Subsea Concept Alternatives for Brazilian Pre-Salt Fields

Abstract

The objective is to identify and compare subsea development concept alternatives for typical Brazilian pre-salt deep water applications, based on generic system functional requirements, SWOT analysis and comparative cost-benefit analysis of each alternative. This is a fast track approach to perform screening assessment of multiple subsea concept alternatives. Key premises from project disciplines are set as givens to determine the subsea functional specifications. The process consists of identifying subsea layout architecture options capable to meet those functionalities and defining ways of application. A SWOT analysis of each selected subsea concept is performed, together with a superficial cost-benefit analysis comparing those concepts. In order to meet the premises and requirements (Subsurface / Wells / Topsides) for the characteristics of the Brazilian pre-salt deep water fields, the following subsea concepts were considered competitive: Satellite configuration with flexible risers and flowlines Daisy chain configuration with rigid risers and flowlines Subsea cluster configuration with manifolds, rigid risers and flowlines and flexible jumpers Hybrid solutions with rigid risers and flexible flowlines (with and without manifolds) The SWOT analysis of each concept is based on pre-determined requirements / criteria and evaluated considering their TIC (Total Installed Cost) for the possible subsea systems. This essay discusses the preferred subsea concepts depending on application, criteria, premises and field characteristics. Subsea scope represents typically between 25 – 40% of a project in a deep-water development. The relevance of this essay is to serve as a guidance of choice of potential subsea concepts for a project, in view of their benefits and their associated cost, where capital cost intensity and return on investment are key value drivers in a low oil price environment.