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Title: Feasibility of no-proppant stimulation to enhance removal of methane from the Mary Lee Coalbed

Technical Report ·
DOI:https://doi.org/10.2172/5451039· OSTI ID:5451039

One experimental approach to hydraulic stimulation is to use fluid to propagate fractures but not to incorporate solid proppant material in the design. The elimination of solid material negates problems related to wellbore sand proppant influx and allows better fracture height control since extremely low injection rates can be used. The Mary Lee Coalbed was stimulated using a 53,000 gallon no-proppant treatment at a 1,150 foot deep test well located approximately 1,600 feet in advance of mining. The well produced for 147 days and gas flow rates declined sharply, ceasing when intercepted by mining. Production comparison of the no-proppant test with another test incorporating sand proppant indicates that the 53,000 gallon no-proppant treatment was less effective than the more conventional 21,000 gallon treatment. The results from the no-proppant test indicate that very few roof rock fluid penetrations occurred during the course of hydraulic stimulation. It cannot be determined, however, if sparsity of roof penetration was due to the use of very low injection rates or because roof rock in the physical test area was less jointed and, therefore, less prone to stimulation fluid invasions. Because gas flow results gathered are inconclusive, the application of no-proppant stimulation designs for other than research is not recommended at this time. The lower injection rate approach to fracture height control is, however, theoretically sound and because limiting upward fracture growth in coalbeds may be desirable to future borehole gas drainage activities, no-proppant experiments could be justified on a limited scale.

Research Organization:
Department of Energy, Carbondale, IL (USA). Carbondale Mining Technology Center
OSTI ID:
5451039
Report Number(s):
DOE/CMTC/TR-80-1
Country of Publication:
United States
Language:
English