Variable Choke Flow Control Apparatus for Wellbore
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Solution Overview
Problem
Long horizontal wells experience non-uniform flow profiles due to variations in reservoir pressure, permeability, and fluid mobility, leading to premature water or gas breakthrough, screen plugging, and reduced well life and profitability, as well as uneven injection distribution in injector wells.
Innovation Solution
A flow control apparatus with a variable choke or valve that automatically adjusts its flow area and pressure drop in response to upstream and downstream pressure changes, preventing reverse flow and ensuring even fluid distribution along the wellbore.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If pre-set fixed nozzles are used to create pressure drop, then the device complexity is reduced, but the ability to control and adjust flow rate is limited
Solution Approach 1:
The patent employs dynamic elements including a movable piston, adjustable springs, and flexible diaphragms that allow the flow control device to automatically adapt to changing pressure conditions. The piston position can be adjusted to change the flow area, and the springs provide dynamic response to pressure differential changes, enabling the device to maintain constant flow rate despite varying upstream and downstream pressures.
Solution Approach 2:
The flow control device incorporates a feedback mechanism where the pressure differential across the device directly influences the piston position through spring force balance. When downstream pressure increases, the pressure differential decreases, allowing the spring to move the piston to increase flow area, thereby maintaining constant flow rate. This automatic feedback control eliminates the need for external control systems.
2Manufacturing precision
If intelligent completion methods are used to control drawdown and flow rate, then flow control precision is improved, but the device complexity and cost increase
Solution Approach 1:
The flow control device is designed to be self-regulating, using the inherent pressure differential across the device to control its own operation. The piston-m spring system automatically adjusts the flow area based on downstream pressure changes without requiring external control lines, sensors, or power sources. This self-service mechanism achieves precise flow control while minimizing device complexity.
Solution Approach 2:
The patent introduces a piston as an intermediary element that translates pressure differential changes into flow area adjustments. The piston acts as a mechanical mediator between the pressure conditions and the flow path, providing precise control through its position-dependent flow restriction while avoiding the need for complex electronic or hydraulic control systems.
3Ease of manufacture
If fixed flow area pressure drop devices are used, then the ease of manufacture is improved, but the ability to prevent cross-flow is lost
Solution Approach 1:
The device uses a dynamic piston assembly that can move in response to pressure conditions. The piston is equipped with sealing elements that maintain contact with the bore wall, creating a reliable barrier against cross-flow. The dynamic positioning of the piston ensures that sealing surfaces remain engaged under varying pressure conditions, preventing fluid bypass while maintaining manufacturing simplicity.
4Device complexity
If no flow control devices are installed, then the device complexity is minimized, but non-uniform flow profiles cause premature water or gas breakthrough
Solution Approach 1:
The flow control device segments the wellbore into controlled flow zones using multiple nozzles or a distributed nozzle array. Each nozzle or section can be independently controlled to regulate flow from different reservoir intervals, creating a uniform production profile along the wellbore. This segmentation prevents localized over-production that would lead to early water or gas breakthrough.
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 apparatus maintains a constant flow rate by dynamically adjusting the flow area based on pressure differences, preventing cross-flow and enhancing uniform production or injection profiles, thereby extending well life and improving hydrocarbon recovery.
Implementation Method 1
the pressure drop caused by these nozzles varies in different parts of the wellbore depending upon the reservoir characteristics to achieve even flow rate along the length of the well bore
Implementation Method 2
Flow control devices may be utilized in the flow path from the reservoir to the wellbore along the length of the well and help to create a predetermined production or injection profile by automatically adjusting the flow area and the pressure drop through the flow stabilizers
Data Source
AI summary
Disclosed herein is a device for controlling flow within, e.g., a production well or an injection well. The device consists of a movable flow passage and a stationary variable choke or valve that is sensitive to flow parameters and automatically adjusts itself to provide a predetermined flow rate through the device.