Expandable Reamer Stabilizer Ribs and Shear Assembly
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional expandable reamer apparatuses face issues such as wobble, premature actuation, difficulty in removal, and slower cutting rates when passing through smaller diameter boreholes or casings, due to misaligned forces and complex seal configurations, which lead to cocking and jamming, and require sensitive tolerances that are prone to binding with particulate-laden drilling mud.
Innovation Solution
The design incorporates a stabilizer sub with spiral or helical stabilizer ribs directly attached to the expandable reamer apparatus, eliminating intervening drill pipes for enhanced stabilization, and a shear assembly with a push sleeve and blade tracks that allow blades to extend and retract along a shallow angle, reducing the need for sensitive tolerances and preventing cocking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional expandable reamer apparatuses are used to pass through smaller diameter boreholes or casings, then the reamer can be deployed to enlarge boreholes, but the apparatus experiences wobble, premature actuation, and difficulty in removal due to misaligned forces and complex seal configurations
Solution Approach 1:
The reamer apparatus is divided into modular components including a stabilizer sub with stabilizer ribs, a shear assembly with shear elements, and an expandable reamer body. This segmentation allows each component to perform its specific function independently, reducing overall system complexity and improving reliability by isolating potential failure points.
Solution Approach 2:
Stabilizer ribs are provided on the stabilizer sub that extend generally circumferentially to contact the borehole wall, providing stabilization through a curved surface geometry that distributes forces evenly and reduces wobble during deployment through smaller diameter casings.
2Manufacturing precision
If sensitive tolerances are used in conventional expandable reamer apparatuses, then precise blade actuation can be achieved, but the apparatus becomes prone to binding with particulate-laden drilling mud and requires complex seal configurations
Solution Approach 1:
The shear assembly is designed to be actuated by axial force alone, extracting the need for complex radial sealing mechanisms. The shear elements fail at a predetermined load to release the blades, simplifying the tolerance requirements and eliminating binding issues with particulate-laden drilling mud while maintaining precise blade actuation.
Solution Approach 2:
The blade tracks are configured with a shallow angle relative to the longitudinal axis, creating a gradual transition surface that allows blades to extend and retract smoothly without binding, even in the presence of particulate-laden drilling mud, while maintaining precise actuation through the shear assembly mechanism.
3Productivity
If blades are extended at steep angles in conventional reamers, then cutting effectiveness can be improved, but the apparatus experiences cocking and jamming due to misaligned forces
Solution Approach 1:
The blade tracks are configured with a shallow angle relative to the longitudinal axis of the reamer apparatus, creating a gradual transition surface that distributes cutting forces evenly along the blade length. This geometric configuration prevents cocking and jamming by maintaining force alignment, while the shallow angle allows blades to extend fully for effective cutting.
Solution Approach 2:
The shear assembly is positioned asymmetrically relative to the blade tracks, with shear elements located to create a mechanical advantage that optimizes the force distribution. This asymmetric configuration ensures that the axial force applied to the shear assembly translates efficiently into blade extension without creating misaligned forces that could cause cocking.
Data Source
AI summary
An expandable reamer apparatus and stabilizer sub having at least one rib thereon attached thereto for drilling a subterranean formation.