Composition for preparing a seismic physical model material, seismic physical model material and use thereof

Abstract

The present application provides a composition for preparing an earthquake physical model material, an earthquake physical model material, and its application. The composition for preparing an earthquake physical model material provided herein comprises polyurethane, a curing agent, and nano-aerogel powder. The earthquake physical model material of the present application exhibits both low velocity and high attenuation characteristics, laying the foundation for physical simulation of near-surface geological bodies or geological structures with low velocity and high attenuation. This will greatly expand the application areas of earthquake physical simulation technology and improve the accuracy of earthquake physical simulation.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of seismic physical simulation, in particular to a composition for preparing a seismic physical model material, a seismic physical model material and application thereof. BACKGROUND

[0002] Seismic physical simulation is a kind of forward simulation that actual stratum structure or geological body is made into a physical model in a certain scale similarity ratio in the laboratory, and data acquisition of field seismic exploration method is carried out by ultrasonic testing method. In the seismic physical model technology, how to construct a model material capable of simulating various stratum velocities is a technical problem. At present, the material sources of the seismic physical model can be divided into two kinds, one is solid industrial plate, and the other is formable material. The industrial plates commonly used for physical model manufacturing include aluminum material, resin plate, organic glass, paraffin wax, etc. By mechanical processing of the industrial plate, a relatively accurate geometric structure can be obtained. Formable material refers to some liquid or powder mixture which becomes solid by adding a curing agent or changing the temperature. Such model material has good uniformity and plasticity, and can conveniently manufacture complex structure physical models. Epoxy resin and silicone rubber are the most commonly used formable materials suitable for constructing seismic physical models. The existing technology is to mix epoxy resin, silicone rubber and inorganic substances such as talc to simulate strata with longitudinal wave velocity ranging from 1000 m / s to 3500 m / s.

[0003] The lower limit of the longitudinal wave velocity of the current seismic physical model material is about 1000 m / s, which is difficult to be further reduced. However, in the actual stratum in the field, the actual longitudinal wave velocity of the near-surface stratum in desert, loess plateau and other areas is often only a few hundred meters per second (500 m / s to 900 m / s), and has a very high attenuation factor (usually represented by Q value; the smaller the Q value, the greater the attenuation factor; Q value not greater than 15 can be considered as high attenuation material). Therefore, when physically simulating geological bodies or geological structures containing near-surface layers, it is very crucial to develop a model material with low velocity and high attenuation characteristics. Wei Jianxin (2006) made a detailed study on the velocity of the two formable mixed materials of epoxy resin and silicone rubber, and pointed out that the velocity of the cured epoxy resin is generally 2600 m / s, and the velocity of the cured rubber is about 1000 m / s. By mixing the two materials in different amounts, the velocity of the cured mixed material changes between 1000-2600 m / s. Ding Pinbo (2020) prepared an attenuation composition by doping vulcanized silicone rubber in epoxy resin, and obtained a high attenuation model material with Q value less than 10, but its velocity is greater than 2000 m / s, which does not conform to the actual near-surface stratum velocity.

[0004] From the above, it can be seen that how to realize a model material with low P-wave velocity and low Q value is the key to determine whether the physical model technology can simulate low-velocity and high-attenuation near-surface strata with high similarity, and is also related to whether the seismic physical model technology can develop rapidly. SUMMARY

[0005] In view of the deficiencies in the prior art, the present application provides a seismic physical model material with low velocity and high attenuation characteristics at the same time, which is prepared by doping nano-aerogel powder in polyurethane, and has a P-wave velocity range of 450 m / s to 950 m / s and a Q value change range of 2 to 15, thereby laying a foundation for physical simulation of geological bodies or geological structures with low velocity and high attenuation near-surface.

[0006] In a first aspect, the present application provides a composition for preparing a seismic physical model material, which comprises polyurethane, a curing agent and nano-aerogel powder.

[0007] According to some embodiments of the present application, the composition comprises 100 parts by weight of polyurethane, 10-30 parts by weight of a curing agent and 1-10 parts by weight of nano-aerogel powder.

[0008] According to some embodiments of the present application, the composition comprises 100 parts by weight of polyurethane, 20 parts by weight of a curing agent and 1-10 parts by weight of nano-aerogel powder.

[0009] According to some embodiments of the present application, the mass ratio of the polyurethane to the nano-aerogel powder is 100:(1-10), for example, it can be 100:1, 100:2, 100:3, 100:4, 100:5, 100:6, 100:7, 100:8, 100:9, 100:10 and any value therebetween. According to a preferred embodiment of the present application, the mass ratio of the polyurethane to the nano-aerogel powder is 100:(1-8). In the present application, by using different proportions of nano-aerogel powder and polyurethane, a seismic physical model material with a P-wave velocity range of 450 m / s to 950 m / s and a Q value change range of 2 to 15 can be prepared. In the present application, the greater the amount of nano-aerogel powder added, the smaller the P-wave velocity and the smaller the Q value of the prepared seismic physical model material. However, if the amount of nano-aerogel powder added is too much, since the density of nano-aerogel powder is very low, there is a certain upper limit for the amount added when mixed with polyurethane, and it is difficult to uniformly mix the raw materials and form a well-cured sample beyond the above range.

[0010] According to some embodiments of the present application, the polyurethane is a two-component polyurethane.

[0011] According to some embodiments of the present application, the curing agent comprises an amine curing agent. According to preferred embodiments of the present application, the curing agent comprises an amine curing agent with an amine value less than 400 mg KOH / g. According to further preferred embodiments of the present application, the curing agent preferably comprises a cashew nut oil modified fatty amine.

[0012] According to some embodiments of the present application, the nano-aerogel powder comprises a silicon-based nano-aerogel powder and / or a carbon-based nano-aerogel powder. According to preferred embodiments of the present application, the nano-aerogel powder comprises a silica aerogel powder.

[0013] According to some embodiments of the present application, the nano-aerogel powder has a particle size of 20-80 nanometers, for example, can be 20 nanometers, 25 nanometers, 30 nanometers, 35 nanometers, 40 nanometers, 45 nanometers, 50 nanometers, 55 nanometers, 60 nanometers, 65 nanometers, 70 nanometers, 75 nanometers, 80 nanometers, and any value therebetween. According to preferred embodiments of the present application, the nano-aerogel powder has a particle size of 20-50 nanometers. According to further preferred embodiments of the present application, the nano-aerogel powder has a particle size of 20-30 nanometers.

[0014] In a second aspect, the present application provides a seismic physical model material prepared from the composition according to the first aspect.

[0015] In a third aspect, the present application provides a preparation method of the seismic physical model material according to the second aspect, comprising the following steps:

[0016] S1: separately preheating the polyurethane and the curing agent to obtain preheated polyurethane and preheated curing agent;

[0017] S2: mixing the nano-aerogel powder, the preheated polyurethane and the preheated curing agent to obtain a mixture;

[0018] S3: placing the mixture in a mold after vacuumizing, curing, demolding to obtain the seismic physical model material.

[0019] According to some embodiments of the present application, in step S1, the preheating temperature is 40-60°C. According to preferred embodiments of the present application, in step S1, the preheating temperature is 40-50°C.

[0020] According to some embodiments of the present application, the preheating time is 1-5h. According to preferred embodiments of the present application, the preheating time is 2-3h.

[0021] According to some embodiments of the present application, in step S2, the nano-aerogel powder and the preheated polyurethane are mixed first, and then mixed with the curing agent.

[0022] According to some embodiments of the present application, the time for vacuumizing in step S3 is 3-10 minutes. According to preferred embodiments of the present application, the time for vacuumizing in step S3 is 4-6 minutes.

[0023] According to some embodiments of the present application, the purpose of vacuumizing in step S3 is to remove air bubbles in the raw material, and the vacuum pressure is controlled at -0.08Mpa to -0.1Mpa, preferably -0.1Mpa.

[0024] According to some embodiments of the present application, the temperature for solidifying in step S3 is 30-50℃. According to preferred embodiments of the present application, the temperature for solidifying in step S3 is 35-45℃.

[0025] According to some embodiments of the present application, the time for solidifying in step S3 is 10-40h. According to some embodiments of the present application, the time for solidifying in step S3 is 20-30h.

[0026] According to some embodiments of the present application, before step S3, silicon rubber is applied on the inner surface of the mold, and the mold is processed after the silicon rubber is solidified.

[0027] According to some embodiments of the present application, in step S3, the mixture after vacuumizing is placed in the mold at room temperature for 5-20h, preferably 10-15h, before solidifying.

[0028] In a fourth aspect, the present application provides an application of the seismic physical model according to the second aspect or the seismic physical model prepared by the preparation method according to the third aspect in seismic physical simulation.

[0029] The seismic physical model material of the present application is prepared by doping nano-aerogel powder in polyurethane. Aerogel is a porous material with a porosity of up to 80% to 99.8%, which has the characteristics of low density and extremely low sound wave propagation speed (as low as 90m / s), and its porous structure will cause great attenuation of sound propagation energy. The inventors of the present application have applied nano-aerogel powder to the field of seismic physical model materials, realized the research and development of near-surface stratum model materials with low speed and high attenuation characteristics, and can realize model materials with low speed and high attenuation characteristics. The model material developed by the present application has a speed range of 450m / s to 950m / s and a Q value change range of 2 to 15, which lays a foundation for physical simulation of geological bodies or geological structures containing low-speed and high-attenuation near-surface, greatly widens the application field of seismic physical simulation technology, and improves the accuracy of seismic physical simulation. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1The case that the P-wave velocity of the seismic physical model material prepared according to Embodiments 1 to 7 of the present application varies with the number of parts of nano-aerogel powder is shown.

[0031] Figure 2 The case that the Q value of the seismic physical model material prepared according to Embodiments 1 to 7 of the present application varies with the number of parts of nano-aerogel powder is shown. DETAILED DESCRIPTION

[0032] In order to make the present application easy to understand, the present application will be described in detail below in conjunction with embodiments, which are only illustrative and do not limit the scope of application of the present application.

[0033] In the following examples and comparative examples:

[0034] Q value measurement calculation method:

[0035] The Q value is often used to represent the size of the material attenuation factor, and the smaller the Q value, the greater the attenuation. The frequency spectrum ratio method is one of the most common methods for Q value measurement in the laboratory. This method mainly measures the Q value of the sample by using the transmission wave excited by the transducer. The measurement process is generally that the transducer is in direct contact with the sample, and the sample and the transducer are coupled by smearing the corresponding coupling agent on the surface of the sample. When the pulse transmission method is used to measure the Q value, a sample with a known Q value is selected as a reference sample, and the geometric shape of the reference sample needs to be similar or identical to that of the measured sample. The Q value of the measured sample is obtained by processing the measurement data spectrum of the measured sample and the measurement data spectrum of the reference sample. In the present embodiment and comparative examples, an aluminum sample is used as a reference sample, and its Q is approximately 15000. The mathematical formula for calculating the Q value by the frequency spectrum ratio method is well known in the industry and will not be described here.

[0036] P-wave velocity test method:

[0037] The P-wave velocity is measured by ultrasonic transmission method. First, the length L of the sample is measured with a vernier caliper, and then the sample is placed between two P-wave ultrasonic probes, and the ultrasonic propagation time difference T is measured from the oscilloscope. The velocity formula V = L / T is used to calculate the P-wave velocity.

[0038] Raw materials used in Embodiments 1-7:

[0039] The polyurethane 101 is purchased from Shanghai Xinguang Chemical Factory;

[0040] The curing agent F50 is cashew oil modified fatty amine ZY-F50 with an amine value of 200-300 mgKOH / g, which is purchased from Xuzhou Zhongyan Chemical Co., Ltd.;

[0041] Nano-aerogel powder: silica nano-aerogel powder, particle size of 10 nm, 20 nm, 50 nm, 80 nm, 100 nm, purchased from Hubei Hui Fu Nanometer Material Co., Ltd.

[0042] Example 1

[0043] The raw materials of the model material for simulating the low-velocity and high-attenuation near-surface layer in a certain area include, by weight fraction

[0044] Polyurethane 101 100 parts

[0045] Curing agent F50 20 parts

[0046] Nano-aerogel powder 1 part;

[0047] The preparation method is as follows:

[0048] (1) Put polyurethane 101 and curing agent F50 in a 45℃ incubator for preheating for 2 hours;

[0049] (2) After weighing the materials according to the above formula, the polyurethane and nano-aerogel powder are fully stirred and uniformly mixed; then the curing agent is added to the above materials, and then stirred to fully mix and uniformly mix;

[0050] (3) Put the raw materials of step (2) into a vacuum machine, stir while extracting vacuum for 5 min, and discharge the bubbles in the raw materials, with the vacuum pressure controlled at-0.1 Mpa;

[0051] (4) Take out the materials from the vacuum machine and pour them into a mold, place them in a normal temperature room for 12 hours, then put them in a 40℃ incubator for curing for 24 hours, and then demold and take out the cured model material.

[0052] Test results show that the longitudinal wave velocity of the model material is 950 m / s, and the Q value is 15.

[0053] Example 2:

[0054] The model material is prepared by the same method as in Example 1, except that the raw materials are different, and the raw materials include, by weight fraction

[0055] Polyurethane 101 100 parts

[0056] Curing agent F50 20 parts

[0057] Nano-aerogel powder 3 parts;

[0058] Test results show that the longitudinal wave velocity of the model material is 832 m / s, and the Q value is 13.

[0059] Example 3:

[0060] The model material is prepared by the same method as in Example 1, except that the raw materials are different, and the raw materials include, by weight fraction

[0061] Polyurethane 101 100 parts

[0062] Curing agent F50 20 parts

[0063] Nano-aerogel powder 5 parts;

[0064] It is tested that the longitudinal wave speed of the model material is 709 m / s, and the Q value is 11.

[0065] Example 4:

[0066] The model material is prepared by the same method as in Example 1, except that the raw materials are different, and the raw materials include, by weight fraction

[0067] Polyurethane 101 100 parts

[0068] Curing agent F50 20 parts

[0069] Nano-aerogel powder 6 parts;

[0070] It is tested that the longitudinal wave speed of the model material is 672 m / s, and the Q value is 10.

[0071] Example 5:

[0072] The model material is prepared by the same method as in Example 1, except that the raw materials are different, and the raw materials include, by weight fraction

[0073] Polyurethane 101 100 parts

[0074] Curing agent F50 20 parts

[0075] Nano-aerogel powder 7 parts;

[0076] It is tested that the longitudinal wave speed of the model material is 638 m / s, and the Q value is 7.

[0077] Example 6:

[0078] The model material is prepared by the same method as in Example 1, except that the raw materials are different, and the raw materials include, by weight fraction

[0079] Polyurethane 101 100 parts

[0080] Curing agent F50 20 parts

[0081] Nano-aerogel powder 9 parts;

[0082] It is tested that the longitudinal wave speed of the model material is 577 m / s, and the Q value is 5.

[0083] Example 7

[0084] The model material was prepared by the same method as in Example 1, except that the raw materials were different, and the raw materials included, by weight fraction,

[0085] polyurethane 101 100 parts

[0086] curing agent F50 20 parts

[0087] nanometer aerogel powder 10 parts;

[0088] It was tested that the longitudinal wave speed of the model material was 450 m / s, and the Q value was 2.

[0089] Example 8

[0090] The model material was prepared by the same method as in Example 1, except that the particle size of the nanometer aerogel powder in the raw materials was 10 nm.

[0091] It was tested that the longitudinal wave speed of the model material was 956 m / s, and the Q value was 15.3.

[0092] Example 9

[0093] The model material was prepared by the same method as in Example 1, except that the particle size of the nanometer aerogel powder in the raw materials was 50 nm.

[0094] It was tested that the longitudinal wave speed of the model material was 965 m / s, and the Q value was 15.5.

[0095] Example 10

[0096] The model material was prepared by the same method as in Example 1, except that the particle size of the nanometer aerogel powder in the raw materials was 80 nm.

[0097] It was tested that the longitudinal wave speed of the model material was 971 m / s, and the Q value was 15.8.

[0098] Example 11

[0099] The model material was prepared by the same method as in Example 1, except that the particle size of the nanometer aerogel powder in the raw materials was 100 nm.

[0100] It was tested that the longitudinal wave speed of the model material was 983 m / s, and the Q value was 16.2.

[0101] Comparative Example 1

[0102] The model material was prepared by the same method as in Example 1, except that no nanometer aerogel powder was added to the raw materials.

[0103] The longitudinal wave velocity of the model material is 1050 m / s and the Q value is 30 after testing. It can be seen that, since the nanometer aerogel powder is not added in the raw material, the prepared model material is greater than 1000 m / s and the Q value is greater than 15, and it is difficult to simulate low-speed high-damping which only represents the formation.

[0104] It should be noted that the above-described embodiments are only used to explain the present application and do not constitute any limitation on the present application. The present application is described by referring to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory words, rather than limiting words. The present application can be modified as specified within the scope of the claims of the present application, and the present application can be revised within the scope and spirit of the present application. Although the present application described therein relates to specific methods, materials and embodiments, it does not mean that the present application is limited to the specific examples disclosed therein, but rather the present application can be extended to all other methods and applications having the same function.

Claims

1. A composition for preparing an earthquake physical model material, comprising polyurethane, a curing agent, and nano-aerogel powder; The mass ratio of the polyurethane to the nano aerogel powder is 100:1; The particle size of the nano aerogel powder is 20 nanometers; The nano aerogel powder is silicon dioxide aerogel powder.

2. The composition according to claim 1, characterized in that The polyurethane is a two-component polyurethane; and / or the curing agent includes an amine curing agent.

3. The composition according to claim 2, wherein The curing agent includes an amine curing agent with an amine value of less than 400 mg KOH / g.

4. The composition according to claim 3, characterized in that The curing agent includes cashew nut oil modified fatty amine.

5. An earthquake physics model material prepared from the composition according to any one of claims 1 to 4.

6. A method for preparing the earthquake physical model material according to claim 5, comprising the following steps: S1: preheating the polyurethane and the curing agent respectively to obtain preheated polyurethane and preheated curing agent; S2: mixing the nano aerogel powder, the preheated polyurethane and the preheated curing agent to obtain a mixture; S3: After evacuating the mixture, place it in a mold, solidify it, and demould it to obtain the earthquake physics model material.

7. The preparation method according to claim 6, wherein In step S1, the temperature of the preheating treatment is 40°C-60°C, and the time of the preheating treatment is 1h-5h; and / or In step S2, the nano-aerogel powder is first mixed with the preheated polyurethane, and then mixed with the curing agent; and / or In step S3, the vacuuming time is 3 min-10 min; and / or In step S3, the curing temperature is 30° C.-50° C., and the curing time is 10 h-40 h.

8. The preparation method according to claim 7, wherein In step S1, the temperature of the preheating treatment is 40°C-50°C, and the time of the preheating treatment is 2h-3h; and / or In step S3, the vacuuming time is 4 min-6 min; and / or In step S3, the curing temperature is 35° C.-45° C., and the curing time is 20 h-30 h.

9. The preparation method according to any one of claims 6 to 8, characterized in that Before step S3, silicone rubber is applied to the inner surface of the mold, and the mold treatment is completed after the silicone rubber is cured; and / or In step S3, before curing, the vacuumed mixture is placed in a mold and left at room temperature for 5 hours to 20 hours.

10. The preparation method according to claim 9, characterized in that In step S3, before curing, the vacuumed mixture is placed in a mold and left at room temperature for 10 hours to 15 hours.

11. Use of the earthquake physics model material according to claim 5 or the earthquake physics model material obtained by the preparation method according to any one of claims 6 to 10 in earthquake physics simulation.

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