Publications

Different characteristics of coal bed reservoirs and conventional natural gas reservoirs give rise to several limitations of the utilization of conventional oil and gas technologies in coal bed methane processes. These differences are most apparent on the storage and flow mechanism of fluids from their initial location to the production facilities. In CBM process, the well commonly will produce high water rate in the early phase of production which would give the need of produced water separators and other treatment facilities such as disposal pond. However, this high water rate decreases significantly as production proceeds and gas rate starts to increase to peak production then slowly decline. The the low tubing head pressure (THP) also requires well head compression of coalbed methane (CBM) gas into the main compression station. On the positive side, the relatively pure composition of methane in CBM might result in simpler produced gas processing. The different mechanism of storage and flow of gas in te reservoir of coal bed and conventional natural gas reservoir causes different interference between wells in the field. In CBM fields closer well spacing results in more efficient dewatering thus increasing more gas production. Other factors influencing the well spacing are permeability anisotropy, thickness, and porosity of the coal seam relate to the effectiveness of dewatering and desorption process. This paper/poster will try to provide understanding of the complete design of CBM production facilities from the bottom hole to the sales point along with the computer simulation of the effects of well spacing and coal properties to the production performance of a coal bed methane reservoir.