Hydrate reservoir model device based on transparent soil and test method

Abstract

The invention discloses a transparent soil-based hydrate reservoir model device and test method.The transparent soil-based hydrate reservoir model device comprises a hydrate preparation device, a hydrate laying device and a hydrate reservoir model device.The hydrate preparation device comprises a liquid injection pipe, an upper clamping plate, an iron wire, an iron wire fixing device, a hydrate core and a lower clamping plate; the hydrate preparation device is used for preparing hydrates; the hydrate laying device comprises a fixing cylinder and a fixing hole; the hydrate reservoir model device comprises a transparent soil model tank, transparent soil and a mining pipeline, the transparent soil is arranged in the transparent soil model tank, the hydrate is arranged in the transparent soil, and the hydrate reservoir model device is used for simulating a hydrate reservoir. The device has the beneficial effects that the hydrate adopts fused quartz sand with different sizes inside and a tetrahydrofuran solid shell outside, so that the defect that the traditional decomposition test cannot be stopped once starting is overcome, and the decomposition degree of the hydrate in different areas is manually controlled.

Description

Technical Field

[0001] The invention relates to the technical field of hydrate mining test simulation, and in particular to a hydrate reservoir model device and a test method based on transparent soil. Background Art

[0003] At present, indoor model tests mainly observe the deformation response of hydrate reservoirs and seabeds by burying sensors. The operation of this method is cumbersome, and the burying of sensors affects the results of model tests. Once hydrates begin to decompose, they cannot be stopped. However, in actual seabed hydrate mining, the degree of hydrate decomposition is related to the distance from the mining well. Seabed hydrates cannot be completely decomposed, and the deformation characteristics of completely decomposed and incompletely decomposed seabeds are different. In addition, if the field test method is adopted, it will be very expensive and technically difficult.

[0004] Therefore, in order to study the reservoir response to incomplete decomposition of hydrates during and after hydrate production is stopped, it is urgent to develop an experimental method that is simple to operate, low-cost and can achieve artificial control of hydrate decomposition. Summary of the invention

[0005] In view of the above-mentioned prior art, the present invention provides a hydrate reservoir model device and test method based on transparent soil, which mainly solves the technical problems existing in the above-mentioned background technology.

[0006] To achieve the above object, the technical solution of the embodiment of the present invention is implemented as follows:

[0007] A hydrate reservoir model device based on transparent soil, comprising a hydrate preparation device, a hydrate deployment device and a hydrate reservoir model device, wherein the hydrate preparation device comprises an injection pipe, an upper clamping plate, an iron wire, an iron wire fixing device, a hydrate core and a lower clamping plate, at least two grooves are respectively arranged on the opposite surfaces of the upper clamping plate and the lower clamping plate, the groove of the upper clamping plate and the groove of the lower clamping plate are opposite to each other up and down, the upper clamping plate is provided with the injection pipe, the injection pipe is connected with the groove, the lower clamping plate is provided with the iron wire fixing device on both sides of the groove, the hydrate core is provided with a through hole, the iron wire passes through the through hole and is connected to the iron wire fixing device in a detachable manner, and the hydrate preparation device is used for preparing hydrate;

[0008] The hydrate deployment device comprises a fixing tube and fixing holes, the fixing tube is provided with the fixing holes equidistantly distributed along the axis, and the fixing holes are used to fix the hydrate;

[0009] The hydrate reservoir model device includes a transparent soil model tank, transparent soil and an extraction pipeline. The transparent soil is arranged inside the transparent soil model tank, and the hydrate is arranged in the transparent soil, which is used to simulate the hydrate reservoir. The extraction pipeline is installed in the transparent soil, and a linear heat source is arranged in the extraction pipeline. The linear heat source is used to provide the heat required for simulating the extraction and decomposition of hydrates. The side wall of the extraction pipeline located in the transparent soil model tank is provided with a plurality of equidistantly distributed extraction holes.

[0010] Preferably, the hydrate nucleus is fused silica sand, and the shape of the fused silica sand can be nodule-like, vein-like, thick-layered or thin-layered.

[0011] Preferably, the groove may be a nodule-shaped, vein-shaped, thick-layered or thin-layered groove, and the groove is used to configure the hydrate in a shape consistent with that of the hydrate core.

[0012] Preferably, the hydrate includes pure hydrate and nucleus-containing hydrate.

[0013] Preferably, the inner diameter of the hydrate arrangement device is 1 to 2 cm larger than the diameter of the hydrate.

[0014] Preferably, the transparent soil is made by mixing mixed oil and fused quartz sand, and the transparent soil is used to simulate marine soil layers and hydrate-containing sediment layers.

[0015] A hydrate reservoir model test method based on transparent soil comprises: S1, selecting hydrate cores of different sizes and shapes of 1mm to 2cm; passing an iron wire through a pre-set through hole in the hydrate core; fixing the iron wire with the hydrate core in an iron wire fixing device on a lower clamping plate of a hydrate preparation device; the upper clamping plate and the lower clamping plate are combined and closed; S2, preparing a tetrahydrofuran aqueous solution with a mass fraction of 19% to 21%, and sending the tetrahydrofuran aqueous solution into a groove of the hydrate preparation device through an injection pipe, and the hydrate preparation device maintains a temperature between 0 and 4°C for 24 to 48 hours, so that the tetrahydrofuran aqueous solution becomes solid and forms a hydrate;

[0016] S3, taking out hydrates from the hydrate preparation device, fixing hydrates formed by hydrate nuclei of different sizes in the hydrate arrangement device with iron wires, and while fixing the hydrates in the hydrate arrangement device, sprinkling transparent soil by the sand rain method; S4, pulling out the iron wires from the fixing holes of the hydrate arrangement device, then placing the hydrate arrangement device in the transparent soil model groove, sprinkling transparent soil in the gap by the sand rain method, and pulling out the hydrate arrangement device after completion; S5, placing the mining pipeline in the transparent soil, and placing a constant line heat source on the inner wall of the mining pipeline;

[0017] S6. Use lasers and cameras to monitor the progress of the test in real time, then record the flow path of the gas produced by hydrate decomposition, and then obtain the hydrate decomposition displacement field, temperature field and formation settlement response results through pixel processing.

[0018] The beneficial effects of the present invention are as follows: the hydrate uses fused quartz sand of different sizes inside and a solid shell of tetrahydrofuran outside, which overcomes the disadvantage that the traditional decomposition test cannot be stopped once it starts, and realizes artificial control of the hydrate decomposition degree in different areas; the hydrate core uses fused quartz sand, which is the same as the configuration material of transparent soil, and can realize visual incomplete decomposition of hydrates, that is, observation of formation settlement response after stopping mining; the hydrate reservoir model test method is low-cost and highly practical. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic structural diagram of a hydrate reservoir model device based on transparent soil in an embodiment of the present application;

[0020] Figure 2 This is a schematic diagram of the structure of the hydrate preparation device in the embodiment of the present application;

[0021] Figure 3 It is a schematic diagram of the structure of the hydrate arrangement device and the transparent soil model tank in the embodiment of the present application;

[0022] Description of Figure Numbers:

[0023] 101. injection pipe; 102. upper clamp; 103. iron wire; 104. iron wire fixing device; 105. hydrate core; 106. lower clamp; 107. groove; 108. through hole; 201. fixing cylinder; 202. fixing hole; 301. transparent soil model groove; 302. transparent soil; 303. mining pipeline; 304. linear heat source; 305. mining hole; 401. laser instrument; 402. camera. DETAILED DESCRIPTION

[0024] The technical solution of the present invention is further elaborated in detail below in conjunction with the drawings and specific embodiments of the specification. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by technicians in the technical field of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention. In the following description, the expression "some embodiments" is related to a subset of all possible embodiments, but it should be understood that "some embodiments" can be the same subset or different subsets of all possible embodiments, and can be combined with each other without conflict.

[0025] It should also be noted that when an element is referred to as being "fixed to" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "inside", "outside", "left", "right" and similar expressions used herein are for illustrative purposes only and are not intended to be the only implementation method.

[0026] Example 1

[0027] Please refer to the attached Figure 1-3 The present application provides a hydrate reservoir model device and an experimental method based on transparent soil, including a hydrate preparation device, a hydrate deployment device and a hydrate reservoir model device, wherein the hydrate preparation device includes an injection pipe 101, an upper clamping plate 102, an iron wire 103, an iron wire fixing device 104, a hydrate core 105 and a lower clamping plate 106, at least two grooves 107 are respectively arranged on the opposite surfaces of the upper clamping plate 102 and the lower clamping plate 106, the groove 107 of the upper clamping plate 102 and the groove 107 of the lower clamping plate 106 are opposite to each other up and down, the upper clamping plate 102 is provided with the injection pipe 101, the injection pipe 101 is connected to the groove 107, the lower clamping plate 106 is provided with the iron wire fixing device 104 on both sides of the groove 107, the hydrate core 105 is provided with The through hole 108, the iron wire 103 passes through the through hole 108 and is connected to the iron wire fixing device 104 in a detachable manner, and the hydrate preparation device is used to prepare hydrates; the iron wire 103 passes through the hydrate core 105 through the through hole 108, and then the iron wire 103 is fixed on the iron wire fixing device 104 of the lower clamping plate 106. The function of the iron wire 103 and the iron wire fixing device 104 is to suspend the hydrate core 105 in the middle of the groove 107, so as to facilitate the preparation of the core-containing hydrate required for the test, and then the upper clamping plate 102 and the lower clamping plate 106 are combined to form a closed space, which is convenient for the preparation of hydrates, and the tetrahydrofuran aqueous solution is injected through the injection tube 1401, and flows into the groove 107 to wrap the hydrate core 105, and the hydrate preparation device is placed in a low temperature state to make the tetrahydrofuran aqueous solution become solid to form a core-containing hydrate.

[0028] The hydrate deployment device includes a fixing tube 201 and fixing holes 202. The fixing tube 201 has the fixing holes 202 equidistantly distributed along the axis, and the fixing holes 202 are used to fix the hydrates. The hydrate deployment device fixes the hydrates through the fixing holes 202, determines the position of the hydrates in the hydrate reservoir, and artificially controls the degree of hydrate decomposition in different areas.

[0029] The hydrate reservoir model device includes a transparent soil model tank 301, transparent soil 302 and a production pipeline 303. The transparent soil 302 is arranged inside the transparent soil model tank 301, and the hydrate is arranged in the transparent soil 302 to simulate the hydrate reservoir. The production pipeline 303 is installed in the transparent soil 302. A wire heat source 304 is arranged in the production pipeline 303 to provide heat required for simulating hydrate production and decomposition. The side wall of the production pipeline 303 located in the transparent soil model tank 301 is provided with a plurality of equidistantly distributed production holes 305. Transparent soil 302 and hydrates are placed in the transparent soil model tank 301. As a hydrate reservoir model, the role of the transparent soil 301 is to clearly and accurately observe the migration process of soil particles in the hydrate reservoir and the mining well caused by hydrate decomposition. The mining pipeline 303 is set in the transparent soil 302. The heat of the line heat source 304 is transferred to the transparent soil 302 through the mining hole 303 to provide heat for the hydrate decomposition. The line heat source 304 can provide a constant temperature and can adjust the temperature to carry out hydrate mining simulation tests at different temperatures.

[0030] Furthermore, the hydrate core 105 is fused silica sand, and the shape of the fused silica sand can be nodule-shaped, vein-shaped, thick-layered or thin-layered. The hydrate core 105 uses fused silica sand in order to have the same configuration material as the transparent soil 302, so as to realize the observation of incomplete decomposition of visualized hydrates. The shapes of the fused silica sand are various in order to simulate different hydrate states of incomplete decomposition of hydrates and artificially control the degree of hydrate decomposition in different regions.

[0031] Furthermore, the groove 107 may be a nodule-shaped, vein-shaped, thick-layered or thin-layered groove 107 , and the groove 107 is used to configure the hydrate in a shape consistent with the shape of the hydrate core 105 .

[0032] Furthermore, the hydrate includes pure hydrate and nucleus hydrate. In the hydrate formation, the hydrate decomposition characteristics around the production pipeline 303 are set to simulate the actual formation hydrate decomposition characteristics and the formation deformation characteristics of the hydrate that is not completely decomposed.

[0033] Furthermore, the inner diameter of the hydrate arrangement device is 1 to 2 cm larger than the diameter of the hydrate. The hydrate in the hydrate arrangement device is also wrapped with a layer of transparent soil so that the position of the hydrate will not change after the hydrate arrangement device is removed, thereby affecting the test results.

[0034] Furthermore, the transparent soil 302 is made of mixed oil and fused silica sand, and is used to simulate the marine soil layer and the hydrate-containing sediment layer. The mixed oil, as the pore fluid of the fused silica sand, is transparent, and the changes inside the transparent soil 302 can be easily observed from the outside of the transparent soil model tank 301.

[0035] The present invention provides a hydrate reservoir model test method based on transparent soil, which is based on the above-mentioned hydrate reservoir model device based on transparent soil, and comprises: S1, selecting hydrate cores 105 of different sizes and shapes of 1mm to 2cm; passing an iron wire 103 through a pre-set through hole 108 in the hydrate core 105; fixing the iron wire 103 with the hydrate core 105 in a wire fixing device 104 on a lower clamping plate 106 of a hydrate preparation device; the upper clamping plate 102 and the lower clamping plate 106 are combined and closed; S2, preparing a tetrahydrofuran aqueous solution with a mass fraction of 19% to 21%, and sending the tetrahydrofuran aqueous solution into a groove 107 of the hydrate preparation device through a liquid injection pipe 101, and the hydrate preparation device maintains a temperature between 0 and 4°C for 24 to 48 hours, so that the tetrahydrofuran aqueous solution becomes solid and forms a hydrate; S3, Hydrates are taken out from the hydrate preparation device, and hydrates formed by hydrate nuclei 105 of different sizes are fixed in the hydrate arrangement device with iron wires 103 according to the design requirements. While the hydrates are fixed in the hydrate arrangement device, the transparent soil 302 is sprinkled by the sand rain method; S4, the iron wires 103 of the fixing holes 202 of the hydrate arrangement device are pulled out, and then the hydrate arrangement device is placed in the transparent soil model groove 301, and the transparent soil 302 is sprinkled in the gap by the sand rain method. After completion, the hydrate arrangement device is pulled out; S5, the production pipeline 303 is placed in the transparent soil 302, and a constant line heat source 304 is placed on the inner wall of the production pipeline 303; S6, the progress of the test is detected in real time by using a laser instrument 401 and a camera 402, and then the flow path of the gas generated by the decomposition of the hydrate is recorded, and then the displacement field, temperature field and formation settlement response results of the hydrate decomposition are obtained by pixel processing.

[0036] The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. The protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A hydrate reservoir model device based on transparent soil, characterized in that: It comprises a hydrate preparation device, a hydrate arrangement device and a hydrate reservoir model device, wherein the hydrate preparation device comprises an injection pipe, an upper splint, an iron wire, an iron wire fixing device, a hydrate core and a lower splint, at least two grooves are respectively arranged on the opposite surfaces of the upper splint and the lower splint, the groove of the upper splint and the groove of the lower splint are opposite to each other up and down, the upper splint is provided with the injection pipe, the injection pipe is connected with the groove, the lower splint is provided with the iron wire fixing device on both sides of the groove, the hydrate core is provided with a through hole, the iron wire passes through the through hole and is connected with the iron wire fixing device in a detachable manner, and the hydrate preparation device is used for preparing hydrate; The hydrate deployment device comprises a fixing tube and fixing holes, the fixing tube is provided with the fixing holes equidistantly distributed along the axis, and the fixing holes are used to fix the hydrate; The hydrate reservoir model device includes a transparent soil model trough, transparent soil and an extraction pipeline. The transparent soil is arranged inside the transparent soil model trough, and the hydrate is arranged in the transparent soil for simulating a hydrate reservoir. The extraction pipeline is installed in the transparent soil. The extraction pipeline is located at the bottom of the transparent soil and is closed. A linear heat source is arranged in the extraction pipeline, and the linear heat source is used to provide heat required for simulating hydrate extraction and decomposition. The side wall of the extraction pipeline located in the transparent soil model trough is provided with a plurality of equidistantly distributed extraction holes.

2. A hydrate reservoir model device based on transparent soil according to claim 1, characterized in that: The hydrate core is fused silica sand, and the shape of the fused silica sand can be nodule-like, vein-like, thick-layered or thin-layered.

3. The hydrate reservoir model device based on transparent soil according to claim 1 is characterized in that: The groove may be a nodule-shaped, vein-shaped, thick-layered or thin-layered groove, and the groove is used to configure the hydrate in a shape consistent with the shape of the hydrate core.

4. The hydrate reservoir model device based on transparent soil according to claim 1, characterized in that: The hydrates include pure hydrates and nucleus-containing hydrates.

5. The hydrate reservoir model device based on transparent soil according to claim 1, characterized in that: The inner diameter of the hydrate arrangement device is 1 to 2 cm larger than the diameter of the hydrate.

6. The hydrate reservoir model device based on transparent soil according to claim 1, characterized in that: The transparent soil is made by mixing mixed oil and fused silica sand, and the transparent soil is used to simulate a marine soil layer and a hydrate-containing sediment layer.

7. The hydrate reservoir model test method based on transparent soil is characterized by: The hydrate reservoir model device based on transparent soil according to claim 1 comprises the following steps: S1. Select hydrate cores of different sizes and shapes ranging from 1 mm to 2 cm; pass the iron wire through the pre-set through hole in the hydrate core; fix the iron wire with the hydrate core in the iron wire fixing device on the lower clamping plate of the hydrate preparation device; and close the upper clamping plate and the lower clamping plate after merging; S2. Prepare a tetrahydrofuran aqueous solution with a mass fraction of 19% to 21%, and feed the tetrahydrofuran aqueous solution into the groove of the hydrate preparation device through an injection tube. The hydrate preparation device maintains a temperature between 0 and 4° C. for 24 to 48 hours, so that the tetrahydrofuran aqueous solution becomes solid and forms a hydrate; S3, taking out hydrates from the hydrate preparation device, fixing hydrates formed by hydrate nuclei of different sizes in the hydrate arrangement device with iron wires, and while fixing the hydrates in the hydrate arrangement device, sprinkling transparent soil by the sand rain method; S4, pulling out the iron wire of the fixing hole of the hydrate deployment device, then putting the hydrate deployment device into the transparent soil model groove, and sprinkling transparent soil into the gap by sand rain method, and after completion, pulling out the hydrate deployment device; S5. The mining pipeline is placed in transparent soil, and a constant line heat source is placed on the inner wall of the mining pipeline; S6. Use lasers and cameras to monitor the progress of the test in real time, then record the flow path of the gas produced by hydrate decomposition, and then obtain the hydrate decomposition displacement field, temperature field and formation settlement response results through pixel processing.

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