Case Studies

Gas Lift Surveillance by Tracer Method

QUICK FACTS:

Where: North Sea

When: January 2019

What: Gas Lift Surveillance

Duration: 12 hours

Crew: 2 Engineers

Equipment: 5 Handcarried pelicases

Tracer Medium: CO2


Challenge

An operator in the North Sea, experienced a sudden pressure drop in the injection annulus during production on gas lifted oil well.

Sudden pressure drop in injecting annulus can be an indication of an integrity loss of primary barriers downhole and had to be immediately addressed.

Solution

ScanWell was requested to investigate what caused the pressure drop, using its interventionless tracer system.

The method is a direct measurement of the Gas Lift gas propagation. By injecting a tracer medium in the gas lift supply while sampling the produced fluids.

Results

The tracer fingerprint indicates multiple injection points downhole.

15% of the gas was flowing through the GLV installed at 11154 ft MD and 85% from the apparent leak at approximately 11400 ft MD.

An acoustic measurement confirmed liquid level at 11409 ft MD, just below the leak point.

Client value

By using ScanWell method, the client confirmed tubing leak/collapse 246 ft below orifice GLV.

The client saved multiple days of shut-in production and cost, compared to conventional WL intervention.


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Scanwell-Case-Study-Gas-Lift-Surveillance