P&A Application in Norway North Sea

Identification of problem

Two separate wells had previously been abandoned by setting bridge plugs and dump bailing cement inside a liner to isolate the producing zone. The wells continued to build gas pressure at surface through the production tubing up to 1,200 psi.

Issues to overcome

Traditional methods of setting bridge plugs and spotting cement on top does not generate a gas tight seal. In order to continue with the abandonment of the well, the operator needed to ensure the producing zone was properly isolated and there was not pressure in the production tubing string.

Application

wel-lok™ TS tools were set inside the liner of each well.

Outcomes/Conclusion

An initial pressure test of 4,000 psi was performed, followed by a successful 24-hour negative pressure test which resulted in no bubbles or gas pressure at surface. Further, each of these wells underwent a 1-year monitoring period prior to resuming the well abandonment, resulting in no bubbles or gas pressure build up over this period.

About the application

The wel-lok™ TS (Tubing Seal) was developed to overcome the shortcomings of traditional methods, using bridge plugs and cement during well abandonment. It is typically run on electric line but can be deployed on a slick line or coil tubing as well. It can pass through small restrictions such as damaged or crushed tubing, yet still create the gas tight seal. It has a higher expansion ratio than conventional plugs, higher pressure ratings than inflatable packers and gas blocking abilities that cement cannot match.

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