Modelling of ECBM recovery from Amasra Coalbed in Zonguldak Basin, Turkey

Bartin-Amasra coal field was found convenient for enhanced coalbed methane (ECBM) recovery among the other fields in Zonguldak Coal Basin, Turkey. The lithologic information were examined and the depths of the coal seams and the locations of the wells were visualized to perform a reliable correlation between 63 coal layers existed in the area. The initial methane in place found in the coal layers both in free and adsorbed states were estimated using probabilistic simulations resulted in possible reserve (P10) of 72.97 billion scf, probable reserve (P50) of 47.74 billion scf and proven reserves (P90) of 30.46 billion scf. Since the Amasra coal reservoir is not saturated with water, almost 10% of the total gas in place was found to be in the cleats as free gas. ECBM recovery was simulated with CMG-GEM module using Coal Layer #26 which has more initial gas in place, average thickness of 1.8 m and depth of 545 m. The effects of adsorption, compressibility, density, permeability, permeability anisotropy, and porosity and water saturation parameters were examined. Cumulative methane production was enhanced with the injection of CO2 approximately 23% more than that of CBM recovery. Injected CO2 amount of 5192 tonnes/year in layer #26 was only capable to sequester only 0.3% of the yearly CO2 emission of Zonguldak Catalagzi Power Plant nearby. Considering the gas in place capacity of the coal layer #26 as 15% of the resource area-A, it can be said that the project aiming ECBM recovery rather than CO2 sequestration would be successful