Sharon I. Escalante Nunez (Master of Science in Petroleum Engineering)
Flow Performance Modeling of Pressure Operated Gas-Lift Valves
(104 pp. – Five Chapters)
Directed by Dr.Dale Doty and Dr. Zelimir Schmidt
(169 words)
A simple model for predicting volumteric flow rate in pressure-operated gas-lift valves in throttling and orifice flow was developed based on information available in the TUALP data bank. The new model proposes the use of one equation for the calculation of the flow rate in gas-lift valves in both orifice and throttling flow.
Seven different valves were analyzed during this study. Gas flow rate in the orifice region is calculated using the existing TUALP Orifice Model. For throttling flow, a new relationship between the correlating variable, called “dimensionless stem position”, and the product Cd*Y*Af is used for gas flow rate calculations. A linear relationship for most of the valves shows that the product Cd*Y*Af is predicted by this new variable.
Experimental tests show that the dimensionless stem position variable is sensitive to changes in the valve closing pressure and therefore, a dynamic valve closing pressure is suggested to improve model performance.
Results from a comparison show that the Unified Model works better than existing models.
Download thesis (TUALP members only)