scholarly journals Research on Critical Liquid-Carrying Model in Wellbore and Laboratory Experimental Verification

Processes ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 923
Author(s):  
Wenqi Ke ◽  
Lintong Hou ◽  
Lisong Wang ◽  
Jun Niu ◽  
Jingyu Xu
Keyword(s):  
Liquid Film ◽  
Shear Force ◽  
Liquid Interface ◽  
Force Balance ◽  
Theoretical Research ◽  
Vertical Position ◽  
Gas Velocity ◽  
Gas Wells ◽  
Liquid Loading ◽  
Interface Shear

Liquid loading in gas wells may slash production rates, shorten production life, or even stop production. In order to reveal the mechanism of liquid loading in gas wells and predict its critical flowrates, theoretical research and laboratory experiments were conducted in this work. A new model of liquid-film reversal was established based on Newton’s law of internal friction and gas–liquid two-phase force balance, with the critical reverse point obtained using the minimum gas–liquid interface shear force method. In this model, the influences of the pipe angle on the liquid film thickness were considered, and the friction coefficient of the gas–liquid interface was refined based on the experimental data. The results showed that the interfacial shear force increases by increasing the liquid superficial velocity, which leads first to an increase of the critical liquid-carrying gas velocity and then to a decrease, and the critical production also decreases. With 0° as the vertical position of the pipeline and an increase of the inclination angle, the critical liquid-carrying velocity first increases and then decreases, and the maximum liquid-carrying velocity appears in the range of 30–40°. In addition, the critical liquid-carrying gas velocity is positively correlated with the pipe diameter. Compared with the previous model, the model in this work performed better considering its prediction discrepancy with experiment data was less than 10%, which shows that the model can be used to calculate the critical liquid-carrying flow rate of gas wells. The outcome of this work provides better understanding of the liquid-loading mechanism. Furthermore, the prediction model proposed can provide guidance in field design to prevent liquid loading.

scholarly journals An experimental study of liquid unloading in the curve section of horizontal gas wells

2021 ◽  
Vol 76 ◽  
pp. 69
Author(s):  
Shuzhe Shi ◽  
Guoqing Han ◽  
Bohong Wu ◽  
Kangtai Xu ◽  
Zhun Li ◽  
...  
Keyword(s):  
Experimental Data ◽  
Poor Performance ◽  
Gas Production ◽  
Gas Velocity ◽  
Gas Wells ◽  
Liquid Loading ◽  
Curved Pipes ◽  
Comparison Results ◽  
Calculation Results ◽  
Superficial Gas Velocity

Liquid unloading is a very common and important issue in horizontal gas wells, and the presence of curve sections increases the complexity of the phenomenon and its study. Liquid loading in a gas well will sharply reduce production, therefore, the liquid-unloading onset of different curved pipes is essential to gas production. In this work, liquid-unloading onset experiments were conducted in curved pipes with different curvatures. Then, the critical gas velocity VsgCR can be determined according to the measured pressure gradients, liquid holdup, and liquid film reversal. This work analyzes the factors which will lead to the liquid unloading and explores the trend of the pipe curvature’s influence on the liquid unloading under laboratory conditions. The experimental results show that the critical gas velocity rises with the increase of pipe curvature, the increase is mainly due to the centrifugal force. The present work also compares the predicted results of the OLGA model and Beggs–Brill model with experimental data. The comparison results indicate that both models fit relatively well to the experimental data at the low superficial gas velocity, and both models have poor performance at high superficial gas velocity. The OLGA model fits the experimental data better than the Beggs–Brill model at high superficial gas velocity. The error analysis shows that most of the predicted data is not in good agreement with experimental data. Some errors between experimental data and calculation results are out of the range of 50%.

Liquid Film Model for Prediction and Identification of Liquid Loading in Vertical and Inclined Gas Wells

2020 ◽  
Vol 188 ◽  
pp. 106896
Author(s):  
Arnold Landjobo Pagou ◽  
Xiaodong Wu ◽  
Zhiying Zhu ◽  
Long Peng
Keyword(s):  
Liquid Film ◽  
Gas Wells ◽  
Liquid Loading ◽  
Film Model

Prediction of the Critical Gas Velocity of Liquid Unloading in a Horizontal Gas Well

SPE Journal ◽  
2017 ◽  
Vol 23 (02) ◽  
pp. 328-345 ◽  
Author(s):  
Zhibin Wang ◽  
Liejin Guo ◽  
Suyang Zhu ◽  
Ole Jørgen Nydal
Keyword(s):  
Experimental Data ◽  
Analytical Model ◽  
Empirical Model ◽  
Force Balance ◽  
Real Field ◽  
Entrainment Rate ◽  
Gas Velocity ◽  
Liquid Loading ◽  
Wide Range ◽  
Fluid Properties

Summary Analysis of the experimental data for liquid-entrainment rate, forces exerted on liquid droplet, and secondary flow occurring in the gas core show that the liquid is mainly carried in the form of film in the inclined annular flow. Therefore, it is more reasonable to establish a mathematical model from the bottom-film reversal than from the droplet reversal. In this study, a new analytical model is developed from force balance of the bottom film of the inclined tubing after studying the bottom-film thickness and gas/liquid interfacial friction factor to reveal the liquid-loading mechanism. Furthermore, a new Belfroid-like empirical model is proposed that is based on the calculation results of a wide range of flowing parameters from the new analytical model to predict the liquid-loading status of gas wells. The new empirical model introduces a coefficient Cd,p,uSL,T to consider how the fluid properties under downhole flow condition affect the critical gas velocity. Cd,p,uSL,T in the new empirical model increases with the pipe diameter, liquid velocity, and flowing pressure, and decreases with the flowing temperature. The new analytical model, having an average error of 8.45%, agrees well with the published experimental data, and it also performs well in predicting the pressure gradient at liquid unloading condition. The new empirical model could be applied for the prediction of real field operations and has been validated with an accuracy rate of 95% against data newly collected from 60 horizontal wells. The new work can accurately and easily judge the liquid-loading status, and it also reveals how the fluid properties under downhole flowing condition affect the liquid loading.

Onset of Liquid-Film Reversal In Upward-Inclined Pipes

SPE Journal ◽  
2018 ◽  
Vol 23 (05) ◽  
pp. 1630-1647 ◽  
Author(s):  
Yilin Fan ◽  
Eduardo Pereyra ◽  
Cem Sarica
Keyword(s):  
Liquid Film ◽  
Prediction Models ◽  
Mechanistic Model ◽  
Absolute Error ◽  
Gas Velocity ◽  
Liquid Loading ◽  
New Model ◽  
Velocity Prediction ◽  
Inclined Pipe ◽  
Inclined Pipes

Summary Accumulation of oil and/or water at the bottom of an upward-inclined pipe is known to be the source of many industrial problems, such as corrosion and terrain slugging. Therefore, accurate prediction of the critical gas velocity that can avoid the liquid accumulation is of great importance. An experimental study of onset of liquid-film reversal, which is believed to be the main cause of liquid accumulation, was conducted in a hilly-valley test section at low-liquid-loading condition. A new, easily implemented mechanistic model to predict critical gas velocity, which is specifically developed based on the liquid-film reversal in stratified flow, is proposed in this work. The new model was verified with the data acquired in the study and other studies from the open literature, showing a fair agreement. This work also reviewed and evaluated other critical-gas-velocity-prediction models. The new model performs best compared with other models, especially in terms of the inclination angle and liquid-flow-rate effect on critical gas velocity. The total average absolute error was reduced 6.0% compared with the current best-prediction model (Zhang et al. 2003), and 38.2% for the widely used Turner et al. (1969) droplet-removal model.

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

2021 ◽  
Vol 26 (3) ◽  
pp. 245
Author(s):  
Chuan Xie ◽  
Chunyu Xie ◽  
Yulong Zhao ◽  
Liehui Zhang ◽  
Yonghui Liu ◽  
...  
Keyword(s):  
Gas Wells ◽  
Liquid Loading ◽  
Robust Model
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