Programme details

The use of light well intervention in subsea wells on the Norwegian shelf may provide substantial safety gains and contribute to reduced operating costs, extended lifetime and increased recovery. The Petroleum Safety Authority Norway (PSA) encourages the industry to further develop technology that leads to increased use of light well intervention. Light Well Intervention in Subsea CO2 Injector – Snøhvit: Island Wellserver was used to intervene in a CO2 injector at the Snøhvit Field in March-April 2011. The objectives were to gather data from existing perforation intervals, install a plug and to perforate additional intervals. Several challenges had to be dealt with in the planning phase; the most important was the negative effect that CO2 could have on the elastomeric seals in the well control package (WCP). Several tests were done to investigate the effect that exposure to CO2 had on the elastomeric elements. Based on these tests it was concluded that the intervention could be performed safely. The operation was performed as planned, including all options. No CO2 related failures occurred during the intervention. TOGI – Temporary plug and abandon – Light well Intervention: The Light Well Intervention (LWI) vessel Island Wellserver was successfully used for temporary Plug and Abandonment on the TOGI field in 2011. By using the LWI concept the scope for the rig West Phoenix set up for the final P&A got significantly reduced and major upgrades of the original TOGI workoversystem were avoided. The scope consisted of securing five wells such that West Phoenix could start final P&A without a workover control system. This involved killing each well, setting deep and shallow plugs, punching tubing, reverse circulating and finally disconnecting and pulling all five VXTs to surface. Onshore preparations involved producing adaptor kit from the LWI Well Control Package to the existing VXT, structural work and converting old TOGI running tools and lifting equipment for deployment on wire. The VXTs were controlled via dedicated hydraulic supply from surface.