From Sensors to Algorithms: A Deep Dive into FPSO Control

Floating Production Storage and Offloading (FPSO) vessels are having complex oil and gas process with various equipment, sensors and system serving as mobile platforms for the extraction, processing, and storage of hydrocarbons. Central to their operation is the FPSO control system, a sophisticated network of hardware and software designed to monitor and manage the vessel’s various functions. This system comprises several key components, including the Distributed Control System (DCS), which oversees production processes and ensures optimal performance. The Safety Instrumented System (SIS) is crucial for maintaining safety protocols, detecting, and mitigating potential hazards. The Integrated Control and Safety System (ICSS) unifies these elements, providing a comprehensive interface for operators to manage and monitor all aspects of the FPSO’s operations. This article delves into the intricacies of FPSO control systems, highlighting their critical role in enhancing operational efficiency and safety in the challenging offshore environment.

In principle the process of the “Control” on board FPSO are like the other offshore or onshore oil & gas facilities. They will have various sensors who read flow, pressure, temperature, velocity, volume, level, etc. Then these sensors will send their reading to the control system where it will feed specific functional algorithm which are triggering some action from the equipment or components like various valves within the facilities. The type of control system on board of the FPSO can be summarized as per the following function:

·?????? Distributed Control System (DCS) is a platform for automated control and operation of a plant or industrial process. It integrates various components such as human-machine interfaces (HMI), logic solvers, historians, common databases, alarm management, and engineering suites into a single automated system. The DCS is responsible for controlling and monitoring the production processes, ensuring that they run efficiently and safely. Some of the Oil and Gas company called it Process Control System (PCS)

·?????? Safety Instrumented System (SIS) is designed to monitor and control safety-critical processes. It includes sensors, logic solvers, and actuators that work together to detect hazardous conditions and take corrective actions to prevent accidents. The SIS is crucial for maintaining safety protocols and ensuring that the plant operates within safe limits.

·?????? Integrated Control and Safety System (ICSS) combines the functionalities of both the DCS and SIS into a single, unified system. This integration allows for better coordination between control and safety functions, reducing complexity and improving overall system reliability. The ICSS provides a comprehensive interface for operators to manage and monitor all aspects of the plant’s operations, enhancing both efficiency and safety.

·?????? Electrical Control System (ECS) is a system designed to monitor, control, and manage electrical processes and devices within a plant or industrial site. It integrates various intelligent devices and systems to ensure efficient operation and management of electrical power. This includes the control of motors, generators, transformers, inverters, and other electrical equipment. The ECS is essential for maintaining the stability and reliability of electrical systems, optimizing performance, and ensuring safety.

In principle the control system is implementing the process and safety control as presented on the Process and Instrumentation Diagram (P&ID). During the engineering design, a document called Process control description will be developed to describe all the control in place on board of the FPSO. Each control schemes description will be further design in detail in document called Functional analysis (FA) before it is converted into algorithm on the control system. On top of that Cause-and-Effect Matrix will present each connectivity between the various sensors with their consequence action from the equipment or components like various valves within the facilities which will be translated to Input/Output (I/O) list as a feeder/result of the control system algorithm. Overall control system schematic normally presented within the ICSS architecture and network diagram like sample below.

All the hardware (Marshalling cabinet, UCP, system cabinet) of the control system is normally centralized in the technical building modules where all cables deliver the input from the sensors and vice versa to deliver the command to the respective equipment or components. All the cable normally distributed through the main cable tray as part of the Pipe rack before it distributed specifically for each module. The main control room will be located on the hull or accommodation modules to allow safe operation including during emergency scenario (in many cases, the technical building and main control room are equipped with blast wall).

In summary, the control system of an FPSO is a marvel of modern automation and technology. It is the central nervous system that ensures operational integrity, safety, and efficiency in the challenging offshore environment. By integrating advanced control algorithms, real-time data acquisition, and remote monitoring capabilities, FPSO control systems not only optimize production but also safeguard the crew and marine ecosystem. As the industry advances towards more autonomous operations, the sophistication of FPSO control systems will play a pivotal role in propelling offshore exploration to new frontiers, ensuring that even the most remote and harsh environments can be harnessed for their energy potential with precision and care.