Potencjał metanotwórczy węgli kamiennych w odniesieniu do ich pojemności sorpcyjnej oraz współczesnej ilości zakumulowanego metanu termogenicznego w złożu Pawłowice (Górnośląskie Zagłębie Węglowe)

Abstract

Methane associated with deposits of hard coal generates mainly as a result of thermal alterations of coal substance during coalification process. The one of quantitative indicators of generated gases is among others the volatiles (Vdaf) loss, i.e. more Vdaf loss involves more quantities of generated gases. Owing to this, the attempt was made to assess the possible quantities of generated gas within Paw³owice coal deposit based on the present Vdaf content in coal. The base of calculation is one of patterns of methane generation from coal seams worked out by Kowalski et al. (1995). On the ground of this, 100,604 mln m3 of generated methane within the area of research was estimated. This estimation was compared with sorption capacity of coal which was calculated based on sorption isotherms at 23,549 mln m3 and also with calculated value of currently accumulated thermogenic methane in coal deposit, which amounts about 5,358 mln m3. The obtained differences between the quantities of generated and currently accumulated methane have an interpretive meaning with reference to both scale of methane migration and degassing of coal series in geological past, and also possibilities of economic using for methane. Based on American experiences the economic reserves of methane for the investigated area were calculated at 373.69 mln m3. The dependence between the quantities of generated methane and current methane resources is well-known in the whole of the Upper Silesian Coal Basin and the same trend is observed in case of individual Paw³owice coal deposit which is well geologically prospected by the bore-holes.