Abstract

In October /1994 PETROBRAS, leading a team of six companies (Reda, Lasalle, Tronic, Pirelli, Cameron, Sade-Vigesa) has installed for the first time in the world an Electrical Submersible Pump in a subsea well. The subsea ESP system in the well RJS-221, located in 86 meters water depth, in the Carapeba oilfield, completed two years and ten months in operation without failures.

The success of this pioneer installation has encouraged PETROBRAS to start Phase II of this PROCAP 2000 project, in order to extend the application of this new technology from 300 meters water depth (limit of power cable design on Phase I) into deep water and long platform/well distances.

Since 2/June/1998 an ESP operates in Deepwater for the first time: in the subsea well 4-RJS-477A, located in 1109 meters water depth, in the East-Albacora Oilfield, Campos Basin, razil. The oil is produced over nearly 8,5 Km to the production platform, located in the neighbor Albacora Oilfield.

The development of ESP components, of a Guidelineliness Horizontal Tree, Power Cables, Subsea Power Transformer, Power Connectors, the integration of all these subsystems, many of them unique in the market, and their installation in the field will be the main focus of this paper, that intends to demonstrate the viability and importance of this new technology to develop offshore oilfields, specially in deepwater.

Introduction

In the 80s, Petrobras has found very important reservoirs in deepwater and initiated a Program for the development of Deepwater Technology: the so-called Procap. The excellent results from Procap and new reservoir discoveries in even deeper waters have stimulated Petrobras to undertake a new Phase: the Procap 2000. By the end of 1992, a project portfolio was created including a project to develop alternatives of artificial lift for subsea wells.

At that time oil production in the Brazilian coast was started to be planned for the giant deepwater reservoirs and the development of these fields would make use mainly of floating production systems, that receive the production directly from the subsea satellite wells or from subsea manifolds.

Subsea wells would bring longer flowlines and other aspects that also impact flowrates, like well depletion and reservoir specific limitations. Production from subsea wells was for a long time based on natural flow or aided by the artificial lift method of gas lift or even by water injection in the reservoir to reduce pressure decline rates. 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.

This scenario required a new method of artificial lift, that could mainly deal with oil production over long distances, specially from deepwater wells, allowing the platform to be placed in shallow waters, allow for a reduction in the number of platforms, thus simplifying the production layout, reducing the investments, a key factor in deepwater, increasing and anticipating production.

Some alternatives were in the market, but among them, the Electrical Submersible Pumps seemed to be most suitable to meet the requirements. The project started, in fact, in 1993. In October 1994, the first in the world subsea ESP was installed in Campos Basin still in shallow waters. This well produced over 2 years and 10 months before a failure. With such a successful prototype, Petrobras was stimulated to move further and in June 1998 the first in the world deepwater ESP started to produce from the deep waters of Campos Basin.

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