绿河页岩干酪根分步瞬时热解演化特征及机理研究

分步瞬时热解法可以有效的用于研究干酪根（或其他相关样品）结构组分随温度变化而演变的详细特征。利用分步瞬时热解法从300℃到600℃共分七个温度点，依次对绿河页岩干酪根样品进行热模拟分析。结果表明:在300℃时，绿河页岩干酪根样品基本没有热解产物，在350℃时可检测到少量吸附烃但含量极少；400℃、450℃和500℃是热解产物十分丰富的三个温度点，主要产物是成对出现的正构烷烃和直链烯烃，同时含有一定量的异构烷烃和姥鲛-1-烯；随着热解温度升高，异构烷烃和长链烃类的相对含量逐渐减少；姥鲛-1-烯在400℃和450℃一直占据主要地位；550℃出现了长碳链烷烃（C₂₇~C₃₂），很有可能是绿河页岩干酪根样品中类似于绿藻等的组分经高温裂解产生的；600℃之后热解产物基本消失，说明在低温阶段干酪根裂解作用就基本完全。另外，绿河页岩干酪根样品在不同温度点的瞬时热解均给出了相应的产物组分构成，对比研究发现，其产物种类及相对含量具有逐渐变化的特征，由此将更有利于研究干酪根的热演化及其成烃机制。

Study on Characterization and Mechanism of Thermal Evolution of Green River Shale Kerogen by Flash Stepwise Pyrolysis

Flash stepwise pyrolysis provide more efficient information than the simple one step pyrolysis for the same samples. This technique could be used to study on the specific thermal evolution trends of kerogen ( or other samples) and its changes of structural characteristics effectively with temperature increased. In this study, thermal simulation a-nalysis of was carried out by flash stepwise pyrolysis on the kerogen samples of the Green River shale at seven heating temperatures separatedly. There was almost no pyrolysed products at 300 ℃ while a little absorbed hydrocarbons ap-peared at 350 ℃. Three pyrolysis temperatures were enriched in pyrolysates at 400 ℃, 450 ℃and 500 ℃, respec-tively, and the pyrolysis products reached a peak at 450℃. The products were mainly in pairs of n-alkanes and n-al-kenes, accompanied by the gradual reduction of isoprenoids and long carbon hydrocarbons, prist-1-ene was the domi-nated single component at both 400℃and 450℃.;There were only a very small quantity of hydrocarbons liberated at 550 ℃. After 600 ℃, pyrolysates almost disappeared, indicating the thermal cracking mainly occurred at lower tem-peratures. These results may demonstrate that the pyrolysates by flash stepwise pyrolysis at temperatures from 300℃ to 600 ℃ with an interval of 50 ℃ could provide enough information for the study of thermal evolution and hydrocarbon generation mechanism of kerogen.