--> ABSTRACT: Coalbed Methane Resource Potential, Eastern Upper Silesian Coal Basin, Poland, by Jeffrey R. Levine, Tim Hunt, Harvey Price; #91020 (1995).

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Coalbed Methane Resource Potential, Eastern Upper Silesian Coal Basin, Poland

Jeffrey R. Levine, Tim Hunt, Harvey Price

Coal seam gas potential was evaluated for a 280 km2 area in the eastern Upper Silesian Coal Basin (USCB), southern Poland. Selected data on coal thickness, coal quality, and gas composition were compiled from 176 wells. Nearly 8000 data records were included. Adjustments were needed to reconcile Polish data with North American data. Detailed structure contours and locations of over 200 faults were digitized from mine maps.

Compared with North American Carboniferous basins the USCB is exceptionally coal-rich, with as many as 30 to 50 individual seams encountered in each well. Coals become generally thicker and more numerous toward the west, with net coal thickness increasing from less than 20 m to more than 72 m. The shallower coals are depleted in CH4. The CH4/N2 ratio is near zero in shallow coals, but increases rapidly with depth to >80% within a "transition zone" usually around 200 meters thick. The transition zone defines a mappable surface, varying in depth from less than 200 m to more than 1000 m, roughly following the structural configuration of the basin. The degree of gas saturation of these coals remains to be reliably established.

Methane sorption isotherms, estimated individually for each coal seam, were used for resource estimation and producation simulations. Estimates of methane gas in place range from 10 × 106 to over 900 × 106 m3/km2 (1-80 BCF/mi2), generally increasing east to west, averaging around 386 × 106 m3/km2 (36 BCF/mi2). Production simulations predict that with multiple-zone completions accessing 67% of the coal seams, gas wells will produce at economic rates, given adequate permeabilities. Exploration for enhanced permeability will provide the key to success in this basin.

AAPG Search and Discovery Article #91020©1995 AAPG Annual Convention, Houston, Texas, May 5-8, 1995