摘要
四川盆地川中古隆起磨溪北斜坡区上震旦统灯影组具有良好的勘探前景,而关于北斜坡构造演化背景下的成藏条件研究极少论及,直接制约了天然气勘探的突破和发现。为此,从钻井、地震资料分析入手,恢复磨溪北斜坡灯影组构造演化过程,并探讨构造演化对烃源岩和圈闭成藏条件的控制作用,以期为川中震旦系天然气扩展勘探提供理论支撑。结果表明:①磨溪北斜坡经历了早期古隆起-晚期斜坡的构造演化过程。桐湾运动末期,磨溪北斜坡处于古隆起构造高部位,海西晚期沉积前受伸展裂陷作用下沉。印支晚期至现今,受前陆造山运动影响,形成现今构造斜坡区。②受加里东早期盆内伸展裂陷作用,川北地区形成裂陷槽,同时在磨溪以北形成斜坡相沉积,是下寒武统烃源岩在裂陷槽北部和斜坡腹部优质分布的重要控制因素。③灯影组沉积期,磨溪北斜坡处于古隆起构造高部位,北斜坡台缘区灯影组发育岩溶丘滩相沉积和岩性圈闭,后期稳定继承性斜坡构造演化有利于岩性圈闭保存。
Sinian Dengying Formation,Moxi slope area,central Sichuan paleo-uplift,Sichuan Basin,has a good exploration prospect.But its reservoir-forming conditions under the background of tectonic evolution are rarely studied and discussed,which may directly restrict its exploration breakthrough and natural-gas discovery.So,the tectonic evolution process of Sinian Dengying Formation in Moxi north slope was restored by drilling and seismic data analysis.And an effect of tectonic evolution on source rock and reservoir-forming conditions was discussed so as to provide theoretical support for an extensional exploration of Sinian natural gas in central Sichuan Basin.Results show that(1)the Moxi north slope experienced some tectonic evolution process of paleo-uplift in the early stage and slope in the late stage.At the end of Tongwanian movement,the slope was located at the structural high of paleo-uplift.And in the late Hercynian,it went down under extensional rifting before deposition.Since the late Indosinian,the present tectonic slope area has been formed under the effect of foreland orogeny;(2)under extensional rifting in the early Caledonian basin,a rift trough was formed in northern basin while a deposition of slope facies was formed to the north of Moxi.It’s an important factor affecting high-quality distribution of Lower Cambrian source rock in northern rifting trough and in the slope belly;and(3)during a deposition of Dengying Formation,the Moxi north slope was located at the structural high of paleo-uplift.Karst bioreef and beach facies and lithologic traps were developed in Dengying Formation,marginal platform of north slope.The later tectonic evolution of stable successive slope is beneficial to the preservation of lithologic traps.
作者
马奎
张玺华
彭瀚霖
孙奕婷
杨岱林
田兴旺
钟佳倚
王云龙
Ma kui;Zhang Xihua;Peng Hanlin;Sun Yiting;Yang Dailin;Zhong Jiayi;Wang Yunlong;Tian Xingwang(Exploration and Development Research Institute,PetroChina Southwest Oil&Gasfield Company,Chengdu Sichuan 610041,China)
出处
《天然气勘探与开发》
2020年第1期8-15,共8页
Natural Gas Exploration and Development
基金
中国石油西南油气田公司科技处项目“川中古隆起北斜坡震旦系--下古生界天然气成藏地质条件研究”(编号:20190301-10)。
关键词
磨溪北斜坡
震旦纪
丘滩体储层
灯影期成藏
构造演化
烃源岩
岩性圈闭
Moxi north slope
Sinian
Bioreef and beach reservoir
reservoir-forming of Dengying Formation
Tectonic evolution
Source rock
Lithologic trap
