尕斯库勒油田不同赋存状态烃类的地球化学特征

新疆石油地质 ›› 2007, Vol. 28 ›› Issue (5): 557-562.

尕斯库勒油田不同赋存状态烃类的地球化学特征

赵欣^1,2,3, 史基安¹, 王金鹏^1,3, 王琪¹, 王有孝¹

1.中国科学院地质与地球物理研究所, 兰州 730000;
2.长安大学地球科学与国土资源学院, 西安 710054;
3.中国科学院研究生院, 北京 100039

收稿日期:2006-11-12 修回日期:2006-12-27 出版日期:2007-10-01 发布日期:2020-08-03
作者简介:赵欣(1968-), 男, 陕西凤翔人, 讲师, 在读博士研究生, 地球化学,(Tel) 13992845326(E-mail) zhaoxin68@sina.com.
基金资助:
国家自然科学基金“油气聚集历史及成藏年代精细分析”(40272065)和中国科学院知识创新重要方向项目“中国西部典型沉积盆地优质油藏形成条件及动力学过程”(KZCX3-SW-128)资助

Geochemical Characteristics of Hydrocarbons in Different States in Gasikula Oilfield, Qaidam Basin

ZHAO Xin^1,2,3, SHI Ji-an¹, WANG Jin-peng^1,3, WANG Qi¹, WANG You-xiao¹

1. Institute of Geology and Geophysics, CAS, Lanzhou, Gansu 730000, China;
2. School of Earth Science and Land Resources, Chang'an University, Xi'an, Shaanxi 710054, China;
3. Graduate School, CAS, Beijing 100039, China

Received:2006-11-12 Revised:2006-12-27 Online:2007-10-01 Published:2020-08-03

摘要/Abstract

摘要： 通过对柴达木盆地尕斯库勒油田古近、新近系六个油砂样品中游离烃、封闭烃、碳酸盐胶结物烃、束缚烃和石英颗粒包裹体烃的分步分离和GC-MS分析,研究了不同赋存状态饱和烃馏分生物标记化合物的地球化学特征。研究结果表明,①正构烷烃的峰形为单峰型;碳数范围为nC₁₃—nC₄₂,在不同赋存状态烃中略有差异;碳优势指数(I_CP)小于1.2,具有较弱的奇碳优势;m(Pr)/m(Ph)值小于0.39,具有植烷优势,形成于强还原环境;高含量的伽马蜡烷指示了源岩的盐湖相沉积环境,不同赋存状态烃之间差异反映了盐湖的咸化演化过程。②油砂中不同赋存状态烃中含有丰富C₂₇规则甾烷、藿烷和长链三环萜,4-甲基甾烷的含量相对较高,显示出低等水生生物的藻类和细菌对成烃的贡献。m(C₂₉甾烷20S)/m[C₂₉甾烷(20S+20R)]和m(C₂₉甾烷ββ)/m[C₂₉甾烷(ββ+αα)]的比值表明不同赋存状态烃为低熟-成熟生油岩生成的原油。油藏储集层(油砂)中这些不同赋存类型(期次)烃类,反映出油气从烃源岩进入储集层成藏的先后差异。

关键词: 柴达木盆地, 尕斯库勒, 古近系, 新近系, 烃, 地球化学特征

Abstract: Based on the stepwise separation and extraction on free oil, sealed oil, hydrocarbon in carbonate cement, bounded oil and inclusion hydrcarbon within quartz grain in six oil sand samples from Paleogene system and Neogene system in Gasikula oilfield of Qaidam basin, all these hydrocarbons are analyzed by GC-MS. The biomarkers of saturated hydrocarbon fractions in different states and their geochemical characteristics are studied. The result shows that the n-alkanes with single peak are dominant in the studied area with the range of carbon number from nC₁₃ to nC₄₂, I_CP is lower than 1.2, being of weak odd-carbon preference. The ratio of m(Pr)/m(Ph) is lower than 0.39, being of phytane preference, assuming strong reducing environment. The high concentration of gammacerane indicates saline lacustrine depositional environment of source rocks. These differences of hydrocarbons in different states reflect the saline evolution process of lacustrine. Also, the relative high concentration of C₂₇ regular steranes, hopanes and long-chain tricyclene from the oil sands suggest significant contributions of bacteria and algae to formation of hydrocarbons. The ratios of m (C₂₉ sterane ₂₀S)/m [C₂₉ sterane (20S+ 20R)] and m(C₂₉sterane ββ)/m(C₂₉ sterane ββ+C₂₉ sterane αα) suggest that the hydrocarbons in different states are crude oils generated from low mature and mature source rocks, and also reflect the different filling steps of sources into reservoirs.

Key words: Qaidam basin, Gasikula oilfield, Paleogene, Neogene, hydrocarbon, geochemical feature

中图分类号:

TE112.113

赵欣, 史基安, 王金鹏, 王琪, 王有孝. 尕斯库勒油田不同赋存状态烃类的地球化学特征[J]. 新疆石油地质, 2007, 28(5): 557-562.

ZHAO Xin, SHI Ji-an, WANG Jin-peng, WANG Qi, WANG You-xiao. Geochemical Characteristics of Hydrocarbons in Different States in Gasikula Oilfield, Qaidam Basin[J]. Xinjiang Petroleum Geology, 2007, 28(5): 557-562.

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