Distributed Drill String Sensors for Accurate Positioning

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Current downhole sensors are primarily used for discrete regions and lack the capability to provide reliable, accurate positioning of the bottom hole assembly over a wide area, leading to potential errors in hydrocarbon recovery operations due to cumulative stressors and length changes in the drill string.

Innovation Solution

A distributed sensor system along the drill string, utilizing accelerometers and strain gauges to measure acceleration and strain, allowing for real-time calculation of the bottom hole assembly's actual location by transmitting data to a remote location for computational analysis.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If discrete downhole sensors are used for discrete regions, then device complexity is reduced, but measurement precision and positioning accuracy deteriorate

Engineering Contradiction:

Improvesensor configurationVSAvoidpositioning accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The drill string is divided into multiple discrete sensor units spaced at intervals along its length. Each sensor unit independently measures acceleration and strain at its local position, allowing the system to achieve high positioning accuracy through distributed measurements without requiring a single complex sensor system

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Strain gauges are used as intermediary elements that convert mechanical strain in the drill string into measurable electrical signals. These strain measurements serve as intermediaries to calculate both the actual string length and the position of the bottom hole assembly, bridging the gap between physical deformation and positional information

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of operation

If the drill string length is used to determine depth, then ease of operation is maintained, but reliability deteriorates due to cumulative stressors and length changes

Engineering Contradiction:

Improvedepth calculationVSAvoiddepth measurement

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The system continuously monitors strain and acceleration at multiple points along the drill string and uses this feedback to calculate the actual string length in real-time. This feedback mechanism compensates for cumulative stressors and length changes, maintaining reliable depth measurement without complicating the operational process

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent replaces the simple mechanical assumption that drill string length equals depth with a physics-based model that incorporates strain and acceleration measurements. By substituting direct mechanical measurement with sensor-based calculations, the system achieves higher reliability while maintaining ease of operation through automated computations

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If distributed sensor units are deployed along the drill string, then measurement precision improves, but device complexity increases

Engineering Contradiction:

Improvepositioning accuracyVSAvoidsensor system

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

Each sensor unit is designed as a universal module that performs multiple functions: measuring both acceleration and strain, providing positional information, and contributing to both string length calculation and bottom hole assembly positioning. This multi-functionality reduces the need for separate specialized sensors, thereby limiting the increase in device complexity while maintaining high measurement precision

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

Instead of using a single complex positioning system, the patent employs multiple simplified sensor units spaced along the drill string. Each unit is a simplified copy that measures local conditions, and the collective data from these copies enables accurate positioning through computational analysis, trading hardware complexity for data processing

Inventive Principle:

Principle #26Copying

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 approach provides accurate and real-time positioning of the bottom hole assembly, reducing errors in depth and azimuth, thereby enhancing the success of hydrocarbon recovery operations by accurately determining the assembly's location and stress conditions.

Implementation Method 1

a plurality of sensor units each sensing at least one of acceleration and strain in the string

Methodology Applied

Scientific EffectAcceleration measurement: Accelerometer

Implementation Method 2

a plurality of sensor units each sensing at least one of acceleration and strain in the string

Methodology Applied

Scientific EffectStrain measurement: Piezoresistive Effect

Data Source

PatentUS8188882B2Depth measurement by distributed sensors

Publication Date: 2012.05.29 BAKER HUGHES CO

AI summary

A downhole device, position verifiable string includes a downhole device; a string in operable communication with downhole device; and a plurality of sensor units each sensing at least one of acceleration and strain in the string and spaced from each other along the string from downhole device to a remote location of the drill string and method.