Reliability of Laboratory Measurement of Porosity in Tight Gas Sands

Summary A study was conducted to verify or to improve the routine laboratory procedures normally used to measure porosities of cores from tight gas sands. After routine analysis of 242 core plugs from the Travis Peak formation in east Texas, 20 of the plugs were analyzed for porosity by two additional laboratories. Each of the three laboratories had problems with their results that normally would have gone unnoticed but were recognized because of disagreement with results from the other laboratories. After reruns, agreement was excellent, with a standard deviation of about 0.25 porosity units (p.u.) when comparing one laboratory against another. To improve reliability of routine porosity measurements, recommended practices and quality-control procedures are presented.