天然气勘探与开发2026，Vol.49Issue(3)：13-23,11.DOI:10.12055/gaskk.issn.1673-3177.2026.03.002
四川盆地蓬莱—南充地区茅二段高频层序划分及滩体分布特征
High-frequency sequence division and shoal distribution in the second member of Maokou Formation in Penglai-Nanchong area,Sichuan Basin
摘要
Abstract
The Middle Permian Maokou Formation is a critical gas-bearing interval in the Sichuan Basin.It mainly develops dolomite shoals,which are thin,highly heterogeneous,and significantly controlled by sequences.High-frequency sequences can reflect short-period seal level fluctuations,thereby controlling sedimentary facies migration of shallow-water carbonates.So far,the high-frequency sequences and their controls on shoal evolution and distribution in the Penglai-Nanchong area of the Sichuan Basin have been rarely studied.Based on seismic data,core observations,thin section identification,and logging data,the high-frequency sequence stratigraphic framework of the Maokou Formation in the study area was established.The microfacies were identified and classified,and the responding relationship between shoal evolution,migration and high-frequency sequences was defined.Moreover,the planar distribution of shoals under the control of high-frequency sequences was analyzed.Results show that(i)the Maokou Formation can be divided into 3 third-order sequences(SQ1-SQ3)and 11 fourth-order sequences(SSQ1-SSQ11).Each third-order sequence consists of a transgressive system tract and a highstand system tract;(ii)the sedimentary cycles present multiple assemblage sequences,including intershoal sea-bioclastic shoal-psammitic shoal,bioclastic shoal-psammitic shoal,intershoal sea-bioclastic shoal,psammitic shoal-psammitic shoal,and bioclastic shoal-bioclastic shoal.The types of sedimentary cycles are jointly governed by fourth-order sea-level fluctuations and sedimentary microgeomorphology.Psammitic shoals are susceptible to dolomitization and constitute favorable shoal reservoirs;and(iii)favorable shoals are mainly developed in the upper part of Mao-2 Member,with a thickness ranging from 5 to 16 meters.At platform margins,favorable shoals are mainly distributed in SSQ7 of the Well PY10 area as well as in SSQ8 of the Well PY10 and Well PS2 areas.Also,within open platforms,favorable shoals are concentrated in SSQ9 of the Well PS12-NC2 area.It is concluded that the exploration of the Mao-2 Member dolomite shoals in the Penglai-Nanchong area should focus on fine characterization of micro-geomorphology constrained by fourth-order sequences,especially the micro-geomorphic highlands.关键词
四川盆地/蓬莱—南充地区/二叠系中统茅口组/高频层序/沉积旋回/有利滩体分布/微地貌刻画Key words
Sichuan Basin/Penglai-Nanchong area/Middle Permian Maokou Formation/High-frequency sequence/Sedimentary cycle/Distribution of favorable shoal/Characterization of micro-geomorphology分类
能源科技引用本文复制引用
陈文凯,张云峰,谢静平,王锐,彭瀚霖,李天军,阳聪,张迈,李昌伟..四川盆地蓬莱—南充地区茅二段高频层序划分及滩体分布特征[J].天然气勘探与开发,2026,49(3):13-23,11.基金项目
国家自然科学基金项目"峨眉地幔柱活动与海洋环境协同作用对川中地区二叠系茅口组白云石化的制约"(编号:42472174),中国石油—西南石油大学创新联合体研究项目"深层碳酸盐岩规模储层形成、改造机理及优质储集区带预测"(编号:2020CX010301). （编号:42472174）
