CNRI files decommissioning plans for two floating units off UK
CNR International (CNRI) has filed its Banff and Kyle fields decommissioning programs for an FPSO and FSO float-off with the UK authorities.
The document submitted to the UK authorities contains the decommissioning programs for the removal of the Petrojarl Banff floating production, storage and offloading (FPSO) vessel and the Apollo Spirit floating storage and offloading vessel (FSO) and the associated risers and mooring systems from the Banff and Kyle fields.
The Petrojarl Banff FPSO and Apollo Spirit FSO will be utilised for the initial decommissioning activities, namely the flushing/deoiling of the subsea infrastructure i.e. manifolds, risers, subsea pipelines and umbilicals, and to support with the implementation of isolations for the subsea wells.
However, the floating units will then not be required to perform any further decommissioning related activities and it is proposed that the vessels are removed from their current locations. Activities associated with the subsequent decommissioning stages of the subsea pipelines, umbilicals, risers and other subsea infrastructure will require the services provided by other specialist vessels.
The Banff field is located in blocks 29/2a and 22/27a in the UK Sector of the Central North Sea some 200km due east of Aberdeen in approximately 95m water depth.
The Kyle field is located in block 29/2c and 29/2h in the UK Sector of the Central North Sea some 200km due east of Aberdeen in approximately 90m water depth.
There is one drill centre for the Banff and two drill centres for the Kyle field – North Kyle and South Kyle. The Banff wells and manifolds are located approximately 1.6km southeast of the Petrojarl Banff FPSO. The Kyle wells and manifolds are located between 13km and 16km south of the Petrojarl Banff FPSO.
The Banff and Kyle fields are tied back to the Petrojarl Banff FPSO.
The Apollo Spirit is an FSO vessel, which is moored via a Submerged Turret Loading (STL) system. The vessel receives processed oil from the Petrojarl Banff via a 12” flexible riser. Oil is stored in the vessel’s cargo tanks, and periodically offloaded to shuttle tankers. The Apollo Spirit has nine cargo tanks, with a total capacity of 910,000 bbl.
Currently, alternative production strategies have been found to be uneconomic. A Cessation of Production application for the field was submitted to the Oil and Gas Authority (OGA), with approval granted on March 2, 2020.
Three phases of decom
The removal of the FPSO and FSO is part of the wider Banff and Kyle field decommissioning, which will be carried out in three distinct phases executed over a five-year period.
The first phase includes removal of the FPSO and FSO vessels from the field, the second one decommissioning of subsea installations and pipelines, and the third phase includes well plug and abandonment.
The decommissioning programs which have been submitted now address only phase 1 only, which is currently planned for summer 2020.
It will involve flushing and cleaning of the subsea production system and FPSO and FSO; implementation of required isolations; removal of the FPSO and FSO vessels from the field; removal of buoyant flexible pipelines, and vessel mooring infrastructure.