银额盆地查干凹陷稠油油藏特征及成因  

The characteristics and genesis of heavy oil reservoir in Chagan Sag,Yingen-Ejinaqi Basin

作　　者：耿师江[1] 周勇水[1] 王亚明[1] 张莹莹 GENG Shijiang;ZHOU Yongshui;WANG Yaming;ZHANG Yingying(Exploration and Development Research Institute,Zhongyuan Oilfield Company,SINOPEC,Puyang 457001,China)

机构地区：[1]中国石化中原油田分公司勘探开发研究院,河南濮阳457001

出　　处：《断块油气田》2021年第4期463-469,共7页Fault-Block Oil & Gas Field

基　　金：国土资源部重点项目“‘十三五’全国油气资源评价”(2017YQZYPJ01)。

摘　　要：文中对银额盆地查干凹陷原油密度、黏度、族组成和生物标志化合物等特征进行了综合分析,以明确其稠油油藏的特征及成因。结果显示,查干凹陷发育生物降解和未成熟—低成熟2种成因类型的稠油,分别分布在1500 m以浅的苏二段(K1s2)、银根组(K1y)和2300~2450 m深度内的巴二段(K1b2)。未成熟—低成熟稠油正构烷烃分布完整,具有一定的双峰特征和明显的奇偶碳优势,各项成熟度生标参数均较低;生物降解稠油正构烷烃经历了不同程度的损失,各项成熟度生标参数均较高;生标特征指示2种成因类型稠油均来自K1b2烃源岩。凹陷构造演化史分析表明,K1s2末构造抬升过程中,K1s2已形成的古油藏遭受破坏,经历了不同程度的生物降解作用;新生代挤压反转阶段,乌力吉构造带K1s2稠油局部调整至K1y成藏,K1b2稀油油藏向上调整使得部分稠油油藏接受了再充注过程。现今发现的未成熟—低成熟稠油,均为新生代以后成藏。研究成果可为银额盆地稠油资源的勘探提供指导,也对油气成藏规律的研究具有指示意义。The characteristics of oil density,viscosity,composition and biomarkers in Chagan Sag of Yingen-Ejinaqi Basin are analyzed in this paper to clarify the characteristics and genesis of heavy oil reservoir.Two genetic types of heavy oil,biodegradation and immature or low-maturity,have been developed in Chagan Sag of Yingen-Ejinaqi Basin.Biodegraded heavy oil is mainly distributed in K1s2 and K1y with depth less than 1500 m,and immature or low-maturity heavy oil is concentrated in K1b2 with depths of 2300-2450 m.The n-alkanes in immature or low-maturity heavy oil is normal and complete,with certain bimodal characteristics and obvious odd-even carbon advantages and all the biomarker parameters of maturity are low.The n-alkanes in biodegradation heavy oil has experienced different degrees of loss,and various biomarker maturity parameters are high.The combination characteristics of biomarkers indicate that the two genetic types of heavy oil are from K1b2 source rocks.The analysis of structural evolution history of the depression shows that during the tectonic uplift at the end of K1s2,the ancient reservoirs derived from K1s2 were damaged and underwent different degrees of biodegradation.During the extrusion inversion stage of Cenozoic,K1s2 heavy oil reservoirs in the Uliji structural belt was partially migrated to K1y reservoir formation,and the upward migration of K1b2 normal oil reservoirs made some heavy oil reservoirs accept the re-filled process.The immature to low-maturity heavy oil discovered today is formed after Cenozoic.Heavy oil is an important petroleum resource.The study in this paper can provide guidance for the exploration of heavy oil resources in Yingen-Ejinaqi Basin,and also has significance indicative for the study of hydrocarbon accumulation law.

关 键 词：稠油 生物降解作用 未成熟—低成熟稠油 查干凹陷 银额盆地 

分 类 号：TE122.114[石油与天然气工程—油气勘探]