Milling of Cast Iron Bridge Plug  

June 2007

On a North Sea platform in the UK, the Well Miller in conjunction with the Well Tractor were used to remove a cast iron bridge plug at 15,000 ft.

 
The well is a gas producer with a high water-cut and a low bottom hole pressure of 2000 psi and therefore, gas production was threatened by water ingress. A PLT carried out during March 2007 indicated that all water production was coming from a depth below 16,295 ft. The proposed intervention strategy was to set a permanent bridge plug at 16,280 ft but it was set prematurely at 16,200 ft. In order to remove the prematurely set plug, Welltec was chosen to mill it out on electric wireline, which was a world’s first.

 

Achievements

• Total operational time from rig up to rig down was 67 hours
• Actual milling time 9 hours
• Unique operation all milled material was recovered,
• The challenges of controlling rate and milling penetration were achieved
• Production increase paid for the operation in a limited number of time