NMR Flow Meter for Multiphase Fluid Measurement
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing multiphase flow meters based on differential pressure devices, such as venturi tubes, struggle to accurately measure flow rates in multiphase fluids with high oil viscosity due to variations in Reynolds number, emulsion type, and water-cut ratios, leading to significant measurement errors, especially in heavy oil applications.
Innovation Solution
A method that measures the Reynolds number of the multiphase mixture using a pipe section with known wall roughness, allowing for the calculation of a correct discharge coefficient for differential pressure-based flow meters, thereby improving the accuracy of flow rate measurements across varying viscosity and emulsion conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional test separator is used to measure multiphase flow rates, then the measurement can be performed with simple equipment, but the measurement accuracy deteriorates to ±5-10% and the system occupies valuable space and time
Solution Approach 1:
The patent replaces the mechanical test separator system with an electromagnetic measurement system using NMR (nuclear magnetic resonance) technology. This substitution eliminates the need for physical separation equipment while achieving superior measurement accuracy of ±2% or better for individual phase flow rates in multiphase streams.
Solution Approach 2:
The patent introduces an NMR flow meter as an intermediary measurement device that directly measures phase compositions and flow rates without requiring physical separation. This intermediary device provides accurate measurements while occupying minimal space and requiring no flow stabilization, resolving the contradiction between accuracy and system complexity.
2Measurement precision
If a test separator is used for allocation metering of multiple wells, then the flow rates can be measured, but dedicated test pipelines are required for each well increasing infrastructure complexity
Solution Approach 1:
The NMR flow meter serves as a universal measurement device that can be installed on a common pipeline to measure and allocate flow rates from multiple wells simultaneously. This eliminates the need for dedicated test pipelines for each well, reducing infrastructure complexity while maintaining accurate allocation metering for cost allocation among different operators.
3Reliability
If gravity or cyclone based separators are used to separate oil and water phases, then the separation can be achieved, but the separation fails when oil and water densities are similar and oil viscosity is high
Solution Approach 1:
The patent replaces mechanical separation methods (gravity or cyclone based) with electromagnetic NMR measurement technology. This substitution eliminates the fundamental limitation of density-dependent separation, allowing reliable measurement of oil and water phases even when their densities are similar or when oil viscosity is high, achieving both reliability and adaptability.
4Quantity of substance
If a venturi tube or differential pressure device is used to measure multiphase flow, then the total flow rate can be measured, but the individual phase flow rates cannot be determined accurately
Solution Approach 1:
The patent combines the total flow measurement capability of differential pressure devices with NMR technology for phase composition analysis. This merging allows the system to simultaneously measure both the total flow rate and the individual phase flow rates (oil, water, gas) accurately, resolving the contradiction between measuring total quantity and determining individual phase quantities.
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 enables accurate and reliable measurement of multiphase flow rates by accounting for changes in Reynolds number and emulsion type, reducing measurement errors to within ±5% and enabling effective monitoring of heavy oil applications.
Implementation Method 1
The invention uses a permanent installation of a flow meter based on nuclear magnetic resonance (NMR) to measure the flow rates of the individual phases
Implementation Method 2
The invention also uses a roughened pipe section to measure the Reynolds number of the multiphase mixture
Implementation Method 3
Other devises for measurement of flow rates of a multiphase mixture may be based on measurement of differential pressures across a restriction in the pipe such as a Venturi tube
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A method for determining the flow rates of a multi-component mixture in a pipe including a gas phase and a liquid phase, the method comprising the following steps: a. the flow rates of the individual components of the multi-component mixture are measured, b. the Reynolds number of the multi-component mixture is measured separately from the flow rate measurements, and c. based on the result from step a and b, a more accurate flow-rate of the individual components of the multi-component mixture is calculated. An apparatus for performing the method is also disclosed.