Downhole Ultrasonic Probe for Multiphase Flow Measurement
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Solution Overview
Problem
Conventional downhole tools face challenges in accurately measuring flow properties of multiphase fluid flows due to limitations in turbine-based flow-meters and ultrasonic techniques, such as debris jamming, slow or high velocity measurements, non-Newtonian behavior, contamination susceptibility, and reduced accuracy from refraction and scattering effects in large boreholes.
Innovation Solution
A downhole tool equipped with an ultrasonic probe that focuses transmitted acoustic waves into a focal volume within 50 mm of the transmission/receiving surface, using a transducer unit with piezoelectric elements and an electronic controller to measure fluid flow properties, avoiding moving parts and enhancing local sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If ultrasonic waves are transmitted across a large borehole diameter, then flow features near the casing wall can be measured, but measurement accuracy deteriorates due to refraction and scattering effects
Solution Approach 1:
The patent applies local quality by creating a focused acoustic field with a defined focal volume at a specific distance from the transducer surface. This focal volume concentrates acoustic energy to provide enhanced local sensitivity for measuring flow features at specific locations, rather than attempting to measure across the entire borehole diameter. The focused measurement zone maintains high accuracy while the tool can be positioned to measure different radial locations.
Solution Approach 2:
The patent introduces an acoustic lens or phased array transducer configuration as an intermediary to focus and direct ultrasonic waves. This intermediary component shapes the acoustic field to create a concentrated focal volume, preventing beam diffusion and maintaining measurement accuracy. The phased array elements act as intermediaries to electronically focus and steer the acoustic beam without mechanical movement.
2Measurement precision
If turbine flow-meters are used to measure flow velocity, then velocity measurements can be obtained, but the rotation can be jammed by debris in the flow
Solution Approach 1:
The patent replaces the mechanical turbine-based flow measurement system with an ultrasonic acoustic field-based measurement system. Instead of using moving turbine blades that rotate with the flow, the invention uses ultrasonic waves transmitted through the fluid to measure flow velocity based on Doppler shift or transit time differences. This eliminates mechanical contact with debris while maintaining velocity measurement capability.
Solution Approach 2:
The patent extracts the measurement function from mechanical moving parts and implements it through acoustic wave propagation. By taking out the turbine mechanism entirely and using only stationary transducers that emit and receive acoustic waves, the system achieves debris resistance while preserving flow velocity measurement capability through non-contact acoustic sensing.
3Measurement precision
If local probes are used to measure phase holdups, then oil/water/gas holdups can be measured, but the probes are highly susceptible to contamination
Solution Approach 1:
The patent replaces mechanical contact-based local probes with ultrasonic acoustic wave propagation for phase holdup measurement. Instead of inserting physical probes into the flow that can be contaminated by sticky phases, the system uses acoustic waves transmitted through the fluid. The acoustic impedance differences between oil, water, and gas phases are detected, providing contamination-free phase holdup measurements.
4Measurement precision
If ultrasonic transducers are mounted on a logging tool body, then flow measurements can be performed, but the tool body diameter is large (17-25 mm)
Solution Approach 1:
The patent segments the ultrasonic measurement function from the main logging tool body by using deployable probe assemblies or modular transducer units. Instead of mounting large transducers directly on a substantial tool body, the system uses smaller, segmented transducer elements that can be deployed on slender probes or integrated into compact modular units, reducing the overall tool body diameter while maintaining measurement capability.
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 provides improved accuracy in measuring fluid flow properties by maintaining local sensitivity and avoiding the limitations of conventional methods, enabling precise characterization of multiphase fluid flows in subterranean boreholes.
Implementation Method 1
the transducer unit being further having at least one piezoelectric element for producing the acoustic waves
Implementation Method 2
the transducer unit being further configured to focus the transmitted acoustic waves into a focus volume located in the multiphase fluid flow, wherein the focus volume contains a position of maximum intensity of the transmitted acoustic waves, which position is spaced a distance of 50 mm or less from said surface
Implementation Method 3
the transducer unit being configured to transmit ultrasonic acoustic waves into the multiphase fluid flow at said surface and to receive reflections of the acoustic waves from the multiphase fluid flow at said surface
Implementation Method 4
to receive reflections of the acoustic waves from the multiphase fluid flow at said surface
Implementation Method 5
Ultrasonic techniques have been attempted in the past to measure flow velocity in production logging applications. The techniques used including particle tracking, Doppler imaging, transit time measurements
Data Source
AI summary
A downhole tool for measuring flow properties of a multiphase fluid flow at a location within a subterranean borehole includes at least one ultrasonic probe with a transducer unit having an ultrasound transmission/receiving surface which, in use, interfaces with the multiphase fluid flow. At the surface, the transducer unit transmits ultrasonic acoustic waves into the multiphase fluid flow and receives reflections of the acoustic waves from the multiphase fluid flow. At least one piezoelectric element of the transducer unit produces the acoustic waves. The transducer unit focuses the transmitted acoustic waves into a focus volume in the multiphase fluid flow, which focus volume contains a position of maximum intensity of the transmitted acoustic waves that is spaced a distance of 50 mm or less from the surface. An electronic controller operates the transducer unit, and a signal processor measures properties of the fluid flow from the received reflected acoustic waves.