Seal-Less Frangible Wellbore Isolation for Adjustable Pressure Opening
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Solution Overview
Problem
Prior art frangible seal systems in wellbore tubulars are not field-adjustable, requiring disassembly and reassembly to change pressure-response characteristics, which increases the risk of seal failure and is not suitable for long-term placement due to exposed seals deteriorating in harsh wellbore environments.
Innovation Solution
A field-adjustable downhole device with a tubular body, a hollow piston, and a breakable domed disc that can be selectively segregated using a détente mechanism, allowing for pressure-controlled fluid flow without exposing seals to harsh environments, and enabling adjustment of the détente means without complete disassembly by changing shear pins.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If prior art frangible seal systems are used with multiple body pieces and exposed seals, then pressure control function is achieved, but seal reliability deteriorates due to exposure to harsh wellbore fluid environment
Solution Approach 1:
The invention extracts the seals from the harsh wellbore fluid environment by placing them inside a sealed chamber formed by the piston and body. The piston moves within this chamber, maintaining seals in a protected state away from direct contact with deteriorating wellbore fluids, thereby preserving seal reliability over long-term placement.
Solution Approach 2:
The invention introduces an intermediary sealed chamber between the seals and the harsh wellbore environment. This chamber acts as a barrier, allowing the seals to function while being protected from the harmful fluid environment, thus resolving the contradiction between achieving pressure control and maintaining seal reliability.
2Adaptability or versatility
If prior art frangible seal systems require disassembly and reassembly to change pressure-response characteristics, then adaptability is improved, but seal failure risk increases due to field disassembly without controlled environment
Solution Approach 1:
The invention enables parameter changes (pressure-response characteristics) by allowing replacement of the frangible disc and détente means through access ports without disassembling the sealed chamber. This maintains seal integrity while providing field adjustability, as the seals remain protected during parameter modifications.
Solution Approach 2:
The invention segments the device into a sealed chamber containing the seals and an external access system. This allows the frangible disc and détente means to be replaced independently through access ports, enabling adaptability without exposing the seals to field disassembly risks, thus maintaining reliability while achieving adjustability.
3Duration of action of stationary object
If prior art systems use multiple body pieces joined together with exposed seals, then ease of manufacture is improved, but device lifespan decreases due to seal deterioration in wellbore environment
Solution Approach 1:
The invention extracts the seals from direct exposure to wellbore fluids by placing them within the sealed chamber. This protection extends the device lifespan by preventing seal deterioration, allowing long-term placement in the wellbore environment without frequent replacements.
Solution Approach 2:
The invention makes the frangible disc disposable while protecting the expensive seals. The frangible disc can be replaced through access ports when needed, while the seals remain protected and reusable, extending the overall device lifespan without requiring replacement of the entire assembly.
4Loss of time
If prior art frangible disc systems require replacing entire subassemblies to change disc characteristics, then manufacturing simplicity is maintained, but loss of time and increased cost occur due to complete subassembly replacement
Solution Approach 1:
The invention segments the subassembly into replaceable components (frangible disc, détente means) and permanent components (sealed chamber, seals). This allows selective replacement of only the frangible disc through access ports, reducing field replacement time and cost while maintaining a robust sealed structure.
Solution Approach 2:
The invention enables parameter changes by allowing independent replacement of the frangible disc with different breaking characteristics. This provides flexibility in pressure-response adjustment without requiring complete subassembly replacement, reducing time loss while maintaining manufacturing simplicity through standardized access port design.
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 device provides controlled pressure segregation and extended lifespan by minimizing seal exposure to wellbore fluids, allowing for field-adjustable pressure control without the need for complex assembly or expensive materials, reducing the risk of seal failure and extending the device's utility in wellbore operations.
Implementation Method 1
fluid pressures exerted on opposite sides of the disc
Implementation Method 2
the détente may be one or more shear pins engaged with both the device body and the piston
Implementation Method 3
the surface of the disc inside the ledge strikes the guillotine and the disc is thereby impacted and broken away
Data Source
AI summary
In well bores with included tubulars, it is often desirable to segregate a portion of the wellbore's pressure-driven fluid flowpath in the conduit portion formed by included tubulars to permit work to be completed in a pressure-controlled portion of that flowpath. The subassembly and included frangible device provided here does so with minimal exposure of seals to well fluid environments, and provides a field-adjustable variability to the pressure differentials required to open the conduit by removal of the frangible sealing device from the flowpath into which the subassembly is installed or included.