Characterizing average permeability in oil and gas formations Conference Paper uri icon


  • This paper shows that the appropriate measure of central tendency or average value of the permeability distribution is the median value rather than the arithmetic mean, a conclusion supported by theoretical considerations, field cases, and simple reservoir simulation examples of production from a hypothetical formation. Use of the correct estimate of average permeability is of particular importance in the classification of tight gas formation under NGPA (Natural Gas Policy Act of 1978) statutes. Another important parameter for classifying a reservoir is the value of stabilized flow rate. Since the flow rate at any given flowing pressure will be proportional to permeability, the engineer should also use the median value of flow rate to determine an appropriate average.

author list (cited authors)

  • Rollins, J. B., Holditch, S. A., & Lee, W. J.

complete list of authors

  • Rollins, JB||Holditch, SA||Lee, WJ

publication date

  • December 1989