Method for testing calibration polarization direction of transverse wave transducer, transverse wave transducer and transverse wave velocity testing method

Abstract

The invention belongs to the field of geophysical exploration and rock physical simulation, and discloses a method for testing a calibration polarization direction of a transverse wave transducer, the transverse wave transducer and a transverse wave velocity testing method. The method comprises the following steps: utilizing a high-voltage pulse generator to send out a high-voltage pulse excitation signal to excite a transverse wave transducer; meanwhile, the high-voltage pulse generator is used for outputting a synchronous signal to a control processing terminal and an A / D of the laser Doppler vibration meter, so that the laser Doppler vibration meter carries out surface scanning on the excited transverse wave transducer, and a polarization energy spectrum of the excited transverse wave transducer is obtained; analyzing the polarization energy spectrum to obtain the transverse wave polarization direction, and further calibrating the position of the transverse wave polarization direction on the transverse wave transducer. According to the method, the polarization direction of the transverse wave transducer can be quickly and accurately calibrated, the time can be saved, the working efficiency can be improved, and help is provided for subsequent research on rock physical test analysis.

Description

Technical Field

[0001] The present invention belongs to the fields of geophysical exploration and rock physics simulation, and more specifically, relates to a method for testing and calibrating the polarization direction of a shear wave transducer, a shear wave transducer, and a method for testing the shear wave velocity. Background Art

[0002] Seismic waves are divided into body waves and surface waves. The longitudinal wave P and the shear wave S both belong to the range of body waves. The shear wave is further divided into a vertically polarized shear wave and a horizontally polarized shear wave. ① Vertically polarized shear wave. It refers to the shear wave energy vibrating within the vertical plane of the wave propagation direction, denoted as the SV wave. It can be converted into a longitudinal wave at the interface. The converted wave (a seismic wave that propagates as a longitudinal wave in part of the path and as a shear wave in part of the path) used in exploration is exactly the shear wave converted from the longitudinal wave, denoted as the P - SV wave. ② Horizontally polarized shear wave. It refers to the horizontal component of the shear wave, or a shear wave with only horizontal vibration, denoted as the SH wave. It does not produce wave conversion at the interface. Shear wave seismic exploration can be divided into the converted wave method and the horizontally polarized shear wave reflection method. The converted wave method does not require special equipment and has a greater exploration depth, but the incident path of the longitudinal wave and the reflection path of the vertically polarized shear wave after conversion are asymmetric, and data processing is relatively difficult. The data processing and interpretation methods of the horizontally polarized shear wave reflection method are the same as those of the longitudinal wave method and are relatively simple, so it has been widely adopted. Shear wave exploration generally specifically refers to the horizontally polarized shear wave reflection method exploration.

[0003] However, when testing a rock sample, a shear wave transducer (the transmitting probe and / or receiving probe of the rock sample) needs to be rotated and docked to obtain the maximum energy of the shear wave (since the shear wave has polarization, rotation and docking are required to obtain the wave with the polarization direction of the shear wave). However, due to the different complexities of the bedding of the rock sample, it is often impossible to obtain the most effective waveform, making the testing work encounter many difficulties. The shear wave velocity plays a crucial role in seismic forward modeling, fluid prediction, and AVO analysis. The shear wave velocity is also an essential and indispensable link in the pre-stack and multi-wave inversion processes. Rock physics modeling technology predicts and measures the geophysical characteristics of rocks by studying the characteristics of rock lithology, pore structure, fluid properties, formation temperature, and pressure, calculates the pore weakness using the measured longitudinal and shear wave velocities, and finally combines the actual data and verifies it using the known data.

[0004] Therefore, aiming at the difficulties and problems existing in the identification of the polarization direction of the shear wave transducer, there is an urgent need to propose a method for quickly testing and calibrating the polarization direction of the shear wave transducer. Summary of the Invention

[0005] The object of the present invention is to propose a method for calibrating the polarization direction of a shear wave transducer, a shear wave transducer, and a shear wave velocity measurement method in view of the deficiencies of the prior art. The present invention can quickly and accurately calibrate the polarization direction of the shear wave transducer. By using the method of the present invention, time can be saved, work efficiency can be improved, and help can be provided for subsequent research on rock physics test and analysis.

[0006] To achieve the above object, in the first aspect of the present invention, a method for calibrating the polarization direction of a shear wave transducer is provided. The method includes the following steps:

[0007] Use a high-voltage pulse generator to send out a high-voltage pulse excitation signal to excite the shear wave transducer;

[0008] At the same time, use the high-voltage pulse generator to send a synchronous signal to the control processing terminal and A / D output of the laser Doppler vibrometer, so that the laser Doppler vibrometer performs a surface scan on the excited shear wave transducer to obtain the polarization energy map of the excited shear wave transducer;

[0009] Analyze the polarization energy map to obtain the shear wave polarization direction, and then calibrate the position of the shear wave polarization direction on the shear wave transducer.

[0010] In the second aspect of the present invention, a shear wave transducer calibrated with the shear wave polarization direction obtained by the above method is provided.

[0011] In the third aspect of the present invention, a shear wave velocity measurement method is provided. The method includes the following steps:

[0012] Obtain two identical shear wave transducers as described above;

[0013] Place the two shear wave transducers on both sides of a rock sample relatively. Use one of the two shear wave transducers as a shear wave probe for exciting ultrasonic waves, and the other as a shear wave probe for receiving ultrasonic waves;

[0014] Use a high-voltage pulse generator to send out a high-voltage pulse excitation signal to excite the shear wave probe for emitting ultrasonic waves;

[0015] There is no need to rotate the two shear wave transducers to find the resonance direction. The shear wave probe for receiving ultrasonic waves receives and outputs the waveform to A / D acquisition, and the shear wave velocity is obtained through calculation.

[0016] The beneficial effects of the technical solution of the present invention are as follows:

[0017] The present invention conducts calibration research on the polarization direction of shear wave transducers using a laser Doppler vibrometer, that is, adopts the method of surface scanning with a laser Doppler vibrometer to receive the polarization energy map of shear wave transducers, effectively examines the energy response characteristics of shear wave transducers, and realizes the rapid calibration of the shear wave polarization direction. After clarifying the polarization direction, when testing rock samples, the shear wave transducer can measure the shear wave polarization direction of the rock sample without rotating the direction.

[0018] The present invention can rapidly and accurately calibrate the polarization direction of shear wave transducers. The method of the present invention can save time and improve work efficiency, and provide assistance for the subsequent research on rock physics test analysis, that is, based on the calibration of these polarization directions, the wave field characteristics of the core can be accurately tested and the wave field propagation mechanism in the core under complex conditions can be analyzed, providing support for rock physics research.

[0019] The present invention can obtain the energy response characteristics of shear wave transducers, analyze the wave field characteristics through a laser Doppler vibrometer, and thus can test the shear wave transducers.

[0020] Other features and advantages of the present invention will be described in detail in the subsequent specific implementation section. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] By describing the exemplary embodiments of the present invention in more detail in conjunction with the drawings, the above and other objects, features, and advantages of the present invention will become more obvious. Among them, in the exemplary embodiments of the present invention, the same reference numerals generally represent the same components.

[0022] Figure 1 FIG. shows the position and structure schematic diagram of each device in a method for testing and calibrating the polarization direction of a shear wave transducer provided in Embodiment 1 of the present invention.

[0023] Figure 2 FIG. shows the position and structure schematic diagram of each device in a method for testing and calibrating the polarization direction of a shear wave transducer provided in Embodiment 2 of the present invention.

[0024] Figure 3 FIG. shows the position and structure schematic diagram of each device in a method for testing and calibrating the polarization direction of a shear wave transducer provided in Embodiment 4 of the present invention.

[0025] Figure 4 FIG. shows the polarization energy map obtained by a method for testing and calibrating the polarization direction of a shear wave transducer provided in Embodiment 1 of the present invention.

[0026] Figure 5Shows the shear wave waveform corresponding to the polarization energy map obtained by a method for calibrating the polarization direction of a shear wave transducer provided in Embodiment 1 of the present invention (times (ms) is time, in milliseconds, and voltage (mV) is voltage, in millivolts).

[0027] Figure 6 Shows the position of the shear wave polarization direction calibrated by a method for calibrating the polarization direction of a shear wave transducer provided in Embodiment 1 of the present invention.

[0028] The reference numerals are explained as follows:

[0029] Shear wave probe 1 for exciting ultrasonic waves; high-voltage pulse generator 2; control processing terminal and A / D 3; laser Doppler vibrometer 4; shear wave probe 5 for receiving ultrasonic waves; rock sample 6. Detailed implementation manners

[0030] The preferred embodiments of the present invention will be described in more detail below. Although the preferred embodiments of the present invention are described below, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to make the present invention more thorough and complete, and to fully convey the scope of the present invention to those skilled in the art.

[0031] The first aspect of the present invention provides a method for calibrating the polarization direction of a shear wave transducer, and the method includes the following steps:

[0032] Use a high-voltage pulse generator to emit a high-voltage pulse excitation signal to excite the shear wave transducer;

[0033] Meanwhile, use the high-voltage pulse generator to output a synchronization signal to the control processing terminal and A / D of the laser Doppler vibrometer, so that the laser Doppler vibrometer performs a surface scan on the excited shear wave transducer to obtain the polarization energy map of the excited shear wave transducer;

[0034] Analyze the polarization energy map to obtain the shear wave polarization direction, and then calibrate the position of the shear wave polarization direction on the shear wave transducer.

[0035] According to the present invention, preferably, the shear wave transducer is a shear wave probe for exciting ultrasonic waves.

[0036] According to the present invention, preferably, the pulse width of the high-voltage pulse excitation signal for exciting the shear wave transducer is the resonant frequency of the shear wave transducer.

[0037] In the present invention, as a preferred solution, the method for calibrating the polarization direction of the shear wave transducer includes:

[0038] Physically connect the high-voltage pulse generator to the shear wave transducer so that the high-voltage pulse generator can send a high-voltage pulse excitation signal to the shear wave transducer, thereby exciting the shear wave transducer;

[0039] Physically connect the high-voltage pulse generator to the control processing terminal and A / D of the laser Doppler vibrometer so that the high-voltage pulse generator can output a synchronization signal to the control processing terminal and A / D of the laser Doppler vibrometer;

[0040] Debug the matching output parameters of the high-voltage pulse generator and the shear wave transducer, and use the high-voltage pulse generator to send a high-voltage pulse excitation signal to excite the shear wave transducer; at the same time, use the high-voltage pulse generator to output a synchronization signal to the control processing terminal and A / D of the laser Doppler vibrometer, so that the laser Doppler vibrometer performs a surface scan on the excited shear wave transducer, and obtains the polarization energy map of the excited shear wave transducer through data acquisition by the control processing terminal and A / D;

[0041] Analyze the polarization energy map obtained by the laser Doppler vibrometer to obtain the shear wave polarization direction, and then calibrate the position of the shear wave polarization direction on the shear wave transducer.

[0042] According to the present invention, preferably, the shear wave transducer includes a shear wave probe for exciting ultrasonic waves and a shear wave probe for receiving ultrasonic waves;

[0043] According to the present invention, preferably, the method includes the following steps:

[0044] Place the rock sample between the shear wave probe for exciting ultrasonic waves and the shear wave probe for receiving ultrasonic waves;

[0045] Use the high-voltage pulse generator to send a high-voltage pulse excitation signal to excite the shear wave probe for exciting ultrasonic waves;

[0046] At the same time, use the high-voltage pulse generator to output a synchronization signal to the control processing terminal and A / D of the laser Doppler vibrometer, so that the laser Doppler vibrometer performs a surface scan on the shear wave probe for exciting ultrasonic waves and the shear wave probe for receiving ultrasonic waves, and obtains the polarization energy maps of the two probes;

[0047] Analyze the polarization energy map to obtain the shear wave polarization direction, and then calibrate the position of the shear wave polarization direction on the two probes.

[0048] According to the present invention, preferably, the synchronization signal is a 5V TTL level output by the high-voltage pulse generator at the same time when it sends a high-voltage pulse excitation signal to trigger the start of A / D acquisition.

[0049] According to the present invention, preferably, after the laser Doppler vibrometer performs a surface scan on the excited shear wave transducer, data acquisition is carried out through the control processing terminal and the A / D to obtain the polarization energy map of the excited shear wave transducer.

[0050] The second aspect of the present invention provides a shear wave transducer for calibrating the shear wave polarization direction obtained by the method described above.

[0051] The third aspect of the present invention provides a method for testing the shear wave velocity, and the method includes the following steps:

[0052] Obtain two identical shear wave transducers as described above;

[0053] Arrange the two shear wave transducers opposite to each other on both sides of the rock sample, and use one of the two shear wave transducers as a shear wave probe for exciting ultrasonic waves, and the other as a shear wave probe for receiving ultrasonic waves;

[0054] Use a high-voltage pulse generator to send a high-voltage pulse excitation signal to excite the shear wave probe for emitting ultrasonic waves;

[0055] The two shear wave transducers do not need to rotate to find the resonance direction anymore. The shear wave probe for receiving ultrasonic waves receives and outputs the waveform to the A / D for acquisition, and the shear wave velocity is obtained through calculation.

[0056] According to the present invention, preferably, the method for calculating the shear wave velocity includes: reading the time from transmission to reception, and dividing the length of the rock sample by the time to obtain the shear wave velocity.

[0057] The present invention is specifically described below through embodiments.

[0058] Embodiment 1

[0059] This embodiment provides a method for testing the calibration polarization direction of a shear wave transducer, as Figure 1 shown, wherein the shear wave transducer in this embodiment is the shear wave probe 1 for exciting ultrasonic waves.

[0060] The method includes the following steps:

[0061] Physically connect the high-voltage pulse generator 2 to the shear wave probe 1 for exciting ultrasonic waves, so that the high-voltage pulse generator 2 can send a high-voltage pulse excitation signal to the shear wave probe 1 for exciting ultrasonic waves, thereby exciting the shear wave probe 1 for exciting ultrasonic waves;

[0062] Physically connect the high-voltage pulse generator 2 to the control processing terminal and the A / D 3 of the laser Doppler vibrometer 4, so that the high-voltage pulse generator 2 can output a synchronization signal to the control processing terminal and the A / D 3 of the laser Doppler vibrometer 4;

[0063] Use the high-voltage pulse generator 2 to send out a high-voltage pulse excitation signal to excite the shear wave probe 1 that generates ultrasonic waves;

[0064] At the same time, use the high-voltage pulse generator 2 to output a synchronization signal to the control processing terminal and A / D 3 of the laser Doppler vibrometer 4, so that the laser Doppler vibrometer 4 performs a surface scan on the shear wave probe 1 that generates ultrasonic waves, and obtains the polarization energy map of the shear wave probe 1 that generates ultrasonic waves through data acquisition by the control processing terminal and A / D 3, as Figure 4 shown;

[0065] Analyze the polarization energy map to obtain the shear wave polarization direction, and then calibrate the position of the shear wave polarization direction on the excitation probe, as Figure 6 shown.

[0066] The synchronization signal is a 5V TTL level output by the high-voltage pulse generator at the same time as it sends out the high-voltage pulse excitation signal.

[0067] Embodiment 2

[0068] This embodiment provides a method for testing and calibrating the polarization direction of a shear wave transducer. As Figure 2 shown, where the shear wave transducer in this embodiment is the shear wave probe 5 that receives ultrasonic waves.

[0069] The method includes the following steps:

[0070] Physically connect the high-voltage pulse generator 2 to the shear wave probe 5 that receives ultrasonic waves, so that the high-voltage pulse generator 2 can send out a high-voltage pulse excitation signal to the shear wave probe 5 that receives ultrasonic waves, and then excite the shear wave probe 5 that receives ultrasonic waves;

[0071] Also physically connect the high-voltage pulse generator 2 to the control processing terminal and A / D 3 of the laser Doppler vibrometer 4, so that the high-voltage pulse generator 2 can output a synchronization signal to the control processing terminal and A / D 3 of the laser Doppler vibrometer 4;

[0072] Use the high-voltage pulse generator 2 to send out a high-voltage pulse excitation signal to excite the shear wave probe 5 that receives ultrasonic waves;

[0073] At the same time, use the high-voltage pulse generator 2 to output a synchronization signal to the control processing terminal and A / D 3 of the laser Doppler vibrometer 4, so that the laser Doppler vibrometer 4 performs a surface scan on the shear wave probe 5 that receives ultrasonic waves, and obtains the polarization energy map of the probe through data acquisition by the control processing terminal and A / D 3;

[0074] Analyze the polarization energy map to obtain the shear wave polarization direction, and then calibrate the position of the shear wave polarization direction on the shear wave probe 5 that receives ultrasonic waves.

[0075] The synchronization signal is a 5V TTL level output simultaneously when the high-voltage pulse generator emits a high-voltage pulse excitation signal.

[0076] Embodiment III

[0077] This embodiment provides a method for testing and calibrating the polarization direction of a shear wave transducer. Among them, the shear wave transducer in this embodiment includes a shear wave probe 1 for exciting ultrasonic waves and a shear wave probe 5 for receiving ultrasonic waves.

[0078] The method includes the following steps:

[0079] Place the rock sample 6 between the shear wave probe 1 for exciting ultrasonic waves and the shear wave probe 5 for receiving ultrasonic waves;

[0080] Physically connect the high-voltage pulse generator 2 to the shear wave probe 1 for exciting ultrasonic waves, so that the high-voltage pulse generator 2 can send a high-voltage pulse excitation signal to the shear wave probe 1 for exciting ultrasonic waves, thereby exciting the shear wave probe 1 for exciting ultrasonic waves;

[0081] Also physically connect the high-voltage pulse generator 2 to the control processing terminal of the laser Doppler vibrometer 4 and the A / D 3, so that the high-voltage pulse generator 2 can output a synchronization signal to the control processing terminal of the laser Doppler vibrometer 4 and the A / D 3;

[0082] Use the high-voltage pulse generator 2 to send a high-voltage pulse excitation signal to excite the shear wave probe 1 for exciting ultrasonic waves;

[0083] At the same time, use the high-voltage pulse generator 2 to output a synchronization signal to the control processing terminal and the A / D 3, so that the laser Doppler vibrometer 4 performs a surface scan on the shear wave probe 1 for exciting ultrasonic waves and the shear wave probe 5 for receiving ultrasonic waves, and obtains the polarization energy maps of the two probes through data acquisition by the control processing terminal and the A / D 3;

[0084] Analyze the polarization energy maps to obtain the shear wave polarization direction, and then calibrate the position of the shear wave polarization direction on the shear wave probe 1 for exciting ultrasonic waves and the shear wave probe 5 for receiving ultrasonic waves.

[0085] The synchronization signal is a 5V TTL level output simultaneously when the high-voltage pulse generator emits a high-voltage pulse excitation signal.

[0086] Embodiment IV

[0087] This embodiment provides a method for testing the shear wave velocity, as Figure 3 shown, the method includes the following steps:

[0088] Obtain two shear wave transducers that are exactly the same as those in Embodiment I;

[0089] Two shear wave transducers are oppositely arranged on both sides of the rock sample 6. One of the two shear wave transducers is used as the shear wave probe 1 for exciting ultrasonic waves, and the other is used as the shear wave probe 5 for receiving ultrasonic waves.

[0090] Use a high-voltage pulse generator to send out a high-voltage pulse excitation signal to excite the shear wave probe 1 for exciting ultrasonic waves.

[0091] The two shear wave transducers do not need to be rotated to find the resonance direction. The shear wave probe for receiving ultrasonic waves receives and outputs the waveform to A / D acquisition, and the shear wave velocity is obtained through calculation.

[0092] Among them, the method for calculating the shear wave velocity includes: reading out the time from transmission to reception, and dividing the length of the rock sample by the time.

[0093] Comparative example

[0094] This comparative example provides a method for testing the shear wave velocity, and the method includes the following steps:

[0095] Obtain two completely identical shear wave transducers that have not been processed by the method of the present invention.

[0096] Two shear wave transducers are oppositely arranged on both sides of the rock sample 6. One of the two shear wave transducers is used as the shear wave probe 1 for exciting ultrasonic waves, and the other is used as the shear wave probe 5 for receiving ultrasonic waves.

[0097] Use a high-voltage pulse generator to send out a high-voltage pulse excitation signal to excite the shear wave probe 1 for exciting ultrasonic waves.

[0098] The two shear wave transducers need to be rotated to find the resonance direction. The shear wave probe for receiving ultrasonic waves receives and outputs the waveform to A / D acquisition, and the shear wave velocity is obtained through calculation.

[0099] Among them, the method for calculating the shear wave velocity includes: reading out the time from transmission to reception, and dividing the length of the rock sample by the time.

[0100] The above has described the embodiments of the present invention. The above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes are obvious to those of ordinary skill in the art in the technical field without departing from the scope and spirit of the described embodiments.

Claims

1. A method for testing the polarization direction of a shear wave transducer. It is characterized in that The method comprises the following steps: A high-voltage pulse generator is used to emit a high-voltage pulse excitation signal to excite the shear wave transducer; At the same time, the high-voltage pulse generator is used to output a synchronization signal to a control processing terminal and an A / D of the laser Doppler vibrometer, so that the laser Doppler vibrometer performs a surface scan on the excited shear wave transducer to obtain a polarization energy spectrum of the excited shear wave transducer; The polarization energy spectrum is analyzed to obtain the shear wave polarization direction, and then the position of the shear wave polarization direction is calibrated on the shear wave transducer.

2. The method for testing a shear wave transducer and calibrating the polarization direction according to claim 1, in, The shear wave transducer is a shear wave probe for exciting ultrasonic waves; The pulse width of the high-voltage pulse excitation signal that excites the shear wave transducer is the resonant frequency of the shear wave transducer.

3. The method for testing a shear wave transducer and calibrating the polarization direction according to claim 1, in, The shear wave transducer comprises a shear wave probe for exciting ultrasonic waves and a shear wave probe for receiving ultrasonic waves.

4. The method for testing a shear wave transducer and calibrating the polarization direction according to claim 3, in, The method comprises the following steps: The rock sample is arranged between the shear wave probe for exciting the ultrasonic wave and the shear wave probe for receiving the ultrasonic wave; Utilize a high-voltage pulse generator to emit a high-voltage pulse excitation signal to excite the shear wave probe that excites the ultrasonic wave; At the same time, the high-voltage pulse generator is used to output a synchronization signal to a control processing terminal and an A / D of the laser Doppler vibrometer, so that the laser Doppler vibrometer performs a surface scan on the shear wave probe for exciting ultrasonic waves and the shear wave probe for receiving ultrasonic waves, and obtains polarization energy spectra of the two probes; The polarization energy spectrum is analyzed to obtain the shear wave polarization direction, and then the position of the shear wave polarization direction is calibrated on the two probes.

5. The method for testing a shear wave transducer and calibrating the polarization direction according to claim 1 or 4, in, The pulse width of the high-voltage pulse excitation signal of the shear wave probe that excites the ultrasonic wave is the resonance frequency of the shear wave probe that excites the ultrasonic wave.

6. The method for testing a shear wave transducer and calibrating the polarization direction according to claim 1 or 4, in, The synchronization signal is a 5V TTL level output by the high-voltage pulse generator while the high-voltage pulse excitation signal is emitted to stimulate the start of A / D acquisition.

7. The method for testing a shear wave transducer and calibrating the polarization direction according to claim 1, in, After the laser Doppler vibrometer performs surface scanning on the excited shear wave transducer, data is collected through the control processing terminal and A / D to obtain the polarization energy spectrum of the excited shear wave transducer.

8. A shear wave transducer with calibrated shear wave polarization direction obtained by the method described in claims 1-7.

9. A method for testing shear wave velocity, It is characterized in that The method comprises the following steps: Obtaining two identical shear wave transducers as described in claim 8; Two shear wave transducers are arranged opposite to each other on two sides of the rock sample, one of the two shear wave transducers is used as a shear wave probe for exciting ultrasonic waves, and the other is used as a shear wave probe for receiving ultrasonic waves; Using a high-voltage pulse generator to emit a high-voltage pulse excitation signal to excite the shear wave probe that emits ultrasonic waves; The two shear wave transducers no longer need to rotate to find the resonance direction. The shear wave probe that receives the ultrasonic wave receives and outputs the waveform to the A / D for collection, and the shear wave velocity is obtained through calculation.

10. The shear wave velocity testing method according to claim 9, in, The method for calculating the shear wave velocity includes: reading the time from emission to reception, dividing the time by the length of the rock sample, and obtaining the shear wave velocity.

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