Marlim-4: A Subsea Production Well Overtaking Deepwater Frontiers-Part L-Planning And Installation Procedures
Authors: Morais M.G.G. , Bonesio P.A. , Armando Salim 
Published: October 2008

Brazilian oil and gas reserves, concentrated offshore and particularly in deep waters, have led Petrobras to establish a careful and strategic plan which has as the main target to get the technical capacity to produce those areas. The exploration results have shown a necessity of surpassing the technology barriers, established in 1000 meters (3280 ft) water depth since 1988, and it has involved both Petrobras and Material/Services Suppliers in research and development of new equipment and installation methods.

The experience gained during the Marlim Field development, putting 10 (ten) production wells on stream to a Floating Production System named Marlim Pilot System (fig. 1), and 3 (three) production wells to Salema-Bijupira Pilot System (fig. 2), has been the main element to be used to ingress in a new stage where 1000 meters of water depth will represent the initial mark.

The beginning of this new stage is characterized by putting Marlim-4, a production well located in 1027 meters (3369 ft) water depth, on stream by April 1994. The constant technological development aimed by Petrobras in offshore production reflects all efforts applied in producing oil and gas fields located in deep waters.

INTRODUCTION

Since the discovery of the first offshore production well in Campos Basin, several emerging technologies have been used in order to anticipate oil production as well as to implement and test new ideas.

Petrobras started its offshore production in 1977 with the Early Production System conception, which was dedicated for:anticipating oil and gas production;reservoir data collection;producing isolated and marginal areas;

After the EPS phase and this conception being renamed to Floating Production Systems (FPS), the experience acquired with 27 FPS installed and/or re deployed, made it so useful and more cost effective to be adopted in Brazil's oil and gas fields.

This conception has proved to be so applicable to our reservoirs scenario that, during the feasibility studies performed to define how a new area will be exploited, this solution appears as the best one when compared to other alternatives.

The advantages of this conception has been:Lower initial investment;Flexibility of changing the drainage grid;Possibility of being completely reused in another area;Possibility of having the oil and gas cash flow anticipated;Possibility of increasing or reducing the number of wells;Anticipation of reservoir information.

The main milestones established by Petrobras in offshore production have been:Enchova Field with a single well producing to EPS by means of a BOP, test tree, completion riser and a dry x-mas tree (1977);Enchova-Leste Field where the first subsea tree was installed in 189 meters (620 ft) water depth as a satellite well of a EPS and flexible pipes were used as dynamic structures (1979);Garoupa Field composed of a gathering system with a manifold center and dry wellhead tree both based on atmospheric chamber conception, installed in an average water depth of 125 meters (410 tt) (1979);