Dual Velocity Flow Meter for Multiphase Slip
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Solution Overview
Problem
Existing flow meter technologies face challenges in accurately measuring individual phase flow rates of multiphase mixtures, particularly in hydrocarbon boreholes, due to velocity slip and limited range of flow regimes, leading to uncertainty and inefficiency in fluid component measurement.
Innovation Solution
A dual velocity method using electrical property signals from strategically positioned sensors to determine dispersed phase fluid velocity, free gas slug velocity, and fluid component volumetric flow rates, independent of flow regime, by solving predetermined mathematical relationships between measured signals and phase fractions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional flow meter technologies are used to measure multiphase mixtures, then the measurement process is simplified, but measurement precision deteriorates due to velocity slip and limited flow regime range
Solution Approach 1:
The patent divides the multiphase flow measurement into separate phase velocity measurements. Multiple sensors are positioned at different locations (e.g., center and wall regions) to independently measure velocities of different phases (gas slugs, liquid mixture). This segmentation allows accurate determination of individual phase flow rates by resolving the velocity slip between phases, directly improving measurement precision without requiring a completely complex new device architecture.
Solution Approach 2:
The measurement system is designed to handle multiple flow regimes (bubble flow, slug flow, annular flow) using the same dual-velocity measurement approach. The apparatus can measure both gas phase velocity and liquid mixture velocity across different flow conditions, making it universally applicable to various multiphase flow scenarios while maintaining measurement precision.
2Measurement precision
If velocity slip is not accounted for in flow measurement, then device complexity is reduced, but measurement precision deteriorates due to uncertainty in fluid component measurement
Solution Approach 1:
The patent explicitly segments the velocity measurement into two distinct components: gas phase velocity and liquid mixture velocity. By placing sensors at different radial positions (center vs. wall), the system captures the velocity slip phenomenon rather than averaging it out. This segmented measurement approach directly addresses velocity slip to improve precision, with the complexity managed through systematic sensor arrangement and signal processing.
Solution Approach 2:
The patent uses electrical property signals as an intermediary to indirectly measure phase velocities. Conductivity and capacitance sensors detect phase distribution and velocity characteristics without direct mechanical contact, allowing the system to resolve velocity slip through electrical property variations while avoiding the complexity of direct mechanical measurement systems.
3Measurement precision
If traditional water cut meters are used, then device complexity is minimized, but measurement precision deteriorates because water cut is not the same as water holdup when phases flow at different velocities
Solution Approach 1:
The patent segments the measurement into water cut determination and water holdup determination as distinct functions. Electrical property sensors measure the instantaneous water cut, while the dual velocity measurement system simultaneously determines gas and liquid velocities to calculate water holdup. This segmentation resolves the equivalence problem between water cut and water holdup by treating them as separate measurable quantities.
Solution Approach 2:
The system uses feedback from velocity measurements to correct the water holdup calculation. The measured gas and liquid velocities provide feedback that allows the system to convert water cut measurements into accurate water holdup values, accounting for the velocity difference between phases. This feedback mechanism improves precision without requiring fundamentally different sensing technology.
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 measurement of water cut, gas fraction, dispersed water fraction, and fluid component volumetric flow rates, reducing uncertainty and improving measurement precision across various flow conditions, thereby enhancing the monitoring and control of fluid production in hydrocarbon boreholes.
Implementation Method 1
measuring the capacitance or impedance of the fluid
Implementation Method 2
the dielectric constant of the oil continuous emulsion may be measured by a capacitance sensor
Implementation Method 3
the conductivity of the water continuous emulsion may be measured by a conductive sensor
Implementation Method 4
dispersed phase fluid velocity may be determined by cross-correlating periodic signals from a first pair of near conduit wall sensitive, adjacent positioned sensors with periodic signals from a second pair of near conduit wall sensitive, adjacent positioned sensors
Implementation Method 5
free gas phase or slug velocity may be determined by cross-correlating periodic signals from a first pair of conduit cross-sectional sensitive, diametrically positioned sensors with periodic signals from a second pair of conduit cross-sectional sensitive, diametrically positioned sensors
Data Source
AI summary
The present invention relates to a dual velocity method and apparatus for measuring flow rate of a fluid, independent of flow regime, the fluid having a plurality of components, at least one of which is capable of existing in an oil continuous phase emulsion in a conduit. The present invention only measures component fluid flow rates for components of the fluid which may comprise at least an oil continuous phase emulsion, but not a component comprising a water continuous phase emulsion. Velocity slip is directly determined by cross correlations of fluid electrical property signals which are used to measure the two most predominant velocities in a multiphase velocity distribution. Furthermore, phase velocity measurements are further improved by cross correlating signals from a pair of downstream sensors which are shifted a predetermined radial angle offset from corresponding pair of upstream diametrically positioned sensors.