Noninvasive Acoustic Fluid Measurement Guided Wave Interference
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Solution Overview
Problem
In the oil/gas industry, noninvasive measurement of acoustical properties of fluids in pipes is hindered by interference from guided waves, which complicates the separation of direct path and circumferential signal propagation, especially in high water-cut fluids and crude oils, leading to inaccurate sound speed measurements.
Innovation Solution
The method involves subtracting the guided wave signal from the combined signal using techniques like Pulse Overlap Frequency Mixing (POFM), signal deconvolution, shaped pulses, and selective frequency excitation to isolate the direct path propagation, allowing for improved observation and measurement of acoustical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If noninvasive acoustic measurement is performed through pipe walls, then fluid properties can be measured without contamination or structural damage, but guided waves in the pipe wall interfere with direct path signal propagation, reducing measurement precision
Solution Approach 1:
The patent segments the received acoustic signal into two distinct components: guided waves propagating through the pipe wall and direct path waves traveling through the fluid. By applying signal processing techniques, the method separates these overlapping signals in the time-frequency domain, allowing independent analysis of each component to accurately determine fluid properties despite the interfering guided waves
Solution Approach 2:
The patent extracts the direct path signal from the combined received signal by removing the guided wave component. Through techniques such as signal subtraction and time-frequency analysis, the method isolates the fluid-borne acoustic signal from the wall-guided wave interference, enabling precise measurement of fluid acoustical properties
2Measurement precision
If signal processing techniques are applied to separate direct path and guided wave signals, then measurement precision improves, but device complexity and processing time increase
Solution Approach 1:
The patent replaces complex mechanical signal separation systems with computational signal processing methods. By using software-based techniques such as Fourier transforms, wavelet analysis, and time-frequency decomposition, the method achieves effective signal separation without requiring additional physical hardware components, thereby reducing device complexity while maintaining high measurement precision
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 enhances the signal-to-noise ratio and enables accurate determination of fluid properties by minimizing interference from guided waves, facilitating reliable measurements even in challenging fluid compositions and flow conditions.
Implementation Method 1
applying a frequency shaped pulse signal to a first ultrasonic transducer in vibrational communication with an outside surface of a pipe having a wall and through which the fluid is flowing, whereby vibrations are generated in the fluid and in the pipe wall
Implementation Method 2
detecting the generated vibrations on a second ultrasonic transducer disposed on the outside surface of the pipe diametrically opposite to the first ultrasonic transducer with fluid flowing through the pipe, wherein a first time-dependent electrical signal is obtained
Implementation Method 3
subtracting the second electrical signal from the first electrical signal whereby a time-dependent difference electrical signal is produced
Implementation Method 4
subtracting the guided wave signal from the combined signal using techniques like Pulse Overlap Frequency Mixing (POFM), signal deconvolution, shaped pulses, and selective frequency excitation to isolate the direct path propagation
Implementation Method 5
determining the time-of-flight of the generated vibrations between the first transducer and the second transducer using the difference electrical signal
Data Source
AI summary
Methods for noninvasive determination of acoustical properties of flowing in pipes having a large ratio (>10) of pipe diameter to wall thickness, and in highly attenuating fluids are described. When vibrations are excited on the outer surface of the wall of a pipe, the resulting vibrations propagate directly through the wall in a normal direction and through the pipe wall as guided waves, appearing on the opposite side of the pipe. This dual path propagation through pipes, where guided waves take the circumferential path in the wall of the pipe and may interfere with the time of-flight measurement obtained from the direct path through the fluid, is at least in part resolved by subtracting the signal from the guided wave from the combined signal, thereby permitting improved observation of the direct path propagation through the fluid.