Subterranean Screen With Variable Flow Resistance Zones
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Solution Overview
Problem
In downhole screens, flow imbalances between and within screen sections lead to high velocities near the surface, causing erosion and undesirable production of water or particulates, as the path of least resistance results in uneven flow distribution.
Innovation Solution
The screen section is designed with variable resistance by varying the number and density of openings along its length, using overlapping screen portions, and reconfiguring the wire wrap cross-section from triangular to trapezoidal to reduce turbulence and achieve uniform flow profiles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If screen sections are used in long horizontal runs, then production service is enabled, but flow imbalance occurs with high velocities near the surface causing erosion and undesirable production
Solution Approach 1:
The screen incorporates zones with different open area percentages along its length, where each zone has locally optimized screen characteristics. Zones closer to the surface have lower open areas to restrict flow, while deeper zones have higher open areas, creating a gradient that balances flow velocities throughout the screen section and prevents erosion at the surface.
2Ease of manufacture
If uniform screen openings are used throughout the screen section, then manufacturing is simplified, but flow balance is compromised with short circuiting to the surface
Solution Approach 1:
The screen is divided into multiple discrete zones along its length, with each zone having a specific open area percentage. This segmentation allows independent optimization of flow characteristics in each zone while maintaining a modular structure that can be manufactured using standard screen fabrication techniques, balancing manufacturing simplicity with flow control requirements.
3Strength
If triangular wire wrap cross-section is used, then structural strength is maintained, but turbulence increases flow resistance
Solution Approach 1:
The wire wrap cross-section is changed from a symmetric triangular shape to an asymmetric trapezoidal shape with a smaller included angle. This asymmetric geometry reduces flow turbulence and resistance while maintaining the structural strength of the wire wrap, optimizing both mechanical integrity and fluid flow characteristics.
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
This design balances flow along the screen length, reducing turbulence and increasing throughput while maintaining particle filtration capability, thereby preventing erosion and optimizing production.
Implementation Method 1
The cross-sectional shape of a wire wrap underlayment for the screen is made closer to trapezoidal to decrease the angle of opening for the incoming flow paths toward the base pipe. In this manner flow resistance is reduced and flow is increased due to reduced turbulence.
Data Source
AI summary
A screen section is made with variable resistance to flow in the screen material to balance the flow along the screen length. In one variation different discrete zones have screens configured for different percentages of open area while all have the same particle filtration capability. In another variation discrete portions have differing amounts of overlapping screen portions so as to balance flow without affecting the particle size screened. The cross-sectional shape of a wire wrap underlayment for the screen is made closer to trapezoidal to decrease the angle of opening for the incoming flow paths toward the base pipe. In this manner flow resistance is reduced and flow is increased due to reduced turbulence.