A Time Function Havlena and Odeh MBE Straight Line Equation

Abstract

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 E o or gas cap expansion function E g or the connate water and rock properties E fw 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.

A Critical Review on Material Balance Equation

“…He presented a generalized MBE applicable to a reservoir where rock/fluid properties change. Buduka et al (2015) showed the limitation of the straight-line method and provided a solution. Based on matching pressure and production data, they developed a mathematical model that is referred to the history matching.…”

“…Estimation of initial-oil-in-place and cumulative oil produced by Havlena and Odeh method does not consider the time function of the average production of the field life. Buduka et al (2015) presented an alternative Havlena and Odeh method in which underground recoverable functions F are plotted against oil plus gas expansion function E per cumulative time so that reservoir engineers can get the updated information each time limit. Warner et al (1979) identified that, though the material balance method is used as a pre-processing tool to estimate the hydrocarbon-in-place, it still has some limitations.…”

“…By using Havlena and Odeh's model for general MBE, Buduka et al (2015) introduced an alternative time function model. They defined all the terms in general MBE by incorporating the time function.…”

Computer modeling and simulation for undersaturated primary drive recovery mechanism

“…The application of material balance has been acknowledged by several researchers for analyzing petroleum reservoirs with simplifying assumptions especially in the works of Yang et al 13 , Xu et al 14 , and Habibi et al 15 Adeloye et al 16 described material balance as zero-dimensional simulator since there are no changes in any direction within the reservoir system being seen as a serious drawback. Buduka et al 17 in their work also used graphical material balance as an equation of a straight line to estimate reservoir fluids in place but with some drawbacks. The material balance equation possesses high degree of inaccuracies of the measured reservoir pressure, and the model fails when decrease in reservoir pressure is not feasible, such as in pressure-maintenance operation.…”