In October11994 Petrobras, leading a team of six companies has installed for the first time in the world an ESP in a subsea well. The subsea ESP system in the well RJS-221, located in 86 meters water depth, in the Carapeba oilfield has now completed more than two years in operation without failures. The success with this installation has encouraged Petrobras to proceed with this project in order to extend the application of this technology to 1150 meters water depth in the second Phase. This paper presents briefly the first subsea ESP installation, calling attention to the main aspects that make the difference from a conventional to a subsea ESP installation and focuses on the developments for the deepwater installation in the well RJS-477, in 11 07 meters water depth, in the East-Albacora oilfield by mid 1997.
The oil production in the Brazilian coast is mainly focused on the giant reservoirs discovered in deepwater, making use of floating production systems, that receive the production directly from the satellite wells or from subsea manifolds. In Campos Basin 13 fixed towers were installed, all of them in shallow waters, up to 300 meters. From these, eight are in the so-called North-east Pole of Campos Basin.
Stimulated by an increased oil demand, this production is being complemented by new discoveries in deeper and deeper waters. This production was for a long time based on natural flow, water injection in the reservoir and in the artificial lift method of gas lift.
Production Development has signified the capacity to deal with the increase in the number of floating production units, with longer flowlines, as well as with the problems brought by well depletion and reservoir specific limitations.
Water and gas lift injection used to be the first options to adopt in the majority of the cases. But the efficiency of these solutions is not high and they are not always feasible. Reservoir pressure may be insufficient to produce over long distances and gas lift loses a lot of efficiency in long horizontal flowlines, typical of subsea wells, as well as with the BSW increase.
A new method was then required for oil production over long distances, specially from deepwater wells, allowing the platform to be placed in shallow waters, and for a reduction in the number of platforms, thus simplifying the production layout and reducing the investments.
Within the PROCAP 2000 Program for deepwater technology development, a project was created by the end of 1992 in order to develop such a method.