Integrated Methods for Coal Gas Reservoir Completion Zone Selection

Abstract

Abstract Successful selection of single and multiple completion zones in heterogeneous, layered coal natural gas reservoir systems is predicated upon vertically partitioning the stratigraphic interval into zones with discrete ranges of geologic and reservoir characteristics. In gassy zones, the estimation and determination of true net pay depths with respect to permeability-thickness product values is accomplished through integrated interpretation of field operation, well test, geophysical log, and core/fluid property data (in order of increasing vertical resolution). Such partitioning of reservoirs enables more accurate and comprehensive estimates of reservoir simulation input parameters required for quantitative reserve assessments to be obtained. Cost effective completion decisions for exploration, development and workover well candidates can consequently be formulated and implemented. The principles and implications of completion zone selection methods are also applicable to most non-coal petroleum reservoir systems, which are inherently heterogeneous and layered.