Self-Orienting Downhole Catcher Eliminates Mandrel Rotation
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Solution Overview
Problem
Existing ESP catchers require rotation of the tubing string and mandrel, necessitate lengthy J-slots, are costly, complex, and less effective, making them difficult to manufacture and use.
Innovation Solution
A self-orienting catcher that moves up and down without rotating the string assembly or mandrel, utilizing a yo-yo slot and rotatable elements to set and retrieve equipment, reducing complexity and cost while increasing stroke length.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the tubing string and mandrel are rotated to set the tool, then the tool can be positioned and engaged, but the electrical cable is twisted and the drag elements experience unnecessary friction
Solution Approach 1:
Instead of rotating the mandrel to engage the slips (conventional approach), the invention inverts the approach by having the slips rotate on the mandrel during setting. The slips are equipped with drive keys that engage slots in the mandrel, allowing the slips to self-orient and engage without mandrel rotation. This eliminates cable twisting and reduces drag element friction.
2Ease of operation
If a J-slot is milled in the mandrel for cycling the tool, then the tool can be set and released, but the slot must extend for several feet increasing cost and complexity
Solution Approach 1:
The invention segments the cycling function into two separate components: a yo-yo slot in the setting device and drive keys on the slips. The yo-yo slot is a short radial slot (not extending several feet) that works in conjunction with the drive keys to provide tool cycling. This segmentation eliminates the need for a long J-slot in the mandrel, reducing mandrel complexity and manufacturing cost.
3Ease of operation
If the J-slot extends for several feet to accommodate the full stroke, then the tool can be cycled, but the stroke length available for actual catching is reduced
Solution Approach 1:
By separating the cycling mechanism (yo-yo slot + drive keys) from the mandrel structure, the invention allows the yo-yo slot to be a short radial feature while the mandrel retains its full length for effective stroke. The cycling action occurs through the interaction of the yo-yo slot with drive keys on the slips, not through a long axial slot in the mandrel.
4Reliability
If rotation is required to set and retrieve the tool, then engagement can be achieved, but the operation becomes more complex and time-consuming
Solution Approach 1:
The invention inverts the rotation approach: instead of rotating the mandrel to engage slips, the slips rotate on the mandrel during setting. The drive keys on the slips engage slots in the mandrel, allowing automatic self-orientation and engagement. This eliminates the need for time-consuming mandrel rotation operations while maintaining reliable engagement.
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 eliminates the need for rotation, reduces manufacturing complexity and cost, and provides a more effective and reliable catcher with a shorter yo-yo slot length, enabling easier installation and retrieval of ESP equipment.
Implementation Method 1
a drag assembly comprising one or more drag elements (e.g., drag blocks or other drag elements) which will contact the cased or an uncased portion of the bore of the well to resist downward and upward movement of the catching assembly in the well
Data Source
AI summary
A catching tool assembly, and method of use, for catching an electric submersible pump string or other equipment string in a well bore in the event of a tubing failure. The catching tool is self-orienting so that the tool can be set and retrieved by simply moving the mandrel of the tool up and down, without any need to rotate the equipment string or the mandrel.