Reserve Growth of Natural Gas Accumulations

Reserve growth is an increase in successive estimates of recoverable quantities (cumulative production and remaining reserves) of crude oil, natural gas, and natural gas liquids in discovered fields. Reserve growth in oil fields has been documented by many studies, whereas reserve growth in gas fields is less well understood. At least three mechanisms contribute to growth in giant gas fields of the U.S.: (1) underestimation of reserves upon discovery followed by increasing reserve estimates through time as the field is developed, (2) merging of adjacent production units and fields, and (3) addition of reserves in previously ignored reservoirs that have become economically feasible to produce. In several of the giant gas fields in the U.S., previously ignored reserves are “tight” formations in which producible gas is present beyond and between traps, indicating (suggesting) the presence of pervasive, continuous accumulations. Assessment of continuous accumulations requires a different method than is used in the evaluation of conventional accumulations. The U.S. Geological Survey developed methods for each have been peer-reviewed and proved.

AAPG Search and Discovery Article #90142 © 2012 AAPG Annual Convention and Exhibition, April 22-25, 2012, Long Beach, California