Tapered Surface Braking Device for Drilling Tool Retention
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Solution Overview
Problem
During drilling operations, particularly in exploration drilling, the inner tube assembly can unintentionally fall out of the drill string, posing hazards due to high velocity egress from the borehole, especially in horizontal or upwardly oriented drilling processes.
Innovation Solution
A braking device is introduced, featuring a brake retainer with tapered surfaces and a bias member that exerts a force to maintain brake elements in contact with the borehole wall, increasing friction and preventing unintended expulsion of drilling tools. This device can be integrated into the core barrel assembly or used as part of a wireline retrieval system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the inner tube assembly is pumped into place using hydraulic pressure in horizontal or upwardly oriented boreholes, then the core sample retrieval time is reduced, but the risk of unintended egress and high velocity expulsion from the borehole increases
Solution Approach 1:
The braking device is pre-installed on the wireline retrieval system before entering the borehole. The brake elements are positioned to engage with the borehole wall in advance, creating a counteracting friction force that prevents unintended egress. The bias member pre-loads the brake elements against the tapered surface, ensuring immediate braking capability upon deployment.
Solution Approach 2:
The braking device acts as an intermediary between the wireline retrieval system and the borehole wall. It transfers and controls the interaction forces between the moving inner tube assembly and the stationary borehole, using friction engagement to regulate motion and prevent hazardous expulsion while allowing controlled retrieval operations.
2Reliability
If the brake elements are maintained in constant contact with the borehole wall through bias member force, then unintended expulsion is prevented, but friction and energy loss increase
Solution Approach 1:
The braking device employs a dynamic friction engagement system where the brake elements can adjust their contact pressure with the borehole wall based on operational conditions. The bias member provides a baseline contact force for reliability, while the tapered surface geometry allows the engagement depth to vary, enabling the system to maintain sufficient friction for safety while minimizing energy loss during normal operations.
3Ease of operation
If the brake elements engage deeply with the tapered surface to increase friction, then control over the drilling assembly is improved, but the device complexity increases
Solution Approach 1:
The braking device utilizes a tapered cylindrical surface geometry that provides gradual engagement of the brake elements. The tapered shape allows for smooth, progressive friction engagement as the wireline assembly moves along the taper, simplifying the control mechanism while maintaining effective braking. The curved tapered surface distributes the friction forces more evenly compared to abrupt engagement surfaces.
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 braking device effectively prevents the drilling assembly from being expelled from the borehole, ensuring safer and more controlled retrieval of core samples by maintaining frictional engagement with the borehole wall, thus reducing the risk of accidents and operational inefficiencies.
Implementation Method 1
a bias member configured to exert a biasing force on the body member to move the body member toward the brake retainer
Implementation Method 2
maintaining frictional engagement with the borehole wall, thus reducing the risk of accidents
Data Source
Figure 1
Figure 2A~2B
Figure 2C
AI summary
A braking device for drilling operations in a borehole includes a brake retainer having a plurality of brake connector openings defined therein, a body member having a tapered surface having a first diameter and a second diameter, the second diameter being larger than the first diameter, at least one brake element positioned at least partially between the brake retainer and the body member and in communication with the tapered surface and at least one of the brake connector openings, and a bias member configured to exert a biasing force on the body member to move the body member toward the brake retainer to move the brake element from contact with the first diameter of the tapered surface toward contact with the second diameter.