四川盆地须家河组坡折带发育特征及油气地质意义  

Development characteristics and oil-gas geological significance of slope break zone of Xujiahe Formation in Sichuan Basin

作　　者：陈友智 臧殿光 杨晓 巫芙蓉 梁虹 王晓阳 吴育林 郭冉 徐敏 陈颖 张帅 王鹏 应倩 赵振伟 陈娜 CHEN Youzhi;ZANG Dianguang;YANG Xiao;WU Furong;LIANG Hong;WANG Xiaoyang;WU Yulin;GUO Ran;XU Min;CHEN Ying;ZHANG Shuai;WANG Peng;YING Qian;ZHAO Zhenwei;CHEN Na(Southwest Geophysical Research Institute,Bureau of Geophysical Prospecting INC.,CNPC,Chengdu,Sichuan 610213,China;Southwest Geophysical Branch,Bureau of Geophysical Prospecting INC.,CNPC,Chengdu,Sichuan 610213,China;Development Division,PetroChina Southwest Oil&Gasfield Company,Chengdu,Sichuan 610000,China)

机构地区：[1]中国石油集团东方地球物理勘探有限责任公司西南物探研究院,成都610213 [2]中国石油集团东方地球物理勘探有限责任公司西南物探分公司,成都610213 [3]中国石油集团西南油气田公司开发事业部,成都610000

出　　处：《石油实验地质》2024年第3期491-498,共8页Petroleum Geology & Experiment

基　　金：国家科技重大专项(2017ZX05035003);中国石油东方地球物理公司油气勘探新领域综合研究项目联合资助。

摘　　要：前人针对断陷盆地坡折带开展了大量研究,但前陆盆地前渊向前缘隆起方向坡度较缓,大型构造欠发育,地形起伏小,坡折带研究较少。四川盆地晚三叠世须家河组四、五段沉积时期发育前陆盆地,学者们已关注到泸州—开江古隆起西侧川中—川西地区缓坡坡折带对沉积岩相的控制,但其他相关研究较少。通过对四川盆地地震反射剖面坡折带构造解释,结合区域地质已有成果,采用颗粒流数值模拟方法,厘清了川中—川西地区坡折带类型,以及坡折带与重力滑动构造之间的关系,分析了与重力滑动构造相关的新型油气圈闭特征。研究获得如下认识:(1)研究区发育断裂坡折带,以坡折带为界,东、西两侧各发育一套重力滑动形成的“前挤后拉”构造组合,构造变形强度弱于被动大陆边缘重力滑动构造;(2)研究区构造坡折带边缘断裂控制沉积相与砂体类型;(3)缓坡带重力滑动构造拉张区正断层下盘上升形成同沉积背斜发育的砂岩,与同期断陷内富有机质泥岩侧接,形成“旁生侧储”型油气藏;(4)陡坡带重力滑动形成的须五段同沉积背斜,被翼部泥岩以及滑动构造结束后沉积的泥岩所围限,形成源内砂体输导成藏;(5)与重力滑动构造相关的同沉积背斜油气藏是源内成藏新类型,研究区须五段可能存在平行坡折带NE向展布的此类油气藏。Previous studies have delved into slope break zones in faulted basins,yet foreland basins,with their gentle slopes toward the forebulge,underdeveloped large-scale structures,and small terrain undulations,have received limited research on slope-fault belts.During the deposition periods of the 4th and 5th members of the Late Triassic Xujiahe Formation,a foreland basin developed in the Sichuan Basin.Scholars have noted the control exerted by the gentle slope break zone on the sedimentary lithofacies in the central and western Sichuan,particu-larly in the west of the Luzhou-Kaijiang Paleo-uplift,but related studies remain limited.By interpreting the tectonic slope break zones in seismic reflection profiles of the Sichuan Basin and incorporating existing regional geological data,this study employed particle flow numerical simulation to clarify the types of slope break zones in the central and western Sichuan regions,as well as their relationship with gravity sliding structures.It also analyzed the characte-ristics of new types of oil and gas traps associated with gravity-sliding structures.The findings are as follows:(1)The study area developed a fault slope break zone,with each side bounded by a“front squeezing and rear extension”tectonic combinations formed by gravity sliding.The tectonic deformation is weaker than those of gravity-sliding structures at passive continental margins.(2)The edge fault of the tectonic slope break zone controls the sedi-mentary facies and sand body types.(3)In the gentle slope zone,the stretching area of gravity-sliding structures lead to the uplift of the footwalls of normal faults,forming syndepositional anticlines with developed sandstones.These sandstones,juxtaposed with organic-rich mudstones within the contemporaneous fault depression,form“side-generated and lateral storage”hydrocarbon reservoirs.(4)In the steep slope zone,gravity sliding forms syndepositional anticlines in the 5th member of the Xujiahe Formation,which are bounded by flank mudstones and post-sliding deposit

关 键 词：重力滑动构造 构造坡折带 源内成藏 须家河组 上三叠统 四川盆地 

分 类 号：TE121.3[石油与天然气工程—油气勘探]