Subsea Production System (SPS) Control Modelling

• Main Author: Abd Koha, Mohd Muslim
• Format: Final Year Project
• Language: English
• Published: Universiti Teknologi Petronas 2013
• Subjects: TJ Mechanical engineering and machinery
• Online Access: http://utpedia.utp.edu.my/13776/1/Final%20Year%20Project%20Thesis%20%28Mohd%20Muslim%20B%20Abd%20Koha%2010767%29.pdf; http://utpedia.utp.edu.my/13776/

The motivations of this project work are to develop a simulation model for a direct hydraulic control system, find the effect of changing key parameters to the system’s response time, and also to demonstrate Emergency Shut Down (ESD) feature which is a requirement for the subsea production control systems (SPCS). The methodology of this project involves selecting a control system to be studied which is a direct hydraulic control system, gathering technical details and data regarding the control system and components that constitute the control system, and translating the technical details and concepts into acceptable simulation forms in the simulation’s software. This project used SimulationX to simulate the developed model. The developed model consist of a hydraulic power unit, a topside control panel, hydraulic lines, a subsea control module and two actuator valves. The Cadlao oil field has been selected as the case study and simulation models were built according to the Cadlao field’s SPCS. The simulated model is validated by comparing the Cadlao’s performance curves and the acquired results. The simulation is done by varying 3 parameters which are umbilical length, umbilical diameter, and actuator size. Each parameter is tested to study its influences on the signal time and shift time. To find the effect of umbilical length on the signal time, umbilical lengths of 6000 ft, 12000 ft, and 18000 ft have been used. Time taken are 47 s, 110 s, and 195 s respectively. For the simulation using different umbilical diameters, 0.15 inch, 0.35 inch and 0.50 inch have been used. Time taken to fully pressurize the umbilical are 111 s, 39 s and 48 s respectively. For the second part, to find the effect of varying parameters on shift time, three parameters are changed (umbilical length, umbilical diameter and actuator diameter). 6000 ft, 12000 ft and 18000 ft umbilical lengths have been used and the recorded shift times are 13 s, 21 s and 31 s respectively. For the simulation using different umbilical diameters, 0.15 in, 0.35 in and 0.50 in have been used and the recorded shift times are 113 s, 19 s and 13 s respectively. Lastly, sensitivity analysis is done using three different piston diameters. Diameters of 6 in, 9 in and 12 in have been used and the recorded shift times are 28 s, 36 s and 56 s respectively. Lastly, emergency shut-down simulated showed that the actuator is able to return to fail safe condition in 33 s.