Electro-Hydraulic Umbilical - A Permanent Challenge for Oil Production in Ultra- Deepwaters
Authors: Martins Ronaldo Mascarenhas Lima , Almeida Fernando Buscacio de 
Published: October 2008

The oil production in deep waters has been taking Petrobras to successive challenges for developing new equipment able to reach the operational requirements for these harder environments. As medullar part of the process of oil production in ultra deep waters, the electric-hydraulic umbilicals has been source of successive developments, and its constant qualification to operate in these new scenarios is been showed up as a more and more complex task.

Because of the great volumes of involved resources, the appropriated qualifying of a new umbilical structure can represent great savings and a preventive vaccine against losses caused by operational failures of these new structures, when operating in the new and hard scenarios of the ultra deep waters.

To develop significant test procedures and test devices, that could represent as close as possible the operational conditions that the umbilical will be submitted, means a permanent objective of the engineering teams of Petrobras and its umbilical suppliers. But this effort cannot lose the horizon of the time demands and involved costs, where every day lost in the oil production means big revenues not affordable.

This work describes the effort of Petrobras in the technological development of umbilicals for ultra deep waters, in partnership with its umbilical suppliers, based on the pre-requirements of API Spec 17E [1}, as well as the actions to improve the qualification tests inside practicable parameters in terms of costs and time, always looking for feasible and cost saving solutions for the required testing facilities.

Scenario

In October 1996 PETROBRAS discovered Roncador [2 and 3] oil field, a new giant oilfield located on Campos Basin, offshore Brazil. Due strategic reasons, PETROBRAS has decided to start the field production in a short period of time [4]. In this way, a production system was planned based on a semi-submersible as a floating production unit, which will export its oil production to a FSO unit through rigid pipes.

As usual, the flexible bundles will be connected to the floating unit by means a free-hanging configuration. Electric-hydraulic umbilicals are installed for control and injection of the wells linked to the P-36 platform.

With a production system as described above it is possible to reduce the time to produce oil and the total investment amount. The special conditions lead to uncertainties and some limitations demanded investigation about the umbilical riser free-hanging configuration.

In the Roncador area, more specifically in the FSO risers area, PETROBRAS team had to consider also the free-hanging umbilical riser behavior when it is hanged in an unit with a turret system. So this paper describes the designing and testing efforts to reach the Roncador field demands.

The Basis

For the Roncador field and for further ultra deep water fields planned production systems based on semisubmersible and or FPSO as floating production units, under the Petrobras point of view, new umbilicals had to be developed to work in deep water. Under this statement the ideas of this work will be developed.