Pending Mitigation Efforts

During 1999, at least one operator on the Southern Ute Indian Reservation is exploring the feasibility of drilling a close-spaced network of vertical shallow mitigation wells intended to intercept outcrop-bound gas. Five gas recovery wells are being considered in the pilot project. Drilling locations would be approximately 1,000 feet apart at different depths in the basal Fruitland coalbed. A nearby low-pressure production pipeline would collect the gas. Compression would be applied to compensate for the extremely low anticipated production pressures. Reservoir conditions and computer modeling of the coal in the area have shown that developing a series of gas wells between the outcrop and basin-ward production gas wells should significantly reduce both the concentration and flow of methane gas at the outcrop. It is anticipated that these “picket fence” wells may recover more than 1 BCF of methane gas, per mile of outcrop – gas that would otherwise be lost to the atmosphere (Cox, 1999). Based upon the outcome of these test “picket fence” wells, projections indicate that numerous recovery gas wells might be drilled (based on 15 acre spacing) to adequately alleviate gas-seepage at the outcrop. Clearly this recovery approach would be benign to the environment and advantageous to production of the natural resource. Unfortunately, the preliminary studies do not indicate that the process would be driven by economic advantages. Also, closely spaced mitigation wells would only be feasible on the Southern Ute Indian Reservation, since this method would not be desirable in close proximity to residential developments on suburban lands along the northern Basin rim.

Other remedial action proposals may be formulated with the knowledge gained from results of the 3M project. However, no mitigation method currently identified is universally effective. All efforts considered to date are relatively expensive. Each carries implications of unresolved surface issues.