The Engineering of Pigging Equipment for Subsea Systems in Campos Basin

Abstract PETROBRAS EXPLOITS oil from fields located in deep water in Campos Basin, a subsea project which faces some problems. One of them is wax build-up subsea production flowlines. So, since 1990, methods to prevent and remove wax deposits have been studied. The occurrence of wax build-up in flowlines installed in cold sea bottoms is a permanent challenge, so pigging among other methods, is used to control wax deposition on pipeline internal surfaces. Pigging in subsea systems is a difficult task, because reliability in equipment, facilities, and procedures. This paper is a continuation of other papers that Petrobras has presented in international conferences and describes pigging requirements for subsea equipment, flowlines, platforms and FPSOs designed for the Campos Basin. Some devices that Petrobras has developed to run pigs in subsea systems, such as dual diameter scraper pig, subsea pig signaler, piggable Y, and piggable loops, are also presented. Introduction The occurrence of different types of deposits on pipelines, which affects operational routine in offshore installations, led Petrobras to deal with this problem. In order to evaluate the available methods for preventing and removing these deposits and to develop others, the Program on Deepwater Exploitation Systems has been studying and testing many techniques. Special attention has been given to wax prevention and removal methods, for this is one of the main operational problems to be faced up to. Since the beginning of first phase of Albacora field exploitation in 1989, it has been noticed that some production flow lines presents organic deposits build-up. This phenomenon happens when paraffin comes out of solution, as the oil reaches the WAF' (Wax Appearance Point), due to low sea bottom temperatures. Although Petrobras is aware of asphaltene, scale and hydrate occurrence, this paper will focus on present diificulties, solutions and procedures adopted by Petrobras to minimize wax deposit impact on deep water exploitation projects applying pigging. The use of pigging techniques implies an additional investment that must be foreseen in the initial phase of the project. The following aspects will be highlighted:Piggable equipment for subsea systems.The use of pigging in Albacora, Marlim and Barracuda fields. The Engineering of Pigging Equipment for Subsea Systems in Campos Basin Petrobras exploits oil from fields located in deep water in Campos Basin, a subsea project which faces some problems. One of them is wax build-up in subsea production flowlines. So, since 1990, methods to prevent and remove wax deposits have been studied. The occurrence of wax build-up in flowlines installed in cold sea bottoms is a permanent challenge, so pigging among other methods, is used to control wax deposition on pipeline internal surface.