Differential Velocity Sensor for Autonomous Downhole Tool Positioning

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Solution Overview

Problem

In subterranean well completion processes, reliable and efficient methods are needed to accurately determine the location and velocity of downhole tools, especially in environments where traditional electrical connections may fail due to insulation requirements and signal integrity issues.

Innovation Solution

An autonomous tool equipped with magnetic anomaly sensors and processors calculates velocity by comparing measurements from sensors spaced a fixed axial distance apart, allowing for precise distance calculation and execution of commands at predetermined locations, such as firing a perforating gun or severing tubulars, without relying on continuous electrical connections.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If electrical connections are used to activate the firing head, then the electrical signal can be transmitted from the surface, but the insulation requirements and signal integrity issues reduce reliability

Engineering Contradiction:

Improvereliability of electrical signal transmissionVSAvoidcomplexity of electrical connection system

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces the electrical field-based velocity sensor with a mechanical differential velocity sensor that uses physical mass, springs, and dampers to detect velocity through mechanical displacement. This mechanical substitution eliminates the need for complex electrical connections and insulation requirements while maintaining velocity measurement capability, thereby improving reliability without significantly increasing device complexity.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Extent of automation

If magnetic anomaly sensors are used for velocity calculation, then autonomous operation without wireline is enabled, but the requirement for accurate magnetic field measurements increases measurement difficulty

Engineering Contradiction:

Improveautonomous operation capabilityVSAvoiddifficulty of magnetic field measurement

Core Design Contradiction:

Extent of automationVSDifficulty of detecting and measuring

Solution Approach 1:

The patent introduces magnetic anomaly sensors as intermediary devices that detect magnetic field variations caused by casing collars or other downhole features. These sensors serve as mediators between the moving tool and the surrounding environment, enabling autonomous velocity calculation by measuring magnetic field changes without requiring direct electrical connections to the surface, thus achieving autonomous operation while managing measurement challenges.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent implements a feedback mechanism where magnetic anomaly sensor measurements are continuously processed to calculate velocity, which then feeds back into the control system to adjust tool operations. This closed-loop feedback enables autonomous operation by allowing the tool to self-regulate based on real-time environmental measurements, overcoming the complexity of magnetic field measurement through iterative processing and correction.

Inventive Principle:

Principle #23Feedback

3Measurement precision

If two magnetic anomaly sensors are spaced a fixed axial distance apart for velocity calculation, then accurate velocity determination is achieved, but the length of the sensor assembly increases

Engineering Contradiction:

Improveprecision of velocity measurementVSAvoidlength of sensor assembly

Core Design Contradiction:

Measurement precisionVSLength of moving object

Solution Approach 1:

The patent arranges the two magnetic anomaly sensors at a fixed axial distance apart along the length of the tool assembly, utilizing the spatial dimension to enable velocity calculation through differential measurement. By positioning sensors in sequence along the axial dimension rather than clustering them, the system achieves precise velocity measurement while minimizing the overall length increase, as the sensor spacing is optimized to balance measurement accuracy with compact assembly design.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

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 solution enables accurate tool positioning and execution of tasks within a ±10-foot zone, reducing surface equipment needs and failure modes, and allows for autonomous operation without a wireline, enhancing the reliability and efficiency of downhole operations.

Implementation Method 1

a first magnetic anomaly sensor located within the top housing, a second magnetic anomaly sensor located within the bottom housing and located a fixed axial distance from the first magnetic anomaly sensor

Methodology Applied

Scientific EffectMagnetic anomaly detection: Magnetic Field

Data Source

PatentUS11668187B2Differential velocity sensor

Publication Date: 2023.06.06 HUNTING TITAN INC

AI summary

A method, system, and apparatus for determining the location of a tool traveling down a wellbore by measuring a first borehole magnetic anomaly with respect to time at two known locations on a tool, comparing the time difference between the two measurements, then calculating the velocity of the tool based on the comparison and then further calculating the distance traveled by the tool in the wellbore based on the velocity calculation.