Gas Lift Surveillance by Nitrogen Tracer Method
Tracer Method
Nitrogen as tracer medium
Challenge
Troubleshooting dual string gas lifted production is a challenging task in the industry. Conventional methods do no provide information regarding the distribution of lift gas downhole. Efficient optimization work is dependent on accurate well model, which again requires accurate lift gas rates and downhole distribution.
Solution
ScanWell was requested to investigate the lift gas rate and its downhole distribution. The method is a direct measurement of the Gas Lift propagation. By injecting a Nitrogen tracer medium in the gas lift supply while sampling the produced fluids.
Results
Intervention-less tracer method is used to determine lift gas rates and downhole distribution between the producing strings. The long string was multi-pointing from second, third and forth side pocket mandrel, passing 4%, 6% and 57% of lift gas respectively. The short string was multi-pointing from the second and fourth side pocket mandrel, passing 2% and 31% of lift gas respectively. Gas lift injection rate was measured by N2 dilution method to 910 Mscfd.
Client value
By using ScanWell method, the client obtained information required to further optimize well’s production and plan eventual intervention work. In-line gas lift meter was calibrated and well model constructed based on measured downhole distribution. The client acquired required data for optimizing the well and gaining production, without generating any downtime during troubleshooting.
