Open Access

ARTICLE

Analysis of Maximum Liquid Carrying Capacity Based on Conventional Tubing Plunger Gas Lift

Yanqun Yu^1,*, Wenhao Xu¹, Yahui Huangfu¹, Jinhai Liu^1,2, Bensheng Wang¹, Kai Liu¹
1 College of Mechanical and Electronic Engineering, China University of Petroleum (East China), Qingdao, 266580, China
2 Energy Technology & Services Oil Production Services Company, CNOOC, Tianjin, 300450, China
* Corresponding Author: Yanqun Yu. Email: yuyq@upc.edu.cn
(This article belongs to the Special Issue: Hydraulic Fracturing Theory and Application for Geo-energy Development)

Energy Engineering https://doi.org/10.32604/ee.2024.047986

Received 24 November 2023; Accepted 06 March 2024; Published online 16 April 2024

Abstract

China’s unconventional gas fields have a large number of low-productivity and low-efficiency wells, many of which are located in remote and environmentally harsh mountainous areas. To address the long-term stable production of these gas wells, plunger-lift technology plays an important role. In order to fully understand and accurately grasp the drainage and gas production mechanisms of plunger-lift, a mechanical model of plunger-liquid column uplift in the plunger-lift process was established, focusing on conventional plunger-lift systems and representative wellbore configurations in the Linxing region. The operating casing pressure of the plunger-lift process and the calculation method for the maximum daily fluid production rate based on the work regime with the highest fluid recovery rate were determined. For the first time, the critical flow rate method was proposed as a constraint for the maximum liquid-carrying capacity of the plunger-lift, and liquid-carrying capacity charts for conventional plunger-lift with different casing sizes were developed. The results showed that for 2^3/8'' casing plunger-lift, with a well depth of shallower than 808 m, the maximum drainage rate was 33 m³/d; for 2^7/8'' casing plunger-lift, with a well depth of shallower than 742 m, the maximum drainage rate was 50.15 m³/d; for 3^1/2'' casing plunger-lift, with a well depth of shallower than 560 m, the maximum drainage rate was 75.14 m³/d. This research provides a foundation for the scientific selection of plunger-lift technology and serves as a decision-making reference for developing reasonable plunger-lift work regimes.

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Keywords

Unconventional well; conventional tubing string; plunger gas lift; critical flow rate; liquid carry-over chart version

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