鄂北杭锦旗地区山西组高分辨层序格架下沉积充填及砂体展布规律  

Sedimentary Filling and Sandbody Distribution Patterns under High-Resolution Sequence Framework of the Shanxi Formation in Hangjinqi of North Ordos

作　　者：赵明胜 田景春[2] 张翔[2] 苏炳睿[2] Zhao Mingsheng;Tian Jingchun;Zhang Xiang;Su Bingrui(Shenyang Normal University,Shenyang,Liaoning 110034,China;Chengdu University of Technology,Chengdu,Sichuan 610059,China)

机构地区：[1]沈阳师范大学,辽宁沈阳110034 [2]成都理工大学,四川成都610059

出　　处：《特种油气藏》2019年第6期8-15,共8页Special Oil & Gas Reservoirs

基　　金：国家科技重大专项“低丰度致密低渗油气藏开发关键技术”(2016ZX05048);辽宁省自然科学基金指导计划项目“辽东本溪地区晚石炭世本溪期煤系地层的沉积环境及物质聚集规律”(2019-ZD-0488);沈阳师范大学博士、引进人才科研项目启动基金“基于矿物成分的玄武岩脆性及其裂缝响应定量研究”(BS201911)

摘　　要：杭锦旗地区位于鄂尔多斯盆地北部,是重要的含油气勘探地区,但该区山西组高分辨率层序地层格架的划分少有报道,且地层格架下的充填序列及砂体充填的形成环境存在不同的认识。针对此问题,通过野外剖面、岩心及测井资料建立了山西组高分辨层序地层格架,划分出2个长期、5个中期、10个短期旋回。沉积相研究表明,杭锦旗地区山西组(LSC1、LSC2)沉积期经历了辫状河三角洲沉积体系的改造,其亚相为辫状河三角洲平原,并识别出辫状分流河道、越岸沉积、分流间洼地及泥炭沼泽等微相。在短期层序格架中的沉积充填序列主要为C1、A1、A2型。LSC1沉积期砂体主要分布于分流河道中,具有由北向南的展布特征,研究区东部砂体连通性较好,西部则相对孤立。LSC2沉积期基本继承了前期的沉积格局,砂体走向与LSC1沉积期一致,由于物源区供应减少,分流河道规模较LSC1时期有所减小,而分流间洼地则较前期相对发育,砂体亦呈现东部连片发育、西部相对孤立的分布现象。研究成果为该地区的油气勘探提供了新的方向。Hangjinqi is located in the northern part of Ordos Basin and is considered as a major hydrocarbon exploration area.There are few reports on the high-resolution sequence stratigraphic frameworkdivision of Shanxi Formation in this area,and there are also various understandings of the sedimentary filling sequence and environment in this stratigraphic framework.Based on the field profile,core analysis and logging data,the high-resolution sequence stratigraphic framework of Shanxi Formation was established to divide 2 long-term,5 medium-term and 10 short-term cycles.According to the sedimentary facies analysis,the Shanxi Formation(LSC1,LSC2)in Hangjinqi experiences the transformation of the braided river delta sedimentary system,and the corresponding subfacies is braided river delta plain.A series of sedimentary subfacies were identified,including braided distributary channel,overbank sedimentation,inter-distributary depression,peat bog,etc.The sedimentary sequence of short-term sequence framework is dominated by C1,A1and A2.The sandbodies within the LSC1 sedimentation period mainly distribute in the distributary channel with a North-South pattern.The sandbodies in the eastern part show a better connectivity and the western part is relatively isolated.It basically inherits the sedimentary framework in the LSC2 sedimentation period,and the corresponding sandbody distribution is consistent with that in LSC1 sedimentation period.The reducing provenance leads to a decreasing of distributary channel scale and a relatively developed inter-distributary scale comparing with that in the LSC1 sedimentation period.The sandbodies also show a continuous distribution in the east and a relative isolation in the west.This research could provide a new orientation for the hydrocarbon exploration in this area.

关 键 词：高分辨层序格架 沉积充填 砂体展布规律 山西组 杭锦旗地区 鄂尔多斯盆地 

分 类 号：TE121.3[石油与天然气工程—油气勘探]