Safety of Subsea Systems

Operating within a subsea environment adds a number of safety challenges for organizations. Subsea well valves form an important part of the subsea infrastructure and are used to isolate or control the raw material flow through undersea pipelines. Subsea valves are exposed to massive external pressure, salt-water corrosion and debris in the materials carried therefore safe operation is critical. These valves can degrade and deteriorate over time, both of which can adversely impact operational efficiency and have the potential to affect the safety environment.

Measuring and monitoring data from subsea well valves and sensors is an important operational requirement that provides an insight and helps identify areas of concern. Operators require access to subsea valve data and need to be made aware of any changes to valve characteristics and signatures. However, accessing and storing this information is a very real problem due to the location and environment of the well valves and sensors.

Identifying Safety Risks

To support the safety and operations of the subsea environment, Yokogawa has developed a solution that notifies operators of the early signs of valve degradation by accessing valve signature data.

Subsea data is collected directly from Topside Processing Units (TPUs) containing the subsea well valves and sensors, using the supported topside interfaces. This provides a reliable data stream and storage mechanism that is used to aid the monitoring, analysis and visualization of subsea data to help identify areas of interest. This powerful monitoring tool also detects abnormal operating conditions for temperature, pressure and sand in the subsea system, presenting data to operators to enable them to quickly isolate problems and take corrective actions.

By accessing data directly from the TPUs via Exaquantum, operators are informed of anomalies such as wear, drift and valve stiction and are able to pinpoint areas of concern before affecting production. With a reliable and dependable process historian, past data can be used for comparison and analysis, helping to maintain system performance over time. This information can also assist with maintenance schedules and priorities that help reduce risk by highlighting valve deviations that could ultimately lead to failures in the future.

Operators can easily access this important valve signature data via a user friendly web user interface. This displays not only valve signatures but also Down Hole Pressure and Temperature (DHTP) and Acoustic Sand Detection (ASD), separated into individual screens for intuitive operation and analysis.

Alarm Notifications

Alarm notifications from the distributed control system are displayed alongside valve signatures in this subsea historian solution for rapid identification of problems and an integrated view of the subsea system performance. The valve information displays can also be integrated with the control system for viewing on Human Interface Station (HIS) screens in the control room. Additionally, the subsea historian solution can trigger control system alarms when identifying abnormal valve operations. This provides operators with easy and readily available information that is used to help maintain production.

Switching Data Routes

The process historian collects data from the data collectors with the capability to manually or automatically switch data routes when underlying systems are unavailable. So if data collection is coming from the primary data collectors and becomes interrupted for any reason, it is possible to automatically or manually switch to the redundant secondary data collector. This helps to ensure information flow from the data collectors is constantly available to operators in the control room to enable them to identify and address areas of concern.

Benefits

• Reduces safety risks and enhances the environmental protection of the subsea system by detecting valve degradation and providing an early warning indicator for operators.

• Unexpected operational issues can be reduced with a continuous health check of the subsea system having constant access to data direct from the TPUs. Operators have access to the best available information and are notified rapidly of any potential issues enabling informed decisions to be actioned quickly.

• Increases the situational awareness of operators putting them in a better position to make decisions in response to abnormal conditions. Using the main process historian without a dedicated vendor specific subsea system historian allows for unified access to information and a more inclusive view of the data.

• Maintenance programs and schedules can be improved for operational efficiencies that help ensure a safer working environment.