Window Core for Gamma Ray Detection in Downhole Tools

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Solution Overview

Problem

Conventional gamma ray detection tools face inaccuracies due to contamination from downhole mud and thermal expansion, leading to compromised measurement integrity and frequent recalibration needs.

Innovation Solution

A window core with elastic materials and a middle material is positioned between the window cap and the detector, providing sealing and minimizing thermal expansion, while fasteners with reduced stress concentration and anti-rotation assemblies prevent loosening under harsh conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional window structure is used in gamma ray detection tools, then the tool can operate in downhole environments, but contamination from downhole mud compromises measurement integrity

Engineering Contradiction:

Improvemeasurement integrityVSAvoidcontamination from downhole mud

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The window assembly is segmented into multiple functional components: a window cap providing structural protection, a window core made of elastic material providing sealing, and a middle material layer providing additional protection. This segmentation allows each component to address specific problems - the elastic window core seals against mud contamination while the rigid window cap provides mechanical strength.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The window assembly uses composite materials combining rigid materials (window cap) with elastic materials (window core). This composite structure provides both the mechanical strength needed for downhole operation and the sealing properties needed to prevent mud contamination, resolving the contradiction between durability and contamination resistance.

Inventive Principle:

Principle #40Composite materials

2Strength

If conventional fasteners are used to secure the window assembly, then the structure can be assembled, but stress concentration causes loosening under harsh downhole conditions

Engineering Contradiction:

Improvefastener holding strengthVSAvoidstress concentration

Core Design Contradiction:

StrengthVSStress or pressure

Solution Approach 1:

The fastener design incorporates local quality variations through waisted sections (reduced diameter portions) and multi-radii fillets (curved transitions with varying radii). These local modifications redistribute stress away from concentration points, allowing the fastener to maintain holding strength while withstanding harsh downhole conditions without loosening.

Inventive Principle:

Principle #3Local quality

3Measurement precision

If plastic material is used for the detection window, then gamma ray transmission is maintained, but thermal expansion compromises measurement accuracy

Engineering Contradiction:

Improvegamma ray detection accuracyVSAvoidthermal expansion

Core Design Contradiction:

Measurement precisionVSTemperature

Solution Approach 1:

The window core material is selected with specific elastic properties and thermal characteristics that minimize thermal expansion compared to conventional plastic materials. This parameter change in material properties allows the window to maintain gamma ray transmission while reducing measurement errors caused by temperature-induced expansion in downhole environments.

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

The solution enhances measurement accuracy by preventing contamination and maintaining tool integrity, reducing the need for frequent recalibration and extending tool lifespan.

Implementation Method 1

providing sealing and minimizing thermal expansion

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

at least one gamma ray detector. Gamma rays from the source can pass into a subsurface formation surrounding the borehole... Some of the gamma rays eventually scatter back into the tool and can be detected by a gamma ray detector

Methodology Applied

Scientific EffectGamma ray detection: Photoelectric Effect

Data Source

PatentUS11920458B2Window core for gamma ray detection in a downhole tool

Publication Date: 2024.03.05 HALLIBURTON ENERGY SERVICES INC

AI summary

A downhole tool includes a window cap located in a cover that is positioned between an electromagnetic radiation detector in the downhole tool and a geological formation into which a borehole is formed and where the downhole tool is to be positioned. The electromagnetic radiation detector is to detect an electromagnetic radiation from the geological formation. The downhole tool includes a window core positioned behind the window cap relative to an external environment of the downhole tool, wherein the window core is positioned between the window cap and the electromagnetic radiation detector.