哈拉哈塘凹陷奥陶系原油成藏期次的地球化学示踪  

Geochemical Tracking on Hydrocarbon Accumulation Periods of Ordovician in Hanilcatam Sag,Tarim Basin

作　　者：肖晖[1,2] 赵靖舟[1,2] 朱永峰[3] 李艳霞[1,2] 

机构地区：[1]西安石油大学地球科学与工程学院,西安710065 [2]西安石油大学陕西省油气成藏地质学重点实验室,西安710065 [3]中国石油塔里木油田分公司勘探开发研究院,新疆库尔勒841000

出　　处：《新疆石油地质》2013年第4期465-468,共4页Xinjiang Petroleum Geology

基　　金：国家科技重大专项(2008ZX05005-004-08HZ)

摘　　要：塔北隆起哈拉哈塘凹陷奥陶系原油正构烷烃分布完整,但色谱基线有不同程度的抬升;原油中普遍含有25-降藿烷;原油正构烷烃系列低碳数（nC15—nC26）的碳同位素偏重且变化平缓,高碳数（nC27—nC30）的碳同位素逐渐变轻,这些特征表明,该地区油藏经历了至少2期成藏过程,现今油藏以晚期充注原油为主。油包裹体红外光谱分析表明,早期充注原油为低成熟油,m（CH2）/m（CH3）为4.5~7.3,直链碳原子数约为18~25个;晚期充注原油m（CH2）/m（CH3）为1.9~2.8,直链碳原子数约为7~11个,为正常成熟原油。因此,塔北隆起哈拉哈塘凹陷现今原油为早期低成熟油遭受生物降解作用后又得到正常成熟度原油充注的混合原油。The normal alkanes of crude oils of the Ordovician in Hanilcatam sag in Tarim basin are complete in distribution,with varied rising of the chromatographic baselines,widespread 25-Hopane,partial heavier and gently carbon isotopes of nC15-nC26,and gradually lighter carbon isotopes of nC27-nC30.These features indicate that the reservoirs in this area underwent at least 2-period reservoir-forming processes,the oil source of present reservoirs are dominated by late charging oil.The oil inclusions infrared spectrum analysis shows that the early charging oil is low mature oil,with m（CH2）/m（CH3） value of 4.5~7.3,straight chain carbon atom number Xstd of 18~25;the late charging oil belongs to normal mature oil,with m（CH2）/m（CH3） value of 1.9~2.8,Xstd of about 7~11.Therefore,it is concluded that the oil in Hanilcatam sag nowadays is mixed crude oil charged by normal mature oil after experiencing biodegradation of early low mature oil.

关 键 词：塔里木盆地 哈拉哈塘凹陷 原油 油气地球化学 生物降解 成藏期次 

分 类 号：TE112.1[石油与天然气工程—油气勘探]