Rupture Disc Float Tool for Casing Drag Reduction
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Solution Overview
Problem
In well casing operations, excessive friction between the wellbore and casing creates drag issues, particularly in horizontal and deviated wells, making it difficult to achieve greater depths, and existing flotation methods are costly, time-consuming, and often require specialized equipment or steps like drilling out plugs.
Innovation Solution
A rupture disc assembly that uses hydraulic pressure to shatter against an impact surface within the casing string, allowing for a buoyant chamber to be created without the need for additional weights or complex arrangements, enabling easier installation and removal while maintaining full casing ID for operations like cementing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If conventional flotation methods using plugs and low density fluid are used, then buoyant force is achieved to overcome drag, but completion time increases due to additional drilling out step
Solution Approach 1:
The invention extracts the rupture disc from the traditional plug structure, allowing the buoyant chamber to be opened by rupturing a thin disc rather than drilling out a solid plug. This extraction of the disc from the sealing mechanism enables much faster opening (rupture) compared to the time-consuming drilling out of conventional plugs, directly resolving the time loss issue while maintaining the buoyant force function.
Solution Approach 2:
The invention changes the material parameter of the sealing element from a solid plug requiring mechanical removal by drilling to a thin rupture disc that fails at a specific pressure threshold. This parameter change from solid structural material to thin pressure-sensitive material transforms the opening process from a mechanical removal operation to a pressure-induced failure event, significantly reducing completion time.
2Reliability
If packer is used to seal the casing above the air chamber, then sealing is achieved, but device complexity increases and requires specialized equipment
Solution Approach 1:
The invention applies self-service by using the hydraulic pressure system already present in the wellbore to rupture the disc and open the buoyant chamber. The existing well control equipment and hydraulic infrastructure serve the dual purpose of both operating the well and opening the flotation device, eliminating the need for specialized packers and complex sealing mechanisms while maintaining reliable sealing during the flotation operation.
Solution Approach 2:
The invention achieves universality by designing a system that can be operated using standard wellbore equipment and hydraulic pressure systems already available in conventional well operations. The rupture disc mechanism serves multiple functions: it seals the buoyant chamber during installation, opens the chamber when needed, and can be integrated with standard well control equipment, eliminating the need for specialized packers or complex sealing devices.
3Force
If float shoes and float collars are used in flotation devices, then buoyancy is achieved, but device complexity increases
Solution Approach 1:
The invention applies the disposable principle by using a simple, thin rupture disc that is designed to fail at a specific pressure. This disc is much simpler and less expensive than conventional float shoes or collars, and its temporary function (sealing during installation, then rupturing to open the chamber) is perfectly suited for the flotation operation. The disc is replaced or ruptured once, after which the chamber remains open for subsequent operations.
4Device complexity
If hydraulic pressure alone is used to rupture the disc, then simpler mechanism is achieved, but higher hydraulic pressure is required
Solution Approach 1:
The invention introduces an intermediary mechanical advantage system using a lever arm or cam mechanism that converts hydraulic pressure applied to a small area into a concentrated force that ruptures the disc. This intermediary mechanism allows the use of lower hydraulic pressure than would be required to directly rupture the disc, while still achieving the desired rupture function. The mechanical intermediary amplifies the force from the hydraulic system.
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
The solution reduces the hydraulic pressure required to rupture the disc, allows for efficient depth achievement with reduced completion time and cost, and ensures the casing ID is restored for normal operations, minimizing equipment damage and clogging risks.
Implementation Method 1
the rupture disc, when installed in the wellbore, can be ruptured by engagement with an impact surface of a tubular once a rupturing force is applied to the disc, such as by hydraulic fluid under pressure
Implementation Method 2
The disc can be impelled to impact against this impact surface, and rupture as a result
Implementation Method 3
Techniques to lighten or 'float' the casing have been used to extend the depth of well
Data Source
AI summary
A rupture disc assembly and a float tool incorporating the rupture disc assembly is disclosed. The rupture disc assembly may include a rupture disc assembly comprising a rupture disc, an upper tubular portion and a lower tubular portion, and a securing mechanism for holding the rupture disc between the upper and lower tubular portions. A float tool for creating a buoyant chamber in a casing string may include the rupture disc assembly and a sealing device for sealing the lower end of the casing string, the buoyant, sealed chamber may be created there between. In operation, applied fluid pressure causes the rupture disc to move downward. The rupture disc may be shattered by contact with a surface on the lower tubular portion. Full casing internal diameter may be restored in the region where the rupture disc formerly sealed the casing.