Pre-positioned Capping Device for High Pressure Well Blowout Control
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Solution Overview
Problem
Current systems for capping a well during a blowout, especially subsea, are slow and hazardous, often requiring extensive vessel operations and posing risks of fire or explosion, with existing blowout preventers frequently failing to actuate effectively, leading to prolonged uncontrolled well flow and environmental damage.
Innovation Solution
A pre-positioned capping device with a blind shear ram and independent control system is installed between the wellhead and the blowout preventer stack, providing a higher pressure rating than the BOP stack, allowing immediate activation and closure of the well in case of a pressure exceedance, independent of the drilling rig's power or control systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional blowout preventer (BOP) stack is used to control well pressure, then the system can handle normal drilling operations, but the BOP may fail to actuate effectively under high pressure surge conditions
Solution Approach 1:
The patent applies preliminary action by pre-positioning a capping device with a blind shear ram directly on the wellhead before any blowout occurs. This device is ready to immediately shear and seal the wellbore if the BOP fails, eliminating response time delays. The capping device is installed in advance as a preventive measure, allowing instant activation without requiring complex vessel operations during an emergency.
Solution Approach 2:
The patent introduces an intermediary capping device that acts as a backup between the wellhead and the BOP stack. This intermediate device provides an additional layer of protection that can independently seal the well if the primary BOP system fails. The capping device serves as a mediator that transfers the sealing function from the potentially failing BOP to a more reliable pre-positioned system.
2Productivity
If subsea capping operations are performed using conventional methods, then the well can be capped, but the process takes 10 to 21 days and requires five or more large vessels
Solution Approach 1:
The capping device is pre-installed on the wellhead during normal drilling operations before any blowout occurs. This eliminates the time-consuming process of deploying and installing capping equipment during an emergency. The device is ready for immediate activation, reducing the well capping time from weeks to minutes.
Solution Approach 2:
The patent extracts the capping function from the complex multi-vessel operation and integrates it directly into the wellhead assembly. By taking out the capping device and positioning it directly on the wellhead, the system eliminates the need for multiple vessels and complex coordination, allowing a single device to perform the capping function independently and rapidly.
3Object-affected harmful factors
If conventional capping operations are performed after a blowout, then the well can be sealed, but personnel must evacuate and the operation presents great danger of fire or explosion
Solution Approach 1:
The capping device is pre-positioned and ready for immediate activation during normal operations, before hydrocarbon accumulation creates fire or explosion hazards. This allows the well to be sealed during the initial stages of a blowout when risks are lower, rather than waiting until large amounts of hydrocarbons have accumulated and personnel must evacuate.
Solution Approach 2:
The patent applies skipping by rushing through the capping operation immediately upon detecting BOP failure or kick conditions, before the situation escalates to dangerous levels. The rapid activation of the pre-positioned capping device allows the well to be sealed during the early phase of potential hazards, skipping the dangerous intermediate stage where large volumes of hydrocarbons accumulate and fire or explosion risks peak.
4Strength
If the BOP stack is designed for normal operating pressures, then the system is cost-effective, but it cannot withstand pressure surges exceeding its rating
Solution Approach 1:
The patent applies local quality by concentrating the high pressure containment capability specifically at the wellhead where the capping device is positioned, rather than requiring the entire BOP stack to be rated for maximum surge pressures. The capping device locally provides the enhanced pressure containment capability needed for blowout conditions, while the rest of the system maintains its normal operating pressure rating.
Solution Approach 2:
The patent segments the pressure containment function into two separate systems: the BOP stack for normal operating pressures and the capping device for maximum surge pressures. This segmentation allows each component to be optimized for its specific pressure range, avoiding the need to design the entire system for maximum blowout pressures while maintaining cost-effectiveness.
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
Enables rapid well capping, reducing the risk of fire, explosion, and environmental damage by providing a secondary, independent safety mechanism that can operate even if the primary BOP fails, significantly reducing the duration of uncontrolled flow from minutes to weeks.
Implementation Method 1
A pre-positioned capping device includes a blind shear ram disposed between the wellhead and the blowout preventer stack to close the well
Implementation Method 2
A second pressure rating of the capping device exceeds the first pressure rating of the blowout preventer stack
Data Source
AI summary
Systems and methods contain fluids discharged from a subsea well or at the surface by capping the well blowout with a pre-positioned capping device. The capping device includes at least one blind shear ram and is separate from a blowout preventer. The blowout preventer may operate to control well events up to a certain pressure, above which the capping device is employed since the capping device has a higher pressure rating than the blowout preventer.