Title: A simple and robust model for prediction of liquid-loading onset in gas wells

Authors: Liehui Zhang; Chengcheng Luo; Yonghui Liu; Yulong Zhao; Chunyu Xie; Chuan Xie

Addresses: State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu, Sichuan 610500, China ' State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu, Sichuan 610500, China ' State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu, Sichuan 610500, China ' State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu, Sichuan 610500, China ' Environmental Safety and Technical Supervision Institute, PetroChina Southwest Oil and Gas Field Company, Chengdu, Sichuan, 610041, China ' State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu, Sichuan 610500, China

Abstract: Accurate prediction of liquid loading is of great importance for production optimisation in gas wells. In this paper, the authors present a simple and accurate empirical model based on attached-film reversal for predicting liquid-loading onset in vertical and horizontal gas wells. Unlike established and complicated analytical models based on force balance, this model is developed from the empirical flooding equation by matching the experimental data from previous studies. Further, this model adopts the Belfroid angle-correction term for horizontal gas wells. Compared with the traditional entrained-droplet models, this model considers the effect of pipe diameter and liquid velocity. This study investigated the effect of pressure on the predicted critical gas velocity and scaled up low pressure by comparing some other analytical models. This model was also validated against the experimental data and field data. Results show that the presented model is capable of accurately predicting liquid-loading onset in gas wells. [Received: December 4, 2018; Accepted: December 13, 2019]

Keywords: liquid-loading onset; critical gas velocity; attached-film reversal; entrained-droplet reversal; angle-correction term.

DOI: 10.1504/IJOGCT.2021.113136

International Journal of Oil, Gas and Coal Technology, 2021 Vol.26 No.3, pp.245 - 262

Received: 04 Dec 2018
Accepted: 13 Dec 2019
Published online: 22 Feb 2021 *

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