NMR Flow Meter with Differential Pressure Sensor for Gas Phase

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Solution Overview

Problem

Nuclear magnetic flowmeters face challenges in accurately measuring the flow of gaseous phases due to lower signal magnitude and higher flow speeds, which affects measurement accuracy, especially in multiphase media with low crude oil content, making it difficult to economically exploit oil sources with less than 5% crude oil content.

Innovation Solution

Combining a nuclear magnetic measuring device with a differential pressure flowmeter, where the differential pressure flowmeter measures the total multiphase medium and the nuclear magnetic flowmeter measures the liquid phases, allowing for the calculation of gaseous phase flow by subtracting the liquid phase measurement from the total, and using a Venturi tube design to enhance measurement accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If nuclear magnetic resonance measurement is used to measure gaseous phase flow, then the measurement can be performed non-invasively, but the measurement accuracy deteriorates due to lower signal magnitude and higher flow speeds

Engineering Contradiction:
Improvenon-invasive measurement capabilityVSAvoidgaseous phase flow measurement accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent combines nuclear magnetic resonance flow measurement with differential pressure flow measurement into a single integrated system. The NMR device measures liquid phase flow while the differential pressure device measures total flow (liquid + gas), allowing the gas phase flow to be calculated by subtraction. This merging resolves the contradiction by compensating for the weak NMR gas phase signals using the complementary differential pressure measurements.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent introduces a differential pressure flowmeter as an intermediary measurement device. This intermediary device measures the total multiphase flow, which serves as a reference that, when combined with NMR liquid phase measurements, enables accurate determination of gas phase flow that would be difficult to obtain with NMR alone.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Quantity of substance

If test separators are used to measure multiphase medium composition, then phase separation can be performed, but the ability to separate crude oil fractions below 5% is insufficient

Engineering Contradiction:
Improvephase separation capabilityVSAvoidlow crude oil content detection accuracy
Core Design Contradiction:
Quantity of substanceVSMeasurement precision

Solution Approach 1:

The patent replaces the mechanical separation system of test separators with a nuclear magnetic resonance-based measurement system. NMR technology detects the presence and quantity of crude oil phases through their magnetic resonance signals, enabling accurate measurement of very low crude oil contents (below 5%) without relying on mechanical phase separation, which fails at such low concentrations.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If additional measuring devices are combined to improve measurement accuracy, then the measurement precision for gaseous phase improves, but the device complexity increases

Engineering Contradiction:
Improvegaseous phase flow measurement accuracyVSAvoidmeasurement system structure
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent designs the integrated measurement system to perform multiple functions: the NMR device measures liquid phase flow and provides total flow information, the differential pressure device measures total flow, and together they determine gas phase flow. This multi-functionality reduces the need for separate dedicated devices for each measurement task, thereby limiting the increase in overall system complexity while achieving improved measurement precision.

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 combination significantly improves the measurement accuracy of the gaseous phase flow by accounting for the density and composition of the multiphase medium, enabling precise flow measurement even in low crude oil content sources.

Implementation Method 1

Measurement methods that influence the precession of atomic nuclei in a medium in the presence of a macroscopic magnetic field by excitation using a controlled magnetic field, and evaluate the effect of this influence, are called nuclear magnetic resonance measurement methods.

Methodology Applied
Scientific EffectNuclear magnetic resonance: Resonance

Implementation Method 2

the further measuring device is a differential pressure flowmeter (5), which is designed to measure the differential pressure of the medium (4) in the measuring tube (3)

Methodology Applied
Scientific EffectDifferential pressure measurement: Pressure Gradient

Implementation Method 3

using a Venturi tube design to enhance measurement accuracy

Methodology Applied
Scientific EffectVenturi effect: Venturi Effect

Data Source

PatentEP2733472B1Nuclear magnetic resonance flow measurement device and method for operating nuclear magnetic resonance flow measurement devices
Publication Date: 2020.01.01 KROHNE AG
  • EP2733472B1 patent drawingFigure 1~2

AI summary

The flow meter (1) has a nuclear magnetic measuring device (2) arranged around a measuring pipe (3), and an additional measuring device operating according to measuring principle i.e. nuclear magnetic measuring principle. The additional measuring device is designed as a differential pressure flow measuring device (5) for measuring differential pressure of multi-phase medium in the measuring pipe. Pressure gauges (8a, 8b) i.e. pressure sensors, are arranged at respective longitudinal points (6a, 6b) that are arranged in a longitudinal direction (7) of the measuring pipe. An independent claim is also included for a method for operating a nuclear magnetic volumetric flow meter.