Solving gas lift problems in the North Sea`s Clyde field

Conference · Sat Dec 31 04:00:00 EST 1994

OSTI ID:382643

Pucknell, J K; Goodbrand, S; Green, A S

Gas lift wells in the Clyde field have a history of problems, described in this paper. Due to high temperatures (300 degrees F), the use of corrosion inhibitors and asphaltene dissolvers, it was necessary to use gas lift valves containing high temperature elastomers. These were not always effective at maintaining the nitrogen charge at the correct pressure which resulted in unloading valves opening intermittently causing unstable flow. These and other problems have been corrected. Firstly, spring loaded valves with factory sealed bellows have been installed. The elastomers` integrity in these valves are less critical for reliable valve operation. In addition the lack of temperature sensitivity of their opening and closing mechanism makes unloading more reliable. Secondly, a more conservative gas lift design policy is now used, so that despite fluctuating or uncertain tubing pressures, or slight changes in the valve set pressures, unloading valves do not open. Finally, to ensure that planned gas lift designs are stable, they were also checked using a transient multiphase flow simulator specially constructed to model gas lift wells. The simulator appears effective at predicting when stability problems can be expected. The paper also comments on corrosion in the gas lift wells, a problem that was anticipated. Calliper surveys and other data suggest that it is unlikely to result in workovers in the near future.

• OSTI ID: 382643
• Report Number(s): CONF-9410272--
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
CORROSION PROTECTION
DESIGN
GAS LIFTS
NORTH SEA
OIL WELLS
PERFORMANCE
VALVES