Nuclear Logging Shielding Port for Gamma Ray Noise Reduction

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Solution Overview

Problem

Gamma rays emitted from a nuclear logging tool's source can transmit inside the tool, leading to noise that interferes with accurate formation density measurements, as they do not provide substantial information about the formation properties.

Innovation Solution

A shielding system is implemented within the nuclear logging tool, comprising a shielding insert and chassis shielding block, positioned between the gamma ray source and detector, to block undesirable gamma ray transmissions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If gamma ray source and detector are positioned close to each other in the nuclear logging tool, then the tool size is reduced, but gamma rays transmit inside the tool causing noise and reducing measurement precision

Engineering Contradiction:

Improvetool sizeVSAvoidformation density measurement precision

Core Design Contradiction:

Volume of moving objectVSMeasurement precision

Solution Approach 1:

The shielding system is divided into multiple components: a shielding insert with first and second portions mounted in different locations (collar and chassis), a chassis shielding block, and a shielding top plate. This segmentation allows the shielding function to be distributed across multiple elements rather than requiring a single large shield, enabling effective gamma ray blocking while maintaining compact tool dimensions.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The shielding insert is nested within the collar structure, with the first portion mounted in the collar and the second portion mounted in the chassis. The shielding top plate couples to the collar and retains the shielding insert. This nested arrangement allows multiple shielding components to occupy overlapping or adjacent spaces efficiently, providing comprehensive gamma ray shielding without proportionally increasing the overall tool volume.

Inventive Principle:

Principle #7Nested doll (Nesting)

2Measurement precision

If shielding components are added to block gamma rays inside the tool, then measurement precision is improved, but device complexity increases

Engineering Contradiction:

Improveformation density measurement precisionVSAvoidshielding system complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The collar and chassis serve multiple functions: they provide structural support for the logging tool and simultaneously serve as mounting locations for shielding components. The shielding insert is retained by the collar structure, and the chassis shielding block integrates with the chassis. This multi-functionality reduces the need for separate dedicated shielding structures, thereby limiting the increase in device complexity while still providing effective gamma ray blocking.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Object-affected harmful factors

If shielding material is added to block gamma rays, then noise from internal gamma ray transmission is reduced, but the weight of the tool increases

Engineering Contradiction:

Improvenoise from internal gamma ray transmissionVSAvoidtool weight

Core Design Contradiction:

Object-affected harmful factorsVSWeight of moving object

Solution Approach 1:

The shielding components are strategically positioned only in specific locations where gamma ray transmission occurs: the shielding insert in the collar, the chassis shielding block in the chassis, and the shielding top plate on the collar. This localized shielding approach blocks gamma rays in the most critical paths while avoiding unnecessary shielding material throughout the entire tool, thereby minimizing weight increase while effectively reducing noise from internal gamma ray transmission.

Inventive Principle:

Principle #3Local quality

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 shielding system effectively reduces gamma rays inside the tool, enhancing the accuracy of formation density measurements by minimizing noise and improving signal quality.

Implementation Method 1

Methodology Applied

Scientific EffectGamma ray shielding: Absorption (EM radiation)

Implementation Method 2

These gamma rays may Compton scatter from the electrons present in the formation before being detected by a gamma ray detector spaced some distance from the gamma ray source

Methodology Applied

Scientific EffectCompton scattering: Compton Scattering

Data Source

PatentUS12405398B2Shielding port for nuclear logging tool with gamma ray source

Publication Date: 2025.09.02 SCHLUMBERGER TECH CORP

AI summary

A system includes a shield of a nuclear logging tool. The shield includes a shielding insert configured to mount at least partially inside the nuclear logging tool between a gamma ray source of the nuclear logging tool and a gamma ray detector of the nuclear logging tool. A first portion of the shielding insert is configured to mount in a collar of the nuclear logging tool and a second portion of the shielding insert is configured to mount in a chassis of the nuclear logging tool. The shield also includes a chassis shielding block configured to mount in the chassis between the gamma ray source and the gamma ray detector and a shielding top plate configured to couple to the collar and at least partially retain the shielding insert in the collar.