Core Lifter With Recessed Gripping Projections for Wear Reduction
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Solution Overview
Problem
The core lifter in drilling systems wears down over time, leading to damage that prevents effective gripping and retrieval of core samples, necessitating frequent replacement and increasing the time required for sample collection.
Innovation Solution
A core lifter with a tubular body featuring longitudinally-oriented recesses and projections, a raised contact feature, and a flared skirt, designed to resiliently deform and grip core samples while limiting movement, reducing wear and tear and extending its lifespan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the core lifter is used repeatedly to grip and retrieve core samples, then productivity is improved by avoiding frequent drill string tripping, but the core lifter wears down and damages over time, reducing reliability
Solution Approach 1:
The core lifter is divided into a modular design where the gripping elements (projections and recesses) are integrated into a tubular body that can be independently replaced. This segmentation allows the gripping components to be renewed without replacing the entire core lifter assembly, thus maintaining reliability while preserving productivity gains from repeated use.
Solution Approach 2:
The patent implements a wear-resistant coating applied to the gripping surfaces of the core lifter. This coating can be recovered or reapplied after wear occurs, extending the service life of the core lifter. The coating acts as a sacrificial layer that protects the underlying gripping structures, allowing the core lifter to maintain its gripping capability over multiple cycles of core sample retrieval.
2Ease of manufacture
If the core lifter design is simplified for ease of manufacture, then ease of manufacture is improved, but the gripping effectiveness and durability may be reduced
Solution Approach 1:
The core lifter employs a tubular body design with integrated projections and recesses that can be formed through relatively simple manufacturing processes such as extrusion or stamping. The tubular structure provides flexibility while maintaining structural integrity, and the gripping features are formed as integral parts of the tube rather than separate components, simplifying manufacture while ensuring reliable grip through the distributed contact of multiple projections and recesses.
Solution Approach 2:
The core lifter utilizes composite construction combining a base metal material for the tubular body with a specialized wear-resistant coating material applied to the gripping surfaces. This composite approach allows the bulk material to be manufactured using simple, cost-effective processes while the coating provides enhanced durability and grip strength, resolving the contradiction between ease of manufacture and gripping effectiveness.
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 core lifter effectively grips and retrieves core samples with reduced wear, allowing for repeated use and faster sample collection without the need for frequent drill string tripping, thereby enhancing drilling efficiency.
Implementation Method 1
designed to resiliently deform and grip core samples
Implementation Method 2
a flared skirt configured to limit movement of the core lifter relative to a core lifter case
Data Source
AI summary
A core lifter and method for making same for use in a drilling system. The core lifter can include a tubular body having an exterior surface and an interior surface and can have a plurality of longitudinally-oriented recesses formed in the exterior surface of the tubular body of the core lifter and extending radially inwardly relative to the central axis of the core lifter. The plurality of longitudinally-oriented recesses formed in the exterior surface of the tubular body of the core lifter can extend along at least 50 percent of the length of the core lifter.