J-Slot Collet Mechanism for Low-Pressure Tool Actuation
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Solution Overview
Problem
Existing mechanically operated tool assemblies in hydrocarbon wells, particularly in horizontal bores, face inefficiencies due to the inability to actuate tools positioned below a collet release mechanism at low tubing pressures, as the rigid connection between tool parts restricts relative longitudinal and rotational movements necessary for tool operation.
Innovation Solution
The design incorporates a J-slot profile within the collet mechanism, allowing for relative longitudinal and rotational movement of the mandrel without releasing the collet assembly, enabling the actuation of tools positioned below the release mechanism through weight-down and rotation of the tool string, which activates a sleeve to align with cooperating members and move longitudinally, allowing closure of valves or other mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a rigid connection is used between tool parts in a mechanically operated assembly, then structural strength and stability are improved, but the ability to perform relative longitudinal and rotational movements necessary for tool actuation deteriorates
Solution Approach 1:
The tool assembly is divided into separable components: a tool string with a mandrel, a collet release assembly, and a carried tool. The J-slot mechanism enables controlled relative movement between these segments during actuation, while maintaining structural integrity during non-operational states. This segmentation allows the system to transition between rigid and movable states as needed.
Solution Approach 2:
The connection between tool parts transitions from a static rigid state to a dynamic movable state during actuation. The J-slot mechanism provides a controlled path for longitudinal and rotational movement of the mandrel relative to the collet release assembly, enabling the tool to perform required movements only when needed while maintaining strength otherwise.
2Volume of moving object
If tools are positioned below a collet release mechanism, then space utilization in the wellbore is improved, but the ability to actuate these tools at low tubing pressures deteriorates
Solution Approach 1:
The invention replaces hydraulic or pressure-dependent actuation mechanisms with a purely mechanical actuation system. The J-slot mechanism and collet release assembly enable tool actuation through controlled longitudinal and rotational movements of the mandrel, eliminating dependence on tubing pressure. This mechanical substitution ensures reliable tool actuation regardless of pressure conditions.
Solution Approach 2:
The J-slot mechanism serves as an intermediary between the mandrel and the carried tool, translating rotational and longitudinal movements into the necessary actuation motions. This intermediary mechanism decouples the actuation process from pressure dependencies, allowing reliable operation at low pressures while maintaining compact positioning below the collet release assembly.
3Ease of operation
If a mechanically operated release assembly is used to connect tool parts, then operational control is improved, but the complexity of the device increases
Solution Approach 1:
The J-slot mechanism combines multiple functions into a single integrated structure: it guides longitudinal movement, enables rotational movement, and provides the release path for the collet assembly. By merging these functions into one mechanism rather than using separate components, the design achieves operational control while minimizing the increase in device complexity.
Solution Approach 2:
The J-slot mechanism serves multiple purposes: it acts as a guide for mandrel movement, provides a rotational path for actuation, and defines the release geometry for the collet assembly. This multi-functionality reduces the number of separate components needed, thereby controlling device complexity while maintaining ease of operation.
Data Source
Figure 1A
Figure 1B
Figure 1C
AI summary
A tool string carrying an external tool, such as a liner hanger, on a release mechanism is lowered into the wellbore. Interlocking lugs and J-slot profile, defined between the exterior surface of the mandrel and interior surface of the release mechanism, allow relative movement of release mechanism and mandrel without releasing the release mechanism. The relative movement allows mechanical operation of a valve or other tool positioned below the release mechanism. Weight-down and rotation of the tool string and mandrel actuates the lower valve assembly by turning a sleeve into alignment with cooperating members of the mandrel. The sleeve, no longer constrained, moves longitudinally in response to a biasing mechanism. Movement of the sleeve allows closure of the valve. After actuation of the valve tool, further weight-down releases the release mechanism from the carried tool.