Objectives and problems to be solved:
This project aims at establishing an understanding of the basic scientific phenomena of CO2-CH4 adsorption, desorption, diffusion and flow in coal seams. This is fundamental to the industry's ability to exploit CO2 injection technology for improved methane recovery and CO2 sequestration. Laboratory isotherm measurements for single gases have demonstrated that coal can adsorb approximately twice as much CO2 by volume as methane. However, it is widely accepted by many researchers that the physical chemistry of this process has not yet been fully understood, and there remains the possibility that there are other physical processes active within the reservoir, which could alter this ratio. Latest binary gas mixtures adsorption/desorption research have confirmed that the extended Langmuir isotherm, which is commonly implemented in a number of coal bed methane simulators for modelling binary gas adsorption/desorption, does not represent this phenomena accurately.
Description of the work:
The objectives of the project would be achieved through experimental and theoretical work to be carried by the project partners. This work would first involve the petrographical and petrophysical characterization of European coals followed by experimental characterization of sorption and diffusion behaviour of CH4-CO2 mixtures in coal. The relative permeability of the cleat-matrix structure in coal as well as the capillary pressure and adsorption/desorption characteristics of CH4-CO2 mixtures at high pressure/high temperature environments will be studied in the laboratory. The findings of the experimental work will be used to develop a compositional simulator, which will be validated using real field data provided by the industrial partners. The simulator will be used to optimise of improved methane recovery and CO2 sequestration designs using coalfield data. Effective use of purpose built reservoir simulators, which are based on the fundamental understanding and formulation of the physical and thermodynamic processes, would enable more reliable assessment of European coal bed methane resources and the CO2 sequestration potential of coal seam reservoirs in Europe and world-wide.
Expected results and exploitation plans:
The project will lead to a better understanding of the phenomena of CO2 injection and retention in coal so that the fundamental mechanisms of water and CO2-CH4 sorption, diffusion and flow can be modelled under simulated reservoir conditions. The expected achievement is the development of a reliable CO2-ICBM recovery and CO2 sequestration simulator, which would incorporate the findings of this novel research. World coal resources are estimated at 25,000 billion tonnes, and the worldwide coal bed gas resource is estimated as 84-262 trillion cubic metres. The development of European technology and its indigenous coal bed methane reserves would increase our share of new, cleaner energy sources in the energy system, as well as facilitating a net reduction in global CO2 emissions. The commercial exploitation potential of the technology to be developed lies in its application worldwide, as a tool to assess improved coal bed methane recovery potential of coalfields and in their use as CO2 sinks.
Funding SchemeCSC - Cost-sharing contracts
EC2M 7BA London
2600 GA Delft
92852 Rueil Malmaison
ST5 1PQ Newcastle Under Lyme