Gas Lift

Traditional simulation-based approach for Gas-Lift Optimization depends heavily on the quality of reservoir and fluid data. Excessive OPEX and man-hours are needed to maintain data integrity and to ensure the models are suitably calibrated. Even then, pseudo-steady-state models do not consider losses due to multi-pointing condition and slugging behavior; and for dynamic multiphase flow simulation, the added complexity and man-hours required to assert accurate results cannot be sustained on a full field scale deployment. 

Surface controlled gas lift has several obvious and predictable benefits, such as increased production due to deeper injection and continuous optimization. Installations over recent years have not only proven the validity of these benefits, but they have also offered some surprising and unanticipated advantages. 

This paper presents a novel design of a gas lift check valve featuring an integrated pressure isolation mechanism, aimed at optimizing gas lift operations in oil wells. Operators utilizing High Pressure Gas Lift, or Single Point Gas Lift systems are often converting to conventional gas lift or other Artificial Lift methods once the production has declined. However, this conversion requires a workover and a large capital impact to the operator.

Gas lift is long known to be an effective and versatile form of artificial lift and is widely used in oil and gas production. Compressors are a vital part of the gas lift process and are present in large numbers in the oil and gas industry. The design of these compressors has for many years allowed for the release of hydrocarbons into the environment. Concerns over the environmental impact of these hydrocarbon emissions has increased scrutiny by the public eye and environmental regulators.

Initial lifting new wells with high pressure gas lift valves when BHP and PI are at the highest to achieve a deeper point of injection, thus higher fluid rates. Converting to normal pressure gas lift when production rates are lower utilizing the balance-ported valve. Balance Ported Valve is a gas-lift valve that allows full, available gas injection pressure to be used for the unloading and operating valves. Using full injection pressure allows for a deeper point of gas injection, which lowers the FBHP, thereby increasing production.

The capability of a gas lift system is heavily dependent upon the available gas lift injection pressure. Gas lifting a well from the deepest point of the formation results in higher drawdown pressure, more production with less lift gas, and less gas lift equipment yielding a more efficient system. However this cannot always be achieved because of limited injection pressure, limited gas injection rate and/or limitations of the gas lift equipment. In a gas lift project, what size compressor is needed to deliver the desired production?

Plunger Assisted Gas Lift (PAGL) in the Permian Basin Over the last few years Gas Lift has become a popular artificial lift choice for producing unconventional wells in the Permian Basin. Gas Lift is a good choice for producing wells with high bottom-hole pressures (BHP) and high gas liquid ratios (GLR). Gas Lift is also a good choice for wells that produce solids or have deviated wellbores. Gas Lift however like all artificial lift choices has an optimum range which typically tends to be above five hundred barrels per day.

Shooting fluid levels has become a well-known practice in support of daily production operations. The practice of shooting fluid levels is so well-known, in fact, that the term, “shooting fluid levels” is assumed to mean checking the fluid level to determine if a well is producing the maximum fluid potentially available from the formation. The most common use of an acoustic liquid level instrument is to measure the distance to the liquid level in the casing annulus of a well having a downhole pump.

Since its’ introduction to the unconventional oil and gas realm in 2018, Single Point High Pressure Gas Lift (referred to as HPGL going forward) has emerged as one of the top artificial lift choices for operators in the Permian and Anadarko basins. It has become a proven technology with over 1,250 applications to date as more operators are choosing it as their primary form of artificial lift for their unconventional assets.

This case study has a completion with 2-7/8” tubing in 5-1/2” casing without a packer, with 8 IPO gas lift valves in conventional mandrels with an orifice as the last valve and a chemical screen below that. A grooved plunger was used in this well in combination with gas lift to reduce liquid fall back losses and provides a solid sealing interface between the liquid slug and the gas below it. The liquid rate declined drastically after operating the well on the gas lift at 600 MCFD rate and 1050 psig injection pressure for eight months.