川西北地区中二叠统沉积相及与油气的关系  

作　　者：陈俊杰 王兴志[1,2] 谢圣阳 周坤[3] 曾楷 

机构地区：[1]油气藏地质及开发工程国家重点实验室,四川成都610500 [2]西南石油大学地球科学与技术学院,四川成都610500 [3]中国石油西南油气田分公司川东北气矿,四川达州635000

出　　处：《科技创新导报》2019年第23期65-70,共6页Science and Technology Innovation Herald

摘　　要：本文根据大量野外及钻井资料,结合相关分析及前人研究成果,认为四川盆地西北部在中二叠世期间为一由西向北东方向低角度倾斜的远端变陡均斜台地环境,兼具有孤立台地和远端变陡缓坡的性质,这样的沉积环境主要受到峨眉地幔柱演化的控制。分布于广元绵阳一线的栖二段和茅三段多为均斜台地边缘的产物,堆积的主要是灰白色泥-亮晶生物(屑)灰岩,该相带易于后期云化和溶蚀作用的改造,有利于后期储层的形成与演化;全区的栖一段、茅一段和茅二段主要属于深缓坡沉积相带,多由深灰色“眼球状-似眼球状”生物(屑)灰岩组成,具有一定的生烃和储集潜力,在有裂缝的沟通下可具有一定的储集能力;分布在广元旺苍一线的茅四段属于拉张盆地(拉张槽)环境下的产物,主要由灰黑色硅质岩、硅质泥岩夹重力流沉积构成,生烃潜力良好。并根据碳酸盐岩均斜台地相与油气的关系,总结出3种模式:浅水高能滩模式、深水低能滩模式、深缓坡-盆地模式。According to a large number of field and drilling data,combined with relevant analysis and previous research results,it is believed that the northwestern Sichuan Basin during the Middle Permian was in a low-angled platform environment from west to northeast,which has the characteristics of steep distal end.It also has the property of isolated platform and distally steepened ramp.This sedimentary environment was mainly controlled by the evolution of the Emei mantle plume.The second member of Qixia Formation and the third member of Maokou Formation distributed in the Guangyuan-Mianyang area were platform margin facies sediments,characterized by gray-white mud-sparry bioclast limestone.This facies belt is beneficial to the later modification of dolomitization and dissolution,which is conducive to the formation and evolution of reservoirs.The f irst member of Qixia Formation,the first and second member of Maokou Formation of the whole study area were mainly deep ramp facies sediments,mostly composed of dark gray“eyeball-shaped”bioclast limestone,which has potential for hydrocarbon generation and storage,and has certain reservoir capacity under the connection of cracks.The fourth member of Maokou Formation distributed in the Guangyuan-Wangcang area was formed in the extensional basin(stretching trough)environment,mainly composed of gray-black siliceous rocks and siliceous mudstones with gravity f low deposition,which have good hydrocarbon generation potential.Finally,according to the relationship between carbonate platform and oil/gas,three models are summarized:shallow water bank with high energy,deep water bank with low energy,and deep ramp-basin.

关 键 词：川西北 中二叠统 沉积相 储层 烃源岩 

分 类 号：P534.46[天文地球—古生物学与地层学] P618.13[天文地球—地质学]