Conventional methodologies have failed to address thedifficulties involved in the design and execution of fracturetreatments of reservoirs with complex geology and stressconditions such as coal bed methane (CBM) reservoirs. Thispaper presents an innovative technique to optimize and designhydraulic fracture treatments in naturally fractured CBMreservoirs. This methodology integrates (1) a threedimensional (3D), finite element based numerical design toolto predict the fracture geometry for given reservoir andoperating conditions, (2) a production model to estimate fluidflow in the CBM reservoir, and (3) cost analysis to optimizethe design parameters against different field scenarios using ahybrid genetic-evolutionary optimization tool.The technique has been used to design fracture treatmentsin a coal bed methane reservoir to illustrate its potentialbenefits in improving the reservoir’s productivity. Results ofthis study have shown that the use of a 3D geometry modelenabled realistic post-frac productivity analysis. Thisprovided reliable conservative estimates on the revenuederived from the stimulation program. Furthermore, theoptimization approach allowed operators to incorporateoperating constraints based on sound industry practice andcompany guidelines for a cost-effective exploitation of CBMreservoirs.
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