陆相断陷湖盆层序对成岩演化控制作用探讨——以东营箕状断陷湖盆古近系沙河街组为例  

The control role of stratigraphic sequence in diagenetic evolution in the terrestrial fault basin:a case study of Paleogene Shahejie Formation in Dongying half basin

作　　者：谭先锋[1,2] 田景春[1] 陈兰[2] 张守鹏[3] 王伟庆[3] 

机构地区：[1]成都理工大学油气藏地质及开发工程国家重点实验室,四川成都610059 [2]重庆科技学院石油与天然气工程学院,重庆401331 [3]胜利油田地质科学研究院,山东东营257015

出　　处：《中国地质》2010年第5期1257-1272,共16页Geology in China

基　　金：中石化重点科技攻关项目<济阳断陷湖盆沉积类型与成岩演化研究>(20070300187);重庆市自然科学基金项目(CSTC;2009BB7383)联合资助

摘　　要：以层序地层研究为基础,根据铸体薄片、扫描电镜、镜质体反射率、X衍射及地球化学等分析,对东营凹陷沙河街组层序与成岩的关系进行了系统研究。研究结果表明:不同层序部位具有不同的成岩响应,低位体系域主要发育微晶方解石胶结、硬石膏胶结、黄铁矿胶结等,湖盆扩张体系域主要发育有铁碳酸盐胶结、粘土矿物胶结等;高位体系域主要发育有白云石胶结、铁白云石胶结、溶蚀作用、粘土矿物胶结等;层序界面附近主要发育溶蚀现象和铁碳酸盐岩胶结现象。层序发育过程中,原始水介质条件及元素富集规律是引起早期成岩响应的主要因素,并对早期的成岩物质组分造成强烈影响;讨论了层序对成岩演化的控制作用,主要体现在3个方面:a.层序发育控制了原始成岩组分,进而控制后期成岩改造;b.早期成岩作用对层序发育过程具有一定的响应关系,后期成岩改造掩盖了部分成岩响应;c.层序界面通过河流作用、沉积间断减缓压实作用、后期成岩流体的侵入作用对成岩演化造成影响。Based on stratigraphic sequence,thin-section analysis,SEM observation,vitrinite reflectance,X-ray diffraction and geochemical investigation,the authors systematically studied the relationship between the stratigraphic sequence and diagenesis.The results show that different stratigraphic sequence tracts have different diagenetic responses：crypto-crystal carbonate,anhydrite,iron pyrite are existent in the low tract;ferrous carbonate cementation and clay mineral cementation occur in the expanded tract;dolomite cementation,ferrous dolomite cementation,corrosion,clay mineral cementation exist in the high tract,and corrosion phenomenon and ferrous carbonate cementation are found near the stratigraphic sequence boundary.During the development of the stratigraphic sequence,the original fluid and the enrichment regularity of elements made up the main factors for generating the diagenetic response and affected the components of diagenesis.The control role of the stratigraphic sequence in diagenetic evolution finds expression in three aspects：a.The development of stratigraphic sequence controlled the original components of diagenesis and further controlled the reconstruction of late diagenesis.b.Early diagenesis had some response to the stratigraphic sequence development,whereas late diagenesis covered up most of the diagenestic response.c.Stratigraphic sequence boundary affected the diagenetic evolution by stream action,depositional interruption slowing down the compaction,and late fluid invasion.

关 键 词：层序 成岩演化 断陷湖盆 沙河街组 早期成岩 成岩响应 

分 类 号：P539.2[天文地球—古生物学与地层学]