A new method for finding the optimum gas injection rates for a group of continuous gas lift wells to maximize the total oil production rate is established. The new method uses a quasi-Newton nonlinear optimization technique which is incorporated with the gradient projection method. The method is capable of accommodating restrictions to the gas injection rates. The only requirement for fast convergence is that a reasonable estimate of the gas injection rates must be supplied as an initial point to the optimization method. A method of estimating the gas injection rates is developed for that purpose. A computer program is developed capable of implementing the new optimization method as well as generating the initial estimate of the gas injection rates. This program is then successfully tested on field data under both unlimited and limited gas supply. The new optimization technique demonstrates superior performance, faster convergence, and greater application.

1.
Beggs, H. D., and Brill, J. P., 1973, “A Study of Two-Phase Flow in Inclined Pipes,” Journal of Petroleum Technology, May.
2.
Brown, K. E., 1980, The Technology of Artificial Lift Methods, Vol. 2a, Pen Well Publishing Co., Tulsa, OK.
3.
Fletcher, R., 1987, Practical Methods of Optimization, Second Edition, John Wiley and Sons Ltd., New York, NY.
4.
Gomez, V., 1974, “Optimization of Continuous Flow Gas Lift Systems,” M.S. thesis, University of Tulsa, Tulsa, OK.
5.
Hagedora, A. R., and Brown, K. E., 1965, “Experimental Study of Pressure Gradients Occurring During Continuous Two-Phase Flow in Small Diameter Vertical Conduits,” Journal of Petroleum Technology, Apr.
6.
Hong, H. T., 1975, “Effect of the Variables on Optimization of Continuous Gas Lift System,” M.S. thesis, University of Tulsa, Tulsa, OK.
7.
Kanu, E. P., Mach, J., and Brown, K. E., 1981, “Economic Approach to Oil Production and Gas Allocation in Continuous Gas Lift,” Journal of Petroleum Technology, Oct.
8.
Luenberger, D. G., 1984, Linear and Nonlinear Programming, Second Edition, Addison-Wesley Publishing Co., Reading, MA.
9.
Mayhill, T. D., 1974, “Simplified Method for Gas-Lift Well Problem Identification and Diagnosis,” Paper SPE 5151, presented at the SPE 49th Annual Fall Meeting, Houston, TX, October 6–9.
10.
Nishikiori, N., 1989, “Gas Allocation Optimization for Continuous Flow Gas Lift Systems,” M.S. thesis, University of Tulsa, Tulsa, OK.
11.
Radden, J. D., Sherman, T. A. G., and Blann, J. R., 1974, “Optimizing Gas-Lift Systems,” Paper SPE 5150, presented at the SPE 49th Annual Fall Meeting, Houston, TX, October 6–9.
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