Barracuda Field : Installation of 34 Flexible risers in FPSO System

Abstract

Abstract In order to develop new deep water fields using FPSO's, Petrobras has introduced several innovations to install 34 flexible risers individually connected to the Barracuda FPSO project. This paper provides an overview of design of the pull in and pull out operations. It also deals with I tube dimensions considering studies of interference during the risers transference from the chain table up to the risers connection deck. Additionally, new concepts have been proposed to solve the problem of Chain Table Interface to the pull in of flexible risers to floating production systems. The following advantage of this system which have been considered:Standardization of I tube inner diameters :Standardization of Bell mouth dimensions;Standardization of riser hang off systems; Standardization of flexible riser end fittings;Development of new philosophy of pull in and pull out operations;Considerable reduction in time of diver operations;Considerable reduction in time to change pull in main shaves. lntroductlon The BarracudaICaratinga Pilot System will comprise satellite production wells, directly connezted to the FPSO Petrobnu-34. Each well bundle will comprise three individual lines: a 4 inch production line, a 2 % inch anuulus or service line and a control umbilical. Additionally one 12 inch gas expart line will allow the gas production to be sent to a fixed platfonn called PNA-1 located in the North Area of Campos Basin, 22Km from the FPSO (Figs 1 and 2). This FPSO system, named Petrobras 34 (P-34) will be in service for a five year period in 835 meters (2545 feet) water depth and anchored through an internal Turret device. Nevertheless, after this period, the flexible lines will be retrieved to be reinstalled in the same oil field up to 1000 meters water depth. The Barracuda production system shall remain in service fix at least an extended fifteen years, comprising of the BARRACUDAICARATINGA Development Phases I, I1 and 111 after the Pilot System demobilization. This paper adresses various aspects related to the engineering and installation of the flexible riser bundles of each well and the gas flexile pipe elements of rigid flexible combination riser to the Barracuda FPSO pilot system. Project start Up The amtract for engineering and manufacturing of the Turret was awarded in February 1995 fix a installation planned in May 1997. As part of technical requirements for the design and installation of 34 risers, some premises were established by PETROBRAS as follows: In any situation of the FPSO draft and environmental conditions the risers should not be over tensioned, compressed or extensive bend (less than their minimum bending radius). These conditions are associated with a 50 year return period of the environmental input data.