鄂尔多斯盆地延长组等时格架下的深水坡折带特征及其对砂体的控制作用  

Characteristics of deep-water slope break belt and its control on sandbodies in the isochronous framework of the Yanchang Formation in the Ordos Basin

作　　者：陈波 刘长春 李杰[1] 王义俊 杨雯婷 雷启鸿 户彬 李德胜 冷先刚 赵中平 CHEN Bo;LIU Changchun;LI Jie;WANG Yijun;YANG Wenting;LEI Qihong;HU Bin;LI Desheng;LENG Xian’gang;ZHAO Zhongping(Longdong Oil&Gas Development Branch,PetroChina Changqing Oilfield Company,Qingyang 745000,China;Xi'an Everest Oil&Gas Technology Co.,Ltd.,Xi’an 710021,China)

机构地区：[1]中国石油长庆油田分公司陇东油气开发分公司,甘肃庆阳745000 [2]西安珠峰油气科技有限公司,陕西西安710021

出　　处：《天然气地球科学》2024年第10期1764-1776,共13页Natural Gas Geoscience

基　　金：中国石油天然气集团有限公司前瞻性基础研究重大科技项目(编号:2021DJ1806);国家重点基础研究发展计划(编号:2014CB239003)联合资助。

摘　　要：鄂尔多斯盆地三叠系延长组依据传统似等厚岩性地层划分方案识别出的沉积坡折带有待商榷。采用井震结合、标志层控制、逐井反复对比等综合方法,通过对多个典型标志层的识别和追踪对比,建立了鄂尔多斯盆地西南部环县地区延长组长7段—长4+5段部分地层的等时地层格架,并在此基础上识别出了具有典型地貌学特征的深水沉积坡折带。结果表明,环县地区延长组长7段—长4+5段实际由从西南往东北呈多期逐渐减薄的“S”型楔状前积层构成,其内部各套等时地层发育一系列坡折明显且逐渐往东北迁移的深水沉积坡折带,这些坡折带相对于长7段底界最大倾角可达1.9°、宽约6~8.6 km;各期重力流砂体和致密油层主要分布在坡折带处或坡折带前端的斜坡坡脚处,且平行于坡折带呈带状展布,坡折带控砂和控藏作用明显。研究对其他地区延长组深水沉积坡折带的有效识别和油气勘探开发具有重要的借鉴意义。The sedimentary slope break belt identified by the Triassic Yanchang Formation in the Ordos Basin based on the traditional similar-thickness lithologic stratigraphic division scheme needs to be discussed.The iso⁃chronous stratigraphic framework of Chang 7-Chang 4+5 part of Yanchang Formation in Huanxian area,south⁃western Ordos Basin was established by using the comprehensive methods of well-seismic combination,marker bed control and well-by-well repeated comparison.Based on the identification and tracking comparison of sever⁃al typical marker beds,the deep-water sedimentary slope break belt with typical geomorphological characteris⁃tics was identified.The results show that the Chang 7-Chang 4+5 strata of Yanchang Formation in Huanxian area are actually composed of S-and wedge-shaped foreset,which is gradually thinning from southwest to north⁃east.A series of deep-water sedimentary slope break belts with obvious slope breaks and gradual migration to northeast occurred in the isochronous strata.The maximum inclination angle of these slope break belts relative to the bottom boundary of Chang 7 can reach 1.9°and the width is about 6-8.6 km.The gravity flow sand bodies and tight oil layers of each layer are mainly distributed at the slope break belt or the slope toe at the front end of the slope break belt,and are spread in a band parallel to the slope break belt.The deep-water sedimentary slope break belt has obvious controlling effect on the distribution of sand bodies and oil reservoirs.This has important reference significance for the effective identification of deep-water sedimentary slope break belts and oil and gas exploration and development in other areas.

关 键 词：鄂尔多斯盆地 延长组 等时地层格架 坡折带 砂体 

分 类 号：TE122.2[石油与天然气工程—油气勘探]