Development of a Compact Topside Processing Facility
Authors: Mikkelsen Rene , Carrijo de Melo D. Jose de Castro 
Published: June 2014

Compact separation technologies have been gradually introduced into topside facilities during the last decade. Deployments have typically been motivated by a need to debottleneck facilities in mature fields, where a compact unit could be installed into a congested process plant without major reconstruction. While the advantages of compact separation technologies are generally acknowledged, the lack of data regarding performance, flexibility and reliability - as well the absence of process simulation tools - has until now resulted in a limited utilization of compact processing concepts in new field developments.

A collaboration program has been established with the aim of developing a Compact Topside Gas/Oil/Water Processing Plant, with high efficiency and reliability, capable of handling the new oil properties and high CO2 content that characterizes the recent Pre-Salt discoveries. Inline ultra-compact separation technologies have been combined with optimized vessel designs to achieve a flexible and reliable processing plant for future FPSO's.

During the conceptual design phase extensive process simulations of the complete separation plant have been performed. Dynamic performance modelling has been included into these simulations for each component, allowing detailed predictions of plant performance in the presence of transients. This has been used for design optimisation, evaluating impact of component failure, as well as the development of a control and automation philosophy. Feedback from existing installations has been used to perform a Technology Maturity Assessment of each new technology incorporated in the compact topside facility and to establish a reliability database. For any technology not ranked at the highest Technology Readiness Level the gaps and required qualification activities have been identified.

This paper presents the activities executed during the development of a novel topside facility based on compact separation technologies, including Technology Maturity and Reliability Assessment, as well as capabilities of new process simulation tools.

Overview

The Compact Topside Gas/Oil/Water processing plant (CTOP) project was initiated as a joint collaboration between Petrobras and FMC Technologies in July 2012. Main driver for this project was to develop a compact process facility of reduced size and weight for future FPSO's. The facility must operate with high efficiency and reliability/availability, capable of handling the relevant oil properties and high CO2 content that characterize recent pre-salt discoveries, while leading to reductions in Capital Expenditure (CAPEX) and Operational Expenditure (OPEX).

The facility consists of three main separation and treatment modules, namely Gas, Oil and Water treatment. The oil treatment scheme must achieve oil quality that satisfies export requirements, the water treatment scheme must achieve the quality required for discharge, and the gas treatment scheme must comply with sales specifications and/or reinjection requirements. A fully developed control system to stabilize the flow as well as to guarantee that efficiency levels are maintained has been included as part of the conceptual design phase. To optimize and verify the applicability of the proposed facility, extensive process simulations have been completed building on experience obtained through product development, results from field trials and deployments in operating facilities. While the gas treatment system has been included as part of the CTOP project, further developments of the complete gas treatment plant is ongoing and will be presented in a separate paper.