Polymer-Embedded Flow Tube for Subsurface Safety Valve Impact Absorption
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Solution Overview
Problem
Subsurface safety valves in hydrocarbon recovery operations face damage from high impact forces during sudden closure, leading to reduced inner diameter and inhibited fluid flow, due to conventional hard-faced coatings that are brittle and unable to withstand high impact loads.
Innovation Solution
A subsurface safety valve design featuring a flow tube with a cut-out section at the lower end replaced by an elastically deformable polymeric material, such as rubber or plastics, which absorbs impact energy and reduces damage to the metallic flow tube, allowing it to maintain functionality and prevent sand deposition during production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional hard-faced coatings are used on the flow tube, then abrasive resistance is improved, but impact resistance deteriorates because the coating is brittle and cannot withstand high impact loads
Solution Approach 1:
The flow tube is designed with different material properties at different locations: the upper portion has a hard-faced coating for abrasive resistance, while the lower end has a softer, more ductile material for impact resistance. This local differentiation allows each section to optimize its performance for the specific type of stress it encounters.
Solution Approach 2:
The flow tube combines two different materials in a composite structure: a hard-faced coating material for abrasion protection and a softer, more ductile base material or alternative coating at the lower end for impact absorption. This composite approach allows the flow tube to simultaneously resist both abrasive wear and impact forces.
2Strength
If the flow tube is made entirely of hard material for durability, then strength is improved, but ability to absorb impact energy deteriorates
Solution Approach 1:
The flow tube transitions from uniform hard material to a structure where the lower end portion has different material properties - softer and more ductile - specifically positioned to absorb impact energy from the flapper closure, while the upper portion maintains hard material for overall durability.
3Strength
If the inner diameter of the flow tube reduces due to impact damage, then structural integrity is compromised, but fluid flow capability deteriorates
Solution Approach 1:
The softer, more ductile material at the lower end of the flow tube acts as a cushioning layer that absorbs impact energy before it can transmit to the main flow tube structure. This pre-absorption of impact energy prevents the high-rate gas slam closure from causing deformations that would reduce the inner diameter and compromise fluid flow capability.
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 use of polymeric materials in the cut-out section of the flow tube reduces impact loads on the metallic components, preventing damage and ensuring reliable operation, including high-rate gas slam closure, while maintaining the sealing function and preventing sand deposition.
Implementation Method 1
a lower end that includes a cut out section that is adjacent to the flapper... replaced by polymeric materials (such as rubber, plastics, or other materials that can elastically deform to large strain)
Data Source
AI summary
A safety valve for a wellbore for production of hydrocarbons from a surrounding subsurface formation includes a flow tube through which a flow of fluids from the surrounding subsurface formation downhole to a surface of the wellbore, wherein the flow tube comprises a lower end through which the flow of fluids is to enter the flow tube, wherein the flow tube is composed of metal, except for at least a cut out section of the lower end that is composed a polymeric material. The safety valve includes a flapper configured close the safety valve by changing positions to cover an opening at the lower end of the flow tube such that an impact force of the closing on the flapper onto the flow tube is at least partially absorbed by the polymeric material.