济阳坳陷三合村洼陷古近系原生型稠油成因机制  

Genetic Mechanism of Paleogene Primary Heavy Oil in Sanhecun Sag of Jiyang Depression

作　　者：高长海[1] 张新征 王兴谋[3] 张云银[3] 李豫源 GAO Changhai;ZHANG Xinzheng;WANG Xingmou;ZHANG Yunyin;LI Yuyuan(School of Geosciences,China University of Petroleum,Qingdao 266580,Shandong,China;Geological Logging Company,SINOPEC Shengli Petroleum Engineering Co.Ltd.,Dongying 257064,Shandong,China;Geophysical Research Institute,SINOPEC Shengli Oilfield Branch Company,Dongying 257022,Shandong,China)

机构地区：[1]中国石油大学(华东)地球科学与技术学院,山东青岛266580 [2]中石化胜利石油工程有限公司地质录井公司,山东东营257064 [3]中国石化胜利油田分公司物探研究院,山东东营257022

出　　处：《地球科学与环境学报》2018年第2期176-185,共10页Journal of Earth Sciences and Environment

基　　金：国家科技重大专项项目(2016ZX05006-007);山东省自然科学基金项目(ZR2017MD028);中国石化科技攻关项目(P15084)

摘　　要：济阳坳陷三合村洼陷古近系发育稠油,但其成因机制尚不明确,制约了该区稠油的勘探与开发。通过42个稠油样品的物性、族组成以及地球化学分析,结合烃源岩生排烃史以及原油运聚特征,探讨了三合村洼陷古近系稠油的成因机制。结果表明:渤南洼陷沙四段烃源岩具备低熟油的生烃条件;古近纪东营组沉积末期,沙四段膏盐湖相烃源岩进入低成熟演化阶段,咸化还原环境的早期生烃作用促使其生成低熟油;热化学硫酸盐还原作用造成原油密度、黏度、硫含量增大,这些原油通过古近系与前第三系之间的不整合输导层近距离运移至三合村洼陷古近系沙三段地层圈闭中聚集成藏,由于埋藏较浅,后期遭受轻微生物降解作用而进一步稠化。综上所述,三合村洼陷古近系稠油为低熟油经热化学硫酸盐还原作用、生物降解作用稠变而成,属于原生蚀变型稠油。The Paleogene heavy oil develops in Sanhecun sag of Jiyang depression,and the misunderstanding of genetic mechanism leads to the restriction of further exploration and development.The physical properties,group composition and geochemistry characteristics of 42 heavy oil samples were analyzed;combined with the history of hydrocarbon generation and expulsion,and the characteristics of hydrocarbon migration and accumulation,the genetic mechanism of Paleogene heavy oil was discussed.The results show that the source rocks of member 4 of Shahejie Formation in Bonan sag have the condition of hydrocarbon generation with low mature oil;at the end of Dongying period,the salt-lake facies source rocks of member 4 of Shahejie Formation enter into the low-mature evolution stage,and form low-mature oils through the early-stage hydrocarbon generations of salt reduction environment;the thermochemical sulfate reduction causes the increase of density,viscosity and sulfur content of low-mature oils,and the oils migrate at a short distance into Sanhecun sag through the unconformity carrier between Palaeogene and pre-Tertiary,and then accumulate in the stratigraphic overlap traps of member 3 of Palaeogene Shahejie Formation,and suffer from slight biodegradation due to low embedded depth,which causes further oil densification.In conclusion,the Paleogene heavy oils in Sanhecun sag belong to the primary altered type,which is mainly generated from densification of thermochemical sulfate reduction and biodegradation on low-mature oils.

关 键 词：地球化学 原生型稠油 低熟油 热化学硫酸盐还原作用 生物降解作用 济阳坳陷 

分 类 号：TE122.1[石油与天然气工程—油气勘探] P618.130.1[天文地球—矿床学]