Downhole Explosive Assembly Severing Support Member

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Solution Overview

Problem

In deep and complex wellbores, downhole tools and equipment often become stuck due to friction, making it difficult to apply adequate tension to release tools, which are necessary to disconnect stuck portions of tool strings.

Innovation Solution

A downhole release tool with an explosive assembly that severs a support member, allowing the tool string to be disconnected, even in conditions where mechanical tension is insufficient due to friction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If mechanical tension is applied to the release tool via conveyance line, then the release tool can disconnect the tool string portions, but friction between sidewall and conveyance line prevents adequate tension from being applied in deviated wellbores

Engineering Contradiction:

Improvetension forceVSAvoidfriction

Core Design Contradiction:

ForceVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the mechanical tensioning system with a chemical/explosive system. Instead of relying on mechanical tension transmitted through the conveyance line, the invention uses an explosive charge to sever the support member, thereby disconnecting the tool string portions without requiring high tension forces that would overcome wellbore friction.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The invention extracts the critical function of disconnection from the mechanical tensioning system and isolates it into a separate explosive severing mechanism. The explosive assembly is positioned within the release tool to directly sever the support member, removing the dependency on the conveyance line's mechanical tension transmission capability.

Inventive Principle:

Principle #2Taking out (Extraction)

2Reliability

If conventional release tools are used that rely on tension to break shear pins, then tool string can be disconnected in straight wellbores, but disconnection fails in deviated wellbores with multiple bends

Engineering Contradiction:

Improvedisconnection reliabilityVSAvoidwellbore geometry adaptability

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The invention changes the operational parameter from mechanical tension to explosive force. By using an explosive charge instead of relying on tension forces, the system becomes effective in deviated wellbores where friction prevents adequate tension from being applied, thereby adapting the disconnection mechanism to work in various wellbore geometries.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent substitutes the mechanical shear pin breaking mechanism with an explosive severing mechanism. This replacement eliminates the limitation imposed by wellbore geometry on tension application, allowing reliable disconnection in both straight and deviated wellbores.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Power

If impact tool is used to dislodge stuck tool string, then elastic energy can be generated, but impact tool may not be able to dislodge the stuck tool string in severe cases

Engineering Contradiction:

Improveimpact powerVSAvoiddislodge reliability

Core Design Contradiction:

PowerVSReliability

Solution Approach 1:

The invention extracts the disconnection function from the impact tool and places it in a separate release tool with explosive assembly. This separation allows the impact tool to focus on delivering mechanical impact forces to dislodge the stuck tool string, while the release tool provides a guaranteed disconnection capability through explosive severing if the impact is insufficient.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The release tool with explosive assembly serves as a backup or cushioning measure in case the impact tool fails to dislodge the stuck tool string. The explosive mechanism is pre-positioned within the release tool to provide a definitive disconnection capability if the primary impact method proves insufficient.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

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 reliable disconnection of stuck tool string portions, facilitating the retrieval of free portions and the potential recovery of stuck equipment, even in challenging wellbore geometries.

Implementation Method 1

an explosive charge; a detonator switch operable to detonate the explosive charge

Methodology Applied

Scientific EffectExplosion: Explosion

Data Source

PatentUS12276167B2Downhole apparatus

Publication Date: 2025.04.15 WEATHERFORD TECHNOLOGY HOLDINGS LLC

AI summary

An explosive assembly for a downhole tool operable to connect and selectively disconnect within a wellbore a first portion of a downhole tool string and a second portion of the downhole tool string. The explosive assembly includes an explosive charge, a detonator switch operable to detonate the explosive charge, and a housing assembly containing the explosive charge and the detonator switch. The explosive assembly may be movable as a single unit and installable within an internal space of the downhole tool. The explosive charge may be operable to sever a support member of the downhole tool when the explosive charge is detonated by the detonator switch to therefore disconnect a first portion of the downhole tool and a second portion of the downhole tool from each other and thus disconnect the first portion of the downhole tool string and the second portion of the downhole tool string from each other.