摘要
在西藏尼玛盆地东部赛布错凹陷发现呈东西向展布的沥青显示带,表明该区具有一定的油气勘探前景。为明确该沥青的地球化学特征及具体来源,对尼玛盆地采集的沥青样品进行了饱和烃气相色谱质谱分析,取得以下认识:该沥青处于成熟阶段;高碳数正构烷烃(>nC_(25))含量高,Σ(≤nC_(21))/Σ(≥nC_(22))、(nC_(21)+nC_(22))/(nC_(28)+nC_(29))比值较小,藿烷ααα-20RC_(29)优势较明显,说明在有机质的来源上陆源高等植物更占优势。将沥青样品与康嘎勒出露的牛堡组暗色岩系生物标志化合物特征进行对比分析,结果表明二者具有良好的亲缘关系,证实了尼玛盆地为自生自储的陆相含油气盆地。
An EW-trending oil and gas display belt with 80 km length was discovered in the Saibuya depression of eastern Nima Basin,which indicating satisfactory prospect of oil and gas.Analysis of saturated hydrocarbons by gas chromatography-mass spectrometry was carried out to determine the geochemical characteristics and specific sources of the bitumen.The results show that the bitumen is in the mature stage and has not suffered significant biodegradation.It is characterized by high carbon number alkanes(>nC_(25)),lowerΣ(≤nC_(21))/Σ(≥nC_(22))and(nC_(21)+nC_(22))/(nC_(28)+nC_(29)),with obvious advantage of hopane ααα-20RC_(29),which reveal the superior input of organic materials with terrigenous higher plants.The analysis of bituminous samples and comparison with the dark rock biomarkers of the Niubao Formation outcropped in Kangale show that they have a good genetic relationship,which confirms that the Nima Basin is a self-generating and self-storing continental petroliferous basin.
作者
徐博
伊海生
伍新和
XU Bo;YI Haisheng;WU Xinhe(Institute of Sedimentary Geology,Chengdu University of Technology,Chengdu 610059,Sichuan,China;Oil and Gas Survey Center,China Geological Survey,Beijing 100083,China)
出处
《地质通报》
CAS
CSCD
北大核心
2021年第9期1476-1483,共8页
Geological Bulletin of China
基金
国家自然科学基金项目《藏北羌塘盆地早中侏罗世过渡期缺氧事件沉积与碳同位素异常研究》(批准号:41572089)
中国地质调查局项目《尼玛盆地南部坳陷沉积、构造调查》(编号:DN0018)。
