Study of the kinetics of methane-carbon dioxide exchange in gas hydrates below the ice melting point. Experimental data and computational model.

Currently, gas hydrates are considered to be a potential resource of natural gas in the future. Vast quantities of gas hydrates deposits are located in the deep sea or in the permafrost zone. Among the other potential methods for extracting natural gas from these deposits is the injection of CO2 into a hydrate-bearing reservoir. This method assumes that carbon dioxide will replace methane molecules in the clathrate framework, so this method may be able to provide long-term burial for greenhouse gas CO2 along with the getting of burning gas. Understanding the kinetics of this process might be crucial for assessing the feasibility of implementation of this technology, but there is currently no clear understanding about the applicability of standard equations for heterogeneous reactions to describe the kinetics of this process. In this paper, we present some recent kinetic data on CH4/CO2 exchange at temperature below the ice melting point, focusing on the composition of hydrates. We also propose theoretical explanations for the obtained data.