Summary
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.
© 2010. Society of Petroleum Engineers
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History
- Original manuscript received:
9 May 2009
- Meeting paper published:
4 December 2008
- Revised manuscript received:
26 September 2009
- Manuscript approved:
4 November 2009
- Published online:
15 April 2010
- Version of record:
11 May 2010
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