Gas-Lift Surveillance Techniques Jim Hall, Shell International EP Cleon Dunham, Oilfield Automation 20 – 30 Participants

Gas-Lift Surveillance Techniques Objectives Deep Stable Optimum Data gathering / reporting Charge – 95% of data not used Objective Collect key data once per minute Have “system” check all data If well is OK, nothing is reported If well is sick (exception), it “calls for help” People use data to troubleshoot problem wells What data is needed?

Gas-Lift Surveillance Measurements Need Want Use Surface Pinj Y Y GL analysis Qinj Y Y GL analysis/control Pwh Y Y GL analysis Qliq Y GL optimization Twh Y Detect change in H2O Pfl Y GL analysis Tambient Y Twh analysis Downhole Pwf Y GL optimization T Y GL analysis Qinj Y GL analysis/control Qsinglephase Y GL optimization Tcontinuous Y GL troubleshooting

Gas-Lift Surveillance Performance Indicators TGLR Hydraulic effectiveness IGLR Economic effectiveness FGLR Must be calculated BS&W What is being lifted Others What if Downhole Instruments Fail Run flowing gradient survey Conduct accurate well test Calibrate multi-phase model Use calibrated model with measured surface data in between surveys and well tests

Gas-Lift Control Method Control Method Frequency of Use Lift gas rate Manual Common Automatic Fairly common Downhole1 Very new Injection pressure Manual - Automatic Rarely Production pressure Manual Fairly common Automatic Very specialized 1 If using downhole control, need automatic fallback to surface method