A Novel Calculation Model for Liquid Carrying Capacity of Low-Yield Gas Wells

Abstract

In low-yield gas wells, liquid loading is a common problem due to energy loss and pressure drop along the wellbore, especially in the middle to late phases of development. Because liquid loading is inevitable, it is necessary to calculate how much liquid can be unloaded under the current yield. Inspired by dimensionless analysis, this paper explores the mechanism of liquid carryover at low gas-liquid ratios, analyzes the dynamics of gas-liquid two-phase flow, and then establishes a calculation model of liquid carrying capacity for low-yield gas wells. The effectiveness of our model was verified through the analysis on actual low-yield gas wells. The results show that our model can calculate the liquid carrying capacity at a high accuracy (>85%). The research results provide a good reference for normal production in the late phase of gas fields.

Review on critical liquid loading models and their application in deep unconventional gas reservoirs

“…Zhao and Liu used 10 different models, including those proposed by Turner et al (1969), Coleman et al (2019), Li et al (2012), Belfroid, and the model modified by Zhao and Liu, to predict the wellbore liquid loading of three kinds of pipe diameters (2-3/8′, 2-7/8′, and 5-1/2′) in the FL shale gas field. By comparing the field liquid loading of gas wells, the accuracy of various critical liquid loading models for judging the liquid loading in gas wells with different pipe diameters was analyzed (Figure 8) (Zhao and Liu, 2019). The model modified by Zhao and Liu has the highest discrimination accuracy and the most accurate prediction, with an average accuracy of 90%.…”

“…Data from the casing production period of the well were substituted into the new critical liquid loading model established to analyze the liquid loading situation of the well. The critical liquid loading flow curve is shown in Figure 9 (Zhao and Liu, 2019).…”

“…Compared to the liquid loading curve observed during casing production, the critical liquid loading flow rate of the wellbore during tubing production experiences a significant decrease. This reduction can be attributed to the decrease in the inner diameter of the production string after the tubing is run, and the liquid loading Comparison of critical liquid loading models (Zhao and Liu, 2019).…”

“…frontiersin.org capacity for the gas well is enhanced (Figure 10) (Zhao and Liu, 2019). The gas well enters the casing production section, the liquid loading capacity weakens, and the critical liquid loading flow rate increases.…”

Research progress on the calculation model of critical liquid carrying flow of gas well

“…Yonghui Liu et al 73 conducted a visualization simulation experimental device for horizontal wells, using high‐definition cameras to capture the reversal of liquid‐film as the start of liquid accumulation, and developed a gas critical liquid‐carrying flow rate model at various angles, tubing inner diameter and liquid apparent flow rate. Zhejun Zhao et al 74 conducted experimental research on the actual production status of low‐pressure and low‐production wells based on the principle of similarity, indicting that low‐pressure and low‐production gas wells actually have a mixed state of upper mist flow and lower slug flow. The upper mist flow liquid‐carrying meet the calculation results of droplet model, while the lower slug flow is judged based on the gas phase velocity.…”