Multi-cycle Counter System for Downhole Tool Activation
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Solution Overview
Problem
Existing downhole tool activation systems face challenges in reliably activating tools due to fluctuating wellbore pressures and the need to account for increasing hydrostatic pressure as tools move to deeper depths, leading to difficulties in determining the required surface pressure for activation.
Innovation Solution
A multi-cycle counter system that includes a valve, a counter device, and a piston, where the valve opens when the counter device moves an activation distance, and the piston is configured to move in response to pressure differences between a wellbore fluid and a fluid reservoir, using a flow restrictor to manage fluid flow and equalize pressures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pressure counter system is used to allow predetermined number of pressure cycles for tool activation, then the tool activation reliability is improved, but the device complexity increases due to additional components needed to count pressure cycles
Solution Approach 1:
The patent combines the pressure sensing function and the cycle counting function into a single integrated piston-rod mechanism. The piston responds to pressure differential to move the rod, and the ratchet teeth on the rod simultaneously perform both counting cycles and preventing reverse movement, merging multiple functions into one component system.
Solution Approach 2:
The piston-rod assembly serves multiple functions: it acts as a pressure differential sensor, a cycle counter, a directional control mechanism, and an activation trigger. The ratchet teeth provide both counting capability and one-way motion control, making the system multi-functional without requiring separate dedicated components for each function.
2Reliability
If the piston is configured to move in response to pressure differences between wellbore fluid and fluid reservoir, then the hydrostatic pressure is accounted for in tool activation, but the device complexity increases
Solution Approach 1:
The system uses a counterbalancing pressure approach where the fluid reservoir provides a reference pressure that counteracts the hydrostatic pressure at different depths. The piston responds only to differential pressure exceeding the reservoir pressure, effectively compensating for varying hydrostatic conditions without requiring depth sensing or complex pressure calculation mechanisms.
Solution Approach 2:
The fluid reservoir automatically adjusts to provide the appropriate counterpressure based on the wellbore conditions. The system self-regulates by allowing fluid communication between the reservoir and wellbore through the flow restrictor, enabling the reservoir to naturally equalize pressure and provide the correct reference level without external control or adjustment mechanisms.
3Reliability
If a flow restrictor is used to restrict fluid flow between fluid source and fluid reservoir, then the pressure equalization is controlled, but the device complexity increases
Solution Approach 1:
The flow restrictor serves as an intermediary component that mediates the pressure equalization process between the fluid source and the reservoir. It provides controlled fluid passage that allows gradual pressure balancing without requiring complex valve mechanisms or active control systems, simply using the restrictor's flow characteristics to manage the pressure transition.
4Reliability
If the valve is configured to open only when the counter device has moved an activation distance, then false activation from pressure fluctuations is prevented, but the device complexity increases
Solution Approach 1:
The system requires preliminary action in the form of multiple complete pressure cycles before the valve can open. The counter device must accumulate a predetermined number of cycles, moving the activation distance through incremental ratchet engagement, ensuring that transient pressure fluctuations alone cannot trigger activation. Only sustained, repeated pressure variations will eventually move the counter sufficiently to open the valve.
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 system allows for reliable activation of downhole tools by ensuring that activation occurs only after a predetermined number of pressure cycles, while accounting for hydrostatic pressure, and does so with a minimal number of moving parts, ensuring reliable pressure application.
Implementation Method 1
the piston is configured to move a step distance in a first direction when the wellbore pressure exceeds the pressure in the fluid reservoir, and configured to move a step distance in an opposite direction driven solely by a greater pressure in the fluid reservoir than the wellbore pressure
Implementation Method 2
a flow restrictor in fluid communication with the fluid reservoir and fluid source, configured to restrict the flow of fluid between the fluid source to the fluid reservoir
Data Source
AI summary
The present disclosed technology relates to a downhole tool activation device, and a method of using the device, where the valve is configured to open when the counter device has moved an activation distance in an activation direction, a piston engaged with the counter device, having a wellbore pressure from a fluid source applied to a first side, and a pressure in a fluid reservoir applied to the second side, the piston configured to move a step distance in a first direction when the wellbore pressure exceeds the pressure in the fluid reservoir, and configured to move a step distance in an opposite direction driven solely by a greater pressure in the fluid reservoir than the wellbore pressure, and a flow restrictor in fluid communication with the fluid reservoir and fluid source, configured to restrict the flow of fluid between the fluid source to the fluid reservoir.