Oil

Bringing Angola's Rosa field on stream in 2007 was an indisputable technological feat. Too "small" to warrant a stand-alone development, it is tied into Girassol's FPSO - quite an exploit considering the distance between the two fields.

In the heart of the Gulf of Guinea

Found in 1998, Rosa is one of 15 fields discovered to date by Total in Angola's deepwater Block 17, in the Gulf of Guinea. Nicknamed the "golden block," because of the large number of finds, Block 17 is the stage on which we demonstrate the full range of our deep offshore skills and expertise. The development of Rosa, located 15 kilometers from Girassol in a water depth of 1,350 meters, is a decisive step forward in our strategy of mastering deep offshore technology and operations. Although substantial, its estimated proved and probable reserves of 370 million barrels (versus 1 billion barrels for Girassol-Jasmim) were too small to develop profitably on their own. The solution was to capitalize on Girassol's production installations to monetize Rosa's production. It may sound easy and is consistent with sustainable development of Girassol, but this solution was nonetheless an immense challenge.

Carrying production over long distances

With a maximum temperature of 4°C and high pressures, the subsea environment is not conducive to the flow of effluent. In these conditions, the oil would solidify almost instantly if steps were not taken to prevent this from happening. One of the keys to making sure that blocks of ice do not form and paralyze flow is to control the temperature inside subsea lines, to keep the fluids being carried as warm as possible. The greater the distance traveled, the more of a challenge that is. In that respect, the distance between the Rosa wells farthest away from the Girassol floating production, storage and offloading (FPSO) vessel pushes the envelope of deepwater technology. Oil leaving wells at 50°C must reach the FPSO at a temperature of at least 35°C after traveling nearly 20 kilometers. To meet this challenge, a reinforced insulation technology for flowlines was purpose-designed for Rosa. In the pipe-in-pipe solution adopted, the concentric pipes are separated by high-performance insulation and an annular space. The lines converge to create a 1,200-meter-high riser tower, an innovative assembly that carries production from the seabed to the surface.

Flawless logistics and safety

Another challenge in tying Rosa into Girassol was boosting the FPSO's production capacity without shutting down operations. It took 22 months to install the 5,600 metric tons of additional structures, pipes and equipment required to prepare the immense floating unit for Rosa's production. Twenty-two months of an endless round of ships dedicated to transporting and lifting the equipment, sharing the waters with the drillships and subsea installations in the area. The gargantuan program was estimated to have employed nearly 1,400 people, with 400 people - accommodated at a flotel near the FPSO - on site at the same time. Close to three million man-hours were logged in all. The exemplary end result: a remarkable zero-accident record.

A protected environment

With the help of environmental impact assessments, both offshore and in vulnerable areas where construction was performed, such as the lagoon on the Angolan coast in which the riser tower was assembled, Rosa eliminated all discharges of production water into the sea. In fact, the water produced by Girassol/Jasmim and Rosa is now reinjected into the reservoirs. The associated gas is also reinjected in full, eliminating all emissions.

A spirit of sharing in action

Rosa provided another practical illustration of Total's strategy of maximizing the local economic benefits of our projects. A large portion of the equipment was built in Angola, entailing nearly three million man-hours of work; this local content spurred the growth of the country's oil services industry.