UK-based Subsea 7 has completed the Girassol Pipeline Repair Project for Total E&P Angola.
The Girassol Field is located approximately 210km north-west of Luanda, Angola, in water depth of approximately 1,350 metres.
The project was an entirely diverless pipeline repair in 1,350 metres water depth and was based on a technical design competition issued by Total which resulted in Subsea 7 being awarded the contract for the design, manufacture, testing and operation of a new deepwater pipeline repair system (PRS).
The system would then be used on the repair of a damaged 30.5cm water injection pipeline in the Girassol field, offshore north-west Angola. The PRS system comprises a set of permanent equipment such as the spool deployment frame, rigid spool piece, end connection skids and two mechanical pipeline connectors together with a suite of ROV deployed or operated tools for preparing and aligning the pipeline prior to the connector installation.
The PRS is the latest addition to Subsea 7's extensive pipeline repair capabilities which include both grouted and hyperbaric welded solutions. The project management and engineering was performed at Subsea 7's office in Aberdeen, United Kingdom, and the in-country works supported from Subsea 7's facilities in Luanda, Angola.
The offshore phase comprised two separate phases. In the first phase the permanent works equipment was installed on the seabed at the damage location. In the second phase the ends of the damaged pipeline were lifted, prepared and aligned before the mechanical connectors were installed, set and tested with annulus tests onto the previously installed spool piece.
Final confirmation of the repair was achieved by a pipeline leak test from the Girassol FPSO which was completed in December 2009.