Gold-tube pyrolysis experiments were conducted on miniature core plugs and powdered rock from a bitumen-rich sample of Eagle Ford Shale to investigate the role of rock fabric in gas generation and expulsion during thermal maturation. The samples were isothermally heated at 130, 300, 310, 333, 367, 400, and 425 degrees C for 72 h under a confining pressure of 68.0 MPa, corresponding to six levels of induced thermal maturity: pre-oil generation (130 degrees C/72 h), incipient oil/bitumen generation (300 and 310 degrees C/72 h), early oil generation (333 degrees C/72 h), peak oil generation (367 degrees C/72 h), early oil cracking (400 degrees C/72 h), and late oil cracking (425 degrees C/72 h). Experimental results show that gas retention coupled with compositional fractionation occurs in the core plug experiments and varies as a function of thermal maturity. During the incipient oil/bitumen generation stage, yields of methane through pentane (C-1-C-5) from core plugs are significantly lower than those from rock powder, and gases from core plugs are enriched in methane. However, the differences in C-1-C-5 gas yield and composition decrease throughout the oil generation stage, and by the oil cracking stage no obvious compositional difference in C-1-C-5 gases exists. The decrease in the effect of rock fabric on gas yield and composition with increasing maturity is the result of an increase in gas expulsion efficiency. Pyrolysis of rock powder yields 4-16 times more CO2 compared to miniature core plugs, with delta C-13(CO2) values ranging from -2.9%, to -0.6%0, likely due to carbonate decomposition accelerated by reactions with organic acids. Furthermore, lower yields of gaseous alkenes and H-2 from core plug experiments suggest that the rock fabric plays a role in promoting hydrogenation reactions of alkenes. (C) 2018 Elsevier Ltd. All rights reserved.

中文翻译：

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热成熟过程中岩石结构在气体生成和排出中的作用的实验研究：富含沥青的 Eagle Ford 页岩的无水封闭系统热解

对来自 Eagle Ford 页岩富含沥青样品的微型岩心塞和粉状岩石进行了金管热解实验，以研究岩石结构在热成熟过程中气体生成和排出中的作用。样品在 130、300、310、333、367、400 和 425 摄氏度下等温加热 72 小时，围压为 68.0 兆帕，对应六个诱导热成熟度：产油前（130 摄氏度） /72 小时）、初期产油/沥青（300 和 310 摄氏度/72 小时）、早期生油（333 摄氏度/72 小时）、峰值产油（367 摄氏度/72 小时）、早期石油裂解（400摄氏度/72 小时）和后期油裂化（425 摄氏度/72 小时）。实验结果表明，在岩心塞实验中发生了气体滞留和成分分馏，并且随着热成熟度的变化而变化。在石油/沥青生成初期，岩心塞通过戊烷（C-1-C-5）的甲烷产率明显低于岩粉，岩心塞中的气体富含甲烷。但在整个生油阶段，C-1-C-5 气产率和成分差异逐渐减小，至石油裂解阶段，C-1-C-5 气成分差异不明显。随着成熟度的增加，岩石结构对天然气产量和成分的影响降低是排气效率提高的结果。与微型岩心塞相比，岩粉热解产生的 CO2 多 4-16 倍，delta C-13(CO2) 值范围从 -2.9% 到 -0.6%0，可能是由于与有机酸反应加速了碳酸盐分解。此外，来自岩心塞实验的气态烯烃和 H-2 的产率较低表明岩石结构在促进烯烃的加氢反应中起作用。(C) 2018 Elsevier Ltd。保留所有权利。