Subsurface Safety Valve Axial Brake for Debris-Tolerant Holding
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Solution Overview
Problem
Existing subsurface safety valves (SSSVs) face challenges with debris interference affecting holding force, limited radial space, and the need for continuous power to maintain the open position, which is not suitable for subsea applications.
Innovation Solution
The SSSV employs an electromagnet and a radially compressible member, such as a collet, with an angled target surface to ensure axial fixation of the flow tube, and uses an electropermanent magnet with a self-powered protection circuit to switch to the OFF state when power is lost, ensuring reliable operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an electromagnet is used to hold the flow tube in the open position, then the valve can be controlled to remain open, but continuous power is required which is not suitable for subsea applications
Solution Approach 1:
The patent inverts the traditional electromagnet operation by using a spring mechanism to hold the valve open and an electromagnet only to close it. This inversion eliminates the need for continuous power to maintain the open position, making the system suitable for subsea applications where continuous power is unavailable.
Solution Approach 2:
The electromagnet operates periodically rather than continuously - it is energized only when power is available to close the valve or when a safety signal is received. The spring mechanism provides continuous holding force without power consumption, creating a periodic operation pattern that conserves energy.
2Reliability
If a traditional holding mechanism is used, then the open position can be maintained, but debris interference reduces the holding force
Solution Approach 1:
The patent extracts the holding function from the electromagnet and assigns it to a spring mechanism. This separation allows the electromagnet to focus solely on closing the valve while the spring handles the holding function, eliminating debris interference issues that would affect an electromagnet-based holding mechanism.
Solution Approach 2:
The spring mechanism acts as an intermediary between the valve components, providing a mechanical holding force that is insensitive to debris. This intermediary mechanism transfers the holding function away from electromagnetic fields that could be disrupted by debris accumulation.
3Ease of operation
If the radial space is increased to accommodate components, then the valve operation can be improved, but the available space in subsea applications is limited
Solution Approach 1:
The patent employs a nested arrangement where the collet is positioned within the radial space of the flow tube assembly, and the spring mechanism is integrated into the existing valve structure. This nesting allows complex mechanisms to occupy minimal radial space while maintaining full functionality.
Solution Approach 2:
The collet is designed as a dynamic component that expands and contracts radially to engage and disengage the flow tube. This dynamic mechanism allows for smooth valve operation with minimal radial space, as the collet only occupies additional space during the engagement transition rather than requiring continuous radial clearance.
4Device complexity
If a simple electromagnet design is used, then the device complexity is reduced, but the ability to operate without continuous power is lost
Solution Approach 1:
The spring mechanism serves multiple functions: it provides the holding force to keep the valve open, acts as a return spring to reset the collet, and eliminates the need for continuous power. This multi-functionality reduces overall system complexity while achieving power independence.
Solution Approach 2:
The spring mechanism is a self-service component that requires no external power source to maintain the open position. It automatically provides the necessary holding force throughout the valve's operational cycle, making the system self-sufficient and independent of continuous power supply.
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 provides reliable debris-tolerant and power-efficient operation, maintaining the open position without continuous power, suitable for subsea environments and overcoming space constraints.
Implementation Method 1
an electromagnet fixedly coupled to the housing; a target positioned proximate the electromagnet, the target configured to remain in an axially distal position when the electromagnet is not energized and be axially drawn toward and held in an axially proximal position by the electromagnet when the electromagnet is energized
Implementation Method 2
uses an electropermanent magnet with a self-powered protection circuit to switch to the OFF state when power is lost
Data Source
AI summary
Provided is an SSSV, a well system, and a method. The SSSV, in one aspect, includes an electromagnet fixedly coupled to a housing, a target positioned proximate the electromagnet, and a radially compressible member located radially between a flow tube and the housing. In one aspect, the radially compressible member is engageable with the target and is configured to move between: 1) a radially extended state when the electromagnet is not energized and the target is in an axially distal position to allow the flow tube to move between a closed state and an open state, and 2) a radially compressed state when the electromagnet is energized and the target is in an axially proximal position to hold the flow tube in a flow state.