This paper describes the success of restimulation of CBM wells. Well P3 squeeze-cemented, refraced with N2 foam and 186,000 lbs sand. Increased production paid out investment in 180 days, and added 383 MMcf reserves at $.10/mcf. Well P4 refraced with 117,000 lbs sand without cement squeeze. P4 payout in 500 days, adding 48 MMscf incremental reserves at $.63/mscf.
This paper discusses remedial hydraulic stimulations used to increase production rates from two coalbed methane wells at GRI's Rock Creek project. The poorly performing stimulation was plugged with cement and the well restimulated using a non-damaging gel, nitrogen foam, and sand stimulation. These treatments suggest: 1) cement can be used to abandon undesirable hydraulic fractures prior to restimulation, 2) the use of an alternative gel polymer, identified by core testing for a specific coal sample, minimized permeability damage during stimulation, and 3) a special foam and sand stimulation created a more effective fracture than the original water and sand treatment in the same well.
Author(s): R.A. Schraufnagel, Gas Research Institute; S.D. Spafford, Taurus Exploration Inc.; M.W. Conway, Stim-Lab Inc.
Paper Number: SPE 26198