Atomic Comagnetometer Downhole Orientation Sensing

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Solution Overview

Problem

Existing downhole orientation sensing technologies face challenges such as mechanical complexity, interference with sensitive instruments, inability to find true north direction, large dimensions, and limited operating temperature, especially in ferrous casing environments.

Innovation Solution

Incorporating an atomic comagnetometer and an optical source into the instrument assembly, which generates and adjusts pump and probe beams to sense orientation, utilizing a rubidium gas discharge laser and controller to adjust wavelengths based on light absorption, allowing for accurate orientation sensing in subterranean wells.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional mechanical gyroscopes are used for downhole orientation sensing, then orientation measurement can be achieved, but mechanical complexity increases and moving parts interfere with sensitive tiltmeters and microseismic instruments

Engineering Contradiction:

Improveorientation measurementVSAvoidmechanical complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces mechanical gyroscopes with an optical sensing system using a fiber optic coil and light source. The orientation measurement is achieved through optical phase modulation caused by the Sagnac effect, eliminating all moving mechanical parts while maintaining measurement capability. This substitution resolves the contradiction by removing mechanical complexity and interference with sensitive instruments.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If conventional gyroscopes are used, then orientation sensing is possible, but the dimensions of the device become large

Engineering Contradiction:

Improveorientation sensingVSAvoiddevice dimensions

Core Design Contradiction:

Measurement precisionVSVolume of moving object

Solution Approach 1:

The mechanical gyroscope is replaced with a compact fiber optic coil wound around a small form factor housing. The optical path length is achieved through multiple windings of thin fiber, enabling accurate orientation sensing in a significantly reduced volume compared to conventional mechanical gyroscopes.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If conventional orientation sensing systems are deployed in ferrous casing, then downhole measurement is achieved, but the system cannot operate effectively due to magnetic interference

Engineering Contradiction:

Improveorientation sensingVSAvoidmagnetic interference from ferrous casing

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent replaces magnetic-based orientation sensing with an optical sensing system that uses light propagation through a fiber optic coil. The Sagnac effect detected in the optical domain is immune to magnetic field interference from ferrous casing, allowing effective operation in previously inaccessible downhole environments.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

4Measurement precision

If conventional gyroscopes operate in downhole environments, then orientation measurement is possible, but the operating temperature range is limited

Engineering Contradiction:

Improveorientation measurementVSAvoidoperating temperature

Core Design Contradiction:

Measurement precisionVSTemperature

Solution Approach 1:

The mechanical gyroscope components are replaced with optical components including a light source, fiber optic coil, and photodetector. These optical components can be selected and designed to operate across a wide temperature range, including high-temperature downhole environments, thereby extending the operational temperature limits while maintaining measurement precision.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 provides a compact, temperature-resistant, and interference-minimized orientation sensing system capable of automatically orienting relative to true north, suitable for use in high-temperature downhole environments with minimal moving parts, enhancing the accuracy and reliability of downhole operations.

Implementation Method 1

adjusting an output wavelength of the optical source while the instrument assembly is positioned downhole. The adjusting step may further comprise adjusting the output wavelength in response to an output of a photodetector which measures transmission of the light through a gas cell.

Methodology Applied

Scientific EffectLight absorption: Absorption (EM radiation)

Implementation Method 2

Downhole orientation sensing with nuclear spin gyroscope

Methodology Applied

Scientific EffectNuclear spin gyroscope: Gyroscope

Data Source

PatentEP2622177B1Downhole orientation sensing with nuclear spin gyroscope

Publication Date: 2017.11.01 HALLIBURTON ENERGY SERVICES INC

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AI summary

Downhole orientation sensing with a nuclear spin gyroscope. A method of sensing orientation of an instrument assembly in a subterranean well can include incorporating an atomic comagnetometer and an optical source into the instrument assembly, and installing the instrument assembly in the well. A downhole orientation sensing system for use in conjunction with a subterranean well can include a downhole instrument assembly positioned in the well, the instrument assembly including an atomic comagnetometer and an optical source which transmits light to the atomic comagnetometer.