Directional Neutron Measurement via Axial Offset

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Solution Overview

Problem

Current borehole measurement devices struggle to provide directional neutron measurements due to the need for thick shielding, making it impractical for down-hole applications, while existing methods rely on omni-directional nuclear measurements that do not effectively penetrate formations.

Innovation Solution

An apparatus with a neutron source and detector offset from the longitudinal axis, allowing for directional measurements without shielding, utilizing thermal or epithermal neutron detectors and gamma detectors to determine formation characteristics in radial directions, enabling geo-navigation and optimized drilling paths.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If thick shielding is used to shield neutrons for directional measurements, then measurement directionality is improved, but device complexity and impracticality for down-hole applications increase

Engineering Contradiction:

Improvemeasurement directionalityVSAvoidshielding thickness

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies asymmetry by offsetting the neutron detector from the longitudinal axis of the apparatus. This asymmetric positioning allows the detector to preferentially detect neutrons traveling in a specific radial direction without requiring thick shielding. The offset creates a geometric configuration where the detector is more sensitive to neutrons from one direction, achieving directional measurement capability while avoiding the complexity of extensive shielding materials.

Inventive Principle:

Principle #4Asymmetry

2Device complexity

If omni-directional neutron measurements are used, then device simplicity is maintained, but ability to provide directional information for geo-navigation is lost

Engineering Contradiction:

Improvemeasurement system simplicityVSAvoiddirectional information

Core Design Contradiction:

Device complexityVSLoss of information

Solution Approach 1:

By positioning the neutron detector offset from the longitudinal axis, the system transforms from omni-directional to directional measurement capability. This asymmetric configuration allows the simple apparatus structure to be maintained while gaining the ability to provide directional information about formation characteristics, enabling geo-navigation applications without complex shielding or multiple detectors.

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The invention adds a spatial dimension to the measurement capability by offsetting the detector from the central axis. This dimensional change allows the system to differentiate between different radial directions, transforming a simple omni-directional measurement system into one that provides directional information, effectively adding angular resolution to the measurement capability.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Speed

If neutron measurements are made in radial direction, then formation penetration capability is improved, but shielding requirements become impractical

Engineering Contradiction:

Improveneutron penetration depthVSAvoidshielding requirements

Core Design Contradiction:

SpeedVSDevice complexity

Solution Approach 1:

The offset detector configuration enables radial directional measurements without requiring thick shielding. The geometric asymmetry created by offsetting the detector from the longitudinal axis allows neutrons to travel radially outward into the formation while the detector remains positioned to receive returning neutrons, achieving deep formation penetration capability without the impractical shielding requirements that would otherwise be necessary.

Inventive Principle:

Principle #4Asymmetry

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 directional neutron measurements without shielding, providing higher count rates and accurate formation characteristic data for steering drill paths, enhancing hydrocarbon extraction by determining desired formation characteristics in real-time or near real-time.

Implementation Method 1

these neutrons are able to penetrate further into formations

Methodology Applied

Scientific EffectNeutron penetration: Radiation

Implementation Method 2

the interaction of the applied energy with the formation

Methodology Applied

Scientific EffectNeutron interaction: Nuclear Fission

Implementation Method 3

thermal neutron measurements

Methodology Applied

Scientific EffectThermal neutron detection:

Implementation Method 4

epithermal neutron detectors

Methodology Applied

Scientific EffectEpithermal neutron detection:

Implementation Method 5

gamma detectors

Methodology Applied

Scientific EffectGamma ray detection:

Data Source

PatentEP2959100B1Directional measurements using neutron sources

Publication Date: 2019.09.11 ROKE TECH

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AI summary

A measurement tool, primarily for use in a bore hole, has a neutron source located within a housing and a neutron-based detector located within the housing. At least one of the neutron source and the neutron-based detector offset from a longitudinal axis of rotation. The axially offset neutron source or neutron-based detector allow directional measurements to be made of the formations surrounding the bore hole by rotating the tool within the bore hole.