Developing a mathematical model for optimizing oil production Using Gas-Lift Technology

Abstract

This article is an attempt to presents a mathematical model to optimize oil production from wells which are set to produce oil in accordance with gas lift system. This process is carried out by determining the economic level of oil production of wells and also reduction of production costs by minimizing the rate of gas used for oil production at an optimum level. Therefore, the information on the characteristics of wells are collected and used as input data of the PIPESIM software application. The performance curve of each of the wells was prepared using this application. In the following section, the non-linear multi-objective programming model of oil production optimization has been developed. The validity of the optimum solution depends on the validity of the presented nonlinear mathematical programming model, therefore, the model components and the relationships between them were described. In order to test the validity of the wells’ performance charts in the gas-lift system, the obtained data were compared to the real data obtained from one of the wells through a T paired comparison test and their validity was confirmed at a significance level of 5%. The point which is of more considerable importance in the results of this study is if the wells under study undergo the production at maximum level, the maximum production would be 24,326 BPD which would require 34.702 MMScf/D of gas to be injected into the wells. Now if the level of consumed gas would reduce to 14/835 MMScf/D. Decreases in oil production only 5.7%, if the saved gas is for example used in the gas lift system for a number of wells comparable to the number of wells in this study, an increase of over 100% will be achieved in oil production. This would simultaneously reduce the rate of injected gas and increase the oil production.