摘要
滩砂是我国陆相盆地重要的储集类型之一。基于岩心测试、钻井、测井和三维地震等资料,对准噶尔盆地沙湾凹陷侏罗系八道湾组滩砂的沉积特征进行了系统分析,探讨了其分布规律、沉积模式和勘探潜力。研究结果表明:(1)沙湾凹陷八道湾组滩砂由滩脊和滩槽构成,滩脊富砂,以砂砾岩、含砾砂岩和砂岩为主,发育块状层理、浪成交错层理和局部软沉积变形层理,垂向上呈多期滩脊叠加特征;滩槽贫砂,以薄层粉砂岩沉积为主,垂向上呈反粒序特征;单期滩脊一般由3个沉积序列构成,各序列的粒度概率曲线均呈三段式。(2)研究区滩脊在地震剖面上表现为强振幅透镜状的反射特征,地层切片显示滩脊沿湖岸线成排成带分布,规模大。滩砂分布于西环带两大三角洲扇体间的凹进区,沿湖岸线呈条带状展布,滩脊和滩槽相间分布,单个滩脊面积较小,但数量多,最多可达12道,成群成带出现,滩脊砂体群面积可达145 km^(2)。(3)研究区八道湾组底部脊槽状滩砂勘探开发潜力大,砂体厚度大、物性好、分布面积广,滩槽可作为侧向遮挡层,可形成较好储层和圈闭,二叠系风城组碱湖优质烃源岩提供油气来源,不整合面和断裂为有利油气输导体系。
Beach sand body is one of the essential reservoir types in continental basins in China.Based on core testing,drilling,logging and 3D seismic data,the sedimentary characteristics of the beach sand bodies of Jurassic Badaowan Formation in Shawan Sag of Junggar Basin were systematically analyzed,and their distribution,depositional model and exploration potential were discussed.The results show that:(1)The beach sand bodies of Badaowan Formation in Shawan Sag comprise beach ridges and troughs.The beach ridges are rich in sand,mainly composed of sandy conglomerate,pebbly sandstone and sandstone,with massive bedding,wave cross-bedding and local soft sedimentary deformation bedding being developed,showing multi-phase beach ridge superposition.The beach trough is poor in sand and dominated by thin siltstone,with reversed grain sequence in vertical.The single beach ridge comprises three sedimentary sequences,and each sequence has grain size probability curves in three-stage.(2)The beach ridges in the study area show a reflection characteristic of strong amplitude lenticular discontinuity on seismic section,and the stratal slices show beach ridges distributed in rows and belts along the lake shoreline.Beach sand bodies are distributed in strips along the lake shorelines in the recessed area between the two big delta fan bodies in the west ring belt,and beach ridges and troughs are distributed alternately.The single beach ridge has small area,with large number,up to 12.Appearing in groups and belts,the area of beach ridge sand body group is up to 145 km^(2).(3)The ridged trough beach sand bodies at the bottom of Badaowan Formation in the study area have excellent exploration and development potential,with a considerable thickness of sand bodies,good physical properties,and a wide distribution area.The trough can be used as a lateral barrier layer to form suitable reservoirs and traps.The high-quality source rocks of the alkaline lake of Permian Fengcheng Formation provide oil and gas sources,and the unconformity surface and faults are favorable oil and gas transport systems.
作者
刘国勇
许多年
胡婷婷
潘树新
潘拓
王国栋
马永平
关新
LIU Guoyong;XU Duonian;HU Tingting;PAN Shuxin;PAN Tuo;WANG Guodong;MAYongping;GUAN Xin(PetroChina Xinjiang Oilfield Company,Karamay 834000,Xinjiang,China;PetroChina Research Institute of Petroleum Exploration and Development-Northwest,Lanzhou 730020,China;Research Institute of Exploration and Development,PetroChina Xinjiang Oilfield Company,Urumqi 830013,China)
出处
《岩性油气藏》
CAS
CSCD
北大核心
2023年第5期1-10,共10页
Lithologic Reservoirs
基金
国家自然科学基金“陆相湖盆水下滑坡体的形成机制、识别标志及其石油地质意义”(编号:41872116)资助。
关键词
滩砂
滩脊
滩槽
三角洲前缘砂体
沉积模式
八道湾组
侏罗系
沙湾凹陷
准噶尔盆地
beach sand bodies
beach ridge
beach trough
delta front sand bodies
depositional model
Badao-wan Formation
Jurassic
Shawan Sag
Junggar Basin
