Pressure-Actuated Toe Valve Assembly for Cement-Resistant Opening
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Solution Overview
Problem
Toe valves in subterranean wells often fail due to cement obstruction or stuck sleeves, leading to partial radial flowpath obstruction, which hampers the selective opening required for fluid circulation and operations like hydraulic fracturing.
Innovation Solution
A downhole tool with a valve assembly comprising an inner and outer cap, and retainers that are configured to yield and eject from a port in response to pressure differentials, allowing for radial fluid flow without relying on fragile disks or sliding sleeves that can foul or fail.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional toe valve designs with sliding sleeves or fragile disks are used, then the device complexity is reduced, but the reliability deteriorates due to cement obstruction or stuck sleeves
Solution Approach 1:
The valve assembly is segmented into multiple functional components: an inner cap with inner retainers, an outer cap with outer retainers, and a frangible disk. This segmentation allows each component to perform its specific function independently, improving reliability while managing complexity through modular design. The inner and outer caps can be ejected separately under different pressure conditions, ensuring consistent valve opening.
Solution Approach 2:
The inner and outer retainers are pre-configured in a yielded state before cementing operations, allowing the caps to be held in place initially. The retainers are designed to yield at specific pressure thresholds, automatically triggering the ejection sequence without requiring external control systems, thus maintaining simplicity while ensuring reliable operation.
2Reliability
If frangible disks are used to seal the port, then the device complexity is reduced, but the reliability deteriorates due to potential obstruction by cement or particulate matter
Solution Approach 1:
The valve assembly transitions from a static sealing configuration to a dynamic ejection mechanism. The inner and outer caps are designed to move and eject under pressure differentials, actively responding to operational conditions rather than passively relying on fragile disk integrity. This dynamic approach prevents cement and particulate matter from obstructing the sealing function.
Solution Approach 2:
The sealing function is extracted from the frangible disk and transferred to the movable inner and outer caps. By removing the caps from the port under controlled pressure conditions, the system eliminates the risk of cement obstruction that plagues static disk-based sealing mechanisms, while maintaining effective sealing during the cementing operation.
3Ease of operation
If sliding sleeves are used for valve operation, then the ease of operation is improved, but the reliability deteriorates due to sleeves becoming stuck and failing to open
Solution Approach 1:
The mechanical sliding sleeve system is replaced with a pressure-driven ejection mechanism using inner and outer retainers. This substitution eliminates the mechanical complexity of sliding sleeves while maintaining ease of operation through automatic pressure-actuated ejection. The retainers yield at predetermined pressure thresholds, automatically triggering cap ejection without requiring manual intervention or complex mechanical linkages.
Solution Approach 2:
The valve assembly is designed to self-actuate based on pressure differentials during cementing operations. The inner and outer retainers automatically yield and trigger cap ejection when pressure thresholds are reached, eliminating the need for external control systems or manual operation. This self-service mechanism ensures reliable operation while simplifying the control system.
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
Ensures reliable and consistent opening of radial fluid flowpaths, preventing obstruction and ensuring effective fluid communication for operations like hydraulic fracturing by using a mechanism that is robust to cement and particulate matter.
Implementation Method 1
The inner cap is configured to move toward outer cap in response to a first pressure differential between bore and the chamber across the outer cap
Implementation Method 2
The inner cap is configured to dislodge the outer cap from the port in response to the inner cap engaging the outer cap and a second pressure differential between the bore and an exterior of the downhole tool being reached across the inner cap
Implementation Method 3
The inner retainer is configured to yield in response to applying a predetermined pressure to the outer cap, such that the inner cap moves toward and collides with the outer cap
Data Source
AI summary
A downhole tool includes a body defining a bore axially therethrough and a port in communication with the bore and extending radially through the body, an inner cap positioned in the port, the inner cap sealing the port, and an outer cap positioned in the port. The outer cap is spaced apart from the inner cap, and the outer cap seals the port, such that a chamber is defined between the inner and outer caps in the port. The inner cap is configured to move toward outer cap in response to a first pressure differential between bore and the chamber across the outer cap. The inner cap is configured to dislodge the outer cap from the port in response to the inner cap engaging the outer cap and a second pressure differential between the bore and an exterior of the downhole tool being reached across the inner cap.