Downhole Tool Actuator Indexing via Flow Rate Control
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Solution Overview
Problem
Existing downhole tools face challenges in selectively activating or changing configuration without unintended activation, due to limitations in control mechanisms for fluid flow rates and indexing mechanisms.
Innovation Solution
A downhole tool actuator and indexer system that utilizes a control assembly with a control piston, ratchet mandrel, and stroking assembly to manage fluid flow rates, allowing for precise control of tool operation modes by adjusting flow rates and positioning within a wellbore, incorporating a pocket assembly with spline pockets and ratchet teeth for controlled movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single drop ball or electro-mechanical actuator is used to activate downhole tools, then the tool can be activated or reconfigured, but unintended activation or lack of selective control may occur
Solution Approach 1:
The patent utilizes fluid flow rate as a control parameter to selectively activate different tools. By establishing distinct flow rate thresholds (first flow rate for first tool, second flow rate for second tool), the system achieves precise selective control without unintended activation. The flow rate parameter changes enable hierarchical control where higher flow rates activate additional tools in sequence.
Solution Approach 2:
The control system is segmented into multiple independent control mechanisms: a first control assembly with a first piston for the first tool, and a second control assembly with a second piston for the second tool. Each control assembly operates independently响应 to fluid flow, allowing selective activation of individual tools based on flow rate thresholds without affecting other tools.
2Reliability
If constantly-cycling indexing mechanisms are used to activate downhole tools, then tools can be activated or reconfigured, but the mechanism complexity and potential for unintended activation increase
Solution Approach 1:
The patent replaces mechanical indexing mechanisms with a hydraulic control system. Fluid flow through the wellbore directly actuates pistons via pressure differentials, eliminating the need for complex constantly-cycling mechanical indexing mechanisms. The hydraulic system provides reliable tool activation through flow rate thresholds while significantly reducing mechanical complexity.
Solution Approach 2:
The control system is self-actuating through fluid flow. The flowing fluid automatically generates the pressure differentials needed to move pistons and activate tools without requiring external mechanical indexing mechanisms. The system uses the wellbore fluid flow itself as the actuating force, eliminating the need for separate indexing mechanisms.
3Reliability
If multiple control mechanisms are implemented to prevent unintended activation, then selective control improves, but the device complexity increases
Solution Approach 1:
The control assemblies are designed with multi-functionality. Each control assembly not only controls its associated tool but also inherently provides flow rate threshold detection and pressure differential generation. The pistons serve multiple functions: they detect flow rate thresholds, generate activation forces, and physically actuate the tools, reducing the need for separate control mechanisms.
Solution Approach 2:
The patent merges the control mechanism and the actuation mechanism into a single integrated system. The control piston directly becomes the actuation element that opens closure elements. By combining control and actuation functions in one component, the system achieves reliable selective control without increasing overall device complexity.
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
Enables precise and selective activation/deactivation of downhole tools and mode changes based on fluid flow rates, reducing unintended actuations and improving operational control within the wellbore.
Implementation Method 1
a control piston spring positioned between a dynamic control spring stop of the control assembly and a fixed control spring stop mechanically coupled to the outer sub
Implementation Method 2
a stroking piston spring positioned between a dynamic stroking spring stop and a fixed spring stop mechanically coupled to the outer sub
Implementation Method 3
by a hydraulic pressure differential generated by fluid flow
Data Source
AI summary
A downhole tool control apparatus includes a control assembly, a stroking assembly, and a pocket sleeve positioned in an outer sub. The control assembly and stroking assembly are independently slidable axially within the outer sub. The control assembly and stroking assembly slide depending on the flow rate of fluid through the downhole tool actuator. The stroking assembly includes a spline barrel having a spline projection positioned within a spline pocket formed in the pocket sleeve. The pocket sleeve and control assembly include one or more ratchet teeth positioned in the pocket sleeve such that as the flow rate is changed between a high and a low flow rate, the spline projection engages the ratchet teeth until an actuated cycle is completed, allowing the downhole tool actuator to move to an actuation position.