ABSTRACT
This paper presents methane production analysis of thin-bedded coal seams separated by low permeability streaks. Applications of predicting flow responses of vertical, horizontal, undulating and cavity-completed wells are demonstrated for various coal seams. Effectiveness of each type of well completion in triggering methane desorption process is analyzed. As expected, horizontal wells drilled parallel to butt cleats are more effective than cavity-completed wells in accelerating methane production. However, horizontal wells may become ineffective in thin-bedded coal seams separated by low permeability streaks. In these cases, conductivity of permeability streaks controls the productivity of horizontal wells. It is also observed that undulating wells that partially penetrate the isolated layers have the potential of draining coal seams more effectively than vertical, horizontal and cavity-completed wells.
