Commercial production of coalbed methane from under-saturated reservoirs requires producing large volumes of water for extended periods of time. Also known as ineffective water, its production becomes even more challenging under infinitive acting aquifer (IAA) type-of-flow, a condition of sustainable groundwater yield with no imminent flow barriers and structurally complex reservoirs such as synclines. This work predicted series of dewatering scenarios to assess the implications of IAA and the role of structural style to produce methane at the CBM reservoir in the Syncline of Umbita Boyaca Colombia. The results confirmed IAA regime that is supported by recharge, cross-formational flow and preferential flow, served by a U-Tube-like hydraulic setting from the synclinal structure. Predicted dewatering suggests that removal of large volumes of water over a 50-year period would be required in the CBM reservoir of the Syncline of Umbita before commercial production of methane is achieved. However, much of the ineffective water appears to be removed by historic coal-mine-dewatering so the reservoir should entered under desorption mode readily for production.

  • Luis E. Rivera