OGUK Decom Insight Report 2021

CASE STUDY: Norway Case Study – Repsol, Gyda

Both Phase I and III operations have been performed using simultaneous operations (SIMOPS) with phase II activities being conducted by the rig. To perform these operations in parallel with the rig has saved months of rig operations. Preparation for removal is now ongoing and the plan is to de-man the platform late November. Both topside (17,270 tonnes) and jacket (13,386 tonnes) are planned to be removed by Pioneering Spirit during the summer 2022. The bearing blocks for the single lift have been installed while the engineering down and cleaning work is being finalised. The conductors are cut and secured but will be removed with Pioneering Spirit during the summer of next year in conjunction with removal of the jacket.

The Gyda field is located in the Norwegian sector of the North Sea about 280km southwest of Stavanger in 66 metres of water. The field was developed using a single integrated steel platform which combines drilling, processing, and accommodation. Production commenced in June 1990 and oil, gas, andwater have been produced from the reservoir about 4kmbelow seabed. The production from the field ceased February 2020. Repsol, as the operator of the field, finished decommissioning the 32 wells in October this year in a campaign of 715 days. Prior to start-up of the well decommissioning campaign a “ready to operate” project for the rig was executed to make sure it was safe and would operate effectively during the campaign. Decommissioning of the wells was done in three phases: • Phase I: Wireline to install a deep-set mechanical plug, release of the annular safety valves, punch and cutting of production tubing, displace well to kill fluid and install shallow barrier for nippling down X-mas tree • Phase II: Use of the main rig to pull tubing and set the cement plugs in the wells • Phase III: Cut and secure surface casings and conductors

DECOMMISSIONING INSIGHT 2021

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