0011-4561 Safety in subsea petroleum production systems: subsea christmas tree case study Safety in subsea petroleum production systems: subsea christmas tree case study Adamowicz Katarzyna author Sarna Piotr author Szatko Wiesław author Institute of Thermal and Process Engineering, Faculty of Mechanical Engineering, Cracow University of Technology Instytut Inżynierii Cieplnej i Procesowej, Wydział Mechaniczny, Politechnika Krakowska Correspondence to: Katarzyna Adamowicz Correspondence to: Piotr Sarna Correspondence to: Wiesław Szatko 19 09 2016 Mechanika Zeszyt 2-M (3) 2016 2016 3 11 Copyright © 2016 2016 <p style="text-align: justify;"> The paper presents an analysis of valves used for closing and opening production tubing, located on the production line. The main safety valves analysed in this work are located in the Christmas Tree and in the Downhole Safety Valve. The analysis was conducted using FMEA; it found that for each basic Christmas Tree’s gate valve, the most dangerous failure modes are external leaks and “fail to close” in the open position of the valves. For the Downhole Safety Valve, the most dangerous fault can occur in the open position of the valve. The Downhole Safety Valve and the Christmas Tree complement each other, thus ensuring safety during oil and gas production.</p>