Downhole Tractor Wheel Teeth Grooves Debris Management

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Solution Overview

Problem

Downhole tractors in wellbores face low traction due to debris accumulation, limiting their range and payload capacity in open hole wellbore applications.

Innovation Solution

The design incorporates tractor wheels with a unique tooth geometry and arced grooves that channel debris away from the wheel surface, combined with actuator-controlled wheel positioning to enhance traction and prevent damage to the wellbore formation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional smooth wheels are used, then the wheel structure is simple, but traction is low due to debris accumulation

Engineering Contradiction:

ImprovetractionVSAvoidwheel structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The wheel surface is segmented into multiple teeth instead of being smooth, creating distinct contact points that cut through debris and maintain traction in open hole wellbores

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The wheel design transitions from a two-dimensional smooth surface to a three-dimensional toothed structure with grooves, adding vertical dimensionality to the contact interface for improved debris displacement

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Productivity

If wheel traction is increased to improve range and payload capacity, then more debris accumulation occurs, reducing traction

Engineering Contradiction:

Improvetractoring distanceVSAvoidtraction

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The grooves between teeth are designed to capture and channel debris away from the wheel surface, converting the harmful effect of debris accumulation into a beneficial self-cleaning mechanism that maintains traction over extended distances

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The toothed geometry with grooves is designed in advance to proactively displace debris before it can accumulate and compromise traction, preventing the degradation mechanism rather than reacting to it

Inventive Principle:

Principle #10Preliminary action

3Reliability

If wheels are pressed harder against the wellbore wall to improve traction, then contact stress increases and formation damage occurs

Engineering Contradiction:

ImprovetractionVSAvoidformation damage

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The toothed structure concentrates contact forces at specific localized points rather than distributing pressure across the entire wheel surface, achieving high traction at contact points while minimizing overall contact stress on the formation

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The segmented tooth geometry creates multiple discrete contact points that distribute the total traction force across several locations, reducing the stress concentration at any single point on the wellbore wall

Inventive Principle:

Principle #1Segmentation

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 significantly increases the tractoring distance and payload capacity of downhole tractors while maintaining low contact stress on the wellbore wall, ensuring effective conveyance of tools and equipment.

Implementation Method 1

Arced grooves that are parallel to the wheel axis are made in between adjacent teeth... The contact force from the wellbore will channel debris in the wellbore out from the wheel via the grooves

Methodology Applied

Scientific EffectGravitational force: Gravitation

Implementation Method 2

As the wheels of the tractor rotate, debris will accumulate and adhere to the wheel surfaces... The contact force from the wellbore will channel debris in the wellbore out from the wheel via the grooves

Methodology Applied

Scientific EffectCentrifugal force: Centrifugal Force

Implementation Method 3

The range of a tractor and the amount of payload that can be conveyed are determined by the tractor's ability to provide sufficient traction between the wheels and a wall of the wellbore... Each tooth includes an outer face including face grooves on each side of the outer face

Methodology Applied

Scientific EffectFriction: Friction

Implementation Method 4

The teeth on the wheel engage with the wellbore wall through mechanical interlocking... The low contact stress ensures that the wheel will grip onto the formation without damaging the formation

Methodology Applied

Scientific EffectMechanical interlocking: Mechanical Force

Data Source

PatentUS20230137244A1Downhole tractor with wheel assembly

Publication Date: 2023.05.04 HALLIBURTON ENERGY SERVICES INC

AI summary

A downhole tractor assembly operable in a wellbore that includes a tractor body and a tractor wheel assembly. The tractor wheel assembly includes a tractor wheel with teeth around a circumference of the wheel and grooves between adjacent teeth. The grooves include a profile in a plane parallel with the axis of the wheel. Also, each tooth includes an outer face with face grooves on each side of the outer face that extend less than across the wheel.