Case Studies

P&A Application in Norway North Sea April 2017

Well Abandonment with Wel-lok™ STC

Identification of problem

This well had previously been abandoned by circulating a cement balance plug through perforations in 4 ½” tubing into a 7” production casing. The well continued to build gas pressure at surface through the production tubing and casing.

Traditional methods of circulating cement balance plugs does not generate a gas tight seal. In order to continue with the abandonment of the well, the operator needed to ensure the well was free of pressure and gas in order to cut and pull the production tubing.

The production tubing was perforated and a Wel-lok™ STC was set in the well to provide a gas tight seal in the tubing and casing.


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

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