Eccentric Coupling for Directional Drilling Torque Transmission

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Solution Overview

Problem

Existing directional drilling technologies face challenges in maintaining directional control while minimizing deformation and stress in drilling tools, particularly when using 'push-the-bit' methods, which can lead to limited bending or deformation of tool parts.

Innovation Solution

The use of specially designed couplings that transmit torque between elements movable relative to each other in a transverse direction, allowing for radial movement without deformation and reducing stresses, by employing outer and inner eccentric sleeves with complementary tab and groove sets to facilitate torque transmission and radial displacement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If elements are allowed to move radially relative to each other to enable directional control, then directional control capability is improved, but deformation and stress in tool parts increase

Engineering Contradiction:
Improvedirectional control capabilityVSAvoidstress in tool parts
Core Design Contradiction:
Adaptability or versatilityVSStrength

Solution Approach 1:

The coupling acts as an intermediary component between drive shaft sections, enabling radial movement for directional control while maintaining torque transmission. The coupling's design with radial play allows controlled displacement without transmitting deformation stresses between shaft sections, thus resolving the contradiction between adaptability and structural strength.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The drive shaft is divided into multiple sections connected by couplings, allowing each section to maintain its structural integrity while the coupling provides the necessary radial movement capability. This segmentation enables directional control through coupling displacement rather than shaft deformation, reducing stress in the tool parts.

Inventive Principle:
Principle #1Segmentation

2Strength

If rigid connections are used between drive shaft sections, then structural strength is improved, but radial movement capability is reduced

Engineering Contradiction:
Improvestructural strengthVSAvoidradial movement capability
Core Design Contradiction:
StrengthVSAdaptability or versatility

Solution Approach 1:

The coupling introduces dynamic characteristics to the otherwise rigid drive shaft system. The radial play in the coupling allows controlled movement and displacement between shaft sections, transforming the static rigid connection into a dynamic system that can adapt radially while maintaining overall structural strength through the coupling's torque transmission capability.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The coupling changes the connection parameter from completely rigid to semi-rigid with controlled radial play. This parameter modification allows the system to maintain strength while gaining radial movement capability, as the coupling's design specifications (radial play dimension, torque transmission capacity) are optimized to balance both requirements.

Inventive Principle:
Principle #35Parameter changes

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

This solution enables effective directional control during drilling by allowing elements to move radially with minimal deformation, reducing stress and maintaining torque transmission, thus enhancing the reliability and efficiency of directional drilling operations.

Implementation Method 1

The couplings (26, 84) between the sections (3, 20) of the drive shaft enable the sections (3, 20) to move radially with respect to one another to a limited extent while still transmitting torque from one section (3) to the other section (20).

Methodology Applied
Scientific EffectEccentric mechanism: Eccentric

Data Source

PatentEP3090119B1Directional drilling tool with eccentric coupling
Publication Date: 2017.11.01 NABORS LUX 2 SARL
  • EP3090119B1 patent drawingFigure 1~2
  • EP3090119B1 patent drawingFigure 3
  • EP3090119B1 patent drawingFigure 4A~4B

AI summary

A directional drilling tool (1) which comprises a pair of shafts (40, 41) with an eccentric bore to vary the radial position of a stabilizer, such tool including one or more eccentric couplings (25, 26) which are used to transmit torque between a pair of elements of the tool which are intended to be movable relative to each other in a direction transverse to their longitudinal axes.