Evaluating High-Pressure Gas Lift for Accelerated Oil Production: Lessons from a Permian Pilot

Abstract

Gas lift has become a dominant artificial lift method in unconventional oil production, particularly in the Permian Basin. This technology involves injecting pressurized gas into a wellbore producing string to lower the flowing fluid gradient, reduce the flowing bottomhole pressure and enhance the system from the end of tubing to the surface flow line. This lower energy state results in an increase in the pressure differential drawdown from the reservoir to the wellbore, capturing the deliverability of the reservoir. Well production performance can be physically understood as these two components: the interaction between the reservoir capability as an inflow performance relationship (IPR) and the wellbore capability as a vertical lift performance (VLP) curve. Gas lift design targets the operating point defined by the intersection of the IPR and VLP for each well. Gas lift can be optimized by targeting deeper gas injection depth; the lower the gas is injected, the more the hydrostatic head is offset, and the greater the resulting inflow from the reservoir. In conventional gas lift system design, the maximum depth of injection is constrained by the surface gas injection pressure. A typical Permian low-pressure gas lift (LPGL) system operates at a surface injection pressure on the order of 1000 psi to 1,200 psi. On a new annular flow well setup, the producing fluid gradient in the casing-tubing annulus is high, and the surface injection pressure is insufficient to displace fluid down to the deepest gas lift mandrel. Injection occurs through one of the upper unloading valves, FBHP is elevated, and the well does not realize its full drawdown until the production path has unloaded over weeks or months. High-pressure gas lift (HPGL) addresses this depth limitation by raising the surface injection pressure up to 5,000 psi, enabling single-point gas injection at the deepest mandrel from the first day of artificial lift operation. By introducing gas immediately at maximum injection depth, HPGL overcomes the main limiters on the VLP curve: friction in the production path, system and wellhead pressure, the hydraulic head and fluid gradient above the injection point. This produces a step reduction in flowing bottom hole pressure compared to LPGL, assisting the acceleration of production during the well's highest-productivity period.