Evaluation of Alternatives for Offshore Petroleum Production System in Deep and Ultradeep Water Depth

Abstract

Different equipments combined compose an offshore petroleum production system. Several development alternatives are available for a given offshore petroleum field. The selection of the most suitable system for a given scenario depends on field development characteristics and strategies such as its geographical location, water depth, environmental conditions and knowledge about similar systems already selected and in use for oil and gas production and available infrastructure in around. For the purpose of field production system design a database with types of production platforms, mooring systems, subsea equipments, reservoir main characteristics, type of wells and lifting processes is fundamental. Today, offshore petroleum reservoir production is more and more complex due to several variables involved and requirement needed to meet deep and ultra deep water depth, pre-salt petroleum with aggressive fluid characteristics, fields in remote areas and other environmental issues. Large fields in deep and ultra deep water are particularly challenging due to little availability of suitable platform types, among known concepts such as floating, production, storage and offloading unit (FPSO), semisubmersible, spar and tension leg platform (TLP). In the present paper, a database for worldwide offshore petroleum systems in use has been elaborated by searching data available in the literature. The database is organized for more than three hundred platforms distributed on more than four hundred different offshore oil fields. To serve as a basis for the conceptual design of a field production system, this database contains information such as type of the platform, field location, water depth, days for the first production, type of well, completion, mooring system, riser and offloading system. This information is structured for different water depth and environmental condition, for each field. From this database, analysis has been conducted for distribution of each type of platform by worldwide region, distribution of each type of platform by the offshore field by region, among others analysis. Concept of Utility Functions are applied to represent technological trends and to be helpful in the process. Among the results, a preference for FPSOs and semisubmersible was observed in Brazil offshore, semisubmersible, TLPs and Spars in Gulf of Mexico. In Europe, particularly the North Sea, FPSO, semisubmersible, and few TLPs have been found. In West Africa, most of the field production is based on FPSOs, although some semisubmersible and TLP could be observed. Similar analyses were conducted in other regions. Results and discussions show preferences regarding technology selected by each region, region historical data, and growth of water depth in different fields.