Abstract
This paper describes the effects of hydraulic stimulation treatments using foam, gel and water, kiel and water, and water alone in a total of 22 gas-bearing coalbeds in Pennsylvania, Alabama, west Virginia, Illinois, Virginia and Utah. Vertical fractures in coalbeds were discernible for most treatments, and sand-propped portions were usually short in lateral extent. Horizontal fractures, present in about one-half of the treatments, were found generally within bedding planes, most commonly on top of the coalbed. For treatments to which fluorescent paint had been added, evidence of stimulation fluid movement could generally be traced beyond the maximum extent of sand-filled fractures. Penetration of strata overlying the coalbeds was observed in nearly one-half of the treatments intercepted, but most of those were interpreted as penetrations into preexisting planes of structural weakness. No roof falls or adverse mining conditions were encountered that could be attributed to the stimulations.
