Variable Orifice Injection Valve for Flapper Chatter
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Solution Overview
Problem
Injection valves in hydrocarbon wells experience 'chattering' due to insufficient flow rates, leading to premature failure of flapper and seat components, which can result in unsafe well conditions and costly remediation.
Innovation Solution
A tubing retrievable injection valve with a variable orifice nozzle assembly and magnetic locking mechanism that adjusts to maintain the flapper valve in a fully open position, preventing chattering by varying the nozzle area in response to flow rates and using magnets to control the valve's operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a fixed orifice is used in the injection valve, then the valve structure is simple, but the flapper valve experiences chattering when injection rate is insufficient, leading to premature failure
Solution Approach 1:
The patent replaces the fixed orifice with a variable orifice mechanism that includes a movable plug with an adjustable opening. This dynamic structure allows the orifice size to be changed from a closed position to an open position, enabling the system to adapt to different injection rates and eliminate the chattering problem that occurs with insufficient flow rates.
Solution Approach 2:
The invention changes the physical parameter of the orifice from fixed to variable by introducing a movable plug that can adjust its opening degree. This parameter change allows the system to maintain reliable flapper valve operation across a range of injection rates, preventing chattering while preserving structural simplicity through the straightforward mechanical adjustment mechanism.
2Reliability
If the injection rate is increased to prevent chattering, then flapper valve reliability improves, but the risk of wellbore pressure失控 increases
Solution Approach 1:
The variable orifice mechanism allows precise control of the opening size, enabling the system to maintain adequate flow rates to prevent chattering while controlling the pressure increase. By adjusting the orifice opening degree, the system can optimize the balance between preventing flapper chattering and managing wellbore pressure, avoiding the need to simply increase injection rate indiscriminately.
3Reliability
If a variable orifice mechanism is added to the injection valve, then flapper valve reliability improves by preventing chattering, but the device complexity increases
Solution Approach 1:
The patent implements a dynamic orifice control system using a movable plug that can be positioned at different opening degrees. This mechanical dynamic structure, while adding some complexity, provides a straightforward and reliable method to prevent flapper chattering by ensuring adequate flow rates, and the simplicity of the mechanical design minimizes the overall complexity increase.
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 effectively eliminates flapper chattering, ensuring the valve remains open during injection and closes when flow rates decrease, thereby protecting the valve components and maintaining well safety without the need for frequent shut-ins or costly remediation.
Implementation Method 1
a pair of opposite pole magnets are provided. One magnet is attached to an upper sleeve of the nozzle assembly and a second magnet is attached to a middle sleeve member which carriers a variable orifice
Implementation Method 2
The nozzle is designed to generate a pressure drop sufficient to hold the flapper valve fully open
Implementation Method 3
a return spring returns the flow tube to the initial position allowing the flapper to close
Data Source
AI summary
A wireline retrievable injection valve for an oil or gas well has an internal valve that is initially moved to open a flapper safety valve and also opens to allow fluid flow through the valve. The internal valve includes a sleeve that opens the flapper safety valve and shields the flapper safety valve from fluid. In this manner the flapper valve is protected from being caused to “flutter” or “chatter” due to pressure variations in the fluid flow, which may damage the seat.