Abstract

Network of naturally occurring microfractures, called cleats provide the important parameter for flow modeling in coal. In any coal bed methane (CBM) prospect, the key of estimating production potential lies in presence of cleat networks/ fractures in coal seam. The paper presents the detailed study of coal cleats /fractures identified in coal samples recovered from three R&D wells drilled in Jharia coalfield, India. Generally five different types of natural fractures are observed in CBM prospective coals. In Jharia coal seams, four types of natural fractures i.e. face cleats, butt cleats, tertiary cleats and joints have been identified with the help of CT scan imaging technique. These natural fractures have great influence on porosity and permeability of coal. Cleat porosity and permeability have been determined in the range of 3.01 % to 5.93% and 0.03 mD to 2.88 mD respectively. Detailed description of these parameters of coal could be useful for coal characterization, its flow modeling and performance prediction for any successful exploitation of CBM.