This study contributes long-term (14 to 38 months) experimental evidence for geocatalytically mediated methanogenesis in immature to early mature shale and coal source rocks at temperatures from 80 to 120 °C. Borosilicate glass tubes with pre-outgassed coal and shale source rock chips and water were sealed under vacuum, sterilized, heated isothermally, and finally opened in connection with a vacuum line where headspace gases methane (CH₄) and carbon dioxide (CO₂) were collected. The possibility of admitting pre-existing CH₄ from closed pores into product gases during heating experiments was evaluated by comparative ball milling of original and heated rock chips, followed by quantitation of released gases with a novel closed-circuit laser-based SARAD RTM2200 gas detector system with sub-µmol sensitivity. The yields of produced CH₄ from individual source rocks were corrected by subtracting the amounts of pre-existing CH₄ from formerly closed pores in original source rocks that had leaked during long-term heating. Different shales and coals express contrasting propensities to geocatalytically generate CH₄ and CO_2, with CH₄ yields ranging from 0.1 to 5.5 µmol g⁻¹ total organic carbon (TOC). CH₄ yields from two petrographically different samples of Springfield Coal with comparable thermal maturity suggest that liptinite expresses a far higher propensity for methanogenesis, but liberates less CO₂ than vitrinite. Shale from the Second White Specks Formation generated approximately 10 times more CH₄ than New Albany Shale per g of TOC, further suggesting complex controls on CH₄ generation during catalytic methanogenesis. Higher temperature can enhance the activities of catalytic methanogenesis. The extrapolation of laboratory-based reaction rates to natural conditions in organic-rich buried sediments suggests that geocatalytic methanogenesis can be fast enough in some source rocks to generate economically sizeable gas plays from immature to early mature source rocks over geologic time.

这项研究为长期（14至38个月）的实验证据提供了从80到120°C温度下未成熟到早期成熟的页岩和煤源岩的地质催化介导的甲烷生成作用。将具有预除气的煤和页岩气源岩屑和水的硼硅酸盐玻璃管在真空下密封，灭菌，等温加热，最后与真空管线连接，在真空管线中将顶空气体甲烷（CH ₄）和二氧化碳（CO ₂）集。承认先前存在的CH ₄的可能性通过对原始岩屑和加热后的岩屑进行球磨比较，然后使用新型的基于闭路激光的基于激光的SARAD RTM2200气体检测器系统（亚微摩尔灵敏度）对释放的气体进行定量分析，从而评估了加热实验过程中从封闭孔进入产品气体的过程。通过从长期加热过程中泄漏的原始烃源岩中以前封闭的孔中减去先前存在的CH ₄的量，可以校正各个烃源岩中产生的CH ₄的产量。不同的页岩和煤在地球催化生成CH ₄和CO _2方面表现出不同的倾向_， CH _4的产量范围为总有机碳（TOC）为0.1至5.5 µmol g ^-1。CH从两个岩石学不同的斯普林菲尔德煤样品（具有相似的热成熟度）得出的产率₄表明，锂皂石的甲烷化倾向高得多，但释放出的CO ₂却比镜质石少。第二克白色斑点组的页岩每克TOC比新奥尔巴尼页岩产生的CH ₄大约多10倍，进一步表明对CH _4的控制复杂在催化甲烷生成过程中产生。较高的温度可以增强催化甲烷生成的活性。基于实验室的反应速率对富含有机物的地下沉积物中自然条件的推断表明，在某些烃源岩中，地质催化甲烷生成的速度足够快，可以在地质时间内从未成熟到早期成熟烃源岩产生经济上可观的天然气矿藏。