System and method for measuring rock elastic wave dispersion and attenuation characteristics

Abstract

The application discloses a rock elastic wave frequency dispersion and attenuation characteristic measurement system and method, and relates to the technical field of rock mechanics, and can be used for measuring the rock elastic wave frequency dispersion and attenuation characteristic of a rock sample. The measurement system comprises an axial pressure control chamber, the lower part of the axial pressure control chamber is provided with a confining pressure bin, the pressure application end of the axial pressure control chamber is located at the upper part of the confining pressure bin, the inside of the confining pressure bin is further provided with a probe body, the probe body is used for bonding with a rock sample, the inside of the confining pressure bin is further provided with a positioning and sealing device used for placing the rock sample, heating fins are further installed on the inner wall of the confining pressure bin, the positioning and sealing device is further connected with an exciter through an excitation pipeline, and a force sensor is installed on the excitation pipeline. By pre-embedding an ultrasonic signal generating device in the probe body, the problem that a sample cannot be repeatedly tested in an ultrasonic frequency band during a medium and low frequency band test is solved, a closed loop control servo hydraulic loading mode is adopted for the axial pressure controller and the confining pressure controller to replace a traditional gas pressure application mode, the target pressure can be quickly and accurately reached, and the safety of the experimental process can be ensured under high confining pressure.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of rock elastic wave dispersion and attenuation characteristics measuring instrument in middle, low frequency case, more specifically, the present application is mainly related to a kind of rock elastic wave dispersion and attenuation characteristics measuring system and method. BACKGROUND

[0002] In geophysical exploration, the method for obtaining elastic wave dispersion and attenuation characteristics mainly includes seismic exploration, acoustic logging and laboratory measurement. First, the traditional laboratory velocity measurement is usually carried out in the MHz frequency range, while acoustic logging is carried out in the 10KHz frequency range, and ground seismic is carried out in the 0-100Hz frequency range. There are significant differences in measurement frequency among different methods. Today, challenging exploration work requires comprehensive use of all types of data for quantitative interpretation. However, the dispersion of velocity in different frequency ranges makes data integration difficult. The rock elastic wave dispersion and attenuation characteristics cross-band test procedure is divided into ultrasonic frequency band and middle, low frequency band two parts, however, the middle, low frequency test needs to paste aluminum probe on both ends of the sample and seal the sample with glue, which makes the low frequency test sample unable to be tested again in the ultrasonic frequency band, hindering repeated experiments. At the same time, the existing middle-low frequency test instrument also has the following problems: (1) The stress-strain method is usually used for middle, low frequency test. The strain signal of this method is very weak, usually only a few micro-strains. Any system cannot completely avoid noise, even if repeated measurement, the effective signal can be overwhelmed by strong background noise. (2) Gas medium is used for pressurization, the operation environment is dangerous, and the stress environment of rock cannot be simulated stably. (3) The degree of automation is low, some are completely manually operated. SUMMARY

[0003] One of the purposes of the present application is to provide a rock elastic wave dispersion and attenuation characteristics measuring system and method to solve the technical problems of weak strain signal in similar test methods in the prior art, and the middle-low frequency test sample cannot be repeatedly tested in the ultrasonic frequency band.

[0004] To solve the above technical problems, the present application adopts the following technical solutions:

[0005] The application provides a rock elastic wave dispersion and attenuation characteristic measurement system, which comprises an axial pressure control chamber, a confining pressure bin is arranged at the lower portion of the axial pressure control chamber, the pressure applying end of the axial pressure control chamber is located at the upper portion of the confining pressure bin, a probe body is further arranged in the confining pressure bin, the probe body is used for bonding with a core sample, a positioning and sealing device for placing the core sample is further arranged in the confining pressure bin, and the positioning and sealing device corresponds to the pressure applying end of the axial pressure control chamber; heating sheets are further arranged on the inner wall of the confining pressure bin; the positioning and sealing device is further connected with an exciter through an excitation pipeline; a force sensor is arranged on the excitation pipeline; the confining pressure bin is connected with a hole pressure loader through a hole pressure pipeline, the confining pressure bin is further connected with a pressure relief pipeline, and a pressure relief valve is arranged on the pressure relief pipeline; the pressure applying end of the hole pressure pipeline is used for communicating with the inner hole of the core sample; a pressure relief sensor is arranged on the pressure relief pipeline; the confining pressure bin is connected with a confining pressure loader through a confining pressure pipeline, and the axial pressure control chamber is connected with an axial pressure loader through an axial pressure pipeline; a hole pressure sensor is arranged on the hole pressure pipeline, a confining pressure sensor is arranged on the confining pressure pipeline, and an axial pressure sensor is arranged on the axial pressure pipeline; strain gauges are adhered to the probe body, the strain gauges are further used for adhering to the core sample, the strain gauges are connected with a data acquisition box through a serial interface, and the data acquisition box is connected with a computer respectively through the force sensor, the pressure relief sensor, the hole pressure sensor, the confining pressure sensor and the axial pressure sensor; the computer is further connected with a function generator, and the function generator is connected with the exciter through a signal amplifier; and an ultrasonic signal generating device is further integrated in the probe body.

[0006] As preferred, the further technical scheme is that the exciter is arranged below the positioning and sealing device.

[0007] The further technical scheme is that the hole pressure loader comprises an oil cylinder body, a piston is arranged in the oil cylinder body, the piston is connected with a stepping motor through a shaft coupling, the stepping motor is further connected with a speed controller, the stepping motor and the speed controller are connected with the computer, and the pressurizing medium in the hole pressure pipeline is silicon oil; the confining pressure loader and the axial pressure sensor have the same structure as the hole pressure loader.

[0008] The further technical scheme is that the data acquisition box has a central controller, the central controller is connected with a memory and an A / D converter, the A / D converter is connected with the strain gauges, and the central controller is connected with the computer.

[0009] The further technical scheme is that the core sample is wrapped by a pouring sealant.

[0010] The further technical scheme is that the ultrasonic signal generating device is made of piezoelectric ceramics.

[0011] The application further provides a method for measuring rock elastic wave dispersion and attenuation characteristics, which uses the measuring system and comprises the following steps:

[0012] Step A, placing the elastic wave dispersion and attenuation core sample into the positioning and sealing device.

[0013] Step B, then installing the confining pressure bin and starting the pore pressure loader, confining pressure loader and axial pressure loader to respectively apply pore pressure, confining pressure and axial pressure to the core sample in the positioning and sealing device.

[0014] Step C, starting the ultrasonic signal generating device in the probe body and the exciter to excite high-frequency signals and medium and low-frequency signals to the core sample.

[0015] Step D, collecting data of the core sample by the computer through the force sensor, pressure relief sensor, pore pressure sensor, confining pressure sensor and axial pressure sensor.

[0016] Step E, collecting real-time stress signals of the plurality of strain gauges by the data collection box and transmitting the signals to the computer, and obtaining the energy spectrum of the seismic source by the computer through the cross-correlation interference algorithm of two signals in the frequency domain.

[0017] The attenuation characteristic curve is calculated through the phase difference between the mutual relationship of the continuous signals of the same frequency at any two positions of the collected core sample.

[0018] Further, the shape of the core sample is a rectangular body or a cylindrical body, and the strain gauges are adhered to the surface of the core sample according to the same distance.

[0019] Compared with the prior art, one of the beneficial effects of the application is that the ultrasonic signal generating device is pre-embedded in the probe body, which solves the problem that the sample in the medium and low-frequency band test cannot be repeatedly tested in the ultrasonic frequency band, and the closed-loop control servo hydraulic loading mode is used to replace the traditional gas pressurization mode, which can quickly and accurately reach the target pressure, and can ensure the safety of the experimental process under high confining pressure. At the same time, the internal temperature field can be more stable after the pressurizing medium is changed from gas to silicone oil. At the same time, the interference method is introduced into the processing of the medium and low-frequency signals. The signal accuracy is higher and more stable by processing the strain signals arranged in a specific manner in the medium and low-frequency sample. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 It is a structure schematic diagram of the measuring system for illustrating one embodiment of the application.

[0021] Figure 2 It is a structure schematic diagram of the core sample for illustrating one embodiment of the application.

[0022] Figure 3 Fig. 1 is a schematic view of an end surface structure of a probe body in an embodiment of the present application.

[0023] Figure 4 Fig. 2 is a graph of a measured data velocity curve versus frequency in an embodiment of the present application.

[0024] Figure 5 Fig. 3 is a graph of a measured data attenuation curve versus frequency in an embodiment of the present application.

[0025] In the figure, 1 is a confining pressure pipeline, 2 is an axial pressure control chamber, 3 is a confining pressure chamber, 4 is a heating sheet, 5 is a core sample, 6 is a probe body, 7 is a positioning and sealing device, 8 is a communication serial port, 9 is an excitation pipeline, 10 is a pressure relief pipeline, 11 is a force sensor, 12 is an exciter, 13 is a pore pressure loader, 14 is an axial pressure loader, 15 is a confining pressure loader, 16 is a data acquisition box, 17 is a pressure relief sensor, 18 is a pressure relief valve, 19 is a confining pressure sensor, 20 is an axial pressure sensor, 21 is a pore pressure sensor, 22 is a function generator, 23 is a signal amplifier, 24 is a pore pressure pipeline, a is an aluminum block, b is a reserved pipeline, c is a piezoelectric ceramic, d is potting glue, and e is a strain sheet. DETAILED DESCRIPTION

[0026] The present application is further described below in conjunction with the accompanying drawings.

[0027] Reference Figure 1 As shown in the figure, the rock elastic wave dispersion and attenuation characteristic measurement system in the embodiment of the present application includes a computer, a sample module, a vibration module, a data acquisition and processing module, a heating module, a pore pressure loading module, and a pressure loading module.

[0028] The sample module includes a core sample 5, an aluminum probe 6, and potting glue wrapped around the sample. The top and bottom of the core sample 5 are connected to the aluminum probe 6 through special quick-drying glue, and are placed in the positioning and sealing device 7.

[0029] The vibration module includes a low-frequency signal generator and an ultrasonic signal generator. The low-frequency signal generator includes a function generator 22, a signal amplifier 23, an exciter 12, and a force sensor 11. The function generator 22, the signal amplifier 23, and the exciter 12 are connected in sequence through a serial interface. The exciter 12 is located at the lower part of the positioning and sealing device 7 and is rigidly connected through the force sensor 11. The ultrasonic signal generator is composed of a piezoelectric ceramic and is integrally formed inside the aluminum probe 6, as shown in the figure. Figure 3

[0030] ​The pressure loading module comprises a confining pressure loading system, an axial pressure loading system and a hole pressure loading system. The confining pressure loading system comprises a confining pressure loader 15, a start-up stepper motor, a speed controller, a driving coupling and a piston connected in sequence, and the piston is installed in a silicon oil cylinder. The confining pressure loader 15 is connected with a confining pressure pipeline 1, and a ball screw is driven by a motor and a speed controller, so that the oil cylinder piston pushes pressure medium (silicon oil) to output to a confining pressure chamber 3, and output pressure load. The pressure output range of the confining pressure controller is 0-80 MPa, and the pressure resistance range is -20-100 MPa.

[0031] Similarly, the axial pressure loading system comprises an axial pressure loader 14, a start-up stepper motor, a speed controller, a driving coupling and a piston connected in sequence, and the piston is installed in a silicon oil cylinder. The axial pressure loader 14 is connected with an axial pressure control chamber 2. The axial pressure loader 14 drives a ball screw by a motor and a speed controller, so that the oil cylinder piston pushes pressure medium (silicon oil) to output to the axial pressure control chamber 2, and output pressure load. The pressure output range of the axial pressure controller is 0-6 MPa, and the pressure resistance range is -10-10 MPa.

[0032] The hole pressure loading system comprises a hole pressure loader 13 and a hole pressure control pipeline, and the hole pressure control pipeline is divided into a hole pressure pipeline 24, a pressure relief pipeline 10 and a pressure relief valve 18. The hole pressure loading system generates pressure by the hole pressure loader 13, and the pressure is loaded into the sample through the hole pressure pipeline 24, the core sample 5 and the pressure relief pipeline 10 in sequence at the beginning of the test, and the pressure is unloaded by opening the pressure relief valve 18 after the test is completed; the pressure output range of the hole pressure loader 13 is 0-20 MPa, and the pressure resistance range is -10-30 MPa.

[0033] The heating module is composed of a heating sheet 4 in the confining pressure chamber 3, and the temperature control range is 5-70℃.

[0034] The data acquisition and processing module comprises strain gauges on the sample and aluminum blocks, a data acquisition box 16, a serial interface 8, an axial pressure sensor 20, a confining pressure sensor 19, a hole pressure sensor 21 and a pressure relief sensor 17. The strain gauges are pasted on the aluminum probe 6 and the core sample 5 by using quick-drying glue in specific positions, as shown in Figure 2 and Figure 3 The strain gauges are connected with the data acquisition box 16 through the communication serial port 8 to collect real-time strain information of the core sample 5, and the collected strain information is transmitted to the computer in real time through the communication serial port 8; the axial pressure sensor 20, the confining pressure sensor 19, the hole pressure inlet sensor 21 and the hole pressure outlet sensor 17 are connected with the computer to record real-time stress information of the core sample. At the same time, the data acquisition box 16 comprises a central controller, a memory 8 and a 16-bit A / D converter, and the central controller also ends the computer.

[0035] The specific processing procedure of the above data acquisition and processing module is as follows: In another embodiment of the present invention, the core sample needs to be prepared... Figure 2 As shown in the test sample diagram, core sample 5 was placed in positioning and sealing device 7, and as... Figure 1 After assembling the equipment as shown, close the pressure relief valve 18 and perform the corresponding initialization settings for the test device. According to the test requirements, start the heating element 4, confining pressure loader 15, axial pressure loader 14, and pore pressure loader 13, and input the preset temperature, confining pressure, axial pressure, and pore pressure in the test plan into the computer.

[0036] Specifically, another embodiment of the present invention is a method for measuring the dispersion and attenuation characteristics of rock elastic waves. This method uses the above-mentioned measurement system and operates according to the following steps:

[0037] Step 1: Place the core sample with elastic wave dispersion and attenuation inside the positioning and sealing device. The core sample is rectangular or cylindrical in shape, and as shown in the figure... Figure 2 The strain gauges are attached to their surfaces at the same distance, as shown.

[0038] Step 2: Then install the confining pressure chamber and start the pore pressure loader, confining pressure loader, and axial pressure loader to apply pore pressure, confining pressure, and axial pressure to the core sample in the positioning and sealing device, respectively.

[0039] Step 3: Activate the ultrasonic signal generator and exciter inside the probe to excite high-frequency signals and medium and low-frequency signals to be applied to the core sample.

[0040] Step 4: The computer collects data from the core sample using force sensors, pressure relief sensors, pore pressure sensors, confining pressure sensors, and axial pressure sensors.

[0041] Step 5: The data acquisition box collects real-time stress signals from multiple strain gauges and transmits them to the computer. The computer then uses a cross-correlation interference algorithm between the two signals in the frequency domain to obtain the energy spectrum of the seismic source.

[0042] The energy spectrum of the aforementioned earthquake source includes dispersion and attenuation curves, which are calculated as follows:

[0043] Dispersion curve calculation. A high signal-to-noise ratio system signal can be obtained through interferometric processing. The intermediate, low-frequency, and ultrasonic signals are excited by the piezoelectric ceramics in the exciter 12 and aluminum probe body 6, respectively. The computer receives data from any two positions r in the core sample 5 acquired by the data acquisition box 16. A and r B The real-time stress-strain signal of the strain gauge is u(r) i ,s,ω), (i=A,B), by adjusting r in the frequency domain A place and r BThe energy spectrum of the seismic source can be obtained by cross-correlation interferometry calculation of the signal at the location, as shown in formula (1).

[0044] C AB (ω)=u(r A ,S,ω)*u(r A ,S,ω) (1)

[0045] Where c AB (ω) represents the energy spectrum of the earthquake source, and ω is the angular frequency; u(r) A , s, ω) and r are respectively acquired by the computer through acquisition box 16 A and r B Strain signals at two locations; r A and r B s represents any two strain gauge positions; s represents the location of the seismic source. In this embodiment, the Tau-p transform is used to perform elastic wave decomposition on the data in formula (1), and the frequency-velocity spectrum is calculated to reflect the phase velocity of elastic waves of different frequency components, thereby extracting the elastic wave dispersion curve. This process is expressed as:

[0046]

[0047] In the formula, t = τ + px, d(t, x) represents spatiotemporal domain data, where t is time and x is the time domain. A place and r B distance, For the integration of spatiotemporal data d(t, x), the upper and lower limits of integration are negative infinity (-∞) to positive infinity (+∞), and τ and p are the intercept and slope of the skewed superposition, respectively. Transforming the obtained Tau-p spectrum to the frequency domain and interpolating it yields the frequency velocity spectrum used for dispersion analysis. (See reference...) Figure 4 As shown.

[0048] Attenuation curve calculation. The mid-frequency, low-frequency, and ultrasonic signals are respectively excited by the piezoelectric ceramic excitation module s in the exciter 12 and the aluminum probe body 6. The computer receives continuous signals x(t) and y(t) of the same frequency at any two positions in sample 5 acquired by the data acquisition box 16, and the following expression applies:

[0049]

[0050] α0=2πf0 (5)

[0051] In the formula, x(t) and y(t) represent the strain at any two positions at time t; A and B are the amplitudes of signals x(t) and y(t), respectively, and α0 is the angular frequency. and Let x and y be the initial phases at x and y, respectively. Performing a cross-correlation operation on x(t) and y(t) yields:

[0052]

[0053] where R xy (τ) represents the cross-correlation value of signals x(t) and y(t) at time delay τ; T is the period of the strain signal; represents the upper and lower limits of integration, from 0 to T; x(t) is a function of the first signal varying with time t; y(t+τ) is a function of the second signal, varying with time t plus time delay τ; and dt is the integral variable representing integration with respect to time t.

[0054] When τ = 0

[0055]

[0056] After integration, one term is eliminated, i.e. The cross-correlation of x(t) and y(t) is obtained as follows:

[0057]

[0058] The phase difference is obtained as follows:

[0059]

[0060] According to the phase difference, the attenuation curve is obtained, which can be referred to as shown in FIG. 2, and the process is represented as follows: Figure 5

[0061] Based on the above embodiments of the present application, the present application has the following characteristics:

[0062] 1. The piezoelectric ceramic is pre-embedded in the aluminum block, so that the sample for performing the middle and low frequency band test cannot be repeatedly used for the ultrasonic frequency band test.

[0063] 2. The interference method is introduced into the processing of the middle and low frequency band signals. The strain signals in the middle and low frequency band sample arranged in a specific manner are processed by the interference method, so that the collected signals are more accurate and stable.

[0064] 3. The servo hydraulic loading mode of closed loop control is used for the axial pressure controller and the confining pressure controller, instead of the traditional gas pressurization mode, so that the target pressure can be quickly and accurately reached, and the safety of the experimental process can be ensured under high confining pressure. Meanwhile, the internal temperature field can be more stable after the pressurization medium is changed from gas to silicon oil.

[0065] 4. The computer is used for controlling the axial pressure controller and the confining pressure controller, and the real-time processing and saving of data are performed, so that the automation degree of the measurement system is significantly improved.

[0066] ​

[0067] In addition to the above, it should be understood that "an embodiment", "another embodiment", "some embodiments" or "one embodiment" as described in this specification means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. The appearances of the phrase "in some embodiments" in various places in the specification are not necessarily referring to the same embodiment. Further, where a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the purview of one skilled in the art to effect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described or illustrated.

[0068] Although the application has been described with reference to multiple illustrative embodiments, it will be understood that the application is capable of numerous modifications and embodiments and can be practiced or carried out in various ways. Further, it will be understood that the phraseology and terminology employed herein are for the purpose of description and that the usage of specific terms or specific phrases is not intended as limiting. For example, any of the various illustrative embodiments can be combined with one another to produce other embodiments.

Claims

1. A method of measuring elastic wave dispersion and attenuation characteristics of a rock, characterized by The method comprises the following steps: placing an elastic wave dispersion and attenuation core sample (5) in a positioning and sealing device (7); then installing a confining pressure chamber (3), and starting a pore pressure loader (13), a confining pressure loader (15) and an axial pressure loader (14) to respectively apply pore pressure, confining pressure and axial pressure to the core sample (5) in the positioning and sealing device (7); starting an ultrasonic signal generating device in a probe body (6) and an exciter (12) to excite high-frequency signals and medium and low-frequency signals to the core sample (5); collecting data of the core sample (5) by a computer through a force sensor (11), a pressure relief sensor (17), a pore pressure sensor (21), a confining pressure sensor (19) and an axial pressure sensor (20); a data collection box (16) collects real-time stress signals of a plurality of strain gauges and transmits them to the computer, and the computer obtains an energy spectrum of a seismic source by a cross-correlation interference algorithm of two signals in a frequency domain; the cross-correlation interference algorithm obtains the energy spectrum of the seismic source through formula (1): C AB (ω) = u(r A ,s,ω)*u(r B ,s,ω) (1) where C AB (ω) is the energy spectrum of the source, ω is the angular frequency; u(r A , s, ω) and u(r B , s, ω) are the strain signals collected by the computer through the data acquisition box (16) at r A and r B ; r A and r B are any two strain gauge positions; s is a seismic source occurrence position; formula (2) is used to perform elastic wave decomposition on data of formula (1) through Tau-p transformation, calculate a frequency velocity spectrum to reflect phase velocities of elastic waves of different frequency components, and extract an elastic wave dispersion curve; (2) where t = τ + px, d(t, x) is the spatio-temporal data, t is time, x is r A at r B and the distance, is the integral of the spatio-temporal data d(t, x) from negative infinity (-∞) to positive infinity (+∞), τ and p are the intercept and slope of the tilt stack, respectively; the Tau-p spectrum m(τ, p) obtained through transformation is transformed into a frequency domain and is interpolated, so as to obtain the frequency velocity spectrum; an attenuation characteristic curve is calculated through a phase difference between mutual relations of continuous signals of the same frequency between any two positions of the core sample (5) collected by data collection.

2. The method of measuring rock elastic wave dispersion and attenuation characteristics according to claim 1, characterized in that: The core sample (5) has a shape of a rectangular body or a cylindrical body, and the strain gauges are adhered to surfaces of the core sample (5) at the same distance.

3. The method of measuring rock elastic wave dispersion and attenuation characteristics according to claim 1, characterized in that: A measuring system used in the method comprises an axial pressure control chamber (2), a confining pressure chamber (3) is arranged at a lower portion of the axial pressure control chamber (2), a pressure application end of the axial pressure control chamber (2) is located at an upper portion of the confining pressure chamber (3), a probe body (6) is further arranged in the confining pressure chamber (3), the probe body (6) is used to adhere to the core sample (5), a positioning and sealing device (7) for placing the core sample (5) is further arranged in the confining pressure chamber (3), and the positioning and sealing device (7) corresponds to the pressure application end of the axial pressure control chamber (2); heating fins (4) are further arranged on an inner wall of the confining pressure chamber (3); the positioning and sealing device (7) is further connected with the exciter (12) through an excitation pipeline (9), and the excitation pipeline (9) is provided with the force sensor (11); the confining pressure chamber (3) is connected with the pore pressure loader (13) through a pore pressure pipeline (24), the confining pressure chamber (3) is further connected with a pressure relief pipeline (10), the pressure relief pipeline (10) is provided with a pressure relief valve (18), a pressure application end of the pore pressure pipeline (24) is used to communicate with an inner hole of the core sample (5), and the pressure relief pipeline (10) is provided with the pressure relief sensor (17); the confining pressure chamber (3) is connected with the confining pressure loader (15) through a confining pressure pipeline (1), and the axial pressure control chamber (2) is connected with the axial pressure loader (14) through an axial pressure pipeline; The pore pressure pipe (24) is provided with a pore pressure sensor (21), the confining pressure pipe (1) is provided with a confining pressure sensor (19), and the axial pressure pipe is provided with an axial pressure sensor (20); The probe body (6) is adhered with a strain gauge, which is also used to adhere to the core sample (5), and the strain gauge is connected to a data acquisition box (16) through a serial interface, and the data acquisition box (16) is connected to the force sensor (11), the pressure relief sensor (17), the pore pressure sensor (21), the confining pressure sensor (19), and the axial pressure sensor (20) respectively. The computer is also connected to a function generator (22), which is connected to the exciter (12) through a signal amplifier (23); and the inside of the probe body (6) is also integrated with an ultrasonic signal generating device.

4. The method of measuring rock elastic wave dispersion and attenuation characteristics according to claim 3, characterized in that: The exciter (12) is placed below the positioning and sealing device (7).

5. The method of measuring rock elastic wave dispersion and attenuation characteristics according to claim 3, characterized in that: The pore pressure loader (13) comprises a cylinder body, a piston is installed in the cylinder body, the piston is connected to a stepping motor through a shaft coupling, the stepping motor is also connected to a speed controller, the stepping motor and the speed controller are connected to the computer, and the pressurizing medium in the pore pressure pipe is silicon oil; the confining pressure loader (15) and the axial pressure sensor (20) have the same structure as the pore pressure loader (13).

6. The method of measuring rock elastic wave dispersion and attenuation characteristics according to claim 3, characterized in that: The data acquisition box (16) has a central controller, which is connected to a memory and an A / D converter, the A / D converter is connected to the strain gauge, and the central controller is connected to the computer.

7. The method of measuring rock elastic wave dispersion and attenuation characteristics according to claim 3, characterized in that: The core sample (5) is wrapped by potting glue.

8. The method of measuring rock elastic wave dispersion and attenuation characteristics according to claim 3, characterized in that: The ultrasonic signal generating device is made of piezoelectric ceramic.

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