Coalbed Methane Well Production Forecasting

Abstract

ABSTRACT A method (NWFuel Method) has been developed to predict the cumulative production from coalbed methane (CBM) wells. This Method has been developed from actual production data from over 1,500 wells in the Black Warrior and San Juan Basins. The technique involves ranking of individual wells against a series of generic production curves. These generic curves are based on computer simulations representative of the respective basins. The assigned "Rank" provides an indication of the amount of production anticipated from a given well over its lifetime. Both water and gas production are predicted by this Method. Although the Method is not precise for individual wells, it should be statistically significant for groups of CBM wells. The technique involves ranking individual wells against a series of cumulative production curves. These generic curves are based on computer modeling of wells in the respective basin. It has been observed that most wells proceed along a given cumulative production curve, providing the basis for projecting future production. Applying the Method in the Black Warrior Basin indicates that the average CBM well in that Basin will produce about 200 MMCF (5.7 million m3) in ten years. This is the result based on an evaluation of 641 wells which were on line before 1990. The San Juan Basin typically has a considerably higher production potential per well. An average for the entire Basin is not meaningful. The best and worst wells in that Basin vary in their reserves by two orders of magnitude. The results from the NWFuel Method can be mapped. This allows one to associate production results with geological parameters. The subsequent result can enhance the exploration for new wells in a basin.