四川盆地二叠、三叠系构造—沉积特征及有利勘探区带  

Permian and Triassic in Sichuan Basin:Tectono-sedimentary characteristics and favorable exploration belts

作　　者：文龙 张本健 陈骁 徐亮 马华灵 彭瀚霖 WEN Long;ZHANG Benjian;CHEN Xiao;XU Liang;MA Huaing;PENG Hanin(PetroChina Southwest Oil&Gasfield Company,Chengdu,Sichuan 610051,China;Exploration and Develop-ment Research Institute,PetroChina Southwest Oil&Gasfield Company,Chengdu,Sichuan 610041,China)

机构地区：[1]中国石油西南油气田公司,四川省成都市610051 [2]中国石油西南油气田公司勘探开发研究院,四川省成都市610041

出　　处：《天然气勘探与开发》2023年第4期1-12,共12页Natural Gas Exploration and Development

基　　金：国家科技重大专项下属课题“四川盆地二叠系-中三叠统天然气富集规律与目标评价”(编号:2016ZX05007-004);中国石油天然气股份有限公司重大科技专项“四川盆地二、三叠系天然气富集区带评价”(编号:2016E-0603);中国石油西南油气田科技项目“四川盆地二叠系构造沉积演化特征及勘探区带评价研究”(编号:20230301-04)。

摘　　要：针对二叠系的构造—沉积演化过程复杂、有利相带展布格局恢复困难及有利勘探区带不明朗等问题,利用近年新的二维和三维地震资料、盆缘野外及盆内钻井、录井资料,开展四川盆地二叠系构造沉积演化的系统研究,探索主要构造运动的响应特征及影响因素,建立各组、段之间的连续沉积演化关系,明确多套目的层系的有利沉积相带展布,为有利勘探区带的优选提供重要支撑。通过地质特征综合分析,认为:①二叠系沉积前古地貌、二叠纪拉张构造背景、地幔柱隆升及火山喷发等多种因素,造成了二叠系构造沉积分异;②四川盆地二叠纪表现为区域拉张构造动力背景,属克拉通裂陷盆地沉积体系,控制了多个层系边缘礁滩相带的展布,为发育规模岩性圈闭群奠定了基础;③三叠纪早期继承了二叠纪末期沉积格局,并受盆地边缘古陆、岛链、水下隆起影响,整体呈现填平补齐的特征,属克拉通坳陷盆地沉积体系,滩体受微地貌控制呈垂向加积、侧向进积的特点,平面上在清水台地区大面积席状展布;④基于构造—沉积背景分析以及二维和三维地震资料的综合应用,明确了栖霞组“一缘两环带”,茅口组“一隆一缘”,长兴组“三隆三洼”,飞仙关组“三隆成滩、三洼补齐”等主要沉积面貌。综合含油气地质条件分析,指出川西地区栖霞组台缘带及川中—蜀南地区台内高带,剑阁—南充—石柱地区茅口组台缘带,开江—梁平地区海槽及蓬溪—武胜—石柱地区浅水陆棚长兴组边缘礁滩等,是四川盆地二叠、三叠系的主要勘探领域和方向。The Permian system in Sichuan Basin is complex in tectono-sedimentary evolution,creating difficulties in restoring the distribution of favorable facies zones and uncertainties in favorable exploration belts.So,through the latest 2D and 3D seismic data as well as drilling and mud-logging data in and around the basin,this evolution was investigated systematically to identify response char-acteristics and influential factors of major tectonic movements.The relationship of continuous sedimentary evolution was established to every formation and member and the distribution of favorable facies zones with multiple targets was defined to provide an import-ant support for optimizing the favorable exploration belts.After the comprehensive analysis on geological characteristics,it is revealed that(i)multiple factors,including ancient landform before the Permian deposition,and tensile tectonic setting,mantle plume uplift and volcanic eruption in the Permian,affect the tectonic-sedimentary differentiation of the Permian;(ii)representing a regional tensile tectonic setting,the Permian in Sichuan Basin was a sedimentary system of cratonic rifted basin,which controlled the distribution of bioreef-beach facies zones on the margin of multiple strata,laying a foundation for the development of massive lithologic traps;(iii)in the early Triassic,the basin inherited the sedimentary pattern in the late Permian,and exhibited one feature of filling and leveling up due to some effects,for example,ancient land,island chain and underwater uplift at the basin margin.It was a sedimentary system of cratonic depression basin,whose beaches in vertical and lateral accretion might be controlled by microgeomorphology and presented large-scale sheet-like distribution in Qingshuitai area in plane;and(iv)dependent on the analysis of tectono-sedimentary setting and the comprehensive application of 2D and 3D seismic data,the main sedimentary features were defined,such as“one margin and two ribbons”in Qixia Formation,“one uplift and one margin”in

关 键 词：四川盆地 二叠系—三叠系 构造—沉积特征 油气勘探 有利区带 

分 类 号：P618.13[天文地球—矿床学]