BJ services completes subsea precommissioning projectProjects and Operations // November 11, 2009
BJ Services Company recently completed a major subsea pipeline precommissioning operation for Saipem SA in Nigeria on the Akpo development, one of the largest deepwater developments ever undertaken. The Akpo field lies in the Oil Mining Lease (OML) 130 Block approximately 124 miles (200km) south of Port Harcourt, Nigeria, with water depths of 3,936ft to 4,593ft (1,200m to 1,400m.)
Saipem awarded BJ Services a contract in the autumn of 2007 to provide subsea flooding services on the flowlines after lay. The aim of the process was to displace the raw seawater in the flowlines with filtered, treated seawater.
BJ achieved this during the initial phase by running cleaning and gauging pig trains in the production and gas injection loops.
Working from Bourbon Trieste, BJ used its RFM remote flooding module, which offers a number of benefits. For example, lines can be flooded without connection to a vessel, reducing vessel time and related costs, and seawater from the seabed is used, allowing for immediate hydrotesting of the lines, if required. Finally, safety is enhanced because the process is carried out without a downline and diesel-pumping spread, and impact on the environment is reduced because no byproduct from the diesel engines is released into the atmosphere.
BJ Services supplied a complex series of precommissioning services on the Akpo flowlines and umbilicals, as the result of another contract awarded by Saipem in March 2008. Phase 1 involved precommissioning the gas export line, which is a 16in pipeline that stretches 91 miles (147km).
During Phase 2, the production, water injection, gas injection and oil offloading lines were precommissioned. The overall flowline precommissioning workscope included post-lay flooding cleaning and gauging pigging, post tie-in hydrotesting, dewatering, drying and nitrogen packing services.
The third and final phase of the precommissioning programme was carried out on the infield static and dynamic umbilicals, which range in length from 3-6 miles (5-10km). This included a full range of hydraulic and electrical testing.
Work was carried out from Bourboun Trieste and the Akpo FPSO by BJ Services personnel with equipment from the company’s base in Port Harcourt.
“We have forged an enduring and mutually beneficial working relationship with Saipem in Nigeria, and are extremely fortunate to have been given the opportunity to work on the Akpo Development,” said Lindsay Link, general manager, BJ Services.
“The operation was especially challenging, given the complexity of the subsea pipeline network and the deepwater environment. As the direct result of the Akpo team’s commitment and experience, and the specialist technologies used, I am pleased to report that it was carried out safely and efficiently,” he added.