Rooster Box for Offshore Well Intervention
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Solution Overview
Problem
Existing subsea well intervention systems face challenges such as lengthy and risky operations due to the need for frequent configuration changes between coiled tubing and wireline modes, difficulty in performing complex operations under moving structures, and the complexity of switching between drilling modes, which increases costs and safety risks.
Innovation Solution
A mobile offshore drilling unit equipped with a rooster box that allows for two modes of operation: well intervention and drilling, where the rooster box maintains a constant tension on the conduit, monitors dynamic loads, and enables the injector to be positioned on-axis or off-axis relative to the conduit, reducing relative movement and providing a stable working platform for workers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a coiled tubing lifting frame (CTLF) is used for coiled tubing drilling operations, then the drilling operations can be performed, but the structure is massive and needs to be handled in an unmounted way, requiring removal for wireline operations which takes 4-6 hours
Solution Approach 1:
The intervention frame is designed to perform multiple functions by supporting both the coiled tubing injector during drilling operations and the wireline spool during wireline operations. The frame includes a first configuration for supporting the injector and a second configuration for supporting the spool, allowing the same structure to serve different operational modes without requiring removal or reconfiguration.
Solution Approach 2:
The intervention frame incorporates movable components including the injector that can be positioned in different locations along the conduit, and the working platform that can move between different positions. This dynamic capability allows the frame to adapt to different operational requirements while maintaining structural integrity and eliminating the need for time-consuming reconfiguration.
2Ease of operation
If workers perform operations under a hanging CTLF structure, then coiled tubing drilling can be conducted, but it is unsafe to keep workers under a hanging structure during wireline operations
Solution Approach 1:
A working platform is introduced as an intermediary structure that provides a safe working environment for operators. The platform is supported by the intervention frame and provides a stable, protected environment for workers to perform operations on the injector, spool, or other equipment without being directly under the hanging CTLF structure, thereby eliminating the safety hazard while maintaining operational accessibility.
3Ease of repair
If the injector is lowered to the vessel deck for work, then maintenance can be performed, but the operation becomes time-consuming and risky due to vessel movements
Solution Approach 1:
The working platform provides a new dimensional solution by creating a stable working environment at the intervention frame level rather than requiring movement to the vessel deck. Workers can access and maintain the injector while it remains in its operational position, eliminating the need for vertical movement and associated time losses and safety risks from vessel movements.
4Adaptability or versatility
If the intervention frame is reconfigured to change from coiled tubing drilling to joint-pipe drilling, then different drilling modes can be used, but the frame must be reconfigured to a new weight and the injector disengaged which requires considerable time
Solution Approach 1:
The intervention frame is designed with dynamic capabilities including movable working platforms and positionable injectors that can be adjusted along the conduit. This dynamic design allows for easy reconfiguration between different drilling modes without requiring structural changes or disengagement of components, thereby reducing both the time and complexity of mode switching while maintaining adaptability to different operational requirements.
Data Source
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AI summary
Mobile Offshore Drilling Units (MODUs) are more susceptible to meteorological conditions such as winds, currents and, most importantly, waves. These meteorological conditions generate a movement of the installation that will inevitably be transferred to some extent to the drilling pipe. A mobile offshore drilling unit (10) can include a rooster box (2) configured to move the rooster box along the height of a derrick (3) to which it is attached. An injector (20) configured to attach to an intervention frame of the rooster box, wherein the injector is configured to be releasably coupled to a conduit (4).The injector configured to be positioned on-axis with the conduit in a first configuration and off-axis with the conduit in a second configuration.