Published: 02/08/2016
Coil Tubing Services, a Schlumberger company, proposed CT riserless operations in P&A wells after the zonal and casing packer isolation had been successfully set and tested. Engineering and operational evaluations were performed to address CT string integrity, bottomhole assembly, surface CT stack rig-up, remote operating vehicle use to string the CT into the wellbore, CT depth correlation, cement slurry design, and proper fluid placement.
A total of 14 subsea CT riserless interventions have been completed as part of this campaign without HSE incidents or CT string failures, saving 40% in operational time and complying with federal safety regulations.
Environment
Deepwater
Well depth
4,900-19,000 ft, [1,494-5,791 m]
Hole size
8.5 in [21.6 cm]
Subsea riserless plug-and-abandon (P&A) operations are often completed by setting plugs with drillpipe after production tubing has been removed with the rig, and operations are performed in an average of 22 hours. An operator was seeking an alternative method to reduce the amount of time needed to perform P&A operations in its deepwater wells exceeding 3,500-ft [1,067-m] water depth, all while complying with federal safety regulations.
