The New Deepwater Oil and Gas Province in Brazil: Flow Assurance and Artificial Lift: Innovations for Jubarte Heavy Oil
Authors: Colodette Giovani , Pereira Carlos A.G. , Siqueira Cézar A.M. , Ribeiro Geraldo A.S.M. , Rodrigues Roberto , de Matos João S. , Ribeiro Marcos P. 
Published: October 2008

The Jubarte field, in the Campos Basin, Brazil, was discovered in January 2001. It is located about 80 km offshore from the State of EspÍrito Santo, under water depths between 1,000 and 1,500 m, containing oil of 17° API and viscosity of 14 cP at reservoir conditions.

This work presents a review of the artificial lift and flow assurance aspects faced by PETROBRAS in the exploitation of Jubarte heavy oil, starting from the features of the Pilot Phase. It details all the challenges posed and innovations proposed and implemented for Phase 1 field development, as well as expectations for the subsequent Phase 2.

Introduction

The Jubarte Field is located in the North part of the Campos Basin, about 80 km offshore from the State of EspÍrito Santo, at a water depth between 1,000 and 1,500 m (Figure 1). The field discovery occurred in January 2001, where an interval containing oil of 17° API was identified in sandstones from the Maastrichtian period.

During the evaluation phase, a study based on the concept of value information supported the decision to drill a horizontal appraisal well. In February 2002, the well was drilled, having a horizontal length of 1,070 m, being completed with an open-hole gravel-pack. The result was a well productivity index 13 times higher than the one obtained by the vertical well. An Extended Well Test (EWT) was proposed and approved which allowed collecting complementary valuable information.

In the EWT, which started in October 2002, PETROBRAS made use of the FPSO Seillean, a dynamic positioning vessel with a rig capable of performing light workover operations. The well was connected to the FPSO through a 5.625 in ID drill pipe riser. Using an innovative solution, a 900 HP and 25,000 bpd capacity Electric Submersible Pump (ESP) has been installed above the wet Xmas-Tree. In case of ESP failure, the drill pipe riser should be recovered by the FPSO for pump retrieval and replacement. The good results obtained in the EWT led to its continuation in a Pilot Phase, which lasted until January 2006.

Figure 1 - Jubarte Field Location (available in full paper)

After the Pilot Phase, PETROBRAS has now started the Jubarte Phase 1 production with the FPSO P-34. This new development phase comprises four production wells and will provide an expected oil production of 60.000 bpd. One of wells presents an innovative installation of the ESP on the seabed, another well has a downhole ESP installed, and the remaining two wells produce with gas lift. Gas lift backup can be used in the ESP wells in case of pump failure, while waiting repair.

The definitive Jubarte production system (Phase 2), to be implemented in 2011, will comprehend 11 new wells plus the 4 wells from Phase1, and 7 water injection wells, connected to the FPSO P-57. During this production phase, all production wells will run ESPs installed on the seabed as the main artificial lift method and gas-lift as backup.

In summary, the strategy of development for the Jubarte Field foresees three distinct phases of production, which are presented in Table 1.