The main goal of this paper is to generate a complete phase envelope for natural gases based on a exponential decay distribution for C6+. Using this technique, a single dew point measurement provides enough information to generate an accurate phase envelope. Using the single dew point measurement, appropriate distribution for C6+ is determined. The distribution will contain normal alkanes ranging from nC(6)H(14) to nC(17)H(36). Once the distribution is determined, a complete phase envelope containing the bubble point curve, dew point curve, retrograde curve, and hydrate curve can be generated. We have verified that the exponential decay or logarithmic distribution of hexane plus will improve the accuracy of PHLC (Potential Hydrocarbon Liquid Contenet) prediction by using a hexane plus molecular weight to match a single dew point. This approach enables the generation of full and accurate phase envelopes. This technique may be applied with any EoS of state so long as proper binary interaction coefficients are employed.