Downhole Strain Sensor Cantilever Beam Density Measurement

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Solution Overview

Problem

Conventional sensors used to measure fluid density downhole in boreholes are prone to damage from high flow rates and environmental conditions, making accurate density measurements challenging, especially when fluids change state due to temperature and pressure changes.

Innovation Solution

A downhole fluid density measurement tool employing strain sensors attached to a cantilever beam, where the strain changes due to buoyancy are measured to determine fluid density, with a machine learning model for calibration and reduced sensor requirements, allowing the tool to function even with fewer sensors and protect them from direct exposure to fluids.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional sensors are used to measure fluid density downhole, then density measurement capability is provided, but the sensors are damaged by high flow rates and environmental conditions

Engineering Contradiction:

Improvesensor durabilityVSAvoiddamage from high flow rates and environmental conditions

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

A protective housing structure is introduced as an intermediary between the strain sensor and the downhole fluid environment. The housing contains the sensor while allowing it to measure density through protective walls, isolating the sensor from direct exposure to harmful high flow rates and environmental conditions while maintaining measurement capability.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If multiple strain sensors are used to ensure accurate density measurement, then measurement accuracy is improved, but device complexity and cost increase

Engineering Contradiction:

Improvedensity measurement accuracyVSAvoidnumber of sensors required

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces conventional direct-contact density sensors with a strain sensor-based measurement system. The strain sensor measures mechanical strain on the protective housing caused by buoyancy forces from the fluid, and through machine learning calibration, this mechanical measurement is converted to fluid density. This substitution reduces the number of sensors needed while maintaining measurement accuracy.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the measurement parameter from direct fluid property measurement to mechanical strain measurement. By measuring the strain induced by buoyancy forces and using machine learning to correlate strain patterns with fluid density, the system achieves accurate density measurement with fewer sensors, reducing device complexity.

Inventive Principle:

Principle #35Parameter changes

3Duration of action of stationary object

If sensors are protected from direct fluid exposure, then sensor life is extended, but measurement capability may be compromised

Engineering Contradiction:

Improvesensor lifeVSAvoiddensity measurement accuracy

Core Design Contradiction:

Duration of action of stationary objectVSMeasurement precision

Solution Approach 1:

The patent replaces direct fluid interaction sensors with a mechanical strain measurement system. The protective housing isolates the sensor while buoyancy forces from the fluid still act on the housing structure, inducing measurable strain. This mechanical substitution allows the sensor to remain protected while maintaining measurement capability through indirect measurement of fluid properties.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent implements machine learning calibration that creates a feedback loop between strain measurements and known fluid density values. The system learns the relationship between strain patterns and fluid density through calibration with fluids of known density, then uses this learned model to accurately determine unknown fluid densities from strain measurements alone, ensuring measurement precision is maintained despite sensor protection.

Inventive Principle:

Principle #23Feedback

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 tool accurately measures fluid density and temperature downhole, extending sensor life and maintaining accuracy even with reduced sensor counts, enabling reliable data collection in harsh downhole environments.

Implementation Method 1

The measured strain changes when the cantilever beam is placed in a fluid due to buoyancy of the cantilever beam in the fluid

Methodology Applied

Scientific EffectBuoyancy: Archimedes' Principle (Buoyancy)

Data Source

PatentUS11879905B2Strain sensor based downhole fluid density measurement tool

Publication Date: 2024.01.23 HALLIBURTON ENERGY SERVICES INC

AI summary

Systems and methods for determining fluid density include receiving calibration data for a fluid density measurement tool. The fluid density measurement tool can include a cantilever beam and at least one strain sensor that is coupled to the cantilever beam. The cantilever beam can be housed in the fluid density measurement tool and is buoyed by a fluid that enters the fluid density measurement tool. The systems and methods measure strain values at the at least one strain sensor and determine a density of the fluid based on the calibration data, and the strain values measured at the at least one strain sensor.