A deep clean to enable pre-P&A plug setting

Challenge

A major operator in Denmark needed to set one or more plugs in various sections of the well that had CaCO3 scale for a pre-P&A operation. A multi-finger caliper was run to assess the degree of the scale and the decision was made from the caliper log that the scale was severe enough that the BLUESPARK® treatment would be required.

• Offshore conventional oil field
• Directional well
• CaCO3 scale
• Depth: 150 – 5650 ft (45 – 1720 m)
• Temperature: 62 °C (144 °F)

Solution

Remove CaCO3 scale from the inside of tubing using electro-hydraulic pulsing technology.

• The BLUESPARK® 275 tool was run on third-party E-Line.
• Three 20 ft (6m) deep and intermediate intervals were treated on the 1st run in the well at various pulse densities.
• The caliper was run again over the 3 intervals to determine the extent of the cleaning
• After the unsuccessful setting of a plug in a shallow zone which they attempted to clean with brushes, it was decided to use BLUESPARK® to treat the same shallow zone, which once completed, allowed the plug to be successfully set.

Outcome

• Four zones were successful cleaned with BLUESPARK® with the caliper logs showing significant removal of scale in each zone
• A deep and a shallow plug were successful set and tested