柴达木盆地东部三湖坳陷是新生代晚期形成的大型沉积坳陷,面积约37000km2。到目前为止,业已探明天然气地质储量数千亿立方米。通过对柴达木盆地东部第四系生物气成藏要素与气层分布关系的分析指出,对生物气源岩的评价不能搬用评价生油岩和过成熟气的指标(诸如有机质丰度和成熟度等),而应充分考虑在其沉积环境中有无抑制甲烷菌活动的因素存在,并提出了生物气成因评价的指标。

Through the analyses on the distribution relationship of gas layers and the formation  factors of gas reservoir for the Quaternary biological gas in the east part of Qaidamu basin, the paper points out that the evaluation for the source rock of  biological gas cannot adopt only such parameters as organic matter abundance and maturity adopted to evaluate the oil source rock and over-maturity gas, and the  factors of restraining the activities of methane bacteria inside the deposition environment should be fully taken into account. The evaluation criterion for the  formation of biological gas and the exploration direction are put forward by authors.