Improving Gas Lift Operations Using Liquid-Rich Delaware Basin Gas
Authors: Rathore Devvrat , Guoynes John , Stiles David , Wright Michael , Cipolla John M. 
Published: October 2023

Gas lift is the preferred method of artificial lift of many operators in the Delaware Basin due to high gas/oil ratio's (GOR). The volumes of produced gas have a high liquid yield creating challenges for gas lift compression and surface facilities. Condensate and water drop-out creates pressure fluctuations, out-of-range conditions, and mechanical failures1 with compression if not effectively managed. Problems occur when liquid slug-flow or carry-over in the gas stream enters the compressor, leading to low suction pressures, out-of-range compressor discharge pressures, or inter-stage pressure fluctuations. In the Delaware Basin, the smaller compressors, typically used for gas lift, are not optimized to handle these liquid-rich gas conditions. This study presents methodologies to improve equipment designs and operating conditions for gas lift as well as predicting more accurately the fluid conditions of the rich Delaware Basin gas.

Run time data has been tracked over multiple years for gas lift compressors used by an operator in West Texas.2 Key findings show that 53% of shutdowns were caused by process upsets and gas conditions. Shutdowns occurred from liquid drop-out that triggered alarms designed to protect the equipment, or that caused direct mechanical failures of valves, compressor cylinders, and scrubber level controls. In all cases, production was suspended, and every restart of the gas lift compressor required a blowdown, creating lost production, operational intervention, and release of carbon emissions.

Gas lift compression is set up for single well or multiple well injection utilizing one compressor. Smaller gas lift compressor packages (less than 250 hp) are typically not engineered specifically for the liquid-rich gas. Insufficiently sized suction scrubbers, pocketed piping arrangements, high BTU gas received from flash gas separator/heater treater, and/or lack of adequate temperature control likely contributed to problems of liquid fall-out carrying over into compressors. In the sample well study, gas and liquid samples were collected to conduct process simulation to predict liquid fall-out in the gas lift system design. The results of this work show that the Delaware Basin requires compressor packages and surface facilities specifically engineered for a unique gas composition. The fluid analysis and its findings aided the compressor provider to redesign the compressor system to keep hydrocarbon liquids in solution during all stages of compression allowing gas lift operations in the Delaware Basin to operate more efficiently with fewer mechanical issues.

The new technology derived from this work provided a more effective way to reduce liquids dropping out from the gas stream and improve automation with fewer shutdowns and manned interventions. Overall, better control of gas lift operations was maintained, fugitive methane releases were reduced, and gas production was improved while keeping liquids in the gas stream during compression using a Hot Gas Bypass (HGBP) technique.