On the Usefulness of Usher Logistic and Gompertz Growth Curves

The logistic growth curve and the Gompertz growth curve are the special case of the Usher growth curve． Their functional expressions are introduced respectively which were used for prediction of oilfield development indexes． A repeated dual-variate regression equation aimed to obtain parameters of Usher growth curve is suggested． Based on actual data of oilfield using Usher Logistic and Gompertz growth curves as well as a most functional broad sense growth and decline curve the matching calculation results of mentioned four curves have shown that the generalized growth and decline curve as well as the Usher curve are both very well matched with actual value representing powerful capability of prediction． The Logistic curve shows relatively good matching result have relatively good usefulness． However with respects to Gompertz curve owing to the narrow range of ratio between the peak output corresponding cumulative production and maximum recoverable reserve so the matching result is less good and this curve is less useful． This paper points out that the future study on growth curve should be oriented to generalized growth curve which can be applied to the entire procedure of oilfield development．