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, it was suggested by the third-party e-line provider that integrating their electronically controlled release device system with the Well Tractor might lead to telemetry issues. However, this concern was addressed and dispelled following a successful System Integration Test (SIT).

Following this validation, the Well Tractor 412 was selected for the task of conveying a third-party CBL toolstring within a 9-5/8” casing, aimed at evaluating cement integrity. It is noteworthy that the e-line provider had previously encountered challenges, and three unsuccessful attempts with their own tractor. This experience underscores the importance of thorough testing and validation in ensuring the compatibility and effectiveness of technological solutions in field operations.

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).