MODELING OF GAS GENERATION IN COALS OF THE ZONGULDAK BASIN (NORTHWESTERN TURKEY)

The generation of ps in selected coal seams of the Zonguldak basin (northwestern Turkey) has been modelled by incorporating laboratory-derived non-isothermal reaction kinetics into the geothermal histories of the coal-bearing strata. Kinetic parameters have been determined by programmed-temperature open-system pyrolysis of a low-maturity (0. 5% R(o)) coal at three linear heating rates of 0.1, 0.7 and 5.0 K/min. The mathematical analysis of the bulk hydrocarbon evolution profiles, assuming 25 first-order reactions with activation energies regularly spaced between 46 and 70 kcal/mol and a single pre-exponential factor A, yielded a value of A = 3.17 . 10(16) Min-1 and a rather broad hydrocarbon potential vs. activation energy distribution with a maximum at 55 kcal/mol. Geological time-temperature relationships have been reconstructed by use of the basin modelling technique. Depending on the location within the basin of the wells studied and on the geological history of the coal-bearing sediments, the simulation procedure resulted in a predicted gas generation of up to 40 mg per g of coal.