Core Catcher Closure Members Prevent Formation Material Loss
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional clamshell core catchers in coring tools often lose unconsolidated formation materials like gravel or sand due to gaps between clamshell halves and the base ring, and can fail to retain the core under loading conditions due to yielding hinge pins or tabs.
Innovation Solution
A core catcher design with a retention member and closure members that rotate to form a barrier across the axial bore, utilizing a pivot axis located at a distance from the centerline to ensure full contact and prevent material loss, and a secondary core catcher mechanism that engages the core to prevent axial movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If conventional clamshell halves are used with small tabs hinged to the base ring, then the device complexity is reduced and ease of manufacture is improved, but gaps form between the clamshell halves and base ring causing loss of unconsolidated formation materials
Solution Approach 1:
The core catcher is divided into multiple closure members (typically two clamshell halves) that can independently rotate about hinge pins. Each closure member is segmented into a body portion and a tab portion, allowing the structure to achieve full closure while maintaining manufacturing simplicity. The segmentation enables each piece to contact the base ring independently, eliminating gaps without requiring an overly complex integrated structure.
Solution Approach 2:
The hinge pins are positioned at strategic locations on the base ring, and the closure members are designed to rotate in a circular path about these pins. This dimensional arrangement ensures that when the closure members rotate to the closed position, their outer edges contact the base ring along an arc, creating full coverage in the radial dimension while maintaining simple hinge-tab connections in the axial dimension.
2Reliability
If hinge pins and tabs are made small to reduce device complexity, then ease of manufacture is improved, but the hinge components yield under loading conditions allowing clamshell halves to push through the base ring
Solution Approach 1:
The hinge pin and tab are merged into a single integrated hinge assembly that rotates as one unit about the hinge pin axis. This combination ensures that the hinge pin and tab work together as a unified load-bearing structure, preventing relative movement and yielding. The merged design maintains simplicity by avoiding separate reinforcement components while improving reliability through the integrated mechanical connection.
Solution Approach 2:
The hinge pin is made from a material with high strength and wear resistance properties, while the tab is made from a material that provides both strength and flexibility. This composite material approach allows the hinge assembly to withstand high loading conditions without yielding, while maintaining a simple structural design. The different material properties complement each other to prevent failure under load.
3Loss of substance
If clamshell halves are designed not to contact the base ring to simplify the structure, then ease of manufacture is improved, but gaps form that allow material loss and core loss under certain loading conditions
Solution Approach 1:
The closure members are pre-positioned in an open state during assembly, with the hinge tabs initially clear of the base ring. This preliminary positioning allows for easy assembly and manufacturing, as the closure members can be installed without interference. When activated, the closure members rotate into the closed position where they contact the base ring, achieving full closure and preventing material loss. The preliminary open position simplifies manufacturing while the final closed position prevents core loss.
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 design effectively retains cores by preventing material loss and ensuring secure closure even under varying conditions, enhancing the reliability of core retrieval in coring operations.
Implementation Method 1
A first closure member has a slot that is engaged with the first hinge tab and a pivot edge that is at least partially disposed within the first hinge barrel. In an open position, the first closure member is disposed in an annulus between a sleeve that is slidably disposed within the housing and the housing. In a closed position the first closure member is disposed at least partially across the axial bore of the housing.
Data Source
AI summary
A core catcher includes a housing having an inner wall that defines an axial bore through the housing. A retention member is disposed within the housing and is coupled to a first hinge tab that defines a first hinge barrel with the inner wall of the housing. A first closure member has a slot that is engaged with the first hinge tab and a pivot edge that is at least partially disposed within the first hinge barrel. In an open position, the first closure member is disposed in an annulus between a sleeve that is slidably disposed within the housing and the housing. In a closed position the first closure member is disposed at least partially across the axial bore of the housing.