摘要
塔里木盆地顺北地区奥陶系储层油气勘探潜力巨大,是目前超深层油气勘探重要的研究区域之一。顺北1号和5号断裂带位于顺北油田中部,厘清该区域原油的来源、热成熟度、油裂解程度以及控藏因素对揭示该地区油气成藏模式,指导后期油气勘探至关重要。选取了顺北油田1号及5号走滑断裂带19个原油样品进行饱和烃、芳烃、金刚烷及碳同位素分析,以揭示其地球化学特征。研究结果表明,1号和5号断裂带的原油样品均遭受了不同程度的热应力改造,传统生标参数失真且无法用于指示油源。相似的轻烃碳同位素分布特征指示研究区内原油属于同一族群。原油正构烷烃碳同位素值介于–37‰~–30‰,与寒武系烃源岩具有可比性,认为该区原油均产自下寒武统玉尔吐斯组。5号断裂带原油的成熟度自北向南呈现逐渐增加的趋势,芳烃参数换算的原油等效镜质体反射率平均值介于0.80%~1.43%,指示原油处于成熟-高成熟阶段。1号断裂带南北两侧原油成熟度差异不大,与5号断裂带中部原油的成熟度相当,总体介于1.06%~1.20%,原油处于成熟阶段。研究区原油裂解程度强弱排序依次为5号断裂带南段、5号断裂带北段及1号断裂带。综合分析认为,走滑断裂带发育特征与储层温度差异共同控制着顺北地区1号和5号断裂带油气物性及地化参数变化。该研究可为顺北地区超深层油气勘探提供指导。
The Ordovician reservoir in the Shunbei area has great potential for oil and gas exploration.It is one of the most important research areas for ultra-deep oil and gas exploration.Shunbei No.1 and No.5 fault zones are located in the middle of Shunbei Oilfield.It is very important to clarify the source,thermal maturity,oil cracking degree and reservoir-controlling factors of crude oil in this area to reveal the hydrocarbon accumulation model and guide the later oil and gas exploration.In this paper,19 crude oil samples from No.1 and No.5 strike-slip faults in Shunbei Oilfield were selected for saturated hydrocarbon,aromatic hydrocarbon,adamantane and carbon isotope analysis to reveal their geochemical characteristics.The results show that the crude oil samples of No.1 and No.5 fault zones have been subjected to different degrees of thermal stress transformation,and the traditional biomarker parameters are distorted and cannot be used to indicate the oil source.The similar light hydrocarbon carbon isotope distribution characteristics indicate that the crude oil in the study area belongs to the same group.The n-alkane carbon isotope values of the crude oil range from–37‰to–30‰,which is comparable to the Cambrian source rocks.It is considered that the crude oil in this area is produced from the Lower Cambrian Yuertus Formation.The maturity of crude oil in the No.5 fault zone gradually increases from north to south.The average value of crude oil equivalent vitrinite reflectance converted by aromatic hydrocarbon parameters is between 0.80%and 1.43%,indicating that the crude oil is in the mature-high mature stage.The maturity of crude oil on the north and south sides of the No.1 fault zone is not much different,which is equivalent to the maturity of crude oil in the middle of the No.5 fault zone.The overall maturity is between 1.06%and 1.20%,and the crude oil is in the mature stage.The order of crude oil cracking degree in the study area is the southern section of No.5 fault zone,the northern section of No.5 fault zone and No.1 fault zone.Comprehensive analysis shows that the development characteristics of strike-slip fault zone and the difference of reservoir temperature jointly control the changes of oil and gas physical properties and geochemical parameters of No.1 and No.5 fault zones in Shunbei area.This study can provide guidance for ultra-deep oil and gas exploration in Shunbei area.
作者
朱莲花
徐珊
ZHU Lianhua;XU Shan(Exploration and Development Research Institute,Northwest Oilfield Branch of Sinopec,Urumqi,Xinjiang 830000,China)
出处
《世界石油工业》
2024年第4期58-68,共11页
World Petroleum Industry
基金
中国石油化工股份有限公司科技与信息管理部项目“顺北东部多类型储集体成藏主控因素与目标评价”(P23078)。
关键词
塔里木盆地
顺北地区
走滑断裂带
地球化学特征
控藏因素
Tarim Basin
Shunbei area
strike-slip fault zone
geochemical characteristics
factors of controlling reservoir
