Artificial Toolface Reference System for Directional Drilling

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Solution Overview

Problem

In directional drilling, especially in vertical or near-vertical wells, traditional methods like magnetic toolface and gyroscopes face limitations due to high magnetic latitudes and interference, as well as cost and reliability concerns, making it difficult to determine accurate toolface angles for borehole placement and steering.

Innovation Solution

An artificial toolface reference system is introduced, which includes a power supply, a reference conductor with an insulated and uninsulated portion, and a guidance sensor with magnetometers, generating a reference magnetic field along the conductor to provide a reliable directional reference for borehole steering.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If magnetic toolface is used for directional reference, then toolface determination is possible, but accuracy deteriorates at high magnetic latitudes or where magnetic interference is present

Engineering Contradiction:

Improvetoolface determination capabilityVSAvoidtoolface angle accuracy

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The patent introduces an artificial magnetic field generated by a current-carrying conductor as an intermediary reference system. Instead of relying on the Earth's magnetic field which is subject to interference, a controlled magnetic field is created through a conductor positioned in the wellbore, serving as a mediator that provides a stable reference for toolface determination independent of external magnetic conditions

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the reference parameter from the Earth's magnetic field to an artificially generated magnetic field. By controlling the current through the conductor, the magnetic field parameters (strength, direction) can be optimized and maintained stable, providing a reliable reference that is not affected by magnetic latitude or external interference

Inventive Principle:

Principle #35Parameter changes

2Power

If current is provided through a conductor in the wellbore to generate reference magnetic field, then reference magnetic field strength is improved, but current leakage increases

Engineering Contradiction:

Improvereference magnetic field strengthVSAvoidcurrent leakage

Core Design Contradiction:

PowerVSLoss of energy

Solution Approach 1:

The patent divides the conductor into two distinct segments: an insulated portion and an uninsulated portion. The insulated portion prevents current leakage along the conductor surface, while the uninsulated portion allows controlled current discharge to the formation. This segmentation enables the system to maintain high magnetic field strength from the current through the conductor while minimizing energy loss through leakage

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies different properties to different parts of the conductor. The insulated portion has electrical insulation properties to prevent leakage, while the uninsulated portion has direct electrical contact with the formation to allow controlled current discharge. This local differentiation of properties optimizes both magnetic field generation and current management

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

This system enhances the accuracy of toolface determination by reducing current leakage and generating a stronger reference magnetic field, improving borehole placement and steering in challenging drilling conditions, particularly in vertical or near-vertical wells.

Implementation Method 1

providing a current with the power supply through the reference conductor, the ground, and the ground point such that a reference magnetic field is generated along the reference conductor

Methodology Applied

Scientific EffectElectromagnetic field generation: Electromagnetic Induction

Implementation Method 2

measuring the reference magnetic field with a magnetometer positioned outside of the reference wellbore

Methodology Applied

Scientific EffectMagnetic field detection: Magnetometer

Data Source

PatentUS9938819B2Reducing or preventing dissipation of electrical current and associated magnetic signal in a wellbore

Publication Date: 2018.04.10 APPLIED TECHNOLOGIES ASSOCIATES INC

AI summary

An artificial toolface reference system includes a power supply providing current to a ground lead and a reference lead. A ground point is coupled to the ground lead and in electrical connection with the ground. A reference wellbore includes a reference conductor in electrical connection with the ground. The reference conductor is in electrical connection with the reference lead. The reference conductor includes an uninsulated portion and an insulated portion having an insulating layer positioned thereabout. A guidance sensor positioned outside the reference wellbore includes at least one magnetometer. The power supply may be used to provide a current through the reference conductor, into the ground through the uninsulated portion, and the ground point such that a reference magnetic field is generated along the reference conductor. The guidance sensor may measure the reference magnetic field with a magnetometer. An artificial magnetic toolface may be calculated therefrom.