Directional Core Drilling With Non-Rotating Barrel And Steering Control
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Solution Overview
Problem
Existing directional drilling systems struggle to obtain large core samples efficiently while maintaining directional control and protecting the core samples from damage during retrieval.
Innovation Solution
A directional core drilling assembly featuring a non-rotating core barrel isolated from the rotating drill bit by a torque latch assembly and anti-rotation bearing, combined with steering pads for directional control and a fluid flow control system to protect the core sample during retrieval.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the core barrel is coupled to the rotating drill bit for efficient drilling, then drilling productivity is improved, but the core sample becomes damaged due to rotational forces
Solution Approach 1:
The system divides the core barrel assembly into two independent rotational systems: the outer barrel rotates with the drill bit for drilling, while the inner barrel remains non-rotating for core protection. This segmentation allows each component to perform its function without interfering with the other, resolving the contradiction between drilling efficiency and core sample integrity
Solution Approach 2:
A bearing assembly acts as an intermediary between the rotating outer barrel and the non-rotating inner barrel. This bearing allows the outer barrel to rotate freely while the inner barrel remains stationary, enabling the core barrel to be isolated from rotational forces while still being coupled to the drilling system
2Object-affected harmful factors
If a torque latch assembly is added to isolate the core barrel from rotation, then core sample protection is improved, but device complexity increases
Solution Approach 1:
The torque latch assembly and bearing assembly are merged into a single integrated unit that performs both functions: preventing torque transmission to the core barrel while supporting the non-rotating inner barrel. This combination reduces the number of separate components and simplifies the overall assembly process
Solution Approach 2:
The bearing assembly serves multiple functions simultaneously: it supports the inner barrel, isolates it from rotation, and allows the outer barrel to rotate. This multi-functionality reduces the need for additional components and simplifies the overall device structure
3Ease of operation
If the inner barrel assembly is made movable for core retrieval, then ease of operation is improved, but structural stability deteriorates
Solution Approach 1:
The inner barrel assembly is designed with dynamic characteristics, allowing it to move axially for core retrieval while maintaining rotational stability. The bearing assembly enables this controlled movement while preventing unwanted rotation, providing both ease of operation and structural stability
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
Enables the capture of larger core samples with enhanced directional precision and minimizes damage to the core samples by isolating the core barrel from rotational forces and controlling fluid flow during retrieval.
Implementation Method 1
an anti-rotation bearing assembly... such that the core barrel is rotationally fixed relative to the drive barrel
Implementation Method 2
The torque latch assembly includes latch arms configured to releasably couple a rotational drive input to the drive barrel
Implementation Method 3
an outer barrel assembly including a guide sleeve that defines a tilt angle of a drill bit within a hole
Data Source
AI summary
A directional core drilling includes an outer barrel assembly with a guide sleeve that defines a tilt angle for orientating a drill bit within a hole and a drive barrel rotationally supported within the outer barrel assembly. An inner drive assembly is receivable within the outer barrel assembly and includes a torque latch assembly and an anti-rotation bearing assembly. The torque latch assembly includes latch arms configured to releasably couple a rotational drive input to the drive barrel. A core barrel is coupled to the anti-rotation bearing assembly and is rotationally fixed relative to the drive barrel.