海相油气地质2025，Vol.30Issue(2)：147-156,10.DOI:10.3969/j.issn.1672-9854.2025.02.005
川西北蓬溪—盐亭地区下三叠统飞仙关组层序演化及鲕滩展布特征
Stratigraphic sequence evolution and oolitic shoal distribution of the Lower Triassic Feixianguan Formation in Pengxi-Yanting area,northwestern Sichuan Basin
摘要
Abstract
Abundant oil and gas discoveries have been made in the platform edge oolitic shoals of the Lower Triassic Feixianguan Formation in Sichuan Basin.In order to further promote the research and exploration of the inner platform oolitic shoal,based on drilling,logging,and three-dimension seismic data,the sequence characteristics,sequence evolution and oolitic shoal distribution pattern of the Feixianguan Formation in Pengxi-Yanting area,northwestern Sichuan Basin are studied.The results show that:(1)The Feixianguan Formation can be generally divided into three third-order sequences(SQ1,SQ2,SQ3),with typical rock electrical characteristics and seismic response of each sequence boundary.SB1,SB2,and SB3 are all lithological discontinuity surfaces,corresponding to reflection peaks;SB4 is the lithological conversion surface,corresponding to the reflection trough.The four interfaces exhibit abrupt changes in logging responses such as natural gamma and interval transit time.(2)During the deposition period of SQ1 in the study aera,the terrain slope was relatively steep,with a high-angle S-shaped progradational reflection structure.Mainly controlled by the sea-level fluctuation cycle of high-frequency sequences,a high-frequency restricted oolitic shoal sedimentary pattern was developed,in which the deposition scale of a single-stage shoal body was small,and the shoal bodies migrated rapidly in the horizontal direction towards northwest.(3)During the deposition period of the SQ2,the platform depression was basically filled,the overall terrain slope was relatively gentle,and the sequence had a low-angle progradational reflection structure.Controlled by the sea-level fluctuation cycle of third-order sequences,a stable and widely distributed oolitic shoal sedimentary pattern was developed,and the single-stage shoal body had a relatively large thickness and a stable planar distribution.(4)The SQ3 sequence had a continuous parallel reflection structure,and restricted-evaporative platform facies was developed,characterized by interbedded mudstone and dolomite gypsum with uniform thickness.This study could provide a geological basis for the fine exploration and efficient development of oolitic shoal reservoirs within the platform of the Feixianguan Formation in northwestern Sichuan Basin.关键词
层序/碳酸盐岩/鲕滩/沉积模式/飞仙关组/四川盆地Key words
sequence/carbonate rock/oolitic shoal/sedimentary model/Feixianguan Formation/Sichuan Basin分类
石油、天然气工程引用本文复制引用
林诚诚,刘宏,刘冉,徐唱,谭磊,王东,张坤..川西北蓬溪—盐亭地区下三叠统飞仙关组层序演化及鲕滩展布特征[J].海相油气地质,2025,30(2):147-156,10.基金项目
本文受中国石油-西南石油大学创新联合体科技合作项目"深层/超深层碳酸盐岩气田勘探开发基础理论与关键技术研究"(编号:2020CX010000)资助 （编号:2020CX010000）
