Fracture/cleat analysis of coals from Zonguldak Basin (northwestern Turkey) relative to the potential of coalbed methane production

In this study, the fracture structure of three coals (Sulu K-1, Acihk K-2 and Cay Dogu Ayak) from two different seams in the Zonguldak Basin located on the Black Sea coast of Turkey have been analyzed in relation to coalbed methane recovery. X-ray computerized tomography (CT), light microscopy image analysis and scanning electron microscopy (SEM) analysis have been performed on mine coal samples to have a better understanding of distribution of minerals, fracture morphology and apertures and matrix/fracture interactions via examination of fracture surfaces. Results show that the Acihk and Sulu coals seem to be structurally more prone to be commercially productive. These coals show a high degree of fracturing and cleat development as evidenced by X-ray CT and light microscopy examination of polished surfaces. Although the Cay Dogu Ayak coal shows a high fracture density, the cleat surface morphology and smaller fracture apertures may make this coal unfavorable for gas flow. (C) 2000 Elsevier Science B.V. All rights reserved.