Seismic wave attenuation measurement device based on wave-induced gas dissolution-exsolution mechanism

Abstract

The present invention relates to a seismic wave attenuation measuring device based on a wave-induced gas dissolution mechanism, comprising a measuring container made of a transparent material, with scales arranged on the outer periphery of the measuring container, an opening arranged on the measuring container, a piston sealed and slidably connected in the measuring container, the end of the piston away from the opening being connected to a driving mechanism, and the piston being able to perform linear reciprocating motion along the axial direction of the measuring container under the action of the driving mechanism; a gas-liquid mixing device, for mixing the measuring gas and the measuring liquid to form a fluid with bubbles, and the fluid being able to enter the measuring container through the opening under the action of the driving mechanism; a shooting device, the camera of the shooting device being aimed at the measuring container; and a pressure sensor being arranged between the measuring container and the gas-liquid mixing device. The present invention can measure the change in bubble size caused by the earthquake pressure disturbance, and then calculate the attenuation of seismic waves caused by the fluid stored in the pores.

Description

Technical Field

[0001] The present invention relates to the technical field of seismic wave attenuation measuring devices, and in particular to a seismic wave attenuation measuring device based on a wave-induced gas dissolution-exsolution mechanism. Background Art

[0002] Wave-induced gas dissolution and exsolution (WIGED) is a seismic wave attenuation mechanism that causes a thermodynamic non-equilibrium state between the gas and liquid in the bubbles in the pores of fluid-containing rocks, leading to the attenuation of seismic waves. When seismic waves propagate through, the resulting pressure changes will break the thermodynamic equilibrium between the liquid and the gas. The dissolution and exsolution of the gas in the surrounding liquid, as well as the diffusion in the liquid, will cause phase delay and energy loss of the seismic waves, resulting in attenuation. The WIGED mechanism has been observed in some experiments measuring the attenuation of saturated sandstone at low frequencies.

[0003] However, currently, technicians in this field do not have a practical and effective experimental method to directly measure the attenuation of seismic waves. Summary of the invention

[0004] In view of the defects in the prior art, the technical problem to be solved by the present invention is to provide a seismic wave attenuation measurement device based on the wave-induced gas dissolution-exsolution mechanism, so as to measure the change in bubble size caused by seismic pressure disturbance, and then calculate the attenuation of seismic waves caused by the fluid stored in the pores.

[0005] To solve the above technical problems, the present invention provides a seismic wave attenuation measuring device based on the wave-induced gas dissolution-exsolution mechanism, comprising a measuring container, which is made of a transparent material and is provided with a scale on the outer periphery of the measuring container, an opening is provided on the measuring container, a piston is sealingly and slidably connected in the measuring container, the end of the piston away from the opening is connected to a driving mechanism, and the piston can make a linear reciprocating motion along the axial direction of the measuring container under the action of the driving mechanism; a gas-liquid mixing device, which is used to mix the measuring gas and the measuring liquid to form a fluid with bubbles, and the fluid can enter the measuring container through the opening under the action of the driving mechanism; a shooting device, the camera of the shooting device is aimed at the measuring container; a pressure sensor is arranged between the measuring container and the gas-liquid mixing device.

[0006] The seismic wave attenuation measuring device based on the wave-induced gas dissolution-exsolution mechanism of the present invention, when conducting an experiment, first mixes the measuring gas and the measuring liquid into a fluid with bubbles through a gas-liquid mixing device, and then drives the piston to extend through a driving mechanism to suck the fluid from the opening into a measuring container, and ensures that the bubble size of the fluid sucked into the measuring container meets the measurement requirements (such as less than 4mm). After the injection is completed, the driving mechanism drives the piston to retract and pressurizes the fluid in the measuring container to simulate the seismic wave pressure disturbance. At this time, the pressure sensor returns the pressure value in the measuring container, and the shooting device shoots the image of the measuring container at intervals to record the size change of the bubbles. Finally, the attenuation of the seismic wave caused by the fluid in the pores is calculated based on the volume and pressure changes of the fluid and the deformation of the bubbles.

[0007] Preferably, the gas-liquid mixing device comprises a liquid storage container, a vacuum pumping device and a gas filling bottle; the liquid storage container contains the measuring liquid; the measuring container is connected to the liquid storage container through a three-way valve, the three-way valve has a first interface, a second interface and a third interface, and a reversing handle is arranged on the three-way valve, the first interface is connected to the opening, the second interface and the third interface are respectively connected to a first pipe and a second pipe, the first pipe and the second pipe both extend into the liquid storage container, and the first pipe is located above the liquid level of the liquid storage container, and the second pipe is located below the liquid level of the liquid storage container; the vacuum pumping device is connected to the liquid storage container through a third pipe, and the third pipe is located above the liquid level of the liquid storage container; the measuring gas is contained in the gas filling bottle, the gas filling bottle is connected to the liquid storage container through a fourth pipe, and the fourth pipe is located below the liquid level of the liquid storage container. Before the measurement begins, the measurement system is first evacuated. When evacuating, the gas filling bottle is closed, the driving mechanism drives the piston to move to its extreme retracted position, and the reversing handle of the three-way valve is adjusted so that the first interface and the second interface are connected. At this time, the vacuum device can evacuate the measurement container, the liquid storage container and each connecting pipeline into a vacuum state, and then the vacuum device is closed, the reversing handle is adjusted so that the first interface and the third interface are connected, the gas filling bottle is opened, and the measurement gas is injected into the liquid storage container. After the measurement gas is dissolved in the measurement liquid, the system pressure decreases, and then the measurement gas is continuously injected into the measurement liquid until the pressure value fed back by the pressure sensor is close to the target pressure and remains stable, and the gas-liquid mixing operation can be completed. Subsequently, the driving mechanism drives the piston to extend so that the fluid containing bubbles in the liquid storage container enters the measurement container. When the size of the bubbles in the measurement container exceeds a certain value (such as a diameter of 4mm), the reversing handle is adjusted so that the first interface and the second interface are connected, and the driving mechanism drives the piston to retract to discharge the excess gas through the first pipeline into the liquid storage container, so that the size of the bubbles in the measurement container meets the requirements.

[0008] Preferably, the photographing device is an optical microscope, the eyepiece of which is provided with the camera, and the objective lens of the optical microscope is aimed at the measuring container. The camera photographs the image of the bubbles in the measuring container magnified and displayed by the optical microscope at the eyepiece.

[0009] Preferably, the driving mechanism is a screw stepping motor, the screw of the screw stepping motor is connected to the piston, and the housing of the screw stepping motor is fixedly connected to the measuring container.

[0010] Preferably, the pressure sensor is arranged on the connecting pipe between the first interface and the opening, and the pressure sensor is arranged close to the opening. The position design of the pressure sensor can more accurately monitor the pressure change in the measuring container.

[0011] Preferably, the measurement gas is carbon dioxide, methane or nitrogen, and the measurement liquid is water or oil.

[0012] Preferably, the vacuum pump comprises a vacuum pump, which is connected to the liquid storage container through the third pipe, and a vacuum kettle is arranged on the third pipe. The design of the vacuum kettle can collect the liquid in the medium sucked by the vacuum pump to prevent this part of the liquid from flowing into the vacuum pump, thereby protecting the vacuum pump.

[0013] Preferably, the seismic wave attenuation measurement device based on the wave-induced gas dissolution-exsolution mechanism of the present invention also includes a controller, which controls the shooting device to capture an image once every first interval time, and controls the pressure sensor to measure the pressure in the measurement container once every second interval time.

[0014] Preferably, a flow meter is provided on the fourth pipeline to record the volume of the measurement gas filled into the measurement liquid. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following is a brief introduction to the drawings required for the specific embodiments or the description of the prior art. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn according to the actual scale.

[0016] Figure 1 A schematic diagram of the working principle of a seismic wave attenuation measurement device based on a wave-induced gas dissolution-exsolution mechanism according to an embodiment of the present invention;

[0017] Figure 2 Schematic diagram of the connection structure between the measuring container and the driving mechanism according to an embodiment of the present invention.

[0018] Reference numerals:

[0019] 1-measuring container; 11-piston; 2-driving mechanism; 21-screw rod; 3-liquid storage container; 4-gas filling bottle; 41-fourth pipeline; 5-three-way valve; 51-first pipeline; 52-second pipeline; 6-vacuum pump; 7-vacuum kettle; 8-shooting device; 9-pressure sensor. DETAILED DESCRIPTION

[0020] The following embodiments of the technical solution of the present invention are described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and are therefore only used as examples, and cannot be used to limit the protection scope of the present invention.

[0021] It should be noted that, unless otherwise specified, the technical terms or scientific terms used in this application should have the common meanings understood by those skilled in the art to which the present invention belongs.

[0022] like Figure 1 and Figure 2 As shown, this embodiment discloses a seismic wave attenuation measuring device based on the wave-induced gas dissolution-exsolution mechanism, including a measuring container 1, which is made of a transparent material and is provided with a scale on the outer periphery of the measuring container 1, and an opening is provided on the measuring container 1, and a piston 11 is sealingly and slidably connected in the measuring container 1, and the end of the piston 11 away from the opening is connected to a driving mechanism 2, and the driving mechanism 2 is specifically a screw stepper motor, and the screw 21 of the screw stepper motor is connected to the piston 11, and the housing of the screw stepper motor is fixedly connected to the housing of the measuring container 1, and the piston 11 can make a linear reciprocating motion along the axial direction of the measuring container 1 under the action of the driving mechanism.

[0023] The seismic wave attenuation measurement device based on the wave-induced gas dissolution-exsolution mechanism of this embodiment further includes a gas-liquid mixing device, which is used to mix the measurement gas and the measurement liquid to form a fluid with bubbles.

[0024] Specifically, the gas-liquid mixing device includes a liquid storage container 3, a vacuum device and a gas filling bottle 4. The liquid storage container 3 is filled with a measuring liquid, and in this embodiment, the measuring liquid is water; the measuring container 1 is connected to the liquid storage container 3 through a three-way valve 5, and the three-way valve 5 has a first interface, a second interface and a third interface, and a reversing handle is provided on the three-way valve 5, the first interface is connected to the opening, and the second interface and the third interface are respectively connected to a first pipeline 51 and a second pipeline 52, the first pipeline 51 and the second pipeline 52 are both extended into the liquid storage container 3, and the first pipeline 51 is located above the liquid level of the liquid storage container 3, and the second pipeline 52 is located below the liquid level of the liquid storage container 3; the vacuum device includes a vacuum pump 6, The vacuum pump 6 is connected to the liquid storage container 3 through a third pipe, and the third pipe is located above the liquid level of the liquid storage container 3. A vacuum kettle 7 is arranged on the third pipe. In the prior art, the vacuum kettle and the vacuum pump are usually used together to protect the vacuum pump 6. The gas filling bottle 4 is filled with a measuring gas. In this embodiment, the measuring gas is carbon dioxide. In practice, the measuring gas can also be methane or nitrogen. The gas filling bottle 4 is connected to the liquid storage container 3 through a fourth pipe 41, and the fourth pipe 41 is located below the liquid level of the liquid storage container 3. In addition, a flow meter is also arranged on the fourth pipe 41.

[0025] Furthermore, the seismic wave attenuation measurement device based on the wave-induced gas dissolution mechanism of this embodiment also includes a shooting device 8, a pressure sensor 9 and a controller. Among them, the shooting device 8 is an optical microscope, and a camera is arranged at the eyepiece of the optical microscope. The objective lens of the optical microscope is aimed at the measuring container 1. With this structure, the camera can capture the image of the bubbles in the measuring container magnified and displayed by the optical microscope; the pressure sensor 9 is located on the connecting pipe between the opening of the measuring container 1 and the first interface of the three-way valve 5, and the pressure sensor 9 is arranged close to the opening to detect the pressure of the fluid in the measuring container 1.

[0026] The seismic wave attenuation measurement device based on the wave-induced gas dissolution mechanism of this embodiment mainly includes the following steps during the measurement process:

[0027] (1) Vacuuming step: close the gas bottle 4, drive the piston 11 to its maximum retracted position, adjust the reversing handle of the three-way valve 5 so that the first interface and the second interface are connected, start the vacuum pump 6, and evacuate the measuring container 1, the liquid storage container 3 and the connecting pipes into a vacuum state;

[0028] (2) Gas-liquid mixing step: turn off the vacuum pump 6, adjust the reversing handle of the three-way valve 5 so that the first interface and the third interface are connected, open the gas filling bottle 4, and inject the measuring gas into the liquid storage container 3. After the measuring gas is dissolved in the measuring liquid, the system pressure decreases, and then continue to inject the measuring gas into the measuring liquid until the pressure value fed back by the pressure sensor 9 is close to the target pressure and remains stable;

[0029] (3) Liquid injection step: adjust the reversing handle so that the first interface and the third interface are connected. At this time, the driving mechanism 2 drives the piston 11 to extend so that the fluid containing bubbles in the liquid storage container 3 enters the measuring container 1. When the size of the bubbles in the measuring container 1 exceeds a certain value (such as a diameter of 4 mm), adjust the reversing handle so that the first interface and the second interface are connected. The driving mechanism 2 drives the piston 11 to retract to discharge excess gas into the liquid storage container 3 through the first pipe 51, so that the size of the bubbles in the measuring container 1 meets the requirements;

[0030] (4) Measurement steps: the driving mechanism 2 drives the piston 11 to retract, pressurizing the fluid in the measuring container 1 to simulate seismic waves; the controller controls the pressure sensor 6 to record the pressure value in the measuring container 1 every 5 milliseconds, and the controller controls the shooting device 8 to shoot the bubble image of the measuring container 1 every 125 milliseconds.

[0031] It should be noted that, in this embodiment, the measuring container 1, the liquid storage container 3, the three-way valve 5, the first pipeline 51, the second pipeline 52, the third pipeline, the fourth pipeline 41 and the connecting pipeline between the opening and the first interface are all resistant to high pressure to facilitate the smooth implementation of the vacuum operation.

[0032] In this embodiment, the volume of the measurement gas injected into the measurement liquid can be obtained by a flow meter, and the volume of the fluid in the measurement container 1 can be obtained by the scale on the outer side of the measurement container.

[0033] After the measurement is completed, the attenuation of seismic waves caused by the fluid in the pores can be calculated by the following process:

[0034] The deformation of bubbles in water and gas phases under a certain pressure over time was observed using an optical microscope. The bubble deformation is controlled by the elasticity of the gas and the dissolution and exsolution of the gas in water. The gas dissolution rate (mol s -1 ) can be expressed as:

[0035]

[0036] Where r is the radius of the bubble, D w is the air-water diffusion coefficient (m 2 s -1 ), c wis the concentration of the gas in water (mol m -3 ), P f is the pressure in water (Pa), γ is the surface tension (Pa m), K Hpc is the Henry's law constant for air-water (m 3 Pa mol -1 ). Henry's law constant defines the solubility of a gas in water. According to the ideal gas law for a spherical bubble of radius r, we have:

[0037]

[0038] The deformation rate of the bubble is:

[0039]

[0040] Where R is the gas constant (8.31446m 3 P K -1 mol -1 ), T is the temperature (K). Based on the numerical calculation of the volume strain of the bubble and water ε = dV / V, the bulk modulus of the fluid is calculated This gives the attenuation:

[0041] Q -1 =Im(K) / Re(K)

[0042] In the specification of the present invention, a large number of specific details are described. However, it is understood that embodiments of the present invention can be practiced without these specific details. In some instances, well-known methods, systems and techniques are not shown in detail so as not to obscure the understanding of this specification.

[0043] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, systems, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, systems, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, unless they are contradictory.

[0044] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. These modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be included in the scope of the claims and specification of the present invention.

Claims

1. A seismic wave attenuation measurement device based on the wave-induced gas dissolution-exsolution mechanism, characterized in that: include: A measuring container, which is made of a transparent material and has a scale on its outer circumference. An opening is provided on the measuring container. A piston is sealingly and slidably connected in the measuring container. One end of the piston away from the opening is connected to a driving mechanism. The piston can perform linear reciprocating motion along the axis of the measuring container under the action of the driving mechanism. A gas-liquid mixing device, which is used to mix the measurement gas and the measurement liquid to form a fluid with bubbles, and the fluid can enter the measurement container through the opening under the action of the driving mechanism; A photographing device, wherein a camera of the photographing device is aimed at the measuring container; A pressure sensor is provided between the measuring container and the gas-liquid mixing device; The gas-liquid mixing device comprises a liquid storage container, a vacuum pumping device and a gas filling bottle; The liquid storage container contains the measuring liquid; The measuring container is connected to the liquid storage container through a three-way valve, the three-way valve has a first interface, a second interface and a third interface, and a reversing handle is provided on the three-way valve, the first interface is communicated with the opening, the second interface and the third interface are respectively connected to a first pipeline and a second pipeline, the first pipeline and the second pipeline both extend into the liquid storage container, and the first pipeline is located above the liquid level of the liquid storage container, and the second pipeline is located below the liquid level of the liquid storage container; The vacuum pump is connected to the liquid storage container through a third pipe, and the third pipe is located above the liquid level of the liquid storage container; The measuring gas is contained in the gas filling bottle, which is connected to the liquid storage container through a fourth pipe, and the fourth pipe is located below the liquid level of the liquid storage container.

2. The seismic wave attenuation measurement device based on the wave-induced gas dissolution-exsolution mechanism according to claim 1 is characterized in that: The photographing device is an optical microscope, the camera is arranged at the eyepiece of the optical microscope, and the objective lens of the optical microscope is aimed at the measuring container.

3. The seismic wave attenuation measurement device based on wave-induced gas dissolution-exsolution mechanism according to claim 1 is characterized in that: The driving mechanism is a screw stepping motor, the screw of the screw stepping motor is connected to the piston, and the housing of the screw stepping motor is fixedly connected to the measuring container.

4. The seismic wave attenuation measurement device based on wave-induced gas dissolution-exsolution mechanism according to claim 1 is characterized in that: The pressure sensor is arranged on the connecting pipe between the first interface and the opening, and the pressure sensor is arranged close to the opening.

5. The seismic wave attenuation measurement device based on wave-induced gas dissolution-exsolution mechanism according to claim 1 is characterized in that: The measured gas is carbon dioxide, methane or nitrogen, and the measured liquid is water or oil.

6. The seismic wave attenuation measurement device based on wave-induced gas dissolution-exsolution mechanism according to claim 1 is characterized in that: The vacuum pump comprises a vacuum pump, which is connected to the liquid storage container through the third pipeline, and a vacuum kettle is arranged on the third pipeline.

7. The seismic wave attenuation measurement device based on wave-induced gas dissolution-exsolution mechanism according to claim 1 is characterized in that: The device further includes a controller, wherein the controller controls the photographing device to photograph an image once at a first interval, and the controller controls the pressure sensor to measure the pressure in the measuring container once at a second interval.

8. The seismic wave attenuation measurement device based on wave-induced gas dissolution-exsolution mechanism according to claim 1 is characterized by: The fourth pipeline is provided with a flow meter.

Images