SPE 173837: New Advances in Mechanical Engineering Enables Pulling Forces of up to 60,000 lbs. – Experience Gained from Offshore Norway Case Stories


This paper will present an improvement in engineering in the form of a hydraulic stroking tool with the ability to apply 60,000 lbs. of force. The tool has already been applied offshore Norway and lessons learned from these recent operations will also be disclosed.

Methods, Procedures, Process:
In one operation, a plug was accidentally set across the christmas tree and blowout preventer (BOP), effectively eliminating the christmas tree as a well barrier element, and constituting a serious HSE risk. Conventional solutions failed to release the plug due to an insufficient pull force and then a failing jar. In another well, the setting tool had malfunctioned resulting in a partially set plug and a stuck tool. Repeated attempts with heavy duty fishing equipment had damaged the fishing neck, further complicating the fishing operation as the setting tool had failed before it could break the stud connecting to the plug.

Results, Observations, Conclusions:
The high performance of the recently developed stroking tool turned out to be the correct solution for both of these demanding operations. In the first well, it was estimated that the force required to shear the plug from the setting tool would be 43,300 lbs. The operation was completed in three runs with no misruns, which saved the operator from prolonged exposure to HSE risk including well control situation. In the second well, the force required to shear the stud and free the setting tool was 40,000 lbs. Two release devices were combined in the toolstring, one below the hydraulic stroker and one below the cable head, in order to allow further contingencies to mitigate risk and increase safety. After four attempts the shear stud parted, thus completing the setting sequence and freeing the stuck setting tool. The operator got the well back on track, saved five days of rig time and avoided the costs of a workover rig.

Novel/Additive Information:
The case stories in this paper constitute the first jobs performed with the new tool. Two important features are reduced HSErisks and increased operational efficiency, which will also be captured in the paper.

Find the full paper at onepetro.org

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