东营凹陷樊页1井沙河街组烃源岩元素地球化学特征及其地质意义  

Element geochemical characteristics of source rocks in the Shahejie Formation in Well Fangye-1,Dongying sag and their geological significance

作　　者：刘庆[1] 

机构地区：[1]中国石化胜利油田分公司勘探开发研究院,山东东营257015

出　　处：《油气地质与采收率》2017年第5期40-45,52,共7页Petroleum Geology and Recovery Efficiency

基　　金：国家科技重大专项"渤海湾盆地剩余油气资源潜力研究"(2016ZX05006-001);中国石化油气勘探开发领域重大项目"济阳坳陷油气聚集规律与精细评价关键技术"

摘　　要：为明确东营凹陷樊页1井沙河街组烃源岩元素地球化学特征及其地质意义,对其主量和微量元素组成进行系统分析。根据不同元素含量与Al_2O_3等含量的相关性,将其分为3种类型:第1种类型包括Al,Ti,K,Co,Cr,Ga和V等,以陆源碎屑来源为主;第2种类型包括Ca,Mg,Mn和Sr等,以水成来源为主;第3种类型包括Na,Fe,Cd,Ni,Pb,Ba和Zn等,具有多元复杂来源。根据元素来源的差异,优选CaO/Al_2O_3,Sr/Al_2O_3,Sr/Ba和V/(V+Ni)这4个参数,建立综合地球化学剖面,根据各参数在剖面中的变化分析沙河街组烃源岩沉积环境的演变。从沙四段上亚段—沙三段中亚段,水成来源元素富集程度逐渐下降,湖水盐度逐渐降低,底水还原性逐渐减弱。根据各参数纵向差异及变化特征,将沙四段上亚段和沙三段下亚段划分为4个更小的沉积单元,其古盐度和底水的氧化、还原条件存在明显的差异。The major and minor elements of source rocks in the Shahejie Formation drilled by Well Fanye-1 in Dongying sag were analyzed systematically in order to clarify the element geochemical characteristics of the source rocks and their geological significance. According to the relation of contents of different elements with Al_2O_3 and CaO,the elements are classified into 3 different types. The elements of the first class,including Al,Ti,K,Co,Cr,Ga and V,are mainly sourced from terrestrial debris;those of the second class,which consist of Ca,Mg,Mn and Sr,are mainly sourced from lacustrine water;and those of the third class,including Na,Fe,Cd,Ni,Pb,Ba and Zn,are sourced from multiple and complex sources.Based on the genetic difference of the elements,4 parameters including CaO/Al_2O_3,Sr/Al_2O_3,Sr/Ba and V/(V+Ni)were preferably selected to set up a vertical comprehensive geochemical section,and the sedimentary environment evolution of the Shahejie Formation was discussed according to the changes of the parameters in the geochemical section. It shows that from the upper Es_4 to the middle Es_3,the enrichment of the elements sourced from the water gradually decreases and the salinity of the lake water gradually drops,and the reducibility of bottom water is gradually weakened. Based on the variation tendency,both the upper Es_4 and the lower Es_3 can be subdivided into four smaller sedimentary units where the palaeo-sa-linity and bottom water redox condition are obviously different.

关 键 词：烃源岩 主量元素 微量元素 湖泊演化 沙河街组 东营凹陷 

分 类 号：TE125.6[石油与天然气工程—油气勘探]