Downhole Fluid Flow Control Using Viscosity-Sensitive Switching
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Solution Overview
Problem
Existing downhole fluid flow control systems face limitations such as fatigue failure of biasing devices, intricate component failures, lack of sensitivity to minor fluid property differences, and inability to highly restrict or shut off unwanted fluid flow, particularly in long horizontal completions with multiple production intervals.
Innovation Solution
A downhole fluid flow control system with a viscosity discriminator and differential pressure switch that adjusts fluid flow based on viscosity changes, using a viscosity sensitive channel and valve element to control fluid flow through a main pathway, allowing independent control of production fluids from multiple intervals without well intervention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If autonomous inflow control devices with valve elements are used to control fluid flow, then fluid flow control capability is improved, but device complexity increases leading to fatigue failure of biasing devices and intricate component failures
Solution Approach 1:
The patent extracts the complex biasing devices and valve elements from the system and replaces them with a simple viscosity-sensitive membrane and tortuous channel structure. The flow control function is achieved through the membrane's viscosity-dependent blocking behavior rather than mechanical valve elements, eliminating fatigue failure risks while maintaining autonomous operation.
Solution Approach 2:
The patent replaces the mechanical biasing devices and valve elements with a viscosity-sensitive membrane system that operates based on fluid viscosity differences. This substitution eliminates mechanical fatigue and component failure while maintaining autonomous flow control capability through the membrane's physical response to viscosity changes.
2Measurement precision
If current autonomous inflow control devices are used, then some fluid flow control is achieved, but sensitivity to minor fluid property differences such as light oil viscosity versus water viscosity is insufficient
Solution Approach 1:
The patent applies local quality by designing a tortuous channel with specific geometric characteristics (narrow passages, sharp turns) that amplify the effect of viscosity differences. This localized structural feature enhances the membrane's sensitivity to minor fluid property variations without requiring complex sensing mechanisms throughout the entire device.
Solution Approach 2:
The patent utilizes parameter changes by designing the tortuous channel geometry to be highly sensitive to viscosity variations. The channel's narrow passages and sharp turns create flow conditions where minor viscosity differences result in significant pressure differential changes, enabling high sensitivity detection and response to fluid property changes.
3Ease of operation
If autonomous inflow control devices are used to restrict unwanted fluid flow, then some flow restriction is achieved, but the ability to highly restrict or shut off unwanted fluid flow is limited due to requiring substantial flow or main flow path operation
Solution Approach 1:
The patent introduces a viscosity-sensitive membrane as an intermediary element between the inlet and the main flow path. This membrane acts as a selective gate that automatically blocks unwanted low-viscosity fluids while allowing desired high-viscosity fluids to pass, achieving high flow restriction capability without affecting desired fluid production.
Solution Approach 2:
The patent utilizes parameter changes by designing the system to respond to viscosity parameter variations. The tortuous channel and membrane configuration create a threshold effect where fluids below a certain viscosity threshold are blocked while fluids above the threshold pass freely, enabling high restriction capability for unwanted fluids without impacting desired fluid production.
4Ease of operation
If complex structures with biasing devices are used, then flow control functionality is improved, but reliability decreases due to fatigue failure and component failures
Solution Approach 1:
The patent extracts and removes all biasing devices, springs, and mechanical valve elements from the system. Flow control functionality is achieved through the passive viscosity-sensitive membrane and tortuous channel structure, which have no moving parts or stress-bearing components that could fatigue or fail, dramatically improving reliability.
Solution Approach 2:
The patent employs a simple, robust membrane structure that is inherently resistant to fatigue and component failure. The design philosophy favors simple, durable components over complex, high-performance but fragile mechanisms, achieving reliable long-term operation without requiring maintenance or intervention.
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
Enables autonomous operation to maximize production of desired fluids and minimize production of undesired fluids by responding to minor fluid property differences, reducing the need for complex structures and well intervention.
Implementation Method 1
The magnitude of the third pressure signal is dependent upon the viscosity of the fluid flowing through the secondary fluid pathway such that the differential pressure switch is operated responsive to changes in the viscosity of the fluid
Implementation Method 2
A differential pressure switch is operable to shift the valve element between the open and closed positions. The first and second pressure signals bias the valve element toward the open position while the third pressure signal biases the valve element toward the closed position
Data Source
AI summary
A downhole fluid flow control system includes one or more fluid control modules each having upstream and downstream sides with parallel main and secondary fluid pathways extending between the upstream and downstream sides. A valve element disposed within the main fluid pathway has open and closed positions. A viscosity discriminator including a viscosity sensitive channel forms at least a portion of the secondary fluid pathway. A differential pressure switch operable to open and close the valve element includes a first pressure signal from the upstream side, a second pressure signal from the downstream side and a third pressure signal from the secondary fluid pathway. The magnitude of the third signal is dependent upon the viscosity of the fluid flowing through the secondary fluid pathway such that changes in fluid viscosity operate the differential pressure switch, thereby controlling fluid flow through the main fluid pathway of each module.