Motion Compensator Safety Shutoff for Offshore Drilling
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Solution Overview
Problem
Existing motion compensators on offshore drilling platforms are prone to failure due to wave action, which can lead to vertical displacement of the drilling platform deck, posing risks to equipment and personnel, and lack effective safety shut-off systems to manage cylinder failures.
Innovation Solution
A novel compensator system with a safety shut-off system that isolates failed cylinders, allowing operations to continue using remaining operable cylinders, and a locking mechanism to secure the system in a retracted position, capable of supporting up to 750 tons, comprising an upper and lower compensator carriage, outer and inner cylinder assemblies, and a safety shutoff assembly with valves and actuators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If motion compensators are used to compensate for wave action, then the drilling platform can operate in offshore conditions, but the system is prone to failure due to cylinder failures and lacks effective safety shut-off systems
Solution Approach 1:
The compensator system is divided into multiple independent compensator carriages, each with its own cylinder assembly. This segmentation allows individual carriages to be isolated and shut off if a cylinder fails, preventing total system failure and enabling continued operation with remaining carriages.
Solution Approach 2:
A safety shutoff assembly with valves and actuators is introduced as an intermediary control system. This assembly monitors cylinder performance and automatically isolates failed cylinders by closing valves, preventing harmful effects from propagating through the entire system.
2Reliability
If a cylinder fails in the compensator system, then operations must be stopped immediately, but this causes loss of productivity and potential damage to equipment and personnel
Solution Approach 1:
The safety shutoff system is configured in advance to automatically respond to cylinder failures. When a cylinder fails, the system pre-positioned valves and actuators quickly isolate the failed component, cushioning against total system failure and allowing operations to continue with remaining functional carriages.
Solution Approach 2:
When a cylinder fails, the system discards (isolates) only the failed component while maintaining operation of remaining carriages. The failed cylinder can be repaired or replaced without shutting down the entire system, thereby recovering productivity while maintaining safety.
3Stability of the object's composition
If the compensator system operates without a locking mechanism, then the structure remains simple, but the system cannot be securely positioned in retracted state
Solution Approach 1:
A locking mechanism is incorporated to preliminarily secure the compensator carriage in its retracted position before operations begin. This preliminary action ensures the system starts in a known stable state and prevents unintended movement during operation.
Solution Approach 2:
The locking function is extracted as a separate, dedicated mechanism rather than being integrated into the main motion control system. This allows the locking function to be added without fundamentally redesigning the compensator system, minimizing the increase in overall complexity while achieving position stability.
Data Source
AI summary
A motion compensator system for use on a floating vessel including a compensator cylinder assembly, a guide cylinder assembly, an upper carriage affixed to an upper end of both cylinder assemblies, a lower carriage affixed to a lower end of both cylinder assemblies, and a safety shutoff assembly. The compensator cylinder assembly includes three or more compensator cylinders. The safety shutoff assembly includes a compensator manifold and three or more compensator valves. Each compensator valve is in fluid communication with a pressurized fluid source through the compensator manifold and in fluid communication with a lower chamber of one of the compensator cylinders. The safety shutoff assembly is configured to isolate a failed compensator cylinder by setting the associated compensator valve to a vent setting and continuing normal operation of the remaining compensator cylinders. The motion compensator system optionally includes a lock system for securing the system in a retracted position.