Comparative performance analysis between natural flow wells and artificial lift wells: A case study from the Zelten Field

This paper presents a comparative analysis between natural flow wells and artificial lift wells, focusing on performance indicators such as production rate, water cut, gas-liquid ratio (GLR), and operational parameters. The study uses actual field data from Well C-55 in the Zelten Field, tested under artificial lift (gas lift) conditions using a multiphase flow meter (MPFM). The results are evaluated against typical characteristics of natural flow wells under similar reservoir conditions. The findings highlight the efficiency and limitations of artificial lift systems in enhancing production when natural energy is insufficient. The study also outlines key operational considerations that influence the selection of artificial lift over natural flow methods.

Introduction: In the oil and gas industry, well productivity and efficiency are critical for maximizing recovery and reducing operational costs. Wells generally produce hydrocarbons either through natural reservoir energy (natural flow) or with the assistance of artificial lift systems. Natural flow wells rely on sufficient reservoir pressure to push fluids to the surface, while artificial lift methods—such as gas lift, electric submersible pumps (ESP), and rod pumps—are employed when reservoir pressure declines or fluid characteristics hinder flow. This paper aims to compare these two production mechanisms by analyzing actual performance data from Well C-55 in the Zelten Field, which utilizes gas lift as the artificial lift method. Using MPFM data, we assess production behavior in terms of liquid rate, gas production, water cut, and gas-liquid ratios. The analysis is supplemented with theoretical considerations and a comparison to typical natural flow well profiles, highlighting the advantages and challenges of each system.

Methodology: This comparative study utilizes well testing data from C-55, located in the Zelten Field, Sirte Basin. Two separate tests were conducted using a multiphase flow meter (MPFM Unit #6) under different operating conditions: natural flow (12 July 2025) and artificial lift via gas injection (24 July 2025). The test duration in both cases was approximately six hours.
Measurements included oil and water flow rates, total gas flow, water cut (WC), gas-to-oil ratio (GOR), and other wellhead parameters. Data was collected at regular intervals and averaged over the entire testing period. The same choke size (40/64") was maintained to ensure consistent flow conditions. Fluid properties (Oil API 33.6, water salinity 10,000 ppm) were constant between both tests. The gas lift operation was performed with an injection rate of 330 MSCFPD. Performance metrics from both datasets were extracted and compared directly to evaluate changes in productivity, efficiency, and operational behavior due to the switch from natural flow to artificial lift.