Case Studies

Water Shut Off Application in UK North Sea March 2019

Well Intervention with Wel-lok™ WSO

Identification of problem

A client encountered a well that was producing 100% water from the lower zone of a well. This resulted in the well being shut in and yielding no production.

Isolation was required through a blank section of 4” pipe out to 7” casing with only fluid in the annulus. The tool had to pass through a 3.033” restriction in the tubing and be set at an angle of 70°. The tubing restriction limited the amount of alloy that could be deployed to create a plug as well as the amount of thermite that could be used to melt the alloy.

A Wel-lok™ WSO was set inside the 4” blank pipe to isolate the well out to the 7” casing.


The WSO was successfully set as planned. Due to complications in turning the well back on production, results of the plug’s effectiveness were inconclusive.