Frangible Inner Sleeve for Coring Barrel Jam Management
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Solution Overview
Problem
In subterranean formation coring operations, core jamming frequently occurs, leading to incomplete core samples and damage, especially in deep wells, due to increased compressive loads when the core becomes stuck in the barrel, necessitating costly retrieval of tools.
Innovation Solution
A coring assembly featuring an inner sleeve with axially spaced frangible regions allows the barrel to break at specific points, enabling continued coring operations even after core jams, with varying strength regions to manage multiple jams and maintain maximum core length.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the inner sleeve is made strong to prevent breaking during coring operations, then the structural integrity is improved, but core jamming causes increased compressive loads that can damage the core
Solution Approach 1:
The inner sleeve is segmented into multiple frangible regions with different strengths, creating controlled weak points that allow the sleeve to break at specific locations when subjected to compressive loads from core jamming, thereby protecting the core from damage
Solution Approach 2:
Different regions of the inner sleeve are given different local qualities through varying wall thicknesses, with thinner walls at frangible regions and thicker walls at non-frangible regions, allowing the sleeve to respond differently to stresses at different locations
2Object-affected harmful factors
If the inner sleeve is designed to break at frangible regions to mitigate core jamming, then core protection is improved, but the structural integrity deteriorates
Solution Approach 1:
The inner sleeve is divided into frangible and non-frangible regions, creating a segmented structure where only specific portions are designed to break, maintaining overall structural functionality while providing controlled failure points
Solution Approach 2:
The inner sleeve exhibits local quality variations with different wall thicknesses at different regions, making specific locations more susceptible to breaking while maintaining strength at other critical areas
3Device complexity
If a single frangible region is used in the inner sleeve, then the device complexity is reduced, but the ability to handle multiple core jams deteriorates
Solution Approach 1:
Multiple frangible regions are distributed along the inner sleeve at different locations, allowing the sleeve to break at different points depending on where core jamming occurs, thereby handling multiple potential jamming scenarios
Solution Approach 2:
Different frangible regions have different local qualities with varying wall thicknesses, allowing each region to break at different compressive load thresholds, enabling the sleeve to respond to jams at different locations and severities
4Object-affected harmful factors
If the coring operation is halted and tools are brought to surface when core jam is detected, then core damage is prevented, but the loss of time increases significantly
Solution Approach 1:
The inner sleeve automatically protects the core by breaking at frangible regions when subjected to compressive loads from core jamming, eliminating the need for operator intervention or halting the coring operation, thereby preventing core damage without time loss
Solution Approach 2:
The potential harmful effect of compressive loads from core jamming is converted into a beneficial automatic protection mechanism, where the loads themselves cause the inner sleeve to break at controlled points, protecting the core without requiring operation cessation
Data Source
Figure 1~1B
Figure 2~5
Figure 6A~6D
AI summary
A coring assembly comprises an outer barrel coupled to a coring bit. An inner barrel is disposed within the outer barrel. An inner sleeve is disposed within the inner barrel and includes at least one frangible region that allows the inner sleeve to break so that coring operations can continue after the occurrence of a core jam.