Gas Lift Design and Optimization in One of Central Iranian Oil Field

Continuous flow gas lift is one of the most common artificial lift methods in use. It works by continuous injecting of high pressure gas into the tubing or tubing/casing annulus to lighten the column of oil and thus facilitate extraction. Excessive gas injection is costly because of high gas prices and compressing costs. This project, using wellflo software concerns the design of gas lift operations in a central Iranian oil field. The above mentioned field, that isn’t developed yet, presently consists of three wells producing from two separate layers. The overall flow rate for this field with out any injection is around 2000 stb/day. Since, the exact estimation of the physical properties of the fluids plays a crucial role in verifying the accuracy of the calculations, thus, as the first step, using measured PVT data pertaining to the reservoir fluids it is endeavored to correlate the laboratory data with calculated values. Afterwards, optimum injection points and the spacing of the gas lift valves are evaluate for each individual well. After the above mentioned steps, gas lift performance and the optimum rate of gas injection is evaluated. Finally the field production behavior is investigated in two different production cases (using gas lift & without it) utilizing additional production wells for duration of 1 year up to the bubble point pressure. And as is shown at the future the recovery factor of the field for 1 year period using gas lift has nearly increased four times. Another major complication arises from the limitations, associated with the available injection gas volume, inevitably the operator is challenged with the classical gas lift allocation problem: how does one allocate limited available injection gas to maximize overall field production?In this project, using non linear optimization utilizing the lingo software, attempts are made to solve this problem. That finally by reduction of mere 50bbl/day oil we could conserve an amount of 11MMcuft gas daily.

Keywords:

Continuous Gas Lift , Intermittent Gas Lift , Optimum Injection Point , Maximum Oil Rate