Modeling and Optimization of Continuous Gas Lift Performance in Libya Oil Field

Abstract

With a massive number of oil and gas field becoming mature, the upstream engineering is facing new challenge. How to develop , or at least steady production while keeping obtainable reserves at their existing level, As matter of fact unstable production in gas lift wells. The Key issues most operators encounter with oil fields are the effects of high water production that may lead to wells died and decrease in an economical production period. With the increase of water production or decline of reservoir pressure, reservoir drawdown pressure decreases that causes decline in oil production rate. This study is carried out as a consequence of low production problems in one of the oil Field in Libya due to increasing in water production.

 The LBO well was previously drilled into the X reservoir where the reservoir is supported by a strong aquifer. The well has produced for a period and water cut has increased, which led to reducing reservoir pressure and also rate of production has massively dropped as the water cut reaches 70%, the well die. Several of wells were shut in due to a significant increase in water production to achieve incremental reserve recovery from this field gas lift system was employed. This work discusses the successful case study of the implementation of continuous gas lift in Libya oil field that demonstrations by deploying of a continuous gas lift system production rate appreciated to 990.782 stb/day at a gas injection rate of 1 MMscf/day.

In this work, PROSPER Software has been used to analyse inflow and outflow performance with a change in various operating conditions such as Water cut, well head pressure. In addition, the effect of valve port size in oil production was evaluated using the Prosper recommended valve type database. The results obtained indicated that to improve oil production rate from gas lift wells both valve port size and the amount of gas available for the injection process, is critical regarding production performance of the field. various of the wells were studied in this work, but only a typical well is analysed and discussed in this paper for brevity. Finally, the result is expected to have a real impact in enhancing gas lift behaviour in this field, the Middle East and Worldwide.