Feb 6, ASME/API Gas-Lift Workshop1 Erosion Testing of Standard Monel Gaslift Valve Seats Informal Presentation by Shauna Noonan, Chevron Petroleum Ken Decker, Decker Technology

Feb 6, ASME/API Gas-Lift Workshop2 Erosion Testing of Standard Monel Seats OutlineOutline –Brief history –Testing Methodology –Testing Program –Summary of Test Results –Conclusions and Consequences –The Way Forward

Feb 6, ASME/API Gas-Lift Workshop3 Erosion Testing of Standard Monel Seats Brief HistoryBrief History –No quantitative test had been performed to determine the erosion rate of standard monel seats in gaslift valves. –API recommends an unloading rate based on experience. –Erosion continues to occur even with admonitions to unload slowly.

Feb 6, ASME/API Gas-Lift Workshop4 Erosion Testing of Standard Monel Seats Brief HistoryBrief History –This Erosion Testing program was conducted as a special project of the VPC. –Participating members were… Chevron Petroleum TechnologyChevron Petroleum Technology Shell International Exploration and ProductionShell International Exploration and Production Weatherford Artificial Lift SystemsWeatherford Artificial Lift Systems

Feb 6, ASME/API Gas-Lift Workshop5 Erosion Testing of Standard Monel Seats Testing MethodologyTesting Methodology –Typical erosion testing measures the rate of loss of material from a sample by carefully measuring the weight of the sample both before and after the test. –In gaslift valves, the loss of material is less important than the rate of gas leakage through the valve. –The rate of erosion was correlated to the amount of leakage through the port when a standard TC ball was placed over the port.

Feb 6, ASME/API Gas-Lift Workshop6 Erosion Testing of Standard Monel Seats Testing MethodologyTesting Methodology –A 1-1/2” orifice valve was chosen as the carrier for the seat. –The seat was leak tested prior to running the erosion test. –The seat leak rate was rechecked after 1 hr, 2 hrs, 4 hrs, and 6 hrs.

Feb 6, ASME/API Gas-Lift Workshop7 Erosion Testing of Standard Monel Seats

Feb 6, ASME/API Gas-Lift Workshop8 Erosion Testing of Standard Monel Seats Testing MethodologyTesting Methodology –The valve was installed in a modified pocket. The pocket was enclosed in a fixture which was plumbed to a triplex pump. –The plumbing allowed control of pressure upstream and downstream of the test fixture. –Fresh water from a rusty holding tank was used as the test media.

Feb 6, ASME/API Gas-Lift Workshop9 Erosion Testing of Standard Monel Seats

Feb 6, ASME/API Gas-Lift Workshop10 Erosion Testing of Standard Monel Seats

Feb 6, ASME/API Gas-Lift Workshop11 Erosion Testing of Standard Monel Seats Testing Program #1Testing Program #1 –Seat sizes of 1/8”, 3/16”, ¼”, 5/16”, and 3/8” were erosion tested. –Tests were performed at flow rates of gallons per minute. –The downstream pressure leaving the test fixture was maintained at 100 psig or greater.

Feb 6, ASME/API Gas-Lift Workshop12 Erosion Testing of Standard Monel Seats Testing Program #2Testing Program #2 –Seat sizes of 1/8”, 3/16”, ¼”, 5/16”, and 3/8” were erosion tested. –Tests were performed at flow rates of gallons per minute. –The downstream pressure leaving the test fixture was maintained at 100 psig or greater.

Feb 6, ASME/API Gas-Lift Workshop13 Erosion Testing of Standard Monel Seats

Feb 6, ASME/API Gas-Lift Workshop14 Erosion Testing of Standard Monel Seats

Feb 6, ASME/API Gas-Lift Workshop15 Erosion Testing of Standard Monel Seats

Feb 6, ASME/API Gas-Lift Workshop16 Erosion Testing of Standard Monel Seats Summary of Test ResultsSummary of Test Results –Results are not consistent with expected erosion patterns. Wire drawing and cutting was not evident, rather the erosion occurred very uniformly. –The leak rate increased after 1 hr, then decreased after 2 hrs, and then increased after 4 and 6 hrs. –Highest leak rates occurred with largest port sizes.

Feb 6, ASME/API Gas-Lift Workshop17 Erosion Testing of Standard Monel Seats Summary of Test ResultsSummary of Test Results –The erosion did not appear to extend down into the barrel of the seat. Thus when these seats are used in an orifice valve, the size of the port does not change. –The original backcheck was repeatedly used and after 30 hrs at 2 bbl/min was significantly eroded to the point of being useless as a reverse flow check.

Feb 6, ASME/API Gas-Lift Workshop18 Erosion Testing of Standard Monel Seats Conclusions and ConsequencesConclusions and Consequences –Unloading at rates up to 2 bbl/min will lead to moderate leak rates generally less than 1 Mscfd. –Erosion occurred at the sealing surface and was very uniform. –The biggest effect of the erosion will be the change in R ratio. The seat sealing area will be significantly larger then the port area.

Feb 6, ASME/API Gas-Lift Workshop19 Erosion Testing of Standard Monel Seats The Way ForwardThe Way Forward –The erosion testing program needs to be extended to include… erosive fluids erosive fluids TC seats TC seats effects on backchecks effects on backchecks continued erosion of leaking seats continued erosion of leaking seats erosion of cross-over ported seats erosion of cross-over ported seats erosion with downstream chokes erosion with downstream chokes

Feb 6, ASME/API Gas-Lift Workshop20 Erosion Testing of Standard Monel Seats The Way ForwardThe Way Forward –The VPC will continue the erosion testing program in 2001 to determine the erosion of TC seats. –The VPC program is open to other interested parties. –Contact Decker Technology, Inc.