The straight line model introduced by Havlena and Odeh require plotting of the underground recoverable function F against the oil plus dissolved gas expansion function Eo or gas cap expansion function Eg or the connate water and rock properties Efw or a combination of these drives depending on the existing reservoir drive. The consequence is that the estimation of the initial oil in place and cumulative oil produced do not considered the timing factor of the average production of the field life. Hence, this paper present an alternative Havlena & Odeh model in which the reservoir functions such as F are plotted against E per cumulative time making reservoir engineers to appreciate the reservoir behaviour at each time space/limit and also act as a check to the original Havlena and Odeh model. The average production per day is used as against the cumulative production. An appropriate equation and method of analysis is show in this paper. Nevertheless a practical field case is considered. Result from the new model maintained relevant trend with the old Havlena and Odeh model with error factor of 0.043%, hence suitable for predicting reservoir performance as a function of time and also estimating initial oil in place and cumulative production.