Subsurface Safety Valve Cable Sealing and Flow Path Design
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Solution Overview
Problem
Deep-set surface controlled sub-surface safety valves (SCSSVs) in subterranean wells pose challenges due to the significant volume of hydrocarbons above the valve, requiring large surface hydraulic power systems and creating unreliable cable splices and connection issues when routing cables around or through the valve, leading to potential leakage and installation difficulties.
Innovation Solution
A safety valve system is designed with a central body and supporting body that locks into place above the downhole apparatus, featuring an inner diameter seal that energizes to seal against the cable, diverting fluid flow through an annular path, allowing for on/off valve operation and accommodating axial movement, reducing hydrocarbon volume and eliminating the need for complex cable routing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the SCSSV is placed deep in the wellbore, then the valve can control production tubing closure effectively, but the volume of hydrocarbons above the valve increases significantly and requires large surface hydraulic power systems
Solution Approach 1:
Instead of placing the safety valve deep in the wellbore (conventional approach), the patent inverts the arrangement by positioning the safety valve above the electrical submersible pump assembly, closer to the surface. This inversion reduces the volume of hydrocarbons above the valve while maintaining effective control of the production tubing closure.
2Ease of operation
If the cable is routed around the SCSSV, then the cable can pass by the valve, but the cable splicing becomes unreliable and creates weak points in the cable
Solution Approach 1:
The patent extracts the cable routing complexity by providing a dedicated cable passage through the safety valve body. This allows the cable to pass directly through the valve without requiring splices or complex routing around the valve, eliminating weak points and improving reliability.
3Reliability
If the cable is spliced with the SCSSV flow path routed around it, then fewer electrical splices are needed, but space out and termination issues at the SCSSV remain
Solution Approach 1:
The safety valve body is designed with multi-functionality, incorporating both the valve mechanism and a dedicated cable passage within the same component. This integration eliminates the need for separate cable termination issues and provides a universal solution for both valve operation and cable routing.
4Reliability
If a flapper, split or clamshell type device is used to close around the cable, then the valve can seal against the cable, but alignment and centralization of the cable become difficult and sealing area increases
Solution Approach 1:
Instead of using complex multi-segment devices like flapper or clamshell valves, the patent applies a simple radial seal at a specific location within the valve body. This localized sealing approach maintains effective cable sealing while avoiding the complexity of alignment and centralization required by multi-segment designs.
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 hydrocarbon volume above the safety valve, simplifies cable management, enhances sealing reliability, and enables rig-less installation and maintenance, reducing well downtime and human errors while being compatible with various well types and equipment.
Implementation Method 1
an inner diameter seal located within a central bore of the central body, the inner diameter seal moveable between an unenergized position and an energized position where the inner diameter seal forms a seal between the central bore of the central body and a cable that extends through the central bore
Implementation Method 2
an outer diameter seal that circumscribes the central body and is positioned to seal between the central body and the supporting body
Implementation Method 3
a valve assembly that is moveable between an open position where fluid can flow through the annular fluid flow path, and a closed position where fluid is prevented from flowing through the annular fluid flow path
Data Source
AI summary
A safety valve system for a subterranean well includes a central body with a central body profile and a supporting body having a supporting profile shaped to support the central body profile. An outer diameter seal circumscribes the central body to seal between the central body and the supporting body. An inner diameter seal is located within a central bore of the central body to form a seal between the central bore of the central body and a cable that extends through the central bore. An annular fluid flow path extends through the safety valve system axially past the outer diameter seal and the inner diameter seal. A valve assembly is moveable between an open position where fluid can flow through the annular fluid flow path, and a closed position where fluid is prevented from flowing through the annular fluid flow path.