A method, system, processing equipment and storage medium for measuring sediment acoustic dissipation factor

Abstract

The present invention relates to a method, system, processing equipment and storage medium for measuring the acoustic dissipation factor of sediments. The method is characterized in that the method comprises: determining an excitation waveform for a simulation test on a pure waveguide phenomenon and an excitation waveform for an indoor transducer test on a test sample in a dissipation factor measurement system; based on the determined excitation waveform, performing a simulation test on the pure waveguide phenomenon to obtain a simulated receiving end voltage, and then determining a simulated maximum amplitude; based on the determined excitation waveform, performing an indoor transducer test on the test sample in the dissipation factor measurement system to obtain a wave velocity and a test receiving end signal, and then determining a test maximum amplitude; and calculating a dissipation factor that only considers absorption attenuation based on the simulated maximum amplitude and the test maximum amplitude. The present invention can be widely applied to the technical field of geotechnical testing.

Description

Technical Field

[0001] The present invention relates to the technical field of geotechnical testing, and in particular to a method, system, processing equipment and storage medium for measuring the acoustic wave dissipation factor of sediment. Background Art

[0002] As global energy demand continues to grow, the development of terrestrial and shallow-water oil and gas resources is approaching saturation. Global oil and gas resource development is shifting from these areas to the deep sea, leading to increasingly frequent deep-sea engineering activities. Because deep-sea sediments are located on the seafloor, it is difficult to detect the reserves and distribution of natural gas, oil, and other energy resources within them. Therefore, a new non-destructive deep-sea exploration method is needed. Acoustic wave detection can characterize the internal structure of geomaterials by inverting wave velocity and dissipation factor, making it valuable for detecting deep-sea energy reserves. However, the dissipation factor is affected by both geometric attenuation and absorption attenuation. Geometric attenuation is the energy dispersion caused by the continuous expansion of the wave propagation front, and the attenuation is related to the propagation distance. Absorption attenuation is related to the content and geometric distribution of gas or fluids within the material along the way and can characterize deep-sea energy resources. Therefore, the dissipation factor, which only considers absorption attenuation, is the key parameter for accurately reflecting the structural properties of sediments.

[0003] At present, indoor experiments based on transducers made of ceramic piezoelectric sheets have become a key means of studying the propagation of sound waves in geotechnical materials. However, current research mainly uses sinusoidal pulses as excitation, which can only calculate the wave velocity and usually cannot remove the influence of geometric attenuation. This poses a challenge to the accurate characterization of the internal structure of the soil. In addition, the traditional method of calculating the dissipation factor uses the amplitude of the initial excitation waveform as the initial amplitude, which usually cannot distinguish between geometric attenuation and absorption attenuation. The resulting dissipation factor is too large and has certain limitations.

[0004] Therefore, how to accurately calculate the dissipation factor that can characterize the internal structure of the reservoir is an urgent problem that needs to be solved by those skilled in the art. Summary of the Invention

[0005] In response to the above problems, the purpose of the present invention is to provide a method, system, processing equipment and storage medium for measuring the acoustic dissipation factor of sediments, which can accurately calculate the dissipation factor that can characterize the internal structure of the reservoir.

[0006] To achieve the above objectives, the present invention adopts the following technical solutions: In a first aspect, a method for measuring the acoustic dissipation factor of sediment is provided, comprising:

[0007] Determine the excitation waveform for the simulation test of the pure waveguide phenomenon and the excitation waveform for the indoor transducer test of the test specimen in the dissipation factor measurement system;

[0008] Based on the determined excitation waveform, the pure waveguide phenomenon is simulated to obtain the simulated receiving end voltage, and then the simulated maximum amplitude is determined;

[0009] Based on the determined excitation waveform, an indoor transducer test is conducted on the test specimen in the dissipation factor measurement system to obtain the wave velocity and the test receiving end signal, thereby determining the maximum test amplitude.

[0010] Based on the simulated maximum amplitude and the experimental maximum amplitude, the dissipation factor considering only the absorption attenuation is calculated.

[0011] Furthermore, the determination of the excitation waveform for the simulation test of the pure waveguide phenomenon and the excitation waveform for the indoor transducer test of the test sample in the dissipation factor measurement system includes:

[0012] Comsol multi-physics simulation software was used to simulate and measure the acoustic wave signals of the ceramic piezoelectric transducer under sinusoidal signals modulated by rectangular functions and sinusoidal signals modulated by Gaussian functions, respectively, to obtain simulated time domain schematics and simulated frequency domain schematics.

[0013] According to the simulation time domain schematic diagram and the simulation frequency domain schematic diagram, a sinusoidal signal modulated by a Gaussian function is determined as the excitation waveform for the simulation test of the pure waveguide phenomenon and the excitation waveform for the indoor transducer test of the test specimen in the dissipation factor measurement system.

[0014] Furthermore, the method of performing a simulation test on the pure waveguide phenomenon based on the determined excitation waveform to obtain a simulated receiving end voltage and then determine the simulated maximum amplitude includes:

[0015] Comsol multi-physics simulation software is used to simulate the pure waveguide phenomenon based on the determined excitation waveform to obtain the simulated receiving end voltage;

[0016] Using rectangular window function, extract the simulated first wave packet according to the simulated receiving end voltage;

[0017] Performing Fourier transform on the simulated first wave packet to obtain the simulated first wave packet after Fourier transform, and then obtaining the simulated maximum amplitude.

[0018] Furthermore, according to the inverse process derivation of the following formula, the inverse process V0, i.e. the analog receiving end voltage, is obtained:

[0019]

[0020] D=εE+eS

[0021] T=-eE+cS

[0022]

[0023] Wherein, V0 is the excitation voltage applied by the transmitting end of the transducer; t is the propagation time of the sound wave; T0 is the characteristic time; f0 is the characteristic frequency; E is the electric field strength; V is the voltage; is the gradient operator; D is the electric displacement; S is the strain; ε is the dielectric constant; e is the piezoelectric stress constant; T is the stress; c is the elastic stiffness coefficient; ρ is the density of the test sample; u is the displacement field; C is the elastic modulus of the test sample; V P is the compression wave velocity; μ is the Poisson's ratio of the test specimen; n is the normal direction vector; a is the acceleration of the test specimen; p is the total sound pressure; ρ a is the air density; c a is the wave speed in air.

[0024] Furthermore, the method of performing an indoor transducer test on a test sample in a dissipation factor measurement system based on the determined excitation waveform to obtain a wave velocity and a test receiving end signal, and then determining a maximum test amplitude, includes:

[0025] Conduct indoor transducer tests on the test specimens in the dissipation factor measurement system to obtain the test receiving end signal and wave velocity;

[0026] Using rectangular window function, extract the first wave packet of the test according to the signal of the test receiving end;

[0027] Perform Fourier transform on the first wave packet of the test to obtain the first wave packet of the test after Fourier transform, and then obtain the maximum amplitude of the test.

[0028] Furthermore, the indoor transducer test is performed on the test sample in the dissipation factor measurement system to obtain the test receiving end signal and wave velocity, including:

[0029] The signal generator generates a voltage applied across the ceramic piezoelectric transducer;

[0030] The transmitting end of the ceramic piezoelectric transducer transmits an acoustic wave signal to the test sample based on a determined excitation waveform, and the acoustic wave signal propagates through the test sample to the receiving end of the ceramic piezoelectric transducer;

[0031] The receiving signal of the receiving end of the ceramic piezoelectric transducer is amplified by the filter and then enters the oscilloscope to obtain the filtered test receiving end signal;

[0032] The computer records the excitation signal and the filtered test receiving end signal and calculates the wave velocity.

[0033] Furthermore, the dissipation factor Q that only considers absorption attenuation is A :

[0034]

[0035] Where Δt is the propagation time; f0 is the characteristic frequency of the excitation waveform; A T (f) is the maximum amplitude of the test; A G (f) is the simulated maximum amplitude.

[0036] In a second aspect, a system for measuring the acoustic dissipation factor of sediment is provided, comprising:

[0037] An excitation waveform determination module is used to determine the excitation waveform for a simulation test of a pure waveguide phenomenon and the excitation waveform for an indoor transducer test of a test specimen in a dissipation factor measurement system;

[0038] A simulation maximum amplitude determination module is used to simulate the test pure waveguide phenomenon based on the determined excitation waveform, obtain the simulated receiving end voltage, and then determine the simulation maximum amplitude;

[0039] A test maximum amplitude determination module is used to perform an indoor transducer test on the test sample in the dissipation factor measurement system based on the determined excitation waveform, obtain the wave velocity and the test receiving end signal, and then determine the test maximum amplitude;

[0040] The dissipation factor calculation module is used to calculate the dissipation factor considering only absorption attenuation based on the maximum amplitude of simulation and the maximum amplitude of test.

[0041] In a third aspect, a processing device is provided, comprising computer program instructions, wherein the computer program instructions, when executed by the processing device, are used to implement the steps corresponding to the above-mentioned method for measuring the acoustic dissipation factor of sediment.

[0042] In a fourth aspect, a computer-readable storage medium is provided, on which computer program instructions are stored, wherein the computer program instructions, when executed by a processor, are used to implement the steps corresponding to the above-mentioned method for measuring the acoustic dissipation factor of sediment.

[0043] The present invention has the following advantages due to the adoption of the above technical solution:

[0044] 1. The present invention solves the technical problem that the existing method for measuring the dissipation factor ignores the elimination of geometric attenuation, resulting in the inability of the dissipation factor to accurately characterize the interior of the geotechnical material.

[0045] 2. The present invention can calculate the dissipation factor that only considers absorption attenuation through a formula. The operation method is simple and effective, and can accurately calculate the dissipation factor that can characterize the internal structure of the reservoir in a relatively short time.

[0046] In summary, the present invention can be widely applied in the field of geotechnical testing technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiment below. The accompanying drawings are for illustration purposes only and are not to be considered as limiting the present invention. Throughout the drawings, the same reference numerals are used to denote the same components. In the drawings:

[0048] Figure 1 This is a flow chart of a method provided by one embodiment of the present invention;

[0049] Figure 2 Schematic diagram of a two-dimensional axisymmetric model established according to an embodiment of the present invention, wherein reference numeral 1 represents a transmitting end, reference numeral 2 represents a receiving end, reference numeral 3 represents a test specimen, reference numeral 4 represents an air domain, reference numeral 5 represents a perfectly matched layer, and reference numeral 6 represents an axis of symmetry.

[0050] Figure 3 This is a schematic diagram of a simulation time domain in which the excitation signal provided by an embodiment of the present invention is a sinusoidal signal modulated by a rectangular function;

[0051] Figure 4 1 is a schematic diagram of a simulation frequency domain in which the excitation signal provided by an embodiment of the present invention is a sinusoidal signal modulated by a rectangular function;

[0052] Figure 5 1 is a schematic diagram of a simulation time domain in which the excitation signal provided by an embodiment of the present invention is a sinusoidal signal modulated by a Gaussian function;

[0053] Figure 6 1 is a schematic diagram of a simulation frequency domain in which an excitation signal provided by an embodiment of the present invention is a sinusoidal signal modulated by a Gaussian function;

[0054] Figure 7 This is a time domain schematic diagram of the first wave packet of the extraction test provided by one embodiment of the present invention. DETAILED DESCRIPTION

[0055] Exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present invention are shown in the accompanying drawings, 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. Rather, these embodiments are provided to enable a more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.

[0056] It should be understood that the terms used herein are for the purpose of describing specific example embodiments only and are not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms "one", "an" and "said" as used herein may also be meant to include plural forms. The terms "comprise", "include", "contain" and "have" are inclusive and therefore specify the presence of stated features, steps, operations, elements and / or parts, but do not exclude the presence or addition of one or more other features, steps, operations, elements, parts, and / or combinations thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring them to be performed in the specific order described or illustrated, unless the order of execution is clearly indicated. It should also be understood that additional or alternative steps may be used.

[0057] Although the terms first, second, third, etc. can be used in the text to describe multiple elements, components, regions, layers and / or sections, these elements, components, regions, layers and / or sections should not be limited by these terms. These terms can only be used to distinguish an element, component, region, layer or section from another region, layer or section. Unless the context clearly indicates otherwise, terms such as "first", "second" and other numerical terms do not imply order or sequence when used in the text. Therefore, the first element, component, region, layer or section discussed below can be referred to as the second element, component, region, layer or section without departing from the teaching of the example embodiments.

[0058] At present, indoor experiments based on ceramic piezoelectric transducers have become a key means of studying the propagation of sound waves in geotechnical materials. However, current research mainly uses sinusoidal pulses as excitation, which can only calculate the wave velocity and usually cannot remove the influence of geometric attenuation. This poses a challenge to the accurate characterization of the internal structure of the soil. In addition, in the traditional method of calculating the dissipation factor, the amplitude of the initial excitation waveform is used as the initial amplitude, which usually cannot distinguish between geometric attenuation and absorption attenuation. The obtained dissipation factor is too large and has certain limitations. An embodiment of the present invention provides a method for measuring the dissipation factor of sediment acoustic waves, comprising: determining an excitation waveform for simulating a pure waveguide phenomenon and an excitation waveform for performing an indoor transducer test on a test sample in a dissipation factor measurement system; based on the determined excitation waveform, performing a simulation test on the pure waveguide phenomenon to obtain a simulated receiving end voltage, and then determining the simulated maximum amplitude; based on the determined excitation waveform, performing an indoor transducer test on the test sample in the dissipation factor measurement system to obtain the wave velocity and the test receiving end signal, and then determining the test maximum amplitude; and calculating the dissipation factor that only considers absorption attenuation based on the simulated maximum amplitude and the test maximum amplitude. The present invention solves or partially solves the technical problem that the measurement method of the dissipation factor in the prior art ignores the elimination of geometric attenuation, resulting in the inability of the dissipation factor to accurately characterize the interior of the geotechnical material. The total attenuation is measured by performing indoor acoustic experiments using a transducer, which includes both geometric attenuation and absorption attenuation. The pure waveguide effect is analyzed using Comsol multi-physics software to find out the influence of geometric attenuation. The first wave packet of the received signal of the simulation and experimental results is extracted, Fourier transformed, and the maximum amplitude is extracted. The dissipation factor considering only absorption attenuation is calculated using a formula. The operation method is simple and effective, and the technical effect of being able to accurately obtain the sediment dissipation factor in a relatively short time is achieved.

[0059] Example 1

[0060] like Figure 1 As shown, this embodiment provides a method for measuring the acoustic dissipation factor of sediment, comprising the following steps:

[0061] S1. Determine the excitation waveform for the simulation test of the pure waveguide phenomenon and the excitation waveform for the indoor transducer test of the test specimen in the dissipation factor measurement system, specifically:

[0062] S1.1. Comsol multi-physics simulation software is used to simulate and measure the acoustic wave signals of the ceramic piezoelectric transducer under sinusoidal signals modulated by rectangular functions and sinusoidal signals modulated by Gaussian functions, respectively, to obtain the simulated time domain schematic diagram and the simulated frequency domain schematic diagram.

[0063] Specifically, Comsol multi-physics field simulation software can also be used to simulate and measure the acoustic wave signals of the ceramic piezoelectric transducer under the sinusoidal signals modulated by the rectangular function, the sinusoidal signals modulated by the Gaussian function, and the sinusoidal signals modulated by the Ricker wavelet, respectively, to obtain the simulated time domain schematic diagram and the simulated frequency domain schematic diagram.

[0064] Specifically, the characteristic frequencies of the three excitation voltages, namely, the sinusoidal signal modulated by the rectangular function, the sinusoidal signal modulated by the Ricker wavelet, and the sinusoidal signal modulated by the Gaussian function, are all 400 kHz.

[0065] S1.2. Based on the simulation time domain diagram and the simulation frequency domain diagram, determine the sinusoidal signal modulated by the Gaussian function as the excitation waveform for the simulation test of the pure waveguide phenomenon and the excitation waveform for the indoor transducer test of the test specimen in the dissipation factor measurement system.

[0066] Specifically, in actual research, the test specimen has a boundary, and the sound wave will be reflected and refracted at the boundary, resulting in the dispersion and attenuation of the sound wave (waveguide effect). The speed of the wave propagating along a straight line (the first mode) and the wave propagating by reflection is different. Different wave packets can be observed at the received signal. The first wave packet is the wave with the fastest propagation speed, that is, the wave propagating along a straight line. The present invention finds that the choice of excitation waveform has an important influence on the extraction of wave packets. The present invention uses Comsol multi-physics field software to analyze the pure waveguide effect of the sound wave propagation process in the test specimen, and analyzes the influence of different excitation waveforms (sinusoidal signals modulated by rectangular functions, Ricker wavelets, and sine signals modulated by Gaussian functions) on the received signal, such as Figures 3 to 6 As shown in the figure, it is pointed out that compared with the traditional rectangular function modulated sinusoidal signal, the Gaussian function modulated sinusoidal signal has the smallest characteristic frequency loss when used as the excitation waveform, and the wave packets can be distinguished to calculate the dissipation factor and the flatness of the signal can be improved, making the energy distribution of the signal more uniform and improving the spectral characteristics of the signal, thereby better highlighting the characteristics of the signal and extracting the first wave packet. Based on the result, it is determined that the influence of pure geometric attenuation is analyzed by using the Gaussian function modulated sinusoidal signal as the excitation waveform.

[0067] Specifically, the sinusoidal signal f(t) modulated by the Gaussian function is:

[0068]

[0069] Among them, T0 is the characteristic time, f0 is the characteristic frequency of the excitation waveform; t is the propagation time of the sound wave; and e is the piezoelectric stress constant.

[0070] S2. Comsol multi-physics simulation software is used to simulate the pure waveguide phenomenon based on the determined excitation waveform to obtain the simulated receiving end voltage, and then determine the simulated maximum amplitude A. G(f) to characterize the geometric attenuation, specifically:

[0071] S2.1. Using Comsol multi-physics simulation software, based on the determined excitation waveform, simulate the pure waveguide phenomenon to obtain the simulated receiving end voltage.

[0072] Specifically, Comsol multi-physics simulation software was used to geometrically model the test specimen and the ceramic piezoelectric piece of the ceramic piezoelectric transducer, and a two-dimensional axisymmetric model was established, such as Figure 2 As shown, both the transmitting end 1 and the receiving end 2 of the ceramic piezoelectric transducer use cylindrical ceramic piezoelectric pieces (PZT-5A) with a diameter of 5 mm and a height of 0.5 mm. The test specimen 3 has a cylindrical structure with a diameter of 61.8 mm and a height of 20 mm. To account for the influence of air, an air domain 4 is set outside the two-dimensional axisymmetric model. The two-dimensional axisymmetric model has a symmetry axis 6. The test specimen parameters, the ceramic piezoelectric piece parameters, and the air parameters are all built-in parameters in the software. The wave velocity and density of the test specimen 3 are set to be consistent with the measurement results of the indoor transducer test. The air domain 4 is located between the test specimen 3 and the perfectly matched layer 5.

[0073] Specifically, according to the inverse process derivation of the following formulas (2) to (12), the analog receiving end voltage is obtained, with the parameter V R express:

[0074]

[0075] D=εE+eS (4)

[0076] T=-eE+cS (5)

[0077]

[0078] Wherein, V0 is the excitation voltage applied by the transmitting end of the transducer; t is the propagation time of the sound wave; T0 is the characteristic time; f0 is the characteristic frequency; E is the electric field strength; V is the voltage; is the gradient operator; D is the electric displacement; S is the strain; ε is the dielectric constant; e is the piezoelectric stress constant; T is the stress; c is the elastic stiffness coefficient; ρ is the density of the test sample; u is the displacement field; C is the elastic modulus of the test sample; V P is the compression wave velocity; μ is the Poisson's ratio of the test specimen; n is the normal direction vector; a is the acceleration of the test specimen; p is the total sound pressure; ρ a is the air density; c a is the wave speed in air.

[0079] The specific derivation process is: through the electrostatic physical field, an excitation voltage V0 is applied to the transmitting end of the transducer, and the receiving end of the transducer is grounded. The transducer can generate an electric field strength E; according to the constitutive relationship of the ceramic piezoelectric piece, that is, the second kind of piezoelectric equations: D i =ε ij E j +e iμ S μ and T λ =-e jλ E j +c λμ S μ ,where,i,j=1,2,3,λ,μ=1,2,...6,D i is the electric displacement, ε ij is the dielectric constant, E j is the electric field strength, e iμ is the piezoelectric stress constant, S μ is the strain, T λ is stress, e jλ is the piezoelectric stress constant, c λμ is the elastic stiffness coefficient; then, according to the balance equations of body force and body charge, i.e., formulas (6) and (7), the strain S generated by the transducer can be obtained; the displacement field u can be obtained through the acoustic wave equation (8). The above is the working principle of the transmitter of the transducer. The displacement is based on the geometric compatibility condition, that is, the displacement of the transducer and the test sample surface is the same, and the wave acts on the test sample. The test sample is assumed to be a uniform linear elastic material, that is, the absorption attenuation is not considered, and it has a constitutive relationship, i.e., formula (9); the elastic modulus C of the test sample can be obtained from the density ρ, the compression wave velocity V P and Poisson's ratio μ, which is expressed as formula (10); since the test specimen is assumed to be a linear elastic material, the stress T only undergoes geometric attenuation when passing through the test specimen. In addition, when the stress wave propagates to the boundary, reflection and refraction occur. This process is controlled by the equilibrium equation (11) and the wave equation (12). The stress T propagates through the test specimen to the receiving end transducer. The inverse process of the above process, that is, the inverse process V0 is obtained through the displacement field, which is the simulated receiving end voltage V R .

[0080] Specifically, when using Comsol multi-physics simulation software to simulate the pure waveguide phenomenon in the experiment, the parameters and dimensions of the test specimen must be set to be consistent with the indoor transducer test results in step S1, in order to make the simulated waveguide effect consistent with the experiment.

[0081] S2.2, using the rectangular window function, extract the simulated first wave packet f(t) according to the simulated receiving end voltage, as follows: Figure 7 shown.

[0082] S2.3. Perform Fourier transform (13) on the simulated first wave packet f(t) to obtain the simulated first wave packet F(ω) after Fourier transform, and then obtain the simulated maximum amplitude A G (f):

[0083]

[0084] A G (f)=max(F(ω)) (14)

[0085] Specifically, steps S1 and S2 can be performed simultaneously.

[0086] S3. Based on the determined excitation waveform, perform an indoor transducer test on the test sample in the dissipation factor measurement system to obtain the wave velocity and the test receiving end signal, and then determine the maximum test amplitude A. T (f) is used to characterize the total attenuation, which includes both geometric attenuation and absorption attenuation. At this time, the sound wave is affected by the combined effects of geometric attenuation and absorption attenuation, specifically:

[0087] S3.1. Perform an indoor transducer test on the test specimen in the dissipation factor measurement system to obtain the test receiving end signal and wave velocity (as modeling parameters).

[0088] Specifically, the dissipation factor measurement system includes an acoustic wave measurement device, a test bench and a data acquisition device. The acoustic wave measurement device includes a ceramic piezoelectric transducer, a signal generator, a filter and an oscilloscope. The test bench includes a sample setter, a laser rangefinder and a bracket. The data acquisition device includes a coaxial cable and a computer.

[0089] The ceramic piezoelectric transducer is equipped with a transmitter and a receiver. The transmitter is connected to a signal generator, which generates a voltage across the transducer. Based on a predetermined excitation waveform, the transducer transmits an acoustic signal to the test specimen. It also receives the acoustic vibration signal after it passes through the specimen and converts it into an electrical signal. The propagation of the acoustic wave through the specimen is analyzed to characterize the total attenuation. The receiver is connected to a filter, which amplifies and filters the amplitude of the test receiver signal. The filter is also connected to an oscilloscope, which receives and displays the filtered test receiver signal. A sample holder is used to position the test specimen. The holder has a through-hole for the transducer, ensuring close contact between the transducer and the specimen. A bracket is mounted on one side of the holder. A laser rangefinder is fixed to the bracket and aligned vertically with the specimen. The laser rangefinder determines the specimen dimensions and the extent to which the transducer is submerged within the specimen. The computer is connected to the oscilloscope via a coaxial cable to record the excitation signal and the filtered experimental receiving end signal and calculate the wave velocity.

[0090] The specific process of this step is as follows: a 400kHz Gaussian function modulated sinusoidal pulse waveform is introduced into the signal generator of the dissipation factor measurement system, and the Gaussian function modulated sinusoidal signal is used as the excitation waveform. The signal generator generates a voltage applied to both ends of the ceramic piezoelectric transducer. The transmitting end of the ceramic piezoelectric transducer transmits an acoustic wave signal to the test sample based on the determined excitation waveform. The acoustic wave signal propagates through the test sample to the receiving end of the ceramic piezoelectric transducer. The receiving signal of the receiving end of the ceramic piezoelectric transducer is amplified by 40dB through a filter and then enters the oscilloscope to obtain a filtered test receiving end signal. The excitation signal and the filtered test receiving end signal are recorded by a computer, and the wave velocity C is calculated. p :

[0091]

[0092] Wherein, L is the height of the test sample automatically measured by the laser rangefinder; L0 is the length of the transducer inserted into the test sample; t is the propagation time of the sound wave; and t0 is the relaxation time.

[0093] Specifically, the propagation time t of the sound wave can be obtained by displaying the time between the excitation signal and the first deflection of the received signal on an oscilloscope, the relaxation time t0 can be measured by connecting the ceramic piezoelectric transducers head-to-head, and the height L of the test sample and the length L0 of the transducer inserted into the test sample can be automatically measured by a laser rangefinder.

[0094] In some possible implementations, the characteristic frequency of the excitation waveform is 400 kHz.

[0095] In some possible implementations, the model of the signal generator is Keysight 33522B, and its purpose is to stimulate the required excitation signal through an externally programmed function.

[0096] S3.2. Use a rectangular window function to extract the first wave packet g(t) of the test based on the test receiving end signal.

[0097] S3.3. Perform Fourier transform (16) on the first wave packet g(t) of the test to obtain the first wave packet G(ω) after Fourier transform, and then obtain the maximum amplitude A of the test T (f):

[0098]

[0099] A T (f)=max(G(ω)) (17)

[0100] S4, according to the maximum amplitude of the simulation A G (f) and the maximum test amplitude A T (f), calculate the dissipation factor Q considering only absorption attenuationA .

[0101] Specifically, according to the simulated maximum amplitude A G (f) Maximum test amplitude A T (f) and the following formula (18), the geometric attenuation calculated by simulation is removed from the total attenuation measured by the test to distinguish the absorption attenuation from the geometric attenuation, and thus the dissipation factor Q considering only the absorption attenuation is calculated. A :

[0102]

[0103] Where Δt is the propagation time and f0 is the characteristic frequency of the excitation waveform.

[0104] This is because the maximum amplitude A obtained by the experiment T (f) The amplitude of the first wave packet of the received signal in the frequency domain and the following formula (19) can be used to obtain the dissipation factor Q of the total attenuation. T :

[0105]

[0106] Where A0(f) is the amplitude of the excitation signal.

[0107] And the maximum simulated amplitude A is obtained by G (f) is the amplitude of the first wave packet of the simulated received signal in the frequency domain and the following formula (20), the dissipation factor Q of the geometric attenuation can be obtained. G :

[0108]

[0109] Then only the dissipation factor Q of absorption attenuation is considered A The dissipation factor Q can be obtained from the total attenuation T Dissipation factor Q to eliminate geometric attenuation G , that is, the above formula (18) is finally obtained through the following formula (21):

[0110]

[0111] The dissipation factor is the key parameter for accurately reflecting the structural properties of the sediments. The operation method is simple and effective, easy to operate, and reasonably designed, and can accurately calculate the dissipation factor that can characterize the internal structure of the reservoir in a relatively short time.

[0112] Example 2

[0113] This embodiment provides a system for measuring the acoustic dissipation factor of sediments, comprising:

[0114] The excitation waveform determination module is used to determine the excitation waveform for the simulation test of the pure waveguide phenomenon and the excitation waveform for the indoor transducer test of the test sample in the dissipation factor measurement system.

[0115] The simulation maximum amplitude determination module is used to simulate the test pure waveguide phenomenon based on the determined excitation waveform, obtain the simulated receiving end voltage, and then determine the simulation maximum amplitude.

[0116] The test maximum amplitude determination module is used to perform an indoor transducer test on the test sample in the dissipation factor measurement system based on the determined excitation waveform, obtain the wave velocity and the test receiving end signal, and then determine the test maximum amplitude.

[0117] The dissipation factor calculation module is used to calculate the dissipation factor considering only absorption attenuation based on the maximum amplitude of simulation and the maximum amplitude of test.

[0118] The system provided in this embodiment is used to execute the above-mentioned method embodiments. Please refer to the above-mentioned embodiments for specific processes and detailed contents, which will not be repeated here.

[0119] Example 3

[0120] This embodiment provides a processing device corresponding to the method for measuring the sediment acoustic dissipation factor provided in Example 1. The processing device can be applicable to a client processing device, such as a mobile phone, laptop computer, tablet computer, desktop computer, etc., to execute the method of Example 1.

[0121] The processing device includes a processor, a memory, a communication interface, and a bus. The processor, memory, and communication interface are connected via the bus to facilitate communication between them. The memory stores a computer program executable on the processing device. When the processing device executes the computer program, it executes the method for measuring the acoustic dissipation factor of sediments provided in Example 1.

[0122] In some implementations, the memory may be a high-speed random access memory (RAM), and may also include a non-volatile memory, such as at least one disk storage.

[0123] In other implementations, the processor may be a central processing unit (CPU), a digital signal processor (DSP), or other general-purpose processors, which are not limited herein.

[0124] In addition, the logical instructions in the above-mentioned memory can be implemented in the form of a software functional unit and can be stored in a computer-readable storage medium when sold or used as an independent product. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0125] Those skilled in the art will understand that the structure of the above-mentioned computing device is only a partial structure related to the solution of the present invention and does not constitute a limitation on the computing device to which the solution of the present invention is applied. The specific computing device may include more or fewer components, or combine certain components, or have a different component arrangement.

[0126] Example 4

[0127] This embodiment provides a computer program product corresponding to the method for measuring the sediment acoustic dissipation factor provided in Example 1. The computer program product may include a computer-readable storage medium carrying computer-readable program instructions for executing the method for measuring the sediment acoustic dissipation factor described in Example 1.

[0128] Computer readable storage media can be tangible devices that hold and store instructions used by instruction execution devices. Computer readable storage media can be, for example, but not limited to, electronic storage devices, magnetic storage devices, optical storage devices, electromagnetic storage devices, semiconductor storage devices, or any combination thereof.

[0129] The above embodiment provides a computer-readable storage medium, whose implementation principle and technical effects are similar to those of the above method embodiment, and will not be repeated here.

[0130] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowcharts and / or block diagrams, as well as combinations of processes and / or blocks in the flowcharts and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowcharts and / or block diagrams. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0131] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0132] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0133] The above embodiments are only used to illustrate the present invention, wherein the structure, connection mode and manufacturing process of each component can be changed. Any equivalent transformations and improvements based on the technical solution of the present invention should not be excluded from the scope of protection of the present invention.

Claims

1. A method for measuring the acoustic dissipation factor of sediment, characterized in that: include: Determine the excitation waveform for the simulation test of the pure waveguide phenomenon and the excitation waveform for the indoor transducer test of the test specimen in the dissipation factor measurement system; Based on the determined excitation waveform, the pure waveguide phenomenon is simulated to obtain the simulated receiving end voltage, and then the simulated maximum amplitude is determined; Based on the determined excitation waveform, an indoor transducer test is conducted on the test specimen in the dissipation factor measurement system to obtain the wave velocity and the test receiving end signal, thereby determining the maximum test amplitude. Based on the simulated maximum amplitude and the experimental maximum amplitude, the dissipation factor considering only the absorption attenuation is calculated.

2. The method for measuring the acoustic dissipation factor of sediment according to claim 1, wherein: The determination of the excitation waveform for the simulation test of the pure waveguide phenomenon and the excitation waveform for the indoor transducer test of the test sample in the dissipation factor measurement system includes: Comsol multi-physics simulation software was used to simulate and measure the acoustic wave signals of the ceramic piezoelectric transducer under sinusoidal signals modulated by rectangular functions and sinusoidal signals modulated by Gaussian functions, respectively, to obtain simulated time domain schematics and simulated frequency domain schematics. According to the simulation time domain schematic diagram and the simulation frequency domain schematic diagram, a sinusoidal signal modulated by a Gaussian function is determined as the excitation waveform for the simulation test of the pure waveguide phenomenon and the excitation waveform for the indoor transducer test of the test specimen in the dissipation factor measurement system.

3. The method for measuring the acoustic dissipation factor of sediment according to claim 1, wherein: The method of performing a simulation test on the pure waveguide phenomenon based on the determined excitation waveform to obtain a simulated receiving end voltage and then determine the simulated maximum amplitude includes: Comsol multi-physics simulation software is used to simulate the pure waveguide phenomenon based on the determined excitation waveform to obtain the simulated receiving end voltage; Using rectangular window function, extract the simulated first wave packet according to the simulated receiving end voltage; Performing Fourier transform on the simulated first wave packet to obtain the simulated first wave packet after Fourier transform, and then obtaining the simulated maximum amplitude.

4. The method for measuring the acoustic dissipation factor of sediment according to claim 3, wherein: According to the inverse process derivation of the following formula, the inverse process V0 is obtained, which is the analog receiving end voltage: D=εE+eS T=-eE+eS Wherein, V0 is the excitation voltage applied by the transmitting end of the transducer; t is the propagation time of the sound wave; T0 is the characteristic time; f0 is the characteristic frequency; E is the electric field strength; V is the voltage; is the gradient operator; D is the electric displacement; S is the strain; ε is the dielectric constant; e is the piezoelectric stress constant; T is the stress; c is the elastic stiffness coefficient; ρ is the density of the test sample; u is the displacement field; C is the elastic modulus of the test sample; V P is the compression wave velocity; μ is the Poisson's ratio of the test specimen; n is the normal direction vector; a is the acceleration of the test specimen; p is the total sound pressure; ρ a is the air density; c a is the wave speed in air.

5. The method for measuring the acoustic dissipation factor of sediment according to claim 1, wherein: The method of performing an indoor transducer test on a test sample in a dissipation factor measurement system based on the determined excitation waveform to obtain a wave velocity and a test receiving end signal, and then determining a maximum test amplitude, includes: Conduct indoor transducer tests on the test specimens in the dissipation factor measurement system to obtain the test receiving end signal and wave velocity; Using rectangular window function, extract the first wave packet of the test according to the signal of the test receiving end; Perform Fourier transform on the first wave packet of the test to obtain the first wave packet of the test after Fourier transform, and then obtain the maximum amplitude of the test.

6. The method for measuring the acoustic dissipation factor of sediment according to claim 5, wherein: The indoor transducer test is performed on the test sample in the dissipation factor measurement system to obtain the test receiving end signal and wave velocity, including: The signal generator generates a voltage applied across the ceramic piezoelectric transducer; The transmitting end of the ceramic piezoelectric transducer transmits an acoustic wave signal to the test sample based on a determined excitation waveform, and the acoustic wave signal propagates through the test sample to the receiving end of the ceramic piezoelectric transducer; The receiving signal of the receiving end of the ceramic piezoelectric transducer is amplified by the filter and then enters the oscilloscope to obtain the filtered test receiving end signal; The computer records the excitation signal and the filtered test receiving end signal and calculates the wave velocity.

7. The method for measuring the acoustic dissipation factor of sediment according to claim 1, wherein: The dissipation factor Q, which only considers absorption attenuation, A : Where Δt is the propagation time; f0 is the characteristic frequency of the excitation waveform; A T (f) is the maximum amplitude of the test; A G (f) is the simulated maximum amplitude.

8. A system for measuring the acoustic dissipation factor of sediments, characterized in that: include: An excitation waveform determination module is used to determine the excitation waveform for a simulation test of a pure waveguide phenomenon and the excitation waveform for an indoor transducer test of a test specimen in a dissipation factor measurement system; A simulation maximum amplitude determination module is used to simulate the test pure waveguide phenomenon based on the determined excitation waveform, obtain the simulated receiving end voltage, and then determine the simulation maximum amplitude; A test maximum amplitude determination module is used to perform an indoor transducer test on the test sample in the dissipation factor measurement system based on the determined excitation waveform, obtain the wave velocity and the test receiving end signal, and then determine the test maximum amplitude; The dissipation factor calculation module is used to calculate the dissipation factor considering only absorption attenuation based on the maximum amplitude of simulation and the maximum amplitude of test.

9. A processing device, characterized in that: The method comprises computer program instructions, wherein when the computer program instructions are executed by a processing device, they are used to implement the steps corresponding to the method for measuring the sediment acoustic wave dissipation factor according to any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that The computer-readable storage medium stores computer program instructions, wherein the computer program instructions, when executed by a processor, are used to implement the steps corresponding to the method for measuring the acoustic dissipation factor of sediments according to any one of claims 1 to 7.

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