Foam-assisted gas lift: A novel experimental setup to investigate the feasibility of using a commercial surfactant for increasing oil well productivity

Abstract

Most oil wells require artificial lift at some point to increase the life of the field and enhance production. Conventional methods such as gas lift are not effective in depleted reservoirs with high water cut where very high gas injection rates are required for relatively low oil production rates. Consequently, foamers or surfactants, which have been previously applied for de-liquifying gas wells, are now used in depleted gas-lifted oil wells to either boost production rates or reduce gas lift requirements while maintaining production levels. While there is a growing global interest, foam-assisted gas lift (FAGL) is a relatively modern artificial lifting method with less experience regarding its applications in oil wells.In this study, the feasibility of using a commercial surfactant for improving oil well productivity is investigated via laboratory experiments. A novel laboratory setup resembling a vertical well rig is designed to analyze the impact of surfactant concentration, temperature, brine salinity and phase-specific flow rates (or flow regimes) on the pressure drop across the column. This setup is operational at high temperatures, requires minimal sample amounts, and significantly reduces the experimental errors in pressure drop readings, resulting in highly accurate and stable measurements. The laboratory tests confirm that the addition of foamer reduces pressure drop in the production tubing, thus effectively increasing production. Additionally, an optimal foamer concentration is also detected. The results obtained in this study are very promising and present opportunities to explore a new chapter in artificial lift and production enhancement techniques.