The permeability, pore pressure, and leakoff type interpreted from more than 1,200 diagnostic fracture-injection/falloff tests were collected in a database and statistically evaluated for four Rocky Mountain basins. The statistical analysis includes the range of observed permeability and pore pressure and the fracture leakoff type distribution.

The analysis reveals that pressure-dependent leakoff, fracture-tip extension during shut-in, and fracture-height recession during shut-in are the most common leakoff types. Overall, pressure-dependent leakoff, which can be indicative of highly productive fractured reservoirs, is the most common leakoff type in all Rocky Mountain basins. The analysis also shows orders-of-magnitude variation in gas permeability within all basins, with observed gas permeability ranging from less than 0.001 to greater than 0.10 md.

Keywords:
permeability distribution, fracture closure, leakoff-type distribution, permeability, drillstem/well testing, hydraulic fracturing, before-closure analysis, spe production, upstream oil & gas, falloff test
Subjects:
Drillstem/well testing, Flow in porous media, Formation Evaluation & Management, Hydraulic Fracturing, Pressure transient analysis, Reservoir Characterization, Reservoir Fluid Dynamics, Reservoir geomechanics
Copyright 2005, Society of Petroleum Engineers
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