Torque Reduction Assembly Mandrel Retention Slots
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Solution Overview
Problem
Top drive drilling systems face challenges in managing increased torque requirements for deep or deviated boreholes, with existing solutions either relying on expensive chemical additives or mechanically cumbersome torque reduction methods that may not effectively distribute forces along the drill string.
Innovation Solution
A torque reduction assembly featuring a mandrel with radial retention slots and elements, allowing for axial and rotational fixing through interchangeable retention elements, and a bearing sleeve to distribute forces and reduce wear, enabling robust and efficient attachment to the drill string.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If chemical additives are inserted into the drilling fluid to mitigate torque increase, then torque requirements are reduced, but the cost increases significantly
Solution Approach 1:
The patent replaces chemical additives with a mechanical torque reduction assembly consisting of a mandrel, outer sleeve, and retention elements. This mechanical system reduces torque requirements through physical force distribution and friction management, eliminating the need for expensive chemical substances while achieving the same torque mitigation effect
Solution Approach 2:
The bearing sleeve acts as an intermediary component between the mandrel and outer sleeve, distributing forces and reducing direct contact friction. This intermediary mechanism enables torque reduction without requiring chemical additives, providing a cost-effective mechanical solution
2Force
If multiple clamp-on units are used along the drill string to reduce torque, then torque distribution improves, but the device complexity and risk of units coming loose increases
Solution Approach 1:
The patent combines multiple torque reduction functions into a single integrated assembly unit. The mandrel, outer sleeve, retaining ring, and bearing sleeve work together as one cohesive device, eliminating the need for multiple separate clamp-on units while maintaining effective torque distribution along the drill string
Solution Approach 2:
The assembly is segmented into functional components (mandrel, outer sleeve, retaining ring, bearing sleeve) that can be manufactured separately but operate together as a unified system. This segmentation allows for easier manufacturing and assembly while reducing overall device complexity compared to multiple complete units
3Strength
If retention elements are used to fix the retaining ring, then the connection strength improves, but the manufacturing complexity increases
Solution Approach 1:
The retention elements serve multiple functions: they connect the retaining ring to the mandrel, provide axial positioning, enable rotational fixing when engaged with circumferential grooves, and distribute mechanical loads. This multi-functionality achieves strong connections while maintaining relatively simple manufacturing processes
Solution Approach 2:
The retention elements are nested within the structure of the retaining ring and mandrel assembly. The retaining ring contains apertures that receive retention elements, which in turn engage with features on the mandrel. This nested arrangement creates strong connections through interlocking components while keeping the overall design compact and manufacturable
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 assembly effectively reduces torque requirements by distributing axial and rotational forces, improving the strength of the connection and simplifying manufacturing, while maintaining rotational capability and preventing wear on the mandrel.
Implementation Method 1
a bearing sleeve to distribute forces and reduce wear
Data Source
AI summary
A torque reduction assembly for a drill string has a mandrel for connecting two sections of drill pipe, the mandrel comprising a first annular shoulder and a plurality of radial retention slots arranged circumferentially around an outer surface of the mandrel, including a first retention slot and a second retention slot; an outer sleeve for rotatably mounting on the mandrel; a retaining ring for retaining the outer sleeve between the retaining ring and the first annular shoulder, the retaining ring comprising a first aperture and a circumferential groove about an inner surface of the retaining ring, the first aperture aligned with the circumferential groove, the retaining ring being rotatable about the mandrel so as to progressively align the first aperture with each retention slot; a first retention element for locating in the first retention slot via the first aperture to axially fix the retaining ring relative to the mandrel such that the retaining ring is still rotatable about the mandrel; and a second retention element for locating in the second retention slot via the first aperture to rotationally fix the retaining ring relative to the mandrel.