Cost Reduction in Deep Water Production Systems
Authors: Beltrao R.L.C 
Published: October 2008

This paper describes a cost reduction program that Petrobras has conceived for its deep water field. Beginning with the Floating Production Unit, a new concept of FPSO was established where a simple system, designed to long term testing, can be upgraded, on the location, to be the definitive production unit, Regarding to the subsea system, the following projects will be considered. Subsea Manifold - There are two 8-welldiverless manifolds designed for 1000 meters presently under construction and after a value analysis, a new design was achieved for the next generation. Both projects will be discussed and a cost evaluation will also be provided. Subsea Pipelines: Petrobras has just started a large program aiming to reduce cost on this important item. There are several projects such as hybrid (flexible and rigid) pipes for large diameter in deep water, alternatives laying methods, rigid riser on FPS, new material...etc. We intend to provide an overview of each project.

INTRODUCTION

The technological maturity achieved by the subsea engineering during this decade is certainly one of the most relevant fact in the oil industry. In the Norwegian sector, for instance, the latest projects, namely Statfjord and Norne templates (Statoil), Draugen template (Shell) and Troll manifold (Norks Hydro), clearly represent a consolidation process for keeping similar solutions regarding the main issues - operation, controls, tie-ins, IMR (Inspection, maintenance and repair) philosophy, and so on-. Foinaven (BP), in the British side of North Sea, and Albacora and Marlim (Petrobras), in South America, follow fairly the same route.

The so-called "subsea option", in reality, exhibits a quite promising future in short and medium terms for its competitiveness and the present trend for deep water exploitation. The latter issue brings the problem of the technological bottlenecks for very deep water production, and even though there exists, indeed, some questions to be answered - the organic deposits in subsea equipment, br instance - there is no doubt that the industry will overcome these challenges.

There are, however, some adverse circumstances that need to be considered. First the oil price tends to remain in the range of US$ 15 to US$ 20 per barrel, having a great possibility - according to some experts- to stabilize near the lower limit on the other hand, small or medium fields will most likely prevail in the future deep water developments, since the giants or even the big fields are becoming more and more uncommon figures. The main issue, thus, shifts from technical to economical feasibility, making the cost reduction discussion even more necessary for the sake of the whole industry.

This paper will concentrate upon three basic topics concerning cost reduction that Petrobras is presently undertaking: A new concept of a Floating Production Storage and Offloading (FPSO), subsea manifolds and subsea lines. But before this, let see what other companies have to say about the matter.

GULF OF MEXICO AND NORTH SEA SCENARIO

Much have been written recently about how to accomplish an effective cost reduction in deep water projects on the two major oil provinces.