摘要
在奥陶纪—志留纪之交,川南地区历经全球与区域地质事件的叠加影响,水下地貌复杂,导致龙马溪组页岩沉积期的沉积环境具有差异性,进而对岩相的发育具有控制作用。以川南长宁地区龙马溪组页岩为研究对象,依托钻井、地震以及分析测试资料,深入探究了该地区龙马溪组沉积时期的水下地貌形态及其岩相发育特征。结果表明:(1)长宁地区龙马溪组沉积时期水下地貌具有隆洼相间的格局,可进一步划分为水下隆起区、斜坡区和洼陷区;(2)龙马溪组页岩岩相类型多样,储集性能差异明显,页岩岩相具有明显的“控储控气”特征,其中混合硅质页岩相(S-2)和含灰硅质页岩相(S-3)为长宁地区龙马溪组页岩的优势岩相,具有“三高”(高TOC、高孔隙度和高含气量)特征;(3)水下地貌格局对页岩岩相发育具有明显的差异控制作用,其中水下隆起区主要为混合质页岩相组合(M)和硅质页岩相组合(S),斜坡区以硅质页岩相组合(S)占主导,洼陷区以混合质页岩相组合(M)和硅质页岩相组合(S)为主,而储集性最好的混合硅质页岩相(S-2)主要分布于斜坡区及靠近水下隆起的区域。本研究对于揭示页岩岩相分布规律和预测有利岩相平面分布具有重要意义。
During the Ordovician-Silurian transition,the southern Sichuan Basin experienced the superposition of global and regional geological events,resulting in the complexity of its underwater topography.This complexity led to the variation of the environment during the deposition period of the Longmaxi Formation shale in this area,which in turn controlled the development of shale lithofacies.This study takes the Longmaxi Formation shale in Changning area of southern Sichuan Basin as the research object.Based on drilling wells,seismic data and various analytical test data,the underwater topography and lithofacies development characteristics during the depositional period of the Longmaxi Formation in this area were studied.The results show that:(1)The underwater topography during the depositional period of the Longmaxi Formation in Changning area has a pattern of alternating high land and depression,which can be further divided into underwater high land,slope area and depression;(2)The lithofacies types of the Longmaxi Formation shale in Changning area are diverse and the reservoir differences are obvious.The shale lithofacies have obvious“storage and gas content control”characteristics.Among them,the mixed siliceous shale lithofacies(S-2)and the calcareous siliceous shale lithofacies(S-3)are the dominant lithofacies of the Longmaxi Formation shale in Changning area,which have the“three highs”(high TOC,high porosity and high total gas content)characteristics;(3)The underwater topography pattern has an obvious differential control effect on the development of shale lithofacies.The underwater high land is mainly occupied by mixed shale lithofacies association(M)and siliceous shale lithofacies association(S),the slope area is dominated by siliceous shale lithofacies association(S),and the depression is mainly composed of mixed shale lithofacies association(M)and siliceous shale lithofacies association(S).The mixed siliceous shale lithofacies(S-2),the best lithofacies with high TOC,high gas content and high porosity,is mainly distributed in the slope area and the area close to the underwater high land.This study is of great significance for revealing the distribution law of shale lithofacies and predicting the planar distribution of favorable shale lithofacies.
作者
李启锐
谭秀成
陈雷
樊琪铖
蔡景顺
汪勇
陈鑫
董建华
LI Qirui;TAN Xiucheng;CHEN Lei;FAN Qicheng;CAI Jingshun;WANG Yong;CHEN Xin;DONG Jianhua(Natural Gas Geology Key Laboratory of Sichuan Province,Southwest Petroleum University,Chengdu 610500,China;School of Geoscience and Technology,Southwest Petroleum University,Chengdu 610500,China;Research Branch of Key Laboratory of Carbonate Reservoirs,Southwest Petroleum University,CNPC,Chengdu 610500,China;State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation,Southwest Petroleum University,Chengdu 610500,China;Sichuan Changning Gas Development Co.,Ltd.,Chengdu 610051,China;Shale Gas Research Institute,PetroChina Southwest Oil and Gas Company,Chengdu 610051,China)
出处
《古地理学报》
北大核心
2026年第1期158-172,共15页
Journal of Palaeogeography:Chinese Edition
基金
国家自然科学基金项目(编号:42372173)资助。
关键词
古地貌
页岩岩相
龙马溪组
长宁地区
四川盆地
palaeogeomorphology
shale lithofacies
Longmaxi Formation
Changning area
Sichuan Basin
