Many tie back systems are in use in Brazilian subsea fields today and new systems are being tested. Some go straight to an FPSO while others may be going to shore.
It may be necessary to connect some of the pre salt field to shore and that may be upwards of 250 nm which is quite a long tieback.
A good example of tieback systems in use is the Roncador field in the Campos Basin, which was the world’s first early production drill pipe riser rated for 2,000 m (6,600ft). The Roncador Field was discovered in 1996 at water depths ranging from 1,500 to 2,000 m (4,900 to 6,600 ft) in the Campos Basin. It is 125 km (80 miles) from the coast.
The Roncador Field was a major breakthrough for many reasons, including the world’s first drill pipe riser, subsea tree and early production riser (EPR) rated for 2,000 m (6,600 ft). The first well, RJS-436, produced to the FPSO Seillean from 1999 to 2001 using the EPR at a world water-depth record of 1,853 m (6,077 ft).
Other examples are the Bijupira and Salema Fields which were discovered in 1990 and are located 250 km (150 miles) east of Rio de Janeiro. The blocks range in water depths from 480 to 880 m (1,580 to 2,900 ft). The fields have combined estimated recoverable reserves of around 170 mmbo. The partnership between FMC and MODEC International supplied the FPSO vessel.
Pre-salt fields such as Carioca, Tupi and SugarLoaf may have different tieback systems according to their own characteristics, and according to well depth and distance from shore.
Plans are being made to have different stages in some very long tiebacks. Still many support tiebacks all the way to shore, specially from new gas and deepwater fields. Later we will examine some other solutions being used and planned for the new pre-salt fields and other new discoveries in Brazil.
Claudio Paschoa