Gokhan Hepguler (Master of Science in Petroleum Engineering)
Dynamic Model of Gas-Lift Valve Performance
(179 pp.)
Directed by Dr. Zelimir Schmidt
(147 words)
Theoretical and experimental study is performed to develop a dynamic model for gas passage performance of a gas-lift valve. Experiments are conducted on Teledyne-Merla N- 1 5R, a 1 .5 inch, nitrogen-charged, bellows-operated valve in which internal temperature and pressures were measured during flow performance tests. Performance curves are obtained using air for 0.25 and 0.50 inch port sizes with flow rates reaching 2.5 MMscf/D.
Dynamic model based on principles of physics is developed both for orifice flow and throttling flow. The model predicts valve performance in orifice flow region within 5%. More complicated problem of throttling flow requires special tests to define stem displacement before calculating corresponding flow rate. Static
probe tests provide bellows load rate. Dynamic flow tests produce information for effective force on the stem and discharge coefficient as functions of displacement. The throttling flow model sets guidelines for generalization to other valves. FORTRAN source code is included for incorporating model into a design procedure.
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