Spanish oil company Repsol has filed an application to remove the export pipeline and umbilical of the Rev field, with plans to cease production from the field in the first quarter of 2020.
The Rev Field, is located in the Norwegian Continental Shelf, however, the export pipeline and umbilical cross over into the UKCS and connect to Chrysaor’s Armada platform.
Repsol is now looking to remove 4.8 km of 12-inch gas condensate pipeline from the UK median line to the flange at the Rev Subsea Isolation Valve (SSIV) close to the Chrysaor operated Armada platform; and 4.9 km of the Rev electrical and hydraulic control cable (umbilical) from the UK median line to the point at which it joins the junction box close to Armada.
The Rev Field started production in 2009 but production has decreased to the extent that the field now only produces intermittently (at times of appropriate reservoir pressure).
Based on the periodic nature of production of the Rev Field, Repsol is planning to cease production of the field, the latest date is 31st March 2020, but could be earlier.
Leave it in the ground
As for the decommissioning, the plan is to leave the buried parts of the pipeline in place and remove the exposed sections of the pipeline within the Armada 500-meter zone. Repsol has said this partial removal option is preferred as de-burying the pipeline, buried between 1 m and 2 m, would take up 10 times the activity required to make the pipeline safe and leave it in place.
“Additionally, the potential long-term impacts are minimal due to the depth of burial which has been demonstrated to be broadly constant since installation in 2008. The exposed section of the pipeline up to the 12-inch flexible from the SSIV will be fully removed (150 m),” Repsol said.
The umbilical is to be fully removed by reverse reeling.
“The umbilical has been left to naturally backfill, and although backfill has occurred the depth of burial and the trench profile combined pose a risk in the long term that significant remedial work may be required to ensure the umbilical is safe. Removal by reverse reeling is achievable, safe and economical in the long term,” Repsol said.
The 12-inch export pipeline has in place 22 concrete mattresses and the umbilical has in place 48 concrete mattresses. These will all be removed as part of the Rev UKCS Decommissioning Project.