Subsea Pipe Catcher for Emergency Well Drive-Off
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Solution Overview
Problem
In emergency situations on deep water rigs or onshore applications, existing methods for securing wells often result in irretrievable loss or damage of expensive equipment due to the need to drop the pipe during rapid sealing and drive-off procedures.
Innovation Solution
A method involving a pipe catcher that grabs and anchors the pipe before cutting, allowing sequential ram operations to seal it, enabling the pipe above the cut to be removed and the marine riser disconnected, allowing safe rig movement off the well, with the option to reconnect and retrieve the pipe if the well is reactivated.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the pipe is cut and dropped using shear rams during emergency well sealing, then the well can be quickly secured and the rig can drive off, but expensive equipment on the pipe is lost or damaged irretrievably
Solution Approach 1:
The pipe catcher is activated before the pipe is cut to secure it in advance. This preliminary action of capturing the pipe prevents subsequent loss or damage, allowing the pipe to be retained while still enabling rapid well sealing and rig movement.
Solution Approach 2:
Instead of permanently discarding the pipe by dropping it, the invention enables recovery of the pipe after the emergency is resolved. The pipe catcher holds the pipe temporarily, allowing well sealing operations to proceed, then the pipe can be retrieved and the well reactivated if needed.
2Reliability
If the pipe is dropped during well sealing procedures, then the blowout preventer components can be operated to secure the well, but the pipe and any equipment on it cannot be retrieved if the well is reactivated
Solution Approach 1:
The pipe is captured and secured by the pipe catcher before the blowout preventer components are operated. This preliminary securing action maintains well control reliability while preserving the option for future reactivation by preventing permanent pipe loss.
Solution Approach 2:
The invention transforms the permanent discarding of the pipe into a temporary holding situation. The pipe catcher retains the pipe during well sealing, then allows recovery and reconnection operations if the well needs to be reactivated, providing adaptability without compromising initial well control.
3Loss of substance
If the pipe is retained without dropping it during emergency procedures, then equipment on the pipe can be preserved, but additional complexity is introduced with pipe catcher operation and sequential ram operations
Solution Approach 1:
The pipe catcher is activated as a preliminary action before cutting operations. While this adds a step to the procedure, it prevents the need for more complex recovery operations later, and the sequential ram operations are systematically organized to manage the complexity efficiently.
4Speed
If the pipe is cut and dropped using conventional methods, then the rig can quickly move off the well, but the marine riser and pipe infrastructure cannot be reused
Solution Approach 1:
The pipe is captured by the pipe catcher before the rig moves off. This preliminary capture action enables the rig to move quickly while preserving the pipe and marine riser infrastructure for potential future reuse, combining speed with adaptability.
Solution Approach 2:
Instead of permanently discarding the pipe and marine riser infrastructure, the invention enables their temporary retention during rig movement. The infrastructure can be recovered and reused when the rig returns or another rig arrives, maintaining versatility without sacrificing operational speed.
Data Source
AI summary
This invention involves a method of securing pipe (also referred to as a “string of tools”) when driving off a subsea well or sealing off a well in onshore applications where there is an emergency by grabbing the pipe before it is cut. A pipe ram then is closed on the pipe before a shear ram is actuated to cut the pipe. In subsea applications, the top of the pipe may then be raised clear of the blowout preventer within a marine riser. A blind ram and annular preventer can then be closed above the remnant of the pipe being retained by the pipe catcher. The pipe above the cut is removed through the marine riser and the marine riser itself is then disconnected. The rig is then driven off the well. If the well is reactivated the steps are reversed but the well is safely secured before the blowout preventer components are opened. The pipe supported by the catcher is independently supported before the catcher is released and the pipe lifted through the riser.