Insertable Flapper Safety Valve for Damaged Borehole OSV Sealing
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Solution Overview
Problem
Subsurface safety valves, particularly flapper-type valves, can degrade due to corrosion and physical damage, leading to ineffective sealing and failure to stop fluid flow, compromising their failsafe function.
Innovation Solution
An insertable safety valve (ISV) system that latches onto an outer safety valve (OSV) using a latching mechanism and profile, allowing the ISV to be controlled by the OSV's control system, thereby restoring the failsafe function without requiring removal of the OSV from the borehole, even if the OSV's flapper is damaged.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the OSV flapper is damaged due to corrosion and physical damage, then the sealing function deteriorates, but the OSV cannot be removed from the borehole for replacement
Solution Approach 1:
The patent implements a nested valve system where an Insertable Safety Valve (ISV) is inserted inside the Outer Safety Valve (OSV). The ISV contains a new flapper that can provide sealing functionality when the OSV flapper is damaged. This nested configuration allows the inner valve to compensate for the outer valve's degradation without requiring removal of the OSV from the borehole, directly resolving the contradiction between maintaining sealing reliability and the difficulty of valve replacement.
2Reliability
If a new safety valve is installed inside the OSV, then the sealing function is restored, but the device complexity increases
Solution Approach 1:
The patent segments the safety valve system into two independent functional units: the outer OSV with its existing control system and the inner ISV with its own flapper mechanism. This segmentation allows the ISV to be a simpler, self-contained unit that provides sealing functionality without requiring a complete redesign of the OSV. The ISV includes essential components (flapper, hinge, control line connection) but omits redundant systems, thereby restoring sealing function while minimizing the increase in overall device complexity.
3Reliability
If the ISV is inserted and latched to the OSV, then the failsafe function is restored, but the installation process becomes more complex
Solution Approach 1:
The ISV is designed with pre-integrated latching mechanisms that engage with the OSV structure. The latching system includes protrusions on the ISV that fit into corresponding recesses in the OSV, creating a self-aligning and self-latching configuration. This preliminary design of the latching interface simplifies the installation process by eliminating the need for complex alignment procedures or additional fastening operations, thereby restoring the failsafe function while keeping the installation process manageable.
Data Source
AI summary
An apparatus includes a cylindrical housing having a hinge, a flapper attached to the hinge, and a slidable element is within the cylindrical housing, wherein the flapper can rotate from a first flapper position to a second flapper position. The slidable element is slidable from a first position to a second position and engages with the flapper at the first position to prevent the flapper from moving to the second flapper position. The flapper is movable to the second flapper position when the slidable element is disengaged from the flapper. The apparatus also includes a latching mechanism attached to the slidable element movable from a first latching mechanism position to a second latching mechanism position. The slidable element is at the first position when the latching mechanism is at the first latching mechanism position and at the second position when the latching mechanism is at the second latching mechanism position.