Methanogenic bacteria as a key factor involved in changes of town gas stored in an underground reservoir

Abstract

The microbial population present in stratal water withdrawn from an underground town gas reservoir transformed H2 and CO2, which are the obligatory constituents of town gas, to methane. By a common procedure one type of mesophilic Gram‐positive methanogenic bacteria was enriched. The bacteria grew and produced methane with H2+ CO2 only. This finding suggests that methanogenic bacteria present in the underground town gas reservoir could be responsible for the consumption of hydrogen and carbon dioxide from the stored town gas, causing a diminution of the gas volume and an enrichment of the gas with methane. An isotropic analysis of the stored town gas, in which °13C for methane around −80% was found, supports this suggestion.

Hydrogeochemical Modeling to Identify Potential Risks of Underground Hydrogen Storage in Depleted Gas Fields

“…Typical environments for methanogenic bacteria are, for example, anoxic sediments and flooded soils [21]. However, the existence of methanogenic bacteria was also observed in town gas storages [22]. Methanogenic bacteria prefer temperatures of 30-40 • C for growth [10], but they also have been found at higher temperatures of 80 • C [23,24] and up to 97 • C [10,25].…”

“…With these bacteria, H 2(aq) is the electron donor and CO 2(aq) is the electron acceptor, which is reduced to form CH 4(aq) . The methanogenic bacteria obtain their energy for cell growth from this conversion [21,22]. The problem associated with methanogenesis lies in the loss of hydrogen and the related energy loss [2].…”

“…where ψ growth max is the maximum specific growth rate (mol L −1 s −1 ), c s is the concentration of the limiting substrates (mol L −1 ), and α is the half-velocity constant. The maximum specific growth rate that is assumed in the model is 2.30 × 10 −9 mol kgw −1 s −1 for methanogenesis (at 37 • C) [22] and 9.26 × 10 −8 mol kgw −1 s −1 for BSR (at 30 • C) [52]. For bacterial sulfate reduction, the limiting substrate is sulfate and for methanogenesis it is carbon dioxide.…”

Enhancing Hydrogen Recovery from Saline Aquifers: Quantifying Wettability and Hysteresis Influence and Minimizing Losses with a Cushion Gas

“…To address this issue, researchers recommended using alternative gases to be injected as cushion gas to decrease H 2 loss in the formation, increasing H 2 recovery, and reducing the project's budget [15,16]. In alignment with the operational frameworks observed in European town gas storage projects, where H 2 constitutes up to 60% of the storage volume along with a blend of other gases including CH 4 , N 2 , and CO 2 , researchers have proposed employing these gases as an alternative cushion gas in underground H 2 storage [17]. It is crucial to emphasize that commercialscale underground H 2 projects in depleted gas reservoirs or saline aquifers have not been carried out yet.…”