煤、油、气共存富集的地球化学判识模式

The Geochemical Model of Petroleum,Natural Gas and Coal Multi-resource System

油、气、煤都是由生物先质经有机质的成岩和变质作用转变而成的,生物先质的转化方向取决于沉积有机相。沉积有机相由于集沉积学、有机岩石学和有机地球化学于一体,所以是综合评价盆地煤、油、气等能源矿产成矿潜力的最有效方法。本文通过对油、气、煤生成的地球化学条件综合分析,提出以显微组分分析为基础的四端元划分法则划分沉积有机相和综合判识油、气、煤成矿潜力,将鄂尔多斯盆地中生界和中国东南部吴家坪期沉积划分为高位木本有机相(A)、低位木本有机相(B)、低位木本-残殖壳屑有机相(C)、覆水木本-藻质有机相(D)、深覆水草本-藻质有机相(E)和开阔水体藻质有机相(F),典型的油源岩和典型的腐殖煤是两种极端的有机相,也是鄂尔多斯和其它煤、油、气共存盆地的共同特征和主要的有机相类型,但鄂尔多斯盆地中生界和萍乐盆地龙潭组存在一系列的由煤到油转化的过渡类型的有机相,对油、气、煤成因理论及多种能源共同勘探有着重要的意义。利用多元统计分析将沉积有机相进行了数值化,将各种不同类型的沉积有机相按其对成油、成气和成煤的贡献大小进行赋值,提出了沉积有机相类型指数的数学模型,为可燃有机矿产共存富集的地球化学定量判识提供了基础。

Through diagenesis,catagenesis and metagenesis,biological sources form petroleum,natural gas,and coal.These processes are controlled by organic facies.Integrating sedimentology,organic petrology,and organic geochemistry,organic facies is the most effective method to evaluate the petroleum,natural gas,and coal productivity potential of a certain basin.By comprehensively analyzing the geochemical condition for petroleum,natural gas,and coal productivity,this paper proposes the four end models based on maceral analysis to characterize organic facies and evaluate the petroleum,natural gas,and coal productivity potential.With the method,Mesozoic strata of the Ordos basin and late Permian Wujiaping age strata of the Southeast China are depicted as upper woody plants facies （A）,lower woody plants facies （B）,lower woody plants-exinite facies （C）,shallow water woody plants-algae facies （D）,deep water herb-algae facies （E）,and aquatic algae facies （F）.Typical oil source rock and humic coal are respectively formed in aquatic algal facies and upper woody facies.Upper woody facies and aquatic algal facies are the main types of petroleum,natural gas and coal rich basin such as Ordos basin,but other transitional facies are found in Mesozoic strata of the Ordos basin and Late Permian Wujiaping Age strata of the Southeast China which extend the genesis theory of petroleum,gas and coal and multienergy exploration.By utilizing multistatistic analysis the authors develop an approach to numerical representation of organic facies,build up the organic facies type index model which computes the model value of contribution of organic facies to the genesis of petroleum,gas and coal and provide the basic method for geochemical quantitative modeling of combustible organic mineral concentration.