柴达木盆地九龙山地区中侏罗统湿地型辫状河三角洲沉积特征及油气勘探意义  

Sedimentary characteristics of the Middle Jurassic wetland braided river delta in Jiulongshan area,Qaidam Basin and its significance for oil and gas exploration

作　　者：王波[1] 王艳清 马进业[1] 宫清顺 朱军[1] 朱超 李雅楠 王远飞 裴梓薇 张君 魏巍 WANG Bo;WANG Yanqing;MA Jinye;GONG Qingshun;ZHU Jun;ZHU Chao;LI Yanan;WANG Yuanfei;PEI Ziwei;ZHANG Jun;WEI Wei

机构地区：[1]中国石油青海油田公司 [2]中国石油杭州地质研究院

出　　处：《海相油气地质》2023年第3期250-260,共11页Marine Origin Petroleum Geology

基　　金：中国石油科技重大专项“岩性地层油气藏成藏规律与关键技术研究”(编号:2021DJ0402);“陆相深层超深层油气富集规律与勘探评价技术研究”(编号:2021DJ0202)联合资助。

摘　　要：利用钻井岩心、测井、地震和实验测试等资料,对柴达木盆地九龙山地区中侏罗统沉积特征及成藏条件进行分析。结果表明:①九龙山地区中侏罗统发育潮湿气候下的陆相含煤沉积建造,属于湿地型辫状河三角洲沉积。②中侏罗统发育3类岩相组合:第1类是浅灰色、棕灰色泥岩与砂岩、含砾砂岩、砂砾岩和砾岩互层;第2类是煤层、深灰色碳质泥岩与砂岩、含砾砂岩和砾岩互层;第3类是深灰色碳质泥岩、油页岩和泥岩互层。3类岩相组合分别对应辫状河三角洲的上平原、下平原—前缘和湖相沉积。③中侏罗统沉积时期河道较频繁迁移,砂体在平面上呈辫状、网状和朵状分布,具有多期叠置、侧向变化较快的特征。研究认为中侏罗统辫状河三角洲下平原与前缘河道砂体的油气成藏条件优越,是九龙山地区常规油气勘探的重要领域,湖相油页岩是九龙山地区非常规油气勘探的潜在领域。The exploration of the Jurassic oil and gas system in the Qaidam Basin has led to the discovery of Dongping,Niudong,and Kunteyi bedrock gas fields,as well as Niudong and Lenghu Jurassic oil fields.Currently,there is an urgent need to expand the exploration field of the Jurassic and search for replacement zones.The sedimentary characteristics and reservoir formation conditions of the Middle Jurassic in Jiulongshan area are analyzed by using drilling cores,logging,seismic,and experimental data.The results indicate that:(1)The Middle Jurassic in Jiulongshan area developed continental coal bearing sedimentary formations in a humid climate,belonging to the wetland braided river delta deposits.(2)Three types of lithofacies associations are developed in the Middle Jurassic.The first is interbedding of light grey and brown grey mudstone and sandstone,pebbly sandstone,glutenite and conglomerate;the second is interbedding of coal seam,dark grey carbonaceous mudstone and sandstone,pebbly sandstone and conglomerate;and the third is interbedding of dark grey carbonaceous mudstone,oil shale and mudstone.The three types of lithofacies associations correspond to the upper plain,lower plain to front,and lacustrine deposits of the braided river delta,respectively.(3)The distribution of Middle Jurassic sand bodies are characterized by multiple overlapping periods,rapid lateral changes,and frequent migration of river channels that result in braided,network,and flower shaped features on the plane.It is suggested that the channel sand bodies of lower plain and front in the braided river delta of the Middle Jurassic have excellent oil and gas accumulation conditions,which are important areas for conventional oil and gas exploration in the Jiulongshan area.The lacustrine oil shale is a potential area for unconventional oil exploration in this area.

关 键 词：湿地型辫状河三角洲 沉积特征 中侏罗统 九龙山地区 柴达木盆地 

分 类 号：TE122.2[石油与天然气工程—油气勘探]