Abstract
Over the last few years, we were working to find an alternative deployment solution of the Electrical submersible pumps (ESPs) that help to get rid of the drawbacks associated with the conventional ESP systems:
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Rig availability to install / retrieve ESP systems
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Prohibitive intervention costs
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Unreliable in-well electrical connections
Finally Saudi ARAMCO and Baker Hughes developed the TransCoil rigless-deployed ESP system to address the issues, help operators bring wells on production faster, and lower overall lifting costs to extend the economic life of producing assets. During the project both system design and deployment method were considered to ensure compliance with ARAMCO standards of engineering, operation, and well controls.
The first TransCoil system was installed in December 2016 as a trial well with a pilot plan to operate the system for six months and pull the system to close the trial. This installation was the first to be done globally to prove that the system developed met the statement of requirements. The system installed and operated for 18 months before it was pulled out in operable condition to close the trial in December 2019. This closed the final step in the trial proving that the system can be deployed and retrieved without a rig and met all the success criteria of the TTR.
To complete the pull-out process, it was necessary to find a way to splice the Coiled Tube cable while continued accessing to the power system for testing throughout the pull-out job. This was achieved by inventing a coupling that not only spool-able and testable during pull-out and re-run, but also immune to Hydrogen embrittlement, non-magnetic, can be nitrided for galling, is cheap to work with and has decent strength.
TransCoil ends are hand drilled and coupled together with the splice coupling by a simple procedure which can be safely done on site. The coupling insulation system can withstand 10KV-AC which is sufficient to conduct a 2500VDC megger test on TransCoil after the down-hole coil and remainder of coil on the spool have been coupled together. in addition, resistance and continuity tests can be done at one phase only as the three conductors are connected as one at both ends of the coupling.
Pulling-out process starting from the TransCoil splice preparation then coupling to completely retrieve the whole BHA took approximately 7~8 hours which is a significant operation time saving in comparison with the conventional ESP pull out which takes at least 18 hours.
This paper shares the background of the system development and trial. Details on the deployment background, de-completion events along with the system benefits.
