The Petrobras oil-water subsea separator pilot project includes the qualification test, design and construction of a prototype to be installed in the Marlim Field, at the Campos Basin.
During the OTC 2010 in Houston, Petrobras unveiled its subsea oil-water separation, which is being developed by FMC Technologies. This system will push the limits of the subsea three-phase separation envelope to deep waters and heavy oil. Petrobras and FMC are performing an extensive qualification test program for the key components of the separation unit.
The increasing produced water rate, its respective treatment costs and limited processing capacity at the existing platforms are the main drivers for Petrobras to move towards a subsea three-phase separation and reinjection system.
On the other hand, this technology may also grant production anticipation, increase of the oil recovery factor, and the possibility of longer tie-backs and/or smaller production units.
The system is being testes at the giant Marlim field, in the Campos Basin. The production platform that will control and receive the production of the prototype is P-37, at the Southern area of the field, in a water depth around 870m. The production well assigned to the prototype separator is the MRL-141, that produces a 22°API oil, and the water will be re-injected through the RJS-488 well. The producer is located 2,400 m from the platform and 320 m from the separator. The reinjection well is 2,100 m away from the separator. In this scenario the new technology will allow a reduction on the amount of water handled by P-37 process plant, opening the possibility of an increase of the oil production from other wells.
The key challenge of this system is to meet the reservoir tolerance for the correct specification of the separated water that will be re-injected. Other challenges are the very stable emulsion (up to 80% water in oil) character, the slurry deposits and the provision of chemicals to guarantee free water on the separator.
Petrobras decided for a tubular three-phase gravitational separation concept for its first
deepwater heavy oil separator, because of its higher capability of granting a robust solution for such scenario. The contract for testing, design and construction was signed by Petrobras with FMC late August 2009, and consists of a qualification program that started December 2009 and is planned to end in June 2010. The installation is planned to the third quarter of 2011.
Claudio Paschoa
Illustration courtesy of FMC Technologies