湖相页岩不同赋存状态的可溶有机质定量表征

湖相页岩中可溶有机质可分为游离态、吸附态以及互溶态。不同赋存状态可溶有机质定量研究对油气资源评价、页岩油可动性、烃源岩生烃机理及油气赋存机理研究等具有重要意义。通过不同极性溶剂的组合，对中国东部2种不同岩相的湖相页岩进行了逐次分级抽提，获取了游离态、干酪根吸附-互溶态以及矿物表面吸附态等3种不同赋存状态的可溶有机质含量，并对不同赋存状态的可溶有机质进行地球化学组分分析。分析结果显示，湖相页岩中干酪根吸附-互溶态可溶有机质占有较大比例，其次为游离态有机质。游离态可溶有机质主要以轻质组分为主，压裂有利于轻质组分的析出。干酪根吸附-互溶态可溶有机质主要以中-重质组分为主，同时含有部分轻质组分。岩石矿物表面吸附的可溶有机质主要以含氧杂原子化合物为主。相比纹层不发育的块状页岩，纹层状页岩中游离态可溶有机质占有比例更高，更有利于页岩油的开发。 

Quantitative characterization of extractable organic matter in lacustrine shale with different occurrences

The extractable organic matter (OM) in lacustrine shale can be classified into free, adsorbed or miscible states. The quantitative study of OM of these different occurrences has significance for oil/gas resource evaluation, shale oil mobility, hydrocarbon generation mechanism and oil/gas occurrence. Two lacustrine shale samples of different lithofacies from East China were successively extracted by solvents with different polarities. Three different occurrence states of soluble OM were obtained, including free, kerogen adsorptive-miscible and mineral surface adsorptive states, which were characterized using FT-IR spectra and GC-FID analyses. The kerogen adsorptive-miscible state accounts for a large proportion of the soluble OM, followed by the free OM. The free soluble OM was dominated by light compounds, and fracturing was conducive to the precipitation of light components. The kerogen adsorptive-miscible state OM mainly had heavier components, and also contained a lower portion of light fractions. The mineral surface adsorbed OM was mainly comprised of oxygen-containing compounds. Compared to the massive shale samples, the laminated shale samples had a higher proportion of soluble OM, and the hydrocarbon molecules were smaller.