A pore filling type natural gas hydrate reservoir artificial core and a preparation method and application thereof

Abstract

The application discloses a pore filling type natural gas hydrate reservoir artificial core and a preparation method and application thereof. The raw material of the artificial core of the application comprises quartz sand and kaolin, a cementing agent and water, and optionally a single crystal material. The pore filling type natural gas hydrate reservoir artificial core of the application has certain similarity with an actual pore filling type hydrate reservoir, and can be used for hydrate reservoir petrophysical testing and seismic simulation experiments at normal temperature and pressure.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of rock physics and physical simulation, in particular to a pore filling type natural gas hydrate reservoir artificial core and a preparation method and application thereof. BACKGROUND

[0002] Natural gas hydrate is formed by small molecule natural gas such as methane and water under specific low temperature and high pressure conditions. Natural gas hydrate has high energy density, shallow burial depth, good accumulation physical and chemical conditions, and is clean and environmentally friendly, and is an important strategic energy and potential future resource. In actual natural gas hydrate reservoirs, according to the existence form of natural gas hydrate, the reservoir micro-conclusion of natural gas hydrate can be summarized into six classical models, among which the pore filling type and the particle support type are the most widely studied and the most representative.

[0003] Since hydrate cannot be maintained at normal temperature and pressure, it is very difficult to study its physical properties. At present, many scientists have focused their main efforts on observing the formation and decomposition process of hydrate under specific conditions using instruments, and the research on the influence of the occurrence state of hydrate on the physical properties of natural gas hydrate is mostly limited to theoretical models, and there are few studies in the experimental aspect.

[0004] The rock physical characteristics and seismic response characteristics of natural gas hydrate reservoirs are two important contents of the study of hydrate reservoirs, which can provide very important information for the search for hydrate deposits, the estimation of saturation, the estimation of reserves, etc. However, natural gas hydrate deposits only exist under special conditions (low temperature and high pressure environment), so it is impossible to test and study them at normal temperature and pressure.

[0005] Therefore, the prior art lacks a method for testing and studying the rock physical characteristics and seismic response characteristics of natural gas hydrate deposits at normal temperature and pressure. SUMMARY

[0006] In view of the above problems existing in the prior art, the present application provides a pore filling type natural gas hydrate reservoir artificial core, which is made of hydrate replacement materials to produce artificial rock samples similar to hydrate reservoirs, and has certain similarity with actual pore filling type hydrate reservoirs, and can be used for rock physical testing and seismic simulation experiments of hydrate reservoirs at normal temperature and pressure. The present application also provides a preparation method and application of the pore filling type natural gas hydrate reservoir artificial core.

[0007] The first aspect of the present application provides a pore filling type natural gas hydrate reservoir artificial core, the raw materials of which include quartz sand and kaolin, a cementing agent and water, and optionally a single crystal material.

[0008] When containing a single crystal material, it can be used as a hydrate reservoir of the wedge-shaped pore filling type hydrate reservoir physical model of the present application.

[0009] When not containing the single crystal material, it can be the underlying free gas layer of the wedge-shaped pore filling type hydrate reservoir physical model of the present application.

[0010] According to some embodiments of the present application, the particle size of the quartz sand is 80-120 mesh, more preferably 100 mesh.

[0011] According to some embodiments of the present application, the particle size of the kaolin is 2500-3500 mesh, more preferably 3000 mesh.

[0012] According to some embodiments of the present application, the weight ratio of the quartz sand to the kaolin is 1:(0.08-0.12), more preferably 1:0.1.

[0013] According to some embodiments of the present application, the content of the quartz sand is 75-87% by weight of the total artificial core.

[0014] According to some embodiments of the present application, the content of the kaolin is 7-8% by weight of the total artificial core.

[0015] According to some embodiments of the present application, the cementing agent is an epoxy resin cementing agent.

[0016] According to some embodiments of the present application, the epoxy resin cementing agent comprises an epoxy resin and a curing agent.

[0017] According to some embodiments of the present application, the weight average molecular weight of the epoxy resin is 2000-6000.

[0018] According to some embodiments of the present application, the epoxy resin is selected from at least one of bisphenol A epoxy resin E44, bisphenol A epoxy resin E51 and bisphenol A epoxy resin E55.

[0019] According to some embodiments of the present application, the curing agent is selected from the curing agent corresponding to the epoxy resin. For example, when the epoxy resin is epoxy resin E51, the curing agent can be 593 curing agent (addition product of diethylenetriamine and butyl glycidyl ether).

[0020] According to some embodiments of the present application, the content of the cementing agent is 3-5% by weight of the total of the quartz sand and the kaolin, preferably, the content of the cementing agent is 4% by weight of the total of the quartz sand and the kaolin.

[0021] According to some embodiments of the present application, the single crystal material has a longitudinal wave speed of 3300-3700 m / s, a transverse wave speed of 1680-1800 m / s, and a density of 1.1-1.2 g / cm 3; more preferably, the single crystal material is an organic crystal material, preferably a sugar having a molecular formula of C 12 H 22 O 11 at least one of sucrose, maltose, gentiobiose, single crystal sugar, and white sugar. The single crystal material has a longitudinal wave speed, a transverse wave speed, and a density similar to those of pure hydrate, and is also a crystal. The single crystal material can exist in a solid form at room temperature, and is very suitable for replacing hydrate to make a hydrate reservoir artificial core.

[0022] According to some embodiments of the present application, the weight ratio of the single crystal material to the quartz sand is (0-0.2):1; when the single crystal material is contained, preferably, the weight ratio of the single crystal material to the quartz sand is (0.01-0.2):1.

[0023] The hydrate reservoir is generally semi-consolidated and high-porosity. In order to meet this condition, the present application uses a method of adding water to the artificial core raw material to expand the hole, and uses a method of small pressure forming to ensure that the degree of rock consolidation is small. After many tests, an artificial core with a porosity of about 40% can be made without adding a single crystal material, which reaches the porosity range of the hydrate reservoir, has high similarity to the actual hydrate reservoir, and can be repeatedly prepared, and can be applied to the preparation of a hydrate reservoir artificial core. In the present application, the photos of the pore filling type natural gas hydrate reservoir artificial cores can be as shown in Figure 2 , wherein the numbers are saturations, and each square is a pore filling type natural gas hydrate reservoir artificial core. Figure 2 In the first row from left to right in Figure 2 , there are the pore filling type natural gas hydrate reservoir artificial cores with a saturation of 0%, a saturation of 2.5%, a saturation of 5%, and a saturation of 7.5%, respectively. Figure 2 In the second row from left to right in Figure 2 , there are the pore filling type natural gas hydrate reservoir artificial cores with a saturation of 10%, a saturation of 12.5%, a saturation of 15%, and a saturation of 17.5%, respectively. Figure 2 In the third row from left to right in , there are the pore filling type natural gas hydrate reservoir artificial cores with a saturation of 20%, a saturation of 22.5%, a saturation of 25%, and a saturation of 27.5%, respectively.

[0024] In the fourth row in , there are the pore filling type natural gas hydrate reservoir artificial cores with a saturation of 30%.

[0025] A, mixing quartz sand, kaolin, a cementing agent, and water, and optionally a single crystal material to obtain a mixture;

[0026] B, the mixture is pressed and evaporated.

[0027] According to some embodiments of the present application, preferably, in step A, the quartz sand and the kaolin are sieved respectively, and then mixed thoroughly to obtain a mixed powder of the two minerals; the mixed powder is then mixed with the cementing agent, and then mixed with water.

[0028] According to some specific embodiments of the present application, when the artificial core does not contain single crystal materials, the method for preparing the artificial core comprises:

[0029] A, the quartz sand, the kaolin, the cementing agent and water are mixed to obtain a mixture;

[0030] B, the mixture is pressed and evaporated.

[0031] When not containing single crystal materials, it can be used as the underlying free gas layer of the wedge-shaped pore filling hydrate reservoir physical model of the present application.

[0032] According to some embodiments of the present application, when the artificial core contains single crystal materials, the specific embodiments can be that the single crystal materials are dissolved in water, and then the aqueous solution of the single crystal materials is mixed with the mixed mineral powder to which the cementing agent is added.

[0033] According to some specific embodiments of the present application, when the artificial core contains single crystal materials, the method for preparing the artificial core comprises:

[0034] A, the quartz sand, the kaolin and the cementing agent are mixed to obtain a mixed mineral powder;

[0035] B, the single crystal materials are dissolved in water, and then the aqueous solution of the single crystal materials is mixed with the mixed mineral powder to obtain a mixture;

[0036] C, the mixture is pressed and evaporated.

[0037] When containing single crystal materials, it can be used as the hydrate reservoir of the wedge-shaped pore filling hydrate reservoir physical model of the present application.

[0038] According to some embodiments of the present application, the water is formation water.

[0039] According to some embodiments of the present application, the method for preparing the cementing agent comprises: mixing the epoxy resin with a curing agent.

[0040] According to some embodiments of the present application, the mixing conditions comprise: temperature of 40-50℃, and time of 1.5-2.5 hours; preferably, incubation at 45℃ for 2 hours.

[0041] According to some embodiments of the present application, the weight average molecular weight of the epoxy resin is 2000-6000.

[0042] According to some embodiments of the present application, the epoxy resin is selected from at least one of bisphenol A epoxy resin E44, bisphenol A epoxy resin E51 and bisphenol A epoxy resin E55.

[0043] According to some embodiments of the present application, the curing agent is selected from a curing agent corresponding to the epoxy resin. For example, when the epoxy resin is epoxy resin E51, the curing agent can be 593 curing agent (adduct of diethylene triamine and butyl glycidyl ether).

[0044] According to some embodiments of the present application, the mixture is pressed in a mold, before pressing, the mold is cleaned with alcohol, and vaseline is wiped around the mold to facilitate demolding.

[0045] According to some embodiments of the present application, the process of pressing includes: the mixture is added to the mold layer by layer, and is pressed for 1.5-2.5 hours; preferably, the pressing time is 2 hours. The thickness of each layer can be, for example, but not limited to, 2 cm.

[0046] According to some embodiments of the present application, after the mixture is added to the mold, it is placed under a single-axis hydraulic machine for pressing.

[0047] According to some embodiments of the present application, the evaporation method includes: the temperature is 80-100℃, and the time is 40-56 hours; preferably, the temperature is 90℃, and the time is 48 hours.

[0048] For a pore filling type hydrate reservoir, generally, the rock is formed first, and then the natural gas migrates to the reservoir position through a migration channel, and crystallizes with the formation water in the reservoir to form a hydrate reservoir. According to this characteristic, the present application first dissolves the single crystal material in water, and after the hydrate reservoir core mixture is prepared, the water in the core sample is evaporated, so that the single crystal material dissolved in the water is crystallized and filled in the pores in the rock sample, thereby simulating the filling of hydrate in the rock.

[0049] According to the porosity of the artificial core, the content of the added formation water, and the content of the single crystal material, the saturation of the simulated hydrate can be accurately calculated. By preparing samples with different contents of single crystal materials, the relationship between the physical properties of the pore filling type hydrate reservoir and the saturation of the hydrate can be studied.

[0050] The photo of the pore filling type natural gas hydrate reservoir artificial core obtained by the preparation method of the present application can be as shown in Figure 2 Figure 2 ​The first row from left to right is respectively a pore filling type natural gas hydrate reservoir artificial core with a saturation of 0%, a pore filling type natural gas hydrate reservoir artificial core with a saturation of 2.5%, a pore filling type natural gas hydrate reservoir artificial core with a saturation of 5%, and a pore filling type natural gas hydrate reservoir artificial core with a saturation of 7.5%. Figure 2 The second row from left to right is respectively a pore filling type natural gas hydrate reservoir artificial core with a saturation of 10%, a pore filling type natural gas hydrate reservoir artificial core with a saturation of 12.5%, a pore filling type natural gas hydrate reservoir artificial core with a saturation of 15%, and a pore filling type natural gas hydrate reservoir artificial core with a saturation of 17.5%. Figure 2 The third row from left to right is respectively a pore filling type natural gas hydrate reservoir artificial core with a saturation of 20%, a pore filling type natural gas hydrate reservoir artificial core with a saturation of 22.5%, a pore filling type natural gas hydrate reservoir artificial core with a saturation of 25%, and a pore filling type natural gas hydrate reservoir artificial core with a saturation of 27.5%. Figure 2 The fourth row is a pore filling type natural gas hydrate reservoir artificial core with a saturation of 30%.

[0051] The third aspect of the present application provides a wedge-shaped pore filling type hydrate reservoir physical model, comprising a hydrate reservoir, an underlying free gas layer and a surrounding rock part, wherein the hydrate reservoir is the above-mentioned artificial core containing single crystal materials, and the underlying free gas layer is the above-mentioned artificial core not containing single crystal materials.

[0052] According to some embodiments of the present application, the underlying free gas layer is completely consistent with the hydrate reservoir in raw materials and manufacturing process except that it does not contain single crystal materials.

[0053] According to some embodiments of the present application, the surrounding rock part is an epoxy resin, and the hydrate reservoir and the underlying free gas layer are wrapped with the epoxy resin.

[0054] According to some embodiments of the present application, the weight average molecular weight of the epoxy resin is 2000-6000.

[0055] According to some embodiments of the present application, the epoxy resin is selected from at least one of bisphenol A epoxy resin E44, bisphenol A epoxy resin E51 and bisphenol A epoxy resin E55.

[0056] The model is subjected to data acquisition by using a seismic physical model data acquisition system, and the obtained data is analyzed, so that the seismic data of the pore filling type natural gas hydrate reservoir can be researched.

[0057] The fourth aspect of the present application provides application of the above-mentioned artificial core, the artificial core prepared by the above-mentioned method or the above-mentioned wedge-shaped pore filling type hydrate reservoir physical model in rock physical analysis and seismic data analysis of the hydrate reservoir.

[0058] Compared with the prior art, the present application has the following beneficial effects:

[0059] (1) The pore filling type natural gas hydrate reservoir artificial core provided by the application can make the artificial core with a porosity of about 40%, which is similar to the porosity of the actual hydrate reservoir, and can simulate the natural hydrate reservoir;

[0060] (2) The pore filling type natural gas hydrate reservoir artificial core provided by the application uses single crystal materials instead of natural gas hydrates, and solves the technical problem that hydrates cannot be kept at normal temperature and pressure, thereby making it difficult to carry out hydrate experiments;

[0061] (3) The wedge-shaped pore filling type hydrate reservoir physical model provided by the application is similar to the actual pore filling type hydrate reservoir, and can simulate the hydrate reservoir;

[0062] (4) The artificial core, the artificial core prepared by the preparation method and the physical model can be used for rock physical analysis and seismic data analysis of the hydrate reservoir. BRIEF DESCRIPTION OF DRAWINGS

[0063] Figure 1 The pore filling type hydrate reservoir artificial core preparation flowchart of embodiment 2 of the application;

[0064] Figure 2 The pore filling type hydrate reservoir sample chart of different saturations of the application;

[0065] Figure 3 The relationship chart between the longitudinal and transverse wave velocities of the pore filling type hydrate reservoir artificial core of embodiments 1-7 of the application and the saturation;

[0066] Figure 4 The wedge-shaped pore filling type hydrate reservoir physical model chart of embodiment 9 of the application;

[0067] Figure 5 The wedge-shaped pore filling type hydrate reservoir physical model profile (BSR feature) chart of embodiment 9 of the application. DETAILED DESCRIPTION

[0068] In order to make the application easier to understand, the application will be described in detail below in combination with embodiments, which are only illustrative and do not limit the application range of the application.

[0069] The epoxy resin used in the application is commercially available from Nantong Xingchen Synthetic Material Co., Ltd., and the brand is WSR618 (E-51), and the weight average molecular weight is 4800.

[0070] Example 1

[0071] Preparation of the pore filling type hydrate reservoir artificial core.

[0072] (1) Sieve the quartz sand and select 300 grams of quartz sand with 100 mesh, then mix it with 30 grams of kaolin with 3000 mesh to obtain a mixed powder of the two minerals.

[0073] (2) Put 8 grams of epoxy resin and 4 grams of epoxy resin 593 curing agent (addition product of diethylene triamine and butyl glycidyl ether) in an incubator, incubate at 45°C for 2 hours; take it out, and prepare an epoxy resin binder according to 4% of the total weight of the mixed powder, and finally mix the mixed powder with the binder to make the binder evenly distributed in the mineral powder.

[0074] (3) Take 30 grams of purified water, add it to the mineral powder mixed with the binder, and stir thoroughly to mix them well.

[0075] (4) Clean the mold with alcohol and apply vaseline around the mold for easy demolding; then add the mixture obtained in the previous step layer by layer into the mold, and press it in a single-axis hydraulic machine at 0.5 MPa for 2 hours.

[0076] (5) Take the sample out of the hydraulic machine and demold to obtain an artificial sample that is not completely cured, place it in an oven at 90°C for 48 hours to evaporate the water in the pores, and obtain a pore-filled hydrate reservoir artificial core with a saturation of 0%.

[0077] Example 2

[0078] Prepare a pore-filled hydrate reservoir artificial core, and the preparation process is shown in Figure 1 .

[0079] (1) Sieve the quartz sand and select 300 grams of quartz sand with 100 mesh, then mix it with 30 grams of kaolin with 3000 mesh to obtain a mixed powder of the two minerals.

[0080] (2) Put 8 grams of epoxy resin and 4 grams of epoxy resin 593 curing agent in an incubator, incubate at 45°C for 2 hours; take it out, and prepare an epoxy resin binder according to 4% of the total weight of the mixed powder, and finally mix the mixed powder with the binder to make the binder evenly distributed in the mineral powder.

[0081] (3) Take 5 grams of single crystal sugar and 30 grams of purified water, and dissolve the single crystal sugar in water to form a single crystal aqueous solution.

[0082] (4) Add the single crystal aqueous solution to the mixed mineral powder with the binder, and stir thoroughly to mix them well.

[0083] (5) Clean the mold with alcohol and smear vaseline around the mold for easy demolding; then add the mixture obtained in the previous step into the mold layer by layer, and press under 0.5 MPa in a single-axle hydraulic machine for 2 hours.

[0084] (6) Take the sample out of the hydraulic machine and demold to obtain an incompletely cured artificial sample, which is placed in an oven at 90°C for 48 hours to fully evaporate the water in the pores, so as to precipitate the monocrystal sugar in the solution; thus, a pore-filling type hydrate reservoir artificial core with a saturation of 10% is obtained.

[0085] Example 3

[0086] (1) Sieve the quartz sand, select 300 grams of quartz sand with a mesh size of 100, and then fully mix and uniformly distribute 30 grams of kaolin with a mesh size of 3000 in the quartz sand, to obtain a mixed powder of the two minerals.

[0087] (2) Place 8 grams of epoxy resin and 4 grams of its curing agent, epoxy resin 593 curing agent (an addition product of diethylene triamine and butyl glycidyl ether), in a thermostat, and keep the temperature at 45°C for 2 hours; then take out the mixture, and prepare an epoxy resin binder according to 4% of the total weight of the mixed powder; finally, fully mix the mixed powder and the binder, so that the binder is uniformly distributed in the mineral powder.

[0088] (3) Take 10 grams of monocrystal sugar and 30 grams of pure water, and fully dissolve the monocrystal sugar in the water to form a monocrystal aqueous solution.

[0089] (4) Mix the monocrystal aqueous solution with the mixed mineral powder with the binder, and fully stir them, so that the two are fully mixed.

[0090] (5) Clean the mold with alcohol and smear vaseline around the mold for easy demolding; then add the mixture obtained in the previous step into the mold layer by layer, and press under 0.5 MPa in a single-axle hydraulic machine for 2 hours.

[0091] (6) Take the sample out of the hydraulic machine and demold to obtain an incompletely cured artificial sample, which is placed in an oven at 90°C for 48 hours to fully evaporate the water in the pores, so as to precipitate the monocrystal sugar in the solution; thus, a pore-filling type hydrate reservoir artificial core with a saturation of 20% is obtained.

[0092] Example 4

[0093] (1) Sieve the quartz sand, select 300 grams of quartz sand with a mesh size of 100, and then fully mix and uniformly distribute 30 grams of kaolin with a mesh size of 3000 in the quartz sand, to obtain a mixed powder of the two minerals.

[0094] (2) 8 grams of epoxy resin and its curing agent, epoxy resin 593 curing agent (addition product of diethylene triamine and butyl glycidyl ether) 4 grams, were placed in an incubator and incubated at a temperature of 45°C for 2 hours; removed and mixed with the powder, and the epoxy resin adhesive was prepared according to 4% by weight of the total weight of the mixed powder, and finally the mixed powder and the adhesive were thoroughly mixed to make the adhesive evenly distributed in the mineral powder.

[0095] (3) 15 grams of single crystal sugar and 30 grams of pure water were weighed, and the single crystal sugar was fully dissolved in water to form a single crystal aqueous solution.

[0096] (4) The single crystal aqueous solution was added to the mixed mineral powder with the added adhesive, and thoroughly stirred to fully mix the two.

[0097] (5) The mold was cleaned with alcohol and vaseline was applied around the mold to facilitate demolding; then the mixture obtained in the previous step was added layer by layer into the mold, and was pressed under a single-axis hydraulic machine at 0.5 MPa for 2 hours.

[0098] (6) The sample was removed from the hydraulic machine and demolded to obtain an artificial sample that was not fully cured, and the sample was placed in an oven at 90°C for 48 hours to fully evaporate the water in the pores, thereby precipitating the single crystal sugar in the solution; a pore-filled hydrate reservoir artificial core with a saturation of 30% was obtained.

[0099] Example 5

[0100] (1) The quartz sand was sieved, and 300 grams of 100-mesh quartz sand was selected and thoroughly mixed with 30 grams of 3000-mesh kaolin to obtain a mixed powder of the two minerals.

[0101] (2) 8 grams of epoxy resin and its curing agent, epoxy resin 593 curing agent (addition product of diethylene triamine and butyl glycidyl ether) 4 grams, were placed in an incubator and incubated at a temperature of 45°C for 2 hours; removed and mixed with the powder, and the epoxy resin adhesive was prepared according to 4% by weight of the total weight of the mixed powder, and finally the mixed powder and the adhesive were thoroughly mixed to make the adhesive evenly distributed in the mineral powder.

[0102] (3) 20 grams of single crystal sugar and 30 grams of pure water were weighed, and the single crystal sugar was fully dissolved in water to form a single crystal aqueous solution.

[0103] (4) The single crystal aqueous solution was added to the mixed mineral powder with the added adhesive, and thoroughly stirred to fully mix the two.

[0104] (5) The mold was cleaned with alcohol and vaseline was applied around the mold to facilitate demolding; then the mixture obtained in the previous step was added layer by layer into the mold, and was pressed under a single-axis hydraulic machine at 0.5 MPa for 2 hours.

[0105] (6) The sample is removed from the hydraulic press and demolded to obtain an incompletely cured artificial sample, which is placed in an oven at 90°C for 48 hours to fully evaporate the moisture in the pores, thereby precipitating the single crystal sugar from the solution; a pore filling type hydrate reservoir artificial core with a saturation degree of 40% is obtained.

[0106] Example 6

[0107] (1) The quartz sand is sieved, and 300 grams of quartz sand with a mesh size of 100 is selected and then fully mixed with 30 grams of kaolin with a mesh size of 3000 to obtain a mixed powder of the two minerals.

[0108] (2) 8 grams of epoxy resin and 4 grams of its curing agent, epoxy resin 593 curing agent (an addition product of diethylenetriamine and butyl glycidyl ether), are placed in an incubator and incubated at a temperature of 45°C for 2 hours; then taken out and mixed with the mixed powder to prepare an epoxy resin binder at a proportion of 4% by weight based on the total weight of the mixed powder; finally, the mixed powder and the binder are fully mixed to uniformly distribute the binder in the mineral powder.

[0109] (3) 25 grams of single crystal sugar and 30 grams of pure water are weighed, and the single crystal sugar is fully dissolved in the water to form a single crystal aqueous solution.

[0110] (4) The single crystal aqueous solution is mixed with the mixed mineral powder with the added binder, and fully stirred to fully mix the two.

[0111] (5) The mold is cleaned with alcohol and the periphery of the mold is wiped with vaseline for easy demolding; then the mixture obtained in the previous step is added layer by layer into the mold, and the mold is placed under a single-axis hydraulic press for pressing at 0.5 MPa for 2 hours.

[0112] (6) The sample is removed from the hydraulic press and demolded to obtain an incompletely cured artificial sample, which is placed in an oven at 90°C for 48 hours to fully evaporate the moisture in the pores, thereby precipitating the single crystal sugar from the solution; a pore filling type hydrate reservoir artificial core with a saturation degree of 50% is obtained.

[0113] Example 7

[0114] (1) The quartz sand is sieved, and 300 grams of quartz sand with a mesh size of 100 is selected and then fully mixed with 30 grams of kaolin with a mesh size of 3000 to obtain a mixed powder of the two minerals.

[0115] (2) 8 grams of epoxy resin and its curing agent, epoxy resin 593 curing agent (addition product of diethylene triamine and butyl glycidyl ether) 4 grams, were placed in an incubator and incubated at a temperature of 45°C for 2 hours; they were removed and an epoxy resin binder was prepared at 4% by weight of the total weight of the mixed powder; finally, the mixed powder and the binder were thoroughly mixed so that the binder was uniformly distributed in the mineral powder.

[0116] (3) 30 grams of single crystal sugar and 30 grams of purified water were weighed out, and the single crystal sugar was thoroughly dissolved in the water to form a single crystal aqueous solution.

[0117] (4) The single crystal aqueous solution was added to the mixed mineral powder with the binder, and thorough stirring was performed so that the two could be thoroughly mixed.

[0118] (5) The mold was cleaned with alcohol, and vaseline was applied around the mold to facilitate demolding; then the mixture obtained in the previous step was added to the mold layer by layer, and was pressed in a single-axis hydraulic machine at 0.5 MPa for 2 hours.

[0119] (6) The sample was removed from the hydraulic machine and demolded to obtain an artificial sample that was not completely cured, and the sample was placed in an oven at 90°C for 48 hours to evaporate the water in the pores and thus precipitate the single crystal sugar in the solution; a saturation degree of 60% pore-filling hydrate reservoir artificial core was obtained.

[0120] Example 8

[0121] (1) Quartz sand was sieved, and quartz sand of 100 mesh was selected 300 grams, and then it was thoroughly mixed with 30 grams of kaolin of 3000 mesh to obtain a mixed powder of the two minerals.

[0122] (2) 8 grams of epoxy resin and its curing agent, epoxy resin 593 curing agent (addition product of diethylene triamine and butyl glycidyl ether) 4 grams, were placed in an incubator and incubated at a temperature of 45°C for 2 hours; they were removed and an epoxy resin binder was prepared at 4% by weight of the total weight of the mixed powder; finally, the mixed powder and the binder were thoroughly mixed so that the binder was uniformly distributed in the mineral powder.

[0123] (3) 30 grams of sucrose and 30 grams of purified water were weighed out, and the sucrose was thoroughly dissolved in the water to form a single crystal aqueous solution.

[0124] (4) The single crystal aqueous solution was added to the mixed mineral powder with the binder, and thorough stirring was performed so that the two could be thoroughly mixed.

[0125] (5) The mold was cleaned with alcohol, and vaseline was applied around the mold to facilitate demolding; then the mixture obtained in the previous step was added to the mold layer by layer, and was pressed in a single-axis hydraulic machine at 0.5 MPa for 2 hours.

[0126] (6) The sample is removed from the hydraulic press and demolded to obtain an incompletely cured artificial sample, which is placed in an oven at 90℃ for 48 hours to fully evaporate the moisture in the pores, thereby precipitating the sucrose in the solution; a 60% saturation degree pore filling type hydrate reservoir artificial core is obtained.

[0127] Example 9

[0128] The artificial core prepared in Example 1 (without single crystal material) is used as the underlying free gas layer, the artificial core prepared in Example 4 (with single crystal material) is used as the hydrate reservoir, and the epoxy resin is used as the surrounding rock part to wrap the hydrate reservoir and the underlying free gas layer, thereby obtaining a wedge-shaped pore filling type hydrate reservoir physical model. Figure 4 The photograph of the wedge-shaped pore filling type hydrate reservoir physical model prepared in this example is shown in Figure 9.

[0129] Test Example 1

[0130] The artificial cores prepared in Examples 1-7 are subjected to ultrasonic testing, and the testing method is as follows: an ultrasonic testing system.

[0131] The longitudinal and transverse wave test results of the artificial cores prepared in Examples 1-7 are shown in Figure 8, and according to the test result curve, the longitudinal and transverse wave velocities of the artificial core samples prepared in Examples 1-7 have a good corresponding relationship with the velocities in the hydrate reservoir region of the seabed in the literature (Natural Gas Hydrate Reservoir Rock Physical Model Construction, 2018, Liu Xinxin et al.), and the change rule of saturation and longitudinal and transverse wave velocities is also more consistent with the actual change of the seabed hydrate reservoir, which indicates that the artificial core provided by the present application has high similarity in physical properties with the actual artificial core, can be simulated, and is helpful for rock physical analysis of the pore filling type natural gas hydrate reservoir. Figure 3 Test Example 2

[0132] The wedge-shaped pore filling type hydrate reservoir physical model prepared in Example 9 is subjected to data acquisition by using a seismic physical model data acquisition system, and the obtained data is analyzed, and the self-excitation and self-recovery profile of the model is shown in Figure 10.

[0133] As can be seen from the analysis profile, the bottom of the hydrate reservoir has obvious BSR characteristics, which indicates that the physical model prepared by the present application can be used for seismic data analysis of the hydrate reservoir. Figure 5 In summary, the pore filling type natural gas hydrate reservoir artificial core provided by the present application is similar to the natural hydrate reservoir, can simulate the test of the hydrate reservoir at room temperature, and is suitable for experimental research on the physical properties of natural gas hydrate.

[0134]

[0135] ​The above merely describes the preferred embodiments of the present application. It should be noted that, for those skilled in the art, other equivalent variations and improvements can be made under the technical inspiration provided by the present application, as the common knowledge in the art, which should also be considered as the protection scope of the present application.

Claims

1. A pore-filling type natural gas hydrate reservoir artificial core, characterized by, The raw materials include quartz sand, kaolin, a cementing agent, water, and a single crystal material; The single crystal material is at least one of sucrose, maltose, gentiobiose, single crystal sugar candy, and white sugar; The particle size of the quartz sand is 80-120 mesh; the particle size of the kaolin is 2500-3500 mesh; The content of the quartz sand is 75-87% by weight of the total artificial core; The content of the kaolin is 7-8% by weight of the total artificial core; The content of the cementing agent is 3-5% by weight of the sum of the quartz sand and the kaolin; The weight ratio of the single crystal material to the quartz sand is (0.01-0.2):

1.

2. The artificial core according to claim 1, characterized in that, The particle size of the quartz sand is 100 mesh.

3. The artificial core according to claim 1, characterized in that, The particle size of the kaolin is 3000 mesh.

4. Artificial core according to any one of claims 1-3, characterized in that, The weight ratio of the quartz sand to the kaolin is 1:(0.08-0.12).

5. The artificial core according to claim 4, characterized in that, The weight ratio of the quartz sand to the kaolin is 1:0.

1.

6. The artificial core according to any one of claims 1-3, characterized in that, The cementing agent is an epoxy resin cementing agent.

7. The artificial core according to claim 6, characterized in that, The epoxy resin cementing agent includes an epoxy resin and a curing agent.

8. The artificial core according to claim 7, characterized in that, The weight average molecular weight of the epoxy resin is 2000-6000.

9. The artificial core according to claim 8, characterized in that, The epoxy resin is at least one of bisphenol A epoxy resin E44, bisphenol A epoxy resin E51, and bisphenol A epoxy resin E55.

10. The artificial core according to any one of claims 1-3, characterized in that, The content of the cementing agent is 4% by weight of the sum of the quartz sand and the kaolin.

11. The artificial core according to any one of claims 1-3, characterized in that, The longitudinal wave velocity of the single crystal material is 3300-3700 m / s, the transverse wave velocity is 1680-1800 m / s, and the density is 1.1-1.2 g / cm 3 .

12. The method for producing a pore-filling type natural gas hydrate reservoir artificial core according to any one of claims 1 to 11, characterized by, The preparation method includes the following steps: A. mixing quartz sand, kaolin, a cementing agent, water, and a single crystal material to obtain a mixture; B. pressing the mixture and evaporating.

13. The method of claim 12, wherein, The preparation method of the cementing agent includes mixing an epoxy resin and a curing agent.

14. The method of claim 13, wherein, The mixing condition includes a temperature of 40-50°C and a time of 1.5-2.5 hours.

15. The method of claim 14, wherein, The mixing condition includes incubation at 45°C for 2 hours.

16. The method according to any one of claims 12-15, characterized in that, The pressing process includes layer-by-layer addition of the mixture to a mold and pressing for 1.5-2.5 hours.

17. The method of claim 16, wherein, The pressing time is 2 hours.

18. The method of any one of claims 12-15, wherein, The evaporation method includes a temperature of 80-100°C and a time of 40-56 hours.

19. The method of claim 18, wherein, The evaporation method includes a temperature of 90°C and a time of 48 hours.

20. A model of a hydrate reservoir physics of a wedge-shaped pore filling type, characterized in that, The physical model includes a hydrate reservoir, an underlying free gas layer, and a surrounding rock part, wherein the hydrate reservoir is the artificial core of any one of claims 1-11 containing a single crystal material, and the underlying free gas layer is the artificial core of any one of claims 1-11 not containing a single crystal material.

21. The use of the artificial core of any one of claims 1-11, the artificial core prepared by the method of any one of claims 12-19, or the wedge-shaped pore filling type hydrate reservoir physical model of claim 20 in petrophysical analysis and seismic data analysis of a hydrate reservoir.

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