论文部分内容阅读
生物气源岩生成的是以甲烷为主的天然气,而生油岩生成的主要是液态烃,后者的研究与评价方法已不完全适用于生物气,因而不能用有机碳含量、烃含量等指标来评价生物气源岩。为此建立了一套生物气源岩的综合评价方法:①用Ro来反映演化指标,生物气源岩沉积在未—低熟演化阶段,其Ro<0.7%;②以nC21-/nC22+来反映生源指标,对于生物气源岩来说,富氢、富氧混源输入是有利的;③以姥鲛烷/植烷比值(Pr/Ph)作为环境指标,Pr/Ph低是还原环境加强的结果;④以主峰碳数作为降解指标,奇数碳为主峰的生物气源岩产气率高,偶数碳为主峰的生物气源岩产气率较低。该综合评价方法适用于柴达木、莺—琼、河套和松辽等盆地。
Biogas source rocks generate natural gas, which is dominated by methane. However, the source rocks generate mainly liquid hydrocarbons. The latter research and evaluation methods are not fully applicable to biogas and can not be used for organic carbon content, hydrocarbon content, etc. Indicators to evaluate biogas source rock. Therefore, a comprehensive evaluation method of biogas source rock is established: ① Ro is used to reflect the evolution index; biogas source rocks are deposited in the non-low-maturity stage with Ro <0.7%; ② nC21- / nC22 + For biogas source rocks, the enrichment of hydrogen and oxygen is beneficial. ③ Pr / Ph is the environmental index of pristane / phytane ratio (Pr / Ph) The results showed that the biogas source rock with high peak carbon number as the degradation index and the dominant peak of odd carbon had high gas yield and low carbon gas source rock. The comprehensive evaluation method is suitable for Qaidam, Ying-Qiong, Hetao and Songliao basins.