鄂尔多斯盆地宁县地区三叠系延长组7段湖盆细粒重力流沉积类型、特征及模式  

Sedimentary types,characteristics and model of lacustrine fine-grained gravity flow in the Member 7 of Trassic Yanchang Formation in Ningxian area,Ordos Basin

作　　者：吕奇奇[1] 辛红刚[2,3] 王林 罗顺社[1] 淡卫东[2,3] 冯胜斌[2,3] LU Qiqi;XIN Honggang;WANG Lin;LUO Shunshe;DAN Weidong;FENG Shengbin(School of Geosciences,Yangtze University,Wuhan 430100,China;National Engineering Laboratory for Exploration and Development of Low Permeability Oil&Gas Fields,Xi'an 710018,China;Exploration and Development Research Institute of Changqing Oilfield Branch Company Ltd.,PetroChina,Xi'an 710018,China)

机构地区：[1]长江大学地球科学学院,湖北武汉430100 [2]低渗透油气田勘探开发国家工程实验室,陕西西安710018 [3]中国石油长庆油田分公司勘探开发研究院,陕西西安710018

出　　处：《古地理学报》2023年第4期823-840,共18页Journal of Palaeogeography：Chinese Edition

基　　金：国家自然科学基金项目(编号:42102170);国家重点基础研究发展计划“973”项目(编号:2014CB239003)联合资助。

摘　　要：湖盆细粒重力流沉积砂体是深水盆地勘探的有利目标区。综合利用岩心、钻井、测录井及薄片鉴定资料,对鄂尔多斯盆地宁县地区三叠系延长组7段细粒重力流沉积类型、特征、沉积演化过程以及沉积模式进行探究。研究结果表明:研究区长7段主要发育10种岩相、6种岩相组合和5种深水沉积类型,即滑动—滑塌沉积、砂质碎屑流沉积、混合事件层、浊流沉积和深湖相泥质沉积;并依据其岩相及组合特征、深水沉积类型将半深湖—深湖亚相划分出限制性水道、非限制性水道、堤岸、朵叶体、水道间及半深湖—深湖泥6种沉积微相;三角洲前缘沉积物受外力作用开始失稳运动,经历了滑动、滑塌、砂质碎屑流、混合事件层、浊流5个演化阶段,伴随着“流体转换分离”及“滑水作用”,致使重力流沉积从湖盆边缘至湖盆中心依次发育限制性水道—堤岸、非限制性水道—堤岸、朵叶体等沉积单元。该研究有助于加深对湖盆细粒重力流沉积的认识,为深水油气勘探与开发提供指导。The lacustrine fine-grained gravity flow sand body is a favorable target area for exploration in deep-water basins.Based on core,drilling,well logging,mud logging and thin section identification,the sedimentary types,characteristics,sedimentary evolution process and sedimentary model of fine-grained gravity flow are studied in the Member 7 of Yanchang Formation in the Ningxian area,Ordos Basin.The findings results show the presence of ten lithofacies,six lithofacies associations,and five types of deep-water sediments,including slide-slump deposits,sandy debris flow deposits,hybrid event bed,turbidity current deposits and deep lacustrine muddy deposits.According to the lithofacies and their combination characteristics,the semi-deep to deep lake subfacies can be further divided into six sedimentary microfacies:confined channel,unconfined channel,levee,lobe,inter-channel and semi-deep to deep lake mud.The delta front sediments destabilized under the action of external forces,and experienced five evolution stages of sliding,slumping,sandy debris flow,hybrid event bed,and turbidity currents.With the“fluid transformation and separation”and“hydroplaning”,the gravity flow deposits gradually evolved from confined channel-levees,unconfined channel-levees,to lobes toward the center of basin.This study will help to deepen the understanding of lacustrine fine-grained gravity flow deposits and provides guidance for deep-water oil and gas exploration and development.

关 键 词：细粒重力流沉积 深水沉积类型 沉积模式 延长组7段 三叠系 鄂尔多斯盆地 

分 类 号：TE121.3[石油与天然气工程—油气勘探]