The Carboniferous volcanic reservoir in the Chepaizi Uplift became an exploration hot target in recent years for its substantial amount of oils discovered. However, most of the Carboniferous heavy oils were biodegraded to PM7 or higher with orders of magnitude variation in oil viscosities. Two oil groups (I and II) exactly corresponding to the western and eastern Chepaizi Uplift were distinguished according to their source diagnose. Furthermore, three oil families (II₁, II₂ and II₃), with the biodegradation level of PM7, PM8–8+, PM9+, respectively, were classified based on molecular compositions and parameter-stripping method of strongly bioresistant parameters. Allowing for this extremely high biodegradation case, more biodegradation refractory compound class were added to establish a refined Manco scale to quantitatively evaluate the biodegradation extent. Refined Manco number (RMN₂) positively correlated with the oil density, NSO contents, and absolute concentrations of diasteranes and gammacerane, negatively correlated with the absolute concentrations of diahopane, summed tricyclic terpanes and pentacyclic terpanes. This refined scale showed higher resolution than the PM one to differentiate the biodegradation extent of Carboniferous heavy oils from the Chepaizi Uplift, especially those with same PM values but different oil viscosities.

近年来，车牌子隆起的石炭纪火山岩储层由于发现了大量的石油而成为勘探的热点。但是，大多数石炭系重油都被生物降解至PM7或更高，其油粘度变化了几个数量级。根据油源诊断，区分了与西部和东部切拍子隆起完全对应的两个油类（I和II）。此外，三个石油家族（II ₁，II ₂和II ₃），根据分子组成和强生物抗性参数的参数去除方法，分别对PM7，PM8-8 +，PM9 +的生物降解水平进行分类。考虑到这种极高的生物降解情况，增加了更多的生物降解难降解化合物类别，以建立精制的Manco标度，以定量评估生物降解程度。精致的Manco号码（RMN ₂）与油密度，NSO含量以及非硬脂烷和γ-甘油的绝对浓度成正相关，与二ahopane，加成的三环萜烯和五环萜烯的绝对浓度成负相关。这种精细的规模显示出比PM更高的分辨率，从而区分了石牌子隆起的石炭系稠油的生物降解程度，特别是那些具有相同PM值但油粘度不同的石脑油。