Magnetic Dogleg Severity Estimation Without Depth Data

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Solution Overview

Problem

Existing automated drilling methods for measuring dogleg severity in wellbores require a-priori knowledge of depth and rate of penetration, which is not readily available downhole.

Innovation Solution

A method using a roll-stabilized sensor housing with magnetic field sensors and magnets in a rotating collar to measure cross-axial magnetic fields, transforming these measurements into a frequency domain to estimate dogleg severity by identifying distortions and computing ratios of peak amplitudes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If single sensor measurements are used to measure dogleg severity, then measurement capability is improved, but the method requires a-priori knowledge of depth and rate of penetration which is not readily available downhole

Engineering Contradiction:
Improvedogleg severity measurement capabilityVSAvoiddepth and rate of penetration information
Core Design Contradiction:
Measurement precisionVSLoss of information

Solution Approach 1:

The patent introduces magnetic field sensors and magnets as intermediary elements to enable dogleg severity measurement without requiring depth and rate of penetration data. The magnetic field interactions provide a direct measurement mechanism that eliminates the need for these missing parameters, resolving the information loss problem while maintaining measurement capability

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If magnetic field sensors and magnets are deployed in a rotating collar with roll-stabilized sensor housing, then dogleg severity can be measured without depth or rate of penetration data, but device complexity increases

Engineering Contradiction:
Improvedownhole measurement accuracyVSAvoidsensor housing and collar assembly
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The rotating collar assembly serves multiple functions: it provides structural support for the magnetic field sensors, enables rotational movement for measurement, and stabilizes the sensor housing through roll-stabilization. This multi-functionality reduces the need for separate components, thereby managing device complexity while achieving accurate downhole measurements without requiring depth or rate of penetration data

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 accurate estimation of dogleg severity without requiring depth or rate of penetration data, improving downhole measurement precision.

Implementation Method 1

The sensor housing includes a magnetic field sensor deployed therein. The collar includes at least first and second magnets deployed thereon. The magnetic field sensor makes cross-axial magnetic field measurements while the collar rotates.

Methodology Applied
Scientific EffectMagnetic field: Magnetic Field

Data Source

PatentEP4722491A1Dogleg severity estimation via magnetic field measurements
Publication Date: 2026.04.08 SERVICES PETROLIERS SCHLUMBERGER SA
  • EP4722491A1 patent drawingFigure 1
  • EP4722491A1 patent drawingFigure 2A~2B
  • EP4722491A1 patent drawingFigure 3A~3B

AI summary

A method for estimating dogleg severity includes rotating the downhole tool in a wellbore. The downhole tool includes a roll stabilized sensor housing deployed in a rotating collar. The collar includes at least first and second magnets deployed thereon. Cross-axial magnetic field measurements are made using a magnetic field sensor deployed in the sensor housing while the collar rotates. A distortion is identified in the magnetic field measurements. The dogleg severity is estimated from the distortion.