摘要
准噶尔盆地南缘中侏罗统头屯河组是重要的油气勘探目的层系。通过对准噶尔盆地南缘南安集海河剖面实地丈量,结合岩石样品的薄片鉴定资料和地球化学分析测试资料,对该剖面头屯河组的岩性和沉积构造进行了描述,分析了其沉积环境、沉积相类型及其演化规律。研究结果表明:(1)准噶尔盆地南缘南安集海地区中侏罗世头屯河组沉积期经历了半干旱—干旱—湿润的气候演化,湖盆水体较浅,湖底地形平缓,发育浅水三角洲沉积。(2)在剖面上识别出了分流河道、分流间洼地、水下分流河道、水下分流间湾、席状砂、滩坝等6种沉积微相类型。头屯河组浅水三角洲受河流和湖浪共同作用,在湖盆水体稳定期形成了河控浅水三角洲;在高频振荡期发育了浪控浅水三角洲。(3)从头屯河组沉积早期到晚期,湖平面先下降后上升。头屯河组一段发育河控浅水三角洲,分流河道水动力较强,河流频繁改道分叉,不断向湖盆方向进积,多期河道呈拼接式,此时分流河道和水下分流河道占据主导地位。随着气候进一步干旱,头屯河组二段发育浪控浅水三角洲,河流作用减弱,波浪改造作用增强,三角洲平原以发育切叠式分流河道为主,三角洲前缘水下分流河道砂体被波浪冲刷改造,形成带状展布的席状砂。头屯河组三段,由于准噶尔盆地持续沉降和三角洲朵体侧向迁移作用,浅水湖盆的三角洲朵体表面被湖水覆盖,浅水三角洲前缘的部分碎屑物质受风浪改造,形成平行于湖岸的滩坝沉积。
The Middle Jurassic Toutunhe Formation is an important exploration target zone in the southern margin of Junggar Basin.Based on the field survey of southern Anjihai river outcrops in the southern margin of Junggar Basin,combined with thin section identification of rock samples and geochemical analysis data,the lithologies and sedimentary structure of Toutunhe Formation were descried,and the sedimentary environment,sedimentary facies types and depositional evolution were analyzed.The results show that:(1)The Middle Jurassic Toutunhe Formation in the study area experienced a semi-arid,arid and humid climate evolution during the sedimentary period.The lacustrine basin was shallow,the lake bottom was gentle,and shallow delta deposits were developed.(2)Six types of sedimentary microfacies were developed in the study area,including distributary channel,inter-distributary depression,underwater distributary channel,inter-distributary bay,sheet sand and beach bar.The shallow water delta of Toutunhe Formation was affected by rivers and lake waves,forming a river-dominated shallow water delta in the stable period of lacustrine basin,and wave-dominated shallow water delta was developed.(3)From the early stage to the late stage of Toutunhe Formation,the lake level generally decreased and then increased.Riverdominated shallow water delta was developed in the first member of Toutunhe Formation,the distributary channel had strong hydrodynamic force.The river was frequently diverted and bifurcated,and continuously accumulated towards the lacustrine basin.The multi-stage channels were spliced.At that time,it was dominated by distributary channel and underwater distributary channel.Subsequently,the climate was further dry,wave-controlled shallow water delta was developed in the second member of Toutunhe Formation.The river action was weakened,and the wave action was enhanced.The delta plain was dominated by the development of a folded distributary channel.The sand bodies of underwater distributary channel of the delta front were transformed by wave scouring,forming strip-shaped sheet sand.During the deposition of the third member of Toutunhe Formation,due to the continuous subsidence of the Junggar Basin and the lateral migration of delta lobes,the surface of delta lobes in the shallow lacustrine basin was covered by lake water,and part of the clastic materials in the front of the shallow delta were reconstructed by lake waves,forming beach bar deposits parallel to the lake shore.
作者
付文俊
张昌民
冀东升
娄林
刘家乐
王绪龙
FU Wenjun;ZHANG Changmin;JI Dongsheng;LOU Lin;LIU Jiale;WANG Xulong(School of Geoscience,Yangtze University,Wuhan 430100,China;PetroChina Xinjiang Oilfield Company,Karamay 830013,Xinjiang,China)
出处
《岩性油气藏》
CAS
CSCD
北大核心
2023年第4期145-160,共16页
Lithologic Reservoirs
基金
国家自然科学基金项目“分支河流体系沉积模式与储层定量分布预测模型”(编号:42130813)资助。
关键词
浅水三角洲
河控
浪控
沉积相
沉积模式
头屯河组
中侏罗统
准噶尔盆地
shallow water delta
river-dominated
wave-dominated
sedimentary facies
depositional model
Toutunhe Formation
Middle Jurassic
Junggar Basin
