Specially designed equipment, systems and processes decommission a flooded pipeline, isolate it on the seabed to create a safe working environment, and then repair and recommission the pipeline to resume gas supply services. This makes an above water tie, especially in deeper waters, unnecessary.Dolphin Energy says that this approach is safer and eliminates the need to handle large quantities of seawater mixed with hydrocarbons at the receiving terminal. It also decreases risk of damage to onshore assets such as sensitive emergency shutdown valves because seawater is removed from the pipeline quickly.
Obaid Al Dhaheri, CEO, Dolphin Energy Limited, said: “ASSIST can shorten the repair duration by having the necessary methods and tools ready to carry out a repair, mitigate all associated technical risks, and undertake the work on the seabed. Its versatility means this unique system offers additional significant economic and strategic value by protecting asset integrity, ensuring gas loss is minimized, and restoring production as quickly as possible.”ASSIST was developed for deployment on Dolphin Energy’s subsea pipelines, the 36 inch twin sealines and the 48 inch export pipeline. It compiled technical studies for years to develop this repair strategy. In addition to the diverless launcher and receiver, other subsea tools include handling frames, a welding habitat that allows divers to work in a dry environment, a coating removal tool and topside and subsea ancillaries.
ASSIST can also handle subsea tie-ins, hot tapping, construction or expansion of new and existing subsea fields, in addition to repair. As a result, pipe sizes from 8 to 48 inches can also be accommodated. This means other regional operators can utilize the system – subject to their requirements.
“In addition, the system and its range of subsea tools is helping develop technical innovation and by convening subsea expert companies and operations during the development and deployment of ASSIST, we are promoting local competencies and skills development,” added Mr. Anwar H. Zuarub, SVP projects, projects division, Dolphin Energy Limited.
To support the deployment of ASSIST, Dolphin Energy has worked closely with Khalifa Industrial Zone Abu Dhabi (KIZAD) where a 45,000 m2 purpose built marine base facility stores and handles the subsea tools and also serves as the hub for all maintenance and subsea interventions.