Nuclear Spin Gyroscope Orientation Sensing in Downhole Tools

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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, large dimensions, and limited operating temperature, particularly in ferrous casing environments.

Innovation Solution

A downhole orientation sensing system utilizing a nuclear spin gyroscope with an atomic comagnetometer optically pumped and interrogated from a remote location, employing optical waveguides to transmit light and minimize moving parts and temperature-sensitive components, allowing for accurate orientation sensing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If mechanical gyroscopes are used for downhole orientation sensing, then orientation measurement capability is provided, but mechanical complexity and rapidly spinning components interfere with sensitive tiltmeters and microseismic instruments

Engineering Contradiction:

Improveorientation measurement capabilityVSAvoidmechanical complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces mechanical gyroscopes with an optical gyroscope system that uses laser beams and optical waveguides to sense orientation. The system measures orientation by detecting changes in the interference pattern of laser beams traveling through different paths, eliminating all mechanical moving parts while maintaining measurement capability. This substitution resolves the contradiction by providing orientation measurement without mechanical complexity or interference with sensitive instruments.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If conventional gyroscopes are used, then orientation sensing is achieved, but they lack the ability to find true north direction and have large dimensions

Engineering Contradiction:

Improveorientation sensing capabilityVSAvoiddimensions

Core Design Contradiction:

Measurement precisionVSVolume of moving object

Solution Approach 1:

The patent uses optical waveguides that can be configured in three-dimensional paths within a compact housing. The laser beams travel through multiple reflections and bends in the waveguide structure, allowing the system to achieve the necessary optical path length for accurate orientation sensing while maintaining a small physical footprint. This dimensional approach resolves the contradiction by enabling accurate orientation sensing in a compact form factor.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent introduces a magnetic sensor as an intermediary component that works in conjunction with the optical gyroscope. The magnetic sensor detects the Earth's magnetic field to determine true north direction, while the optical gyroscope provides orientation sensing. This combination allows the system to find true north and maintain accurate orientation sensing in a compact package, resolving the contradiction between measurement capability and dimensions.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Measurement precision

If mechanical gyroscopes operate in downhole environments, then orientation data is provided, but they cannot operate effectively in ferrous casing and have limited acceptable operating temperature

Engineering Contradiction:

Improveorientation data accuracyVSAvoidoperating environment compatibility

Core Design Contradiction:

Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent replaces mechanical gyroscopes with an all-optical system that uses laser beams and optical waveguides enclosed in a non-ferrous housing. This optical system is immune to electromagnetic interference from ferrous casing and can operate at elevated downhole temperatures where mechanical components would fail. The substitution resolves the contradiction by providing orientation data accuracy while achieving adaptability to harsh downhole environments including ferrous casing and high temperature conditions.

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 system provides compact, temperature-resistant, and interference-free orientation sensing, enabling accurate determination of downhole instrument orientation without rapidly spinning components and automatic true north alignment.

Implementation Method 1

a downhole atomic comagnetometer which is optically pumped and interrogated from a remote location

Methodology Applied

Scientific EffectOptical pumping:

Implementation Method 2

at least one or more optical waveguides which transmit light from the surface control system and the atomic comagnetometer

Methodology Applied

Scientific EffectOptical waveguide transmission: Waveguide (optics)

Data Source

PatentEP2576977B1Downhole 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 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 at least one optical waveguide which transmits light between the atomic comagnetometer and a remote location. A method of sensing orientation of an instrument assembly in a subterranean well can include incorporating an atomic comagnetometer into the instrument assembly, and installing the instrument assembly in the well.