Shear Open Valve Retainer Key Mechanism
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Solution Overview
Problem
Existing gas injection valves in oil and gas wells suffer from low efficiency reliability and shear out force, leading to inefficient fluid injection and pressure losses, which limits hydrocarbon production as natural reservoir pressure decreases over time.
Innovation Solution
A gas injection device with a shear open arrangement that uses a retainer key and shear pin mechanism, allowing adjustment of pre-tensioning and positioning to ensure reliable metal-to-metal sealing and controlled fluid injection, preventing damage to sealing surfaces and minimizing pressure losses by opening only at a predetermined pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pressure shear out system is used to open the valve, then the valve can be opened at a predetermined pressure, but the shear out force and reliability are insufficient
Solution Approach 1:
The valve is divided into distinct functional components: a shear pin for predetermined pressure opening, a retainer key for maintaining the open position, and a seal assembly for sealing operations. This segmentation allows each component to be optimized for its specific function, improving overall reliability while maintaining adequate shear out force through the distributed mechanical action of multiple elements.
Solution Approach 2:
The shear pin is pre-installed and positioned to break at a predetermined pressure threshold, automatically initiating valve opening before full pressure buildup occurs. This preliminary action ensures the valve opens at the correct pressure point without requiring excessive shear out force, as the mechanical break point is pre-established through the shear pin design and positioning.
2Productivity
If the valve opens at low pressure, then fluid injection is efficient, but pressure losses increase and sealing reliability decreases
Solution Approach 1:
The valve is designed to change its opening pressure parameter based on well conditions and reservoir pressure. By adjusting the shear pin positioning and pre-tensioning, the valve can be set to open at optimal pressure thresholds that balance injection efficiency with minimal pressure losses, adapting to different operational scenarios rather than using a fixed low pressure opening.
Solution Approach 2:
The valve replaces purely mechanical pressure-driven opening with a controlled mechanical break system. The shear pin provides a predetermined failure point that triggers opening at the optimal pressure moment, substituting uncontrolled mechanical expansion with a designed mechanical event that occurs at the most efficient pressure point, thereby reducing pressure losses while maintaining injection efficiency.
3Device complexity
If the shear open mechanism is simplified, then device complexity is reduced, but sealing reliability and positioning accuracy deteriorate
Solution Approach 1:
The shear pin, retainer key, and seal assembly are merged into an integrated valve body structure where these components work together as a unified system. The shear pin is positioned within the valve body, the retainer key engages with both the shear pin and seal assembly, and all components are coordinated to ensure that opening and sealing operations occur reliably. This merging reduces overall device complexity while maintaining high sealing reliability through the coordinated action of integrated elements.
Solution Approach 2:
The retainer key acts as an intermediary element between the shear pin and the seal assembly. It receives the mechanical action from the shear pin break and transmits it to properly position and activate the seal assembly. This intermediary component ensures that the simplified shear open mechanism still achieves reliable sealing by mediating the transition from shear force to sealing action, maintaining positioning accuracy without adding significant complexity.
4Reliability
If pre-tensioning is increased to ensure sealing, then sealing reliability improves, but the shear open pressure threshold increases
Solution Approach 1:
The pre-tensioning force is made dynamically adjustable through the shear pin positioning mechanism. By changing the position of the shear pin within the valve body, the pre-tensioning level can be optimized for different sealing conditions without permanently altering the shear open pressure threshold. This dynamic adjustment allows the system to adapt to varying well conditions, maintaining sealing reliability while keeping the pressure threshold appropriate for the specific application.
Solution Approach 2:
The shear pin is pre-positioned to establish a specific pre-tensioning level that ensures reliable sealing during normal operation. This preliminary positioning of the shear pin creates the optimal balance between sealing force and shear open threshold before the valve is activated. The pre-tensioning is established in advance through the shear pin location, ensuring that when pressure builds up, the valve opens at the correct threshold while maintaining sealing reliability during closed operation.
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 ensures safer, more efficient fluid injection with reduced pressure losses and enhanced reliability, maintaining a constant open position after shear opening, thus improving hydrocarbon production by optimizing fluid flow and pressure management.
Implementation Method 1
The valve is operated by a pressure differential that is generated across the internal body. Exposing the surfaces of the internal body to different fluids can create this pressure differential. When a preset pressure is exceeded, the pin breaks permitting the valve to open
Implementation Method 2
The pressure differential across the internal body may be assisted by at least one predetermined pressure balanced elastic element to open and close the device
Implementation Method 3
The valve is operated by a pressure differential that is generated across the internal body. Exposing the surfaces of the internal body to different fluids can create this pressure differential
Data Source
Figure 1~2
AI summary
The present invention regards a device designed for injection of fluids in a well bore, typically an offshore well bore for petroleum production and gas injection / gas lift system for fluid injection. The device comprises a outer hollow housing (1) with an internal body (3) moveable within the outer housing (1) which in a first closed position is closed with a metal to metal seal system between the outer housing (1) and the internal body (3), which internal body (3) is operated by pressure differential across the internal body (3). The internal movable body (3) is connected to the outer hollow housing (1) by means of a retainer key (6). The retainer key (6) comprises a shear arrangement and is arranged to keep the valve in a fixed closed position, where fluid pressure is to overcome the pretension of the retainer key (6) in order to open the device. When the device is shear opened, it can be kept in this open position as the retainer key (6) is locked to the outer hollow housing (1).