江汉盆地原油轻烃的地球化学特征

Geochemical characteristics of the light hydrocarbons in Jianghan Basin, China

目前中国石油集团公司油气地球化学重点实验室原油轻烃数据库有548个中国油样的分析数据,样品基本覆盖了中国各个油区,具一定的代表性。在此基础上,选择江汉盆地(中国典型的盐湖相沉积盆地)原油轻烃的地球化学特征进行研究,它们具甲苯含量高、(2甲基己烷+2,3二甲基戊烷)/(3甲基己烷+2,4二甲基戊烷)值高的特征,推测可能与江汉盆地独特的沉积环境有关。原油轻烃中甲苯含量高和(2甲基己烷+2,3二甲基戊烷)/(3甲基己烷+2,4二甲基戊烷)值偏高的特征有望成为判别烃源岩沉积环境的地化指标之一。

The light hydrocarbon database established by the Key Laboratory of Petroleum Geochemistry （KLPG）, CNPC, has accumulated 548 oil sample records, covering almost all the oil areas in China. Based on the database, the light hydrocarbons from the typical salt lake sediment of Jianghan Basin, China, suggest that the oils are characterized by high content of toluene and high （2-MH＋2,3-DMP）/（3-MH4＋2,4-DMP） value. The reason is still unclear. It is supposed that it maybe related with the high-salinity environment. The light hydrocarbons with high toluene contents and abnormal （2-MH＋2,3-DMP）/（3＋MH＋2, 4＋DMP） value may be used as the geochemistry indicator of the deposition of the source rock.