Coil Tubing Fishing

Coil Tubing Fishing

Coil Tubing Fishing


    18 days of 24 hour operations


    While preparing to frac a 4 well Duvernay pad, it was noticed that there was communication at 60mpa pressure on the cemented in 5-½ production string to 9-5/8 intermediate. It was determined through logging that a connection was leaking 120m from surface. The fix was a metal permanent patch that restricted the casing ID to 3.75” from the original casing ID of 4.565” for fraccing. Magnum long ranch plugs were used where as they would fit through the restriction yet set in the larger ID casing. For the millout, Piston had proposed jointed pipe milling but the customer decided that coiled tubing was cheaper. After milling 12 frac plugs, the motor became stuck and stalled due to the lack of hole cleaning through the patch. The customer’s Operations personnel decided to drop the disconnect ball, it was observed seating into the disconnect as pump pressure increased, but the string did not become free. Their next choice was to cut the coil tubing at the heel and release the coil unit after removing the vertical portion of the string.


    Piston was contacted to propose a fishing plan. Piston rig 9 was mobilized and rigged up with 10 BOPs to provide redundancy and a means of securing the coil. Surface pressure was 28mpa with a column of fresh water. The workstring chosen was 2 7/8 slh90ht with 3-1/8 tooljoints. This was not the strongest choice but the slimmest to provide good annular velocity and allow debris to pass through the restricted ID of the patch.

    The first run was a dressing mill to clean up the fishtop, then a 3-5/8 overshot with high pressure packoff was snubbed into the well with tkr plugs in the profiles. The string was latched and plugs were removed with slickline. A circulation rate was established through the stalled motor - 220lpm @ 84 mpa. 15k E-Line was sourced for the free pointing operations, and pumped to within 5m of the motor head assembly (MHA). It was determined that the string was free to that point. A jet cutter was pumped to 5m above the MHA, and the string was separated , slickline reset the plugs in the workstring and the string and fish was pulled 100m from surface. Slickline plugs were removed and slickline ran a gauge ring into the coil. Slickline was rigged out and e line was rigged in. Two permanent plugs were set in the bottom of the coil. After negative testing the plugs the string was hoisted and the coil was secured in the slip rams. The snubbing jack and work window were rigged out and coil tubing injector dimple to dimple connected to the fish. After connecting the coil tail to the fish, the injector was bolted down to the snubbing BOPs and the connector was pull tested. The stack was equalized with the pump above the slip rams to the injector, slip rams were opened and the connector was reeled out of hole. Once the connector reached the reel, chains were welded along the connector as a safety device in case the coil snapped due to the rigidity of the connector. The coil fish was then reeled out of the well. The snubbing jack was then spooled up to house the fishing tools and fish. A washpipe run was made to clean the debris from around the fish. When the washpipe was snubbed out, it was found that the disconnect and the 5m piece of coil had become stuck in the washpipe. An overshot was then made up and snubbed in the hole, latched onto the motor and bit, and jarred free. Once the fish was out of the hole, another motor and 94mm junk mill were made up to the work string. The remaining plugs were milled out without hole cleaning issue due to the string being spun at 120rpm, leaving no debris laying on low side of well. The well was milled to TD at 6200m, the string was pulled from well, a velocity string snubbed to the heel and the unit was rigged out.