Net pay is a crucial parameter in the reservoir characterization process as well as in the determination of both original oil or gas in place and remaining mobile hydrocarbons. Typical industry definitions of net pay suggest that the hydrocarbons must not only be present but must also be able to be economically produced. Net pay is typically estimated from well log data and using core data and production data for calibration.

The purpose of this module is to determine whether each of the four samples presented qualifies as net pay. This determination will involve the calculation of effective porosity, water saturation, and permeability to hydrocarbons: in this case, gas.