Damaged retrievable bridge plug leads to 72 hours of NPT
When an operator was running coiled tubing in hole with a motor and mill
during milling operations on a plug-and-perf well, it tagged and damaged a
retrievable bridge plug in the vertical section. Below the bridge plug were 20
frac stages that had been stimulated, and the bridge plug needed to be pulled
to put the well on production. The bridge plug provider attempted to fish the
plug, but the subsequent fishing operation sheared the retainer nut holding the
plug in place, leaving the plug in the vertical section above the stimulated
zones. The top sub of the overshot tool also broke off during the fishing
attempt, leaving the operator with a complicated engagement profile.
The operator worked with another tool provider to burn over the tool and
mill out the slips. However, after 12 runs, 72 hours, and 25,000 lbf [111,206
N] applied with no success, the operator sought input from Coil Tubing
Services, a Schlumberger company.
CoilTOOLS tools and solutions eliminate additional burnover runs
Instead of performing more burnover runs, Coil Tubing Services proposed
an alternative technique using a taper tap to fish the lost bridge plug
internally. Using CoilTOOLS tools and solutions, Coil Tubing Services
collaborated with the operator and the retrievable bridge plug's design team to
create a taper tap tool specifically designed to spear the inner mandrel of the
bridge plug. By setting down enough weight with the taper tap inside of the
damaged mandrel and getting a friction grab by pulling up approximately 1,000
lbf [4,448 N], the mandrel could be recovered back to a retrievable position.
This would mean the slips would no longer be expanded and would be retracted
off the cone and back into the tool. By retracting this mandrel and then
running in with an overshot, the tool could then be pulled without having to
fight against the slips.
Customized taper tap tool helps operator recover fish in just three
Using centralizers and the custom taper tap, Coil Tubing Services
speared the mandrel and dislodged the fish. A subsequent run with an overshot
tool at 7,000 lbf [31,138 N] successfully engaged the retrievable bridge plug,
pulling it to surface with no issues. The entire operation took three runs over
only 14 hours, allowing the operator to resume milling operations on the
remainder of the well.