Logging 14" casing with 412 Well Tractor®

JANG122891 Cement bond - Well Intervention - Welltec
  • Well deviation 73º
  • Max. temperature 212°F (100°C)
  • Distance tractored 3,609 ft (1,100m)
  • Time of operation 18 hrs


A client in Angola was suffering from cement issues in their production wells, which had made it mandatory for them to run Cement Bond Logs (CBL) after the cement job. Because of the large casing, 14" OD, Welltec's 412 Well Tractor was the only conveyance solution which could accomplish the job on e-line.

During job planning, a third party tried to convince the client that there would be telemetry issues when combining their electronically controlled release device system with the Well Tractor. This is not true and was confirmed by a successful System Integration Test (SIT) done as part of the pre-job planning.

Consequently, the 412 Well Tractor was used to convey the third party CBL toolstring in the 9 5/8” casing for cement integrity evaluation. The e-line provider, SLB, had failed three times to get their TuffTrac to work.


Offshore the toolstring was lowered into the well by gravity to a depth of 9,711 ft (2,960m). Then the Well Tractor was activated and successfully tractored to the total depth at 11,903 ft (3,628m) where logging was performed up to the casing shoe at 5,971 ft (1,820m).

The client decided to log deeper than the initial target depth so the toolstring was run back from the casing shoe by gravity to a depth of 9,692 ft (2,954m). Here the Well Tractor was powered up and successfully conveyed the toolstring to the new target depth of 11,959 ft (3,645m) for logging.


Both the Well Tractor 412 and CBL tools worked flawlessly and met the client’s objectives. Prior to Welltec’s e-line conveyance solution was run a competitor had three failed attempts at high cost for the client.

The Well Tractor 412 had one chance and a 100% success rate. The operation was accomplished in approximately 18 hours and the Well Tractor was activated to convey the tools over a distance of 3,609 ft (1,100m).

Philip Neff, BP Ops Petro physicist

I was very impressed with the team’s motivation and participation in all aspects of the job from safety to execution. I have great faith in your guys’ abilities after seeing this well.