Calibrating and validating a numerical model concept for microbially enhanced coal bed methane production with batch and column data

Simon Emmert,Robin Gerlach,Katherine Davis,Holger Class

doi:10.5194/egusphere-egu2020-9011

Abstract

&lt;p&gt;Microbially enhanced coal-bed methane (MECBM) production is an innovative idea to stimulate biogenic coal-bed methane production by providing nutrients to the native microbial community. Through additional substrate in the subsurface, a stimulation of microbes occurs, which leads to an increased methane production. Experimental studies, performed at Montana State University, provide the basis for modelling MECBM production with two-phase multi-component transport processes using the numerical simulator DuMuX [1].&lt;/p&gt;&lt;p&gt;We will present the calibrated and validated numerical batch model. The conceptual model comprises a food-web that includes two types of bacteria and three types of archaea representing substrate-specific members of the community with the corresponding biogeochemical reactions. These are derived from experimental studies [2]. The model is able to capture the interactions between different microbial groups, coal bioavailability, biofilm growth and decay as well as CH4 production.&lt;/p&gt;&lt;p&gt;The numerical batch model is extended to simulate column studies [3]. The model is being used to test hypotheses on different processes e.g. coal bioavailability and retardation or filtering effects when adding substrate. The numerical model provides a more detailed understanding of the relevant processes involved in MECBM production as well as a general understanding of biogeochemical reactions coupled with possibly changing flow and transport conditions in the subsurface. This model will be an instrumental tool in further development of a more sustainable method of harvesting methane from unmineable coal-beds.&lt;br&gt;&lt;br&gt;[1] Koch, Timo, et al. &quot;DuMu&lt;sup&gt;X&lt;/sup&gt;3--an open-source simulator for solving flow and transport problems in porous media with a focus on model coupling.&quot; &lt;em&gt;arXiv preprint arXiv:1909.05052&lt;/em&gt;&amp;#160;(2019).&lt;br&gt;[2] Davis, Katherine J., et al. &quot;Biogenic Coal-to-Methane Conversion Efficiency Decreases after Repeated Organic Amendment.&quot;&amp;#160;&lt;em&gt;Energy &amp; fuels&lt;/em&gt;&amp;#160;32.3 (2018): 2916-2925.&lt;br&gt;[3] Davis, Katherine J., et al. &quot;Biogenic coal-to-methane conversion can be enhanced with small additions of algal amendment in field-relevant upflow column reactors.&quot; Fuel 256 (2019): 115905.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;

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