Advances in mathematical modeling and real-time monitoring have made it possible to more realistically and accurately model physics and economic performance of gas-lift oilfields. Mature fields, with installed gas-lift facilities (e.g. compressors, flowlines, and downhole valves) and reliably calibrated reservoir and facility flow models present a favorable opportunity to apply improved and more general optimization methods.

This paper describes a new approach for optimizing gas-lift operations in mature oilfields.

The new approach maximizes net present value by integrating mathematical models that describe the behavior of the reservoir, the behavior of the fluid gathering and gas-lift systems, and the future economic performance of the field operating under gas-lift. This integrated approach is in contrast to those in current use that typically seek to either maximize current oil production rate or to maximize the gas-lift efficiency of individual wells, and isolated from the ample economic picture.

To demonstrate the methodology, we tested it on case study for a mature offshore field in South America. Our results showed that the optimal operating conditions that maximize net present value do not necessarily occur at either the maximum production rate or at the maximum gas-lift efficiency. In fact, net present value improved 12% for the base oil price scenario, and up to 57% for the high oil price scenario, when applied the integrated approach of this paper.

You can access this article if you purchase or spend a download.