Subsea Piston Accumulator Sensing for Pressure and Position Feedback
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Solution Overview
Problem
Existing subsea piston accumulators lack reliable and affordable means to monitor pressure in the nitrogen tank and piston position in hydraulic tanks, which is critical for maintaining optimal performance and preventing potential blowouts in oil and gas well operations.
Innovation Solution
Incorporating pressure sensors at the top and bottom of the nitrogen bottle and a piston positioning sensor system within the hydraulic bottle, along with a monitoring and display system for remote data collection and control, to provide real-time pressure readings and piston position feedback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pressure sensors and positioning sensors are added to the accumulator system, then measurement precision and reliability are improved, but device complexity increases
Solution Approach 1:
The patent implements feedback by installing pressure sensors in the nitrogen bottle and piston position sensors in the hydraulic bottle to continuously monitor system parameters. These sensors provide real-time data to a control system that can detect abnormal conditions and trigger alarms or automatic responses, enabling closed-loop monitoring of the accumulator's operational state.
Solution Approach 2:
The patent replaces manual inspection and mechanical gauges with electronic sensing systems. Pressure sensors, position sensors, and wireless communication modules substitute for traditional mechanical measurement methods, enabling remote monitoring and reducing the need for physical intervention while improving measurement precision.
2Reliability
If multiple sensors are installed for monitoring, then reliability is improved, but manufacturing cost increases
Solution Approach 1:
The patent applies preliminary action by pre-charging the nitrogen bottle to a specific pressure and pre-positioning the piston at optimal locations during assembly. Sensors are pre-calibrated and the system is pre-tested before deployment, ensuring reliable operation from the start and reducing the need for costly post-installation adjustments or repairs.
Solution Approach 2:
The accumulator system performs self-monitoring through integrated sensors that automatically detect pressure deviations and position anomalies. The wireless communication module enables the system to self-report its status, and the control system can automatically trigger alarms or protective actions without external intervention, reducing operational costs and improving reliability.
3Loss of information
If real-time monitoring is implemented, then loss of information is reduced, but device complexity increases
Solution Approach 1:
The patent implements feedback through wireless communication modules that continuously transmit pressure and position data from sensors to a remote monitoring system. This real-time feedback loop ensures that operational data is immediately available for analysis, enabling timely detection of abnormal conditions and preventing information loss during critical events.
Solution Approach 2:
The monitoring system is designed with multi-functionality, using a single integrated platform that handles data collection, wireless transmission, alarm generation, and historical recording. This universal approach consolidates multiple functions into one system, reducing overall complexity while maintaining comprehensive real-time monitoring capabilities.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enhances the reliability and efficiency of subsea piston accumulators by providing accurate pressure monitoring and piston position feedback, preventing over- or under-pressurization and ensuring optimal accumulator performance, thus improving safety and reducing operational costs.
Implementation Method 1
providing a pressure sensor at the top of an accumulator nitrogen bottle and a further pressure sensor at the bottom. This provides accurate information on the bottle's performance as well as a warning if pressures are too high or too low
Implementation Method 2
providing a piston positioning sensor in the hydraulic bottle for determining the piston position relative to function. This may also provide a warning if the position of the piston is not optimal
Implementation Method 3
the nitrogen chamber is charged to a specific pressure, which exerts a force on top of the piston, which in turn pressurizes the working hydraulic fluid on the other side of the piston
Implementation Method 4
As the accumulator is lowered deeper into the ocean, the ambient seawater pressure squeezes the hydraulic fluid in the bladder to the same pressure. This seawater pressure from the bladder is exerted on top of the piston in the seawater chamber
Data Source
Figure 1
AI summary
The present invention is a sensor system for a dual bottle accumulator utilized with a subsea blowout preventer that monitors piston position with a position sensor in the hydraulic bottle, the gas pressure in the associated gas bottle with one or more pressure sensors, and sensors and remote actuators for associated valves.