Laser Propelled Tractor for Deviated Wellbores

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Solution Overview

Problem

Conventional downhole tools face challenges in accessing highly deviated and horizontal wellbores due to coiled tubing lockup, where frictional resistance prevents the tool string from being pushed further, and conventional tractors with wheels increase the tool size, limiting access in diverse sized holes.

Innovation Solution

A tractor assembly with a fluid chamber and movable ports uses a heating laser to generate high heat well fluid, which is then expelled to accelerate the tool string, eliminating the need for tractor tires and allowing access in tight spaces, while also enabling logging functions with a logging laser beam.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If conventional tractors with wheels are used to push tool string into highly deviated wellbores, then propulsion force is provided, but the tool size increases and frictional resistance increases

Engineering Contradiction:

Improvepropulsion forceVSAvoidtool size

Core Design Contradiction:

ForceVSVolume of moving object

Solution Approach 1:

The patent replaces the mechanical wheel-based propulsion system with a laser-based heating system. The laser heats the well fluid in the fluid chamber, causing thermal expansion and phase change that generates thrust to propel the tool string forward, eliminating the need for wheels and reducing tool size.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent utilizes phase transition of well fluid from liquid to gas/steam through laser heating. This phase change causes rapid volume expansion, generating high pressure thrust that propels the tool string into the wellbore without requiring mechanical wheels or increasing tool size.

Inventive Principle:

Principle #36Phase transitions

2Force

If conventional tractors with wheels are used to overcome frictional resistance, then propulsion is achieved, but the gross size of the tool increases

Engineering Contradiction:

Improveforce to overcome frictionVSAvoidtool length

Core Design Contradiction:

ForceVSLength of moving object

Solution Approach 1:

The patent substitutes the mechanical wheel-traction system with a thermal propulsion system using laser heating. This eliminates the need for extended tractor structures with wheels, reducing the overall tool length while maintaining the capability to overcome frictional resistance through thermal thrust.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Ease of operation

If coiled tubing is pushed into highly deviated wellbores, then tool string access is attempted, but frictional resistance causes coiled tubing lockup

Engineering Contradiction:

Improvetool string accessVSAvoidfrictional resistance

Core Design Contradiction:

Ease of operationVSForce

Solution Approach 1:

The patent employs the wellbore's own fluid as the propellant medium. The laser heats the existing well fluid within the tool's fluid chamber, and the resulting thermal expansion and phase change of this self-contained fluid generates the thrust needed to overcome friction and propel the tool string forward, making the system self-sufficient.

Inventive Principle:

Principle #25Self-service

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 solution effectively overcomes coiled tubing lockup, enabling tool string access in previously inaccessible wellbores without increasing tool size, allowing for efficient maneuvering and logging operations in complex well geometries.

Implementation Method 1

A heating laser beam is generated with a laser mounted adjacent to the fluid chamber and directed towards the fluid chamber to increase the temperature of the well fluid within the fluid chamber

Methodology Applied

Scientific EffectLaser heating: Laser

Implementation Method 2

The port is moved to the open position to allow the high heat well fluid to flow out of the fluid chamber to accelerate the tractor assembly within the wellbore

Methodology Applied

Scientific EffectThermal expansion and pressure-driven flow: Pressure Gradient

Data Source

PatentUS10087692B2Laser propelled tractor with laser operated logging tools

Publication Date: 2018.10.02 SAUDI ARABIAN OIL CO

AI summary

A method for maneuvering and operating a tool within a wellbore of a subterranean well includes providing a tractor assembly having a fluid chamber with a port extending through a sidewall of the fluid chamber. The port is moved to the open position to allow a well fluid of the subterranean well to flow into the fluid chamber. The port is moved to the closed position to prevent the well fluid from flowing between the interior of the fluid chamber and the exterior of the fluid chamber. A heating laser beam is generated with a laser and directed towards the fluid chamber to increase the temperature of the well fluid within the fluid chamber. The port is moved to the open position to allow the high heat well fluid to flow out of the fluid chamber to accelerate the tractor assembly within the wellbore.