柴达木盆地乌南油田油源及油气运移探讨  

Discussion on oil sources and petroleum migration in the Wunan Oilfield, Qaidam Basin

作　　者：张明峰[1] 妥进才[1] 张小军[2] 吴陈君[1] 郭力军 

机构地区：[1]中国科学院油气资源研究重点实验室 [2]中国石油勘探开发研究院西北分院 [3]中国石油青海油田分公司勘探开发研究院

出　　处：《岩性油气藏》2012年第2期61-66,110,共7页Lithologic Reservoirs

基　　金：国家自然科学基金项目"蛇纹石化的气体地球化学研究"(编号:41103022);国家重点基础研究发展计划"973"项目"页岩气形成与含气性的影响因素研究"(编号:2012CB214705);中国科学院西部之光人才培养项目"柴达木盆地马北油气田成藏地球化学研究"(编号:Y134MF1ZMF)联合资助

摘　　要：对柴达木盆地乌南油田原油样品的地球化学系统分析表明:样品中正构烷烃系列碳数分布具有双重性模式,Pr/Ph值<0.5,呈强植烷优势;具有相对较高含量的三环萜烷和伽马蜡烷,藿烷C35/C34值基本上≤1;指示了乌南油田原油形成于半咸水—咸水湖相较强还原沉积环境,母质来源主要为低等水生生物,藿烷和甾烷成熟度参数反映其主要为低成熟原油。在此基础上开展油源对比研究,指出乌南油田原油和扎哈—切克里克生烃凹陷下干柴沟组烃源岩之间的生物标志化合物对比性很好。原油类型的一致性为应用含氮化合物探讨原油运移提供了基础条件。含氮化合物分析结果反映随着运移距离的增加,咔唑类化合物浓度存在减小的趋势,而异构体化合物中屏蔽型化合物相对富集,表明乌南油田原油自西注入,向北和东南方向运移。由此确定位于乌南油田西侧的扎哈—切克里克生烃凹陷为其油源区,从而为该区的进一步勘探提供了理论指导。The geochemical features of the crude oil samples collected from the Wunan Oilfield in southwestern margin of Qaidam Basin were analyzed.The result shows that the n-alkanes presented a bimodal distribution pattern（odd-toeven and even-to-odd carbon predominance）,with the low ratios for both Pr/Ph（ 0.5） and C 35-Hopane/C 34-Hopane（ 1.0）,and high contents of tricyclic-terpanes and gammacerane,which indicates that the crude oil formed in a midsalty to salty water reduction depositional environment,and the parent material are mainly from the lower aquatic organisms.Moreover,maturity parameters of hopane and sterane reflect its lowmaturity of crude oil.According to the oilsource correlation,the crude oil derived from the Xiaganchaigou Formation（E 3 2） of Zhaha-Qiekelike depression.The type of crude oil is more consistent from the same source,thus the significant oil-migration effects of nitrogen compounds in the oil are observed.The composition and relative abundance of nitrogen compounds in the crude oil were used to discuss the petroleum migration in the Wunan oilfield.With the increasing of the migration distance,the concentration of nitrogen compounds is decreased,which indicates that crude oil generated on its west adjacent depression,and migrated from west to north and from northwest to southeast.It is concluded that the crude oil in the study area came from the western Zhaha-Qiekelike depression.

关 键 词：生物标志化合物 含氮化合物 油源对比 油气运移 乌南油田 柴达木盆地 

分 类 号：TE122.1[石油与天然气工程—油气勘探]