Downhole Check Valve Pressure Differential Control
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Solution Overview
Problem
The existing flow control systems in boreholes experience pressure differentials and cross-flow issues due to delayed control signals from the surface, leading to equipment damage and reduced efficiency in fluid injection processes.
Innovation Solution
A flow control apparatus comprising a tubular body, check valve sleeve, and check valve that controls fluid communication based on pressure differences, allowing the check valve to open when the pressure inside the tubular string exceeds the borehole annulus pressure, and closing when the pressure drops, thereby preventing pressure differentials and cross-flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a surface-controlled valve is used to control fluid flow into the formation, then the fluid flow can be controlled from the surface, but the control signal takes several minutes to communicate from the surface, causing delayed response and pressure differential issues
Solution Approach 1:
The valve assembly performs self-control by using the pressure differential between the tubular interior and formation to automatically open or close the valve without external control signals. When injection pressure exceeds formation pressure by a predetermined amount, the valve opens automatically; when pressure differential decreases, the valve closes automatically, eliminating the need for surface control signals and their associated time delays.
Solution Approach 2:
The patent replaces the surface-controlled mechanical valve system with a pressure-sensitive automatic valve mechanism. The valve uses elastic deformation of a closure member in response to pressure changes to control flow, substituting the complex surface control system with a simple pressure-responsive mechanical mechanism that responds instantaneously to pressure conditions.
2Productivity
If the valve remains open after pump shutdown due to delayed control signal, then cross flow from high pressure zone to lower pressure zones occurs, but this causes sand and debris flow into the tubular and damage to equipment
Solution Approach 1:
The valve is designed to close automatically when the pressure differential between the tubular and formation decreases below a predetermined threshold, preventing the harmful cross-flow and pressure wave propagation before they can occur. This preliminary protective action eliminates the need for surface control signals and their associated time delays.
Solution Approach 2:
The valve incorporates a pressure-sensitive feedback mechanism where the closure member's position is determined by the real-time pressure differential between the tubular interior and formation. When injection pressure exceeds formation pressure by a predetermined amount, the valve opens; when the differential decreases, the valve closes, creating an automatic feedback control system that responds instantaneously to pressure conditions.
3Reliability
If a pressure-sensitive check valve is used to prevent cross-flow, then equipment damage is reduced, but the device complexity increases with additional components like check valve sleeve and biasing member
Solution Approach 1:
The patent combines multiple functions into a single integrated valve assembly that includes the body, closure member, check valve sleeve, and biasing member working together as one unit. The closure member serves both as a flow control element and a pressure-sensing element, while the check valve sleeve integrates the sealing and pressure differential response functions, reducing overall system complexity despite the multiple components.
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 manages fluid flow, reducing equipment damage and maintaining efficient injection processes by automatically adjusting the check valve position based on pressure levels, ensuring consistent fluid communication and preventing pressure waves.
Implementation Method 1
a change of a pressure inside the check valve sleeve causes the check valve to control fluid communication between the check valve sleeve and the borehole outside the tubular body
Implementation Method 2
A flow control apparatus comprising a tubular body, a check valve sleeve and a check valve, wherein a change of a pressure inside the check valve sleeve causes the check valve to control fluid communication between the check valve sleeve and the borehole outside the tubular body
Implementation Method 3
A surface fluid source, such as a pump, provides the pressurized injection fluid to each flow control apparatus downhole
Implementation Method 4
increasing the first pressure to a selected level causes a check valve to move to an open position, wherein the selected level is greater than a second pressure of a borehole annulus outside the tubular
Implementation Method 5
flow of fluid from high pressure zone can cause a high pressure wave or water hammer of fluid to propagate uphole in the tubular
Data Source
AI summary
In one aspect, a flow control apparatus for use in a borehole is provided. The apparatus includes a tubular body, a check valve sleeve and a check valve, wherein a change of a pressure inside the check valve sleeve causes the check valve to control fluid communication between the check valve sleeve and the borehole outside the tubular body.