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Generally, a gas lift is a flexible, and a reliable artificial lift system with the ability to cover a wide range of production rates. Gas lift systems are a closed system empowered by high-pressured gas. The entire process is used to reduce the wellbore fluid pressure gradient by supplementing gas through an external source to withdraw more liquid from the reservoir under higher drawdown. Many parameters affect a gas lift system design, such as changes in the wellhead and bottomhole pressures (BHPs), produced fluid type, and productivity index of the wellbore. As these parameters change, the gas injection pressure changes. Gas lift system demands a surface compressing unit and in the well gas lifts valves (GLVs). Overall, a gas lift system is a forgiving method of enhanced production, in other words, even a poor gas lift design may increase production. To achieve a higher ramp in fluid production rate using gas lift, however, a more sophisticated design of each compartment of the system is required.

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Each gas lift valve (GLV) is a variable orifice until a fully open port area is attained (under maximum stem travel). As the ball (stem) moves away from the ball/seat contact area, the area open to flow increases until the flow area upstream to the port area equals or exceeds the fully open port area. Laboratory gas dynamic throughput testing indicates that each injection-operated GLV often does not open fully in actual operation, mainly because of the bellows stacking phenomena. As a result, the stem forms a restriction upstream to the flow path. Therefore, actual flow through the GLV can be less than expected. This paper addresses such issues and recommends a simple but effective solution. A modified design for the GLV seat was created to help reduce the required stem travel to generate a flow area equal to the port area. Theoretical calculations confirm the actual gas dynamic measurements and show that the minimum stem travel for the modified design improves from 5 to 58% compared to using a conventional sharp-edged seat. This improvement should have a significant impact on GLV performance. The modified seats for all different ports sizes were manufactured and tested using a benchmark valve test. The experiments showed that for the same stem travel, the new design has a larger flowing area than that of the sharp-edged seat. This paper details the new design, theoretical calculations, and experimental results.

Gas lift is considered the most important artificial method in the oil and gas industry. Although, there are several components in the Gas Lift Valve (GLV), the ball and the seats are the only two adjustable components. The objective of this study is to maximize the gas throughput using the new design seats of partially curved design (PCD) and wholly curved design (WCD) to increase oil production.Five main seat designs were evaluated using Computational Fluid Dynamics (CFD): The Sharp Edge, modified design, the optimized design, Partially Curved Design and Wholly Curved Design. The modified design and the optimized design have been previously evaluated. However, PCD and WCD are evaluated in this research. To maximize the gas throughput, seven seat sizes and five different ball sizes have been selected in this simulation study. Each seat has Port Bottom Diameter (PBD) and Port Top Diameter (PTD). The criterion of the best case is to have the highest gas throughput.The CFD results showed that PCD has 11% higher gas throughput than the modified design at the ball size 6/16 inches, PBD 5/16 inches and PTD 7/16 inches. Also, WCD has 6% higher gas throughput than the optimized design at the ball size 7/16 inches, PBD 6/16 inches and PTD 8/16 inches. The results also demonstrated that the best design seat is the Wholly Curved Design compared to the others when the PBD, PTD and stem travel are 5/16 in, 7/16 in and 5/16 in, respectively resulting in the highest gas flow rate of 0.65 kg/s. The novelty of this research is describing four different GLV designs, two of which were created. Additionally, the results show the effect of each of the adjustable GLV components: PBD, PTD, and stem travel.