Immersed Lens Downhole Refractometer for Multiphase Flow Accuracy

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Solution Overview

Problem

Existing downhole refractometers provide erroneous readings in multiphase flow environments, particularly when black oil is not quickly flushed from the window surface, leading to light absorption and reduced contrast.

Innovation Solution

The use of an immersed lens refractometer with a mirror and lens combination, where both the light source and detector are located on the same side of the lens within a single pressure housing, allowing for accurate refractive index measurement without moving parts or interference patterns.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a window interface is used for light reflection measurement, then the refractometer can measure refractive index, but erroneous readings occur in multiphase flow when black oil is not quickly flushed from the window surface

Engineering Contradiction:

Improverefractive index reading accuracyVSAvoidfluid coating on window surface

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a lens as an intermediary component between the light source and the fluid. Instead of using direct light reflection at a window interface, the lens focuses light through the fluid to a point, creating a localized measurement zone that is less susceptible to contamination from fluid coatings on external surfaces.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the traditional mechanical window interface reflection system with an optical lens-based transmission system. This substitution eliminates the need for light to reflect off a window surface, thereby removing the problem of fluid coating interference with the measurement.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If light reflection at window interface is used, then the measurement can be performed, but light absorption by black oil reduces contrast and causes erroneous readings

Engineering Contradiction:

Improvemeasurement reliabilityVSAvoidlight absorption

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The lens acts as an intermediary that focuses light through the fluid sample to a specific point, creating a concentrated measurement zone. This approach minimizes the total path length of light through the fluid, reducing overall light absorption by black oil while maintaining measurement reliability.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

Instead of using extensive light paths that would maximize light absorption, the patent employs a focused lens system that creates a localized measurement zone. This partial action approach measures refractive index at a specific focal point where light absorption is minimized, providing reliable readings even in the presence of black oil.

Inventive Principle:

Principle #16Partial or excessive action

3Ease of operation

If traditional refractometer design is used, then the device can function, but complex engineering and multiple components increase potential failure points

Engineering Contradiction:

Improvedevice simplicityVSAvoidnumber of components

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The patent merges the light source, lens, and detector into a single integrated housing. This consolidation reduces the number of separate components and interfaces, thereby simplifying the device engineering and reducing potential failure points while maintaining operational functionality.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The single housing contains multiple functional elements (light source, lens, detector) that work together to perform the refractive index measurement. This multi-functional design eliminates the need for separate components for each function, reducing overall device complexity while maintaining ease of operation.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 configuration simplifies engineering, reduces potential failure points, and provides more reliable refractive index readings by eliminating the effects of fluid coatings and improving light collection, even in challenging downhole environments.

Implementation Method 1

a lens, positioned at an end of the housing, the lens having a flat side and a curved side, the flat side positioned proximate the chamber to position the flat side closer to the light source than the curved side

Methodology Applied

Scientific EffectRefraction: Refraction

Implementation Method 2

a mirror, arranged outside the housing

Methodology Applied

Scientific EffectReflection: Reflection

Data Source

PatentUS12264581B2Immersed lens downhole refractometer

Publication Date: 2025.04.01 BAKER HUGHES OILFIELD OPERATIONS LLC

AI summary

An apparatus for detecting one or more properties of a downhole fluid includes a housing. The apparatus also includes a location-sensitive optical detector, arranged within a chamber formed by the housing. The apparatus further includes a light source, arranged within the chamber. The apparatus also includes a lens, positioned at an end of the housing, the lens preferably having a flat side and a curved side, the flat side positioned proximate the chamber to position the flat side closer to the light source than the curved side. The apparatus further includes a mirror, arranged outside the housing.