Gonzalo Garcia (Master of Science in Petroleum Engineering)
Design and Optimization of Pig Lift Systems
(79 pp.)
Directed by: Dr. Mauricio G. Prado and Dr. Dale R. Doty
(181 words)
When reservoir depletion reaches a level such that the reservoir pressure is less than 600 psig with a low productivity index less than 0.3 stbd, then conventional production by continuous gas lift does not work effectively. Alternative methods like intermittent gas lift may be more efficient in such cases. The production efficiency for such methods is strongly dependent on the liquid fallback. If liquid fallback can be reduced, then the production efficiency might be improved. The Ball Pump method was developed (1953) to reduce liquid fallback, and was later modified and improved by Lima (1993). This modification was called pig lift.Currently, only simplified models are used to estimate gas requirements for the pig lift method. The objective of this work is to fully model the pig lift operation. The model developed considers the conservation laws of mass and linear momentum for both the gas and liquid phases. The resulting model can be used to determine the relative influence on liquid production of all operational parameters. Consequently, the model can be used as a design tool for the pig lift process.
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