Traditionally, to complete a subsea well with vertical X’mas tree, we will have to land the tubing hanger, install a wireline set tubing hanger plug and pressure test it. Once the plug is tested, we can then remove the subsea BOP, install the vertical X’mas tree, and retrieve the plug through the work-over riser before the well is ready for production or injection. This is a time consuming rig operation and it requires additional handling of the work-over riser and wireline run, which both increases the HSE and operational risks. With the increasing focus on safety, reliability and cost efficiency for deepwater developments, it is critical that we can reduce the operational risk and rig time for drilling and completions. This paper describes the invention of a shallow set barrier plug, Disappearing Tubing Hanger Plug (DTHP), and the case study of the first application on AKPO-214. This ground-breaking solution based on the knowledge of the existing glass barrier plug technology was developed as the result of synergy between Total E&P Nigeria and TCO. The objective of the invention is to provide a more reliable and cost efficient solution for their deepwater completions offshore Nigeria. With the application of this DTHP, it has been proven that the disappearing feature of the DTHP with pressure cycling is effective and reliable. The pressure cycles were applied directly from the FPSO, liberating the expensive rig for other purposes. The DTHP also provides improved well integrity by forming an ISO14310 V0 qualified gas-tight barrier. The rig time savings for the first installation is estimated to be 10 days, which directly translates into savings in millions of USD.
Number of Pages
Looking for more?
Some of the OnePetro partner societies have developed subject- specific wikis that may help.