A New Model for Predicting Gas-Well Liquid Loading
- Desheng Zhou (Xian Petroleum University) | Hong Yuan (IHS)
- Document ID
- Society of Petroleum Engineers
- SPE Production & Operations
- Publication Date
- May 2010
- Document Type
- Journal Paper
- 172 - 181
- 2010. Society of Petroleum Engineers
- 5.2.1 Phase Behavior and PVT Measurements, 5.3.2 Multiphase Flow, 3.1.8 Gas Well Deliquification, 4.1.2 Separation and Treating, 5.1.8 Seismic Modelling, 2.2.2 Perforating, 4.1.5 Processing Equipment
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Liquid loading is a common issue for gas producers. Better predictions of liquid loading will help operators in reducing costs (fewer shutdowns) and improving revenue (greater production).
The Turner et al. (1969) entrained-droplet model--herein referred to as Turner's model--is the most popular one in predicting liquid loading in gas wells. However, there were still quite a few wells that could not be covered even after a 20% upward adjustment (Turner et al. 1969). Field practice also proves that the adjusted model still underestimates liquid loading sometimes. By studying the droplet model and liquid-film mechanisms, this paper presents a new empirical model.
Previous models for liquid loading are independent of the liquid amount in a gas stream. When gas velocity is higher than calculated critical velocity, no liquid loading exists. This paper points out that, in addition to gas velocity, liquid amount (liquid holdup) in a gas stream is also a major factor for liquid loading. There is a threshold value for liquid amount in a gas/liquid mixture. Above this value, liquid loading may appear even when the gas velocity of a well is higher than the critical velocity from Turner's droplet model. The presented model is the first model to include the amount of liquids in the calculation of gas critical velocity. According to the new model, critical gas velocity is not a single value; it varies with the liquid holdup in the gas well once the holdup exceeds the threshold value.
Well data from Turner et al. (1969) were employed in the paper for evaluating the new model's parameters. Data from Coleman et al. (1991) were also used for the validation of the new model. The prediction results from the new model are better than those from Turner's model and are even better than Turner's adjusted model in matching the Turner et al. (1969). The new model is consistent with the Coleman et al. (1991) data and conclusion.
The new model is simple and can be used easily to predict liquid loading in gas wells.
|File Size||618 KB||Number of Pages||10|
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