reservoirs in Maokou Formation.关键词
白云岩/储层特征/成储机制/茅口组/四川盆地Key words
dolomite/reservoir characteristics/formation mechanism/Maokou Formation/Sichuan Basin分类
能源科技引用本文复制引用
印长海,肖笛,李明隆,杨文杰,师江波,谭秀成,王显东,田小彬,鞠林波,韦裕琳,汪海燕,谭万仓..四川盆地中部合川—潼南地区茅二下亚段白云岩储层特征及成储机制[J].海相油气地质,2024,29(2):136-146,11.基金项目
本文受中国石油集团有限公司上游领域基础性前瞻性项目"残留型海相盆地构造-岩相古地理重建技术研究"(编号:2021DJ0501)、国家自然科学基金面上项目"四川盆地早中二叠世白云岩及储层差异成因与峨眉山大火成岩省幕式响应"(编号:42172166)联合资助 （编号:2021DJ0501）
