In oilfield database analyses the relationships between well production and working agent, plus the well bore pressure and working agent are presented as second order polynomials. In the literature, it was found that the most widely used parameter for analysis, was the well production vs. injected gas relationship. However, in some cases, if it is difficult to establish this relationship, then the pressure vs. injected gas formulae relationship can be used. In this paper, we demonstrate a possibility of transition from well production vs. injected gas to the pressure vs. injected gas relationship, and their use. To this end, a new approach was validated by the field test results.