Deep-sea fidelity core triaxial test device suitable for ship-borne laboratory

Abstract

The present invention relates to the technical field of seabed core triaxial tests. Disclosed is a deep-sea fidelity core triaxial test device suitable for a ship-borne laboratory. The deep-sea fidelity core triaxial test device comprises a sample transfer system and a triaxial main unit system. A sample that meets the length requirements for a triaxial test is stored in the sample transfer system, and a ball valve is closed to preserve the high-pressure environment of the sample; and the sample is released from a tube by means of a tube-releasing piston and is then sent into a triaxial test system, and is subjected to a triaxial test in a rubber cylinder, thereby obtaining the mechanical properties of a deep-sea energy soil reservoir sample. The device of the present invention is convenient to carry on a scientific research ship and convenient to connect to the existing natural gas hydrate sample pressure-maintaining transfer system, and a fidelity triaxial test is carried out immediately after a natural gas hydrate sample is obtained, thus having significant scientific research benefits.

Description

A deep-sea fidelity core triaxial test device suitable for shipboard laboratories Technical Field

[0001] The present invention relates to the technical field of seabed core triaxial testing, and in particular to a deep-sea fidelity core triaxial testing device suitable for shipboard laboratories. Background Art

[0002] my country is one of the world's largest energy producers and consumers, endowed with abundant fossil energy resources. However, per capita energy availability is low, and energy security and environmental pollution are becoming increasingly severe. There is an urgent need to develop new, environmentally friendly energy products. Natural gas hydrates, as a new clean energy source, offer broad distribution, deep burial depth, are pollution-free, and possess high energy density, offering promising development prospects. However, the ecological and environmental challenges associated with the mining of deep-sea energy soils (seafloor sediments containing natural gas hydrates) are a pressing challenge that countries around the world must address. Therefore, studying the mechanical properties of deep-sea energy soil gas-bearing reservoirs is crucial for the safe exploitation of deep-sea energy resources and holds significant theoretical and guiding significance for the development of new energy sources.

[0003] Triaxial testing is one of the most widely used methods for studying soil strength and deformation properties. It is highly suitable for studying the mechanical properties of deep-sea energy reservoirs. However, conventional triaxial testing equipment is often only suitable for rock and soil samples subjected to low pressures at room temperature, which does not meet the testing conditions of deep-sea energy reservoirs. To address these issues, a deep-sea core triaxial testing apparatus suitable for shipboard laboratories was designed.

[0004] Summary of the Invention

[0005] The purpose of the present invention is to provide a deep-sea fidelity core triaxial testing device suitable for shipboard laboratories, which is used for the study of the mechanical properties of deep-sea energy soil reservoirs. It can well solve the triaxial testing problems of deep-sea energy soil reservoirs, provide an effective safety design scheme for the safe mining of deep-sea energy soil, and provide corresponding theoretical support for reducing the environmental risks caused by energy mining.

[0006] To achieve the above object, the present invention provides the following solution: The present invention provides a deep-sea fidelity core triaxial test device suitable for shipboard laboratories, comprising

[0007] A sample transfer system, the sample transfer system is used to remove the natural gas hydrate sample from the tube and send it into the three-axis host system. The sample transfer system includes a sample barrel, a tube removal piston, a ball valve and a connector. The sample barrel and the ball valve are connected by bolts. The sample is placed in the sample barrel. The tube removal piston provided in the sample barrel is used to push the sample into the three-axis host system; and

[0008] A three-axis mainframe system is used to complete the triaxial test of natural gas hydrate samples under vacuum conditions. The three-axis mainframe system includes a bottom interface, a rubber cylinder, a three-axis inner wall, a three-axis outer wall and a top interface. The bottom interface and the sample cylinder are sealed and connected by the connecting piece. The bottom interface is communicated with the rubber cylinder arranged in the inner cavity of the three-axis inner wall. The sample is sent into the rubber cylinder for triaxial compression test; the three-axis inner wall is filled with seawater for ensuring the test pressure, and the three-axis outer wall located on the outer periphery of the three-axis inner wall is provided with a water inlet and outlet, and the circulating cold water is connected to the water inlet and outlet on the three-axis outer wall.

[0009] Preferably, the connecting piece is a clamp, and the bottom interface and the sample cylinder are sealed and connected via the clamp.

[0010] Preferably, a triangular groove symmetrically arranged in the upper and lower directions is formed at the tail end of the tube-ejecting piston. When the sample is deposited into the sample cylinder, the oil between the tube-ejecting piston and the sample cylinder flows out through the axial triangular groove.

[0011] Preferably, a plastic tube is attached to the outside of the sample placed in the sample cylinder, and the diameter of the tube-removing piston is smaller than the inner diameter of the plastic tube.

[0012] Preferably, the diameter of the bottom interface is smaller than the outer diameter of the plastic tube; the tube-detaching piston in the sample transfer system pushes the sample forward under the action of seawater until it reaches the bottom interface of the three-axis host system, and the sample is pushed out of the plastic tube and enters the three-axis host system by the tube-detaching piston.

[0013] Preferably, the bottom interface and the top interface are both provided with confining pressure holes, and the confining pressure holes on the bottom interface and the top interface provide confining pressure for the sample in cooperation with an external pressure device.

[0014] Preferably, a pore pressure hole is provided on the top interface, and the pore pressure hole is used to test the pore pressure of the sample during the triaxial test.

[0015] Preferably, the rubber tube is fixedly installed in the inner cavity of the inner wall of the three shafts through a fixing ring.

[0016] Compared with the prior art, the present invention has achieved the following beneficial technical effects:

[0017] The present invention, a deep-sea core triaxial testing apparatus suitable for shipboard laboratories, comprises a sample transfer system and a triaxial host system. Samples meeting the triaxial test length requirements are deposited into the sample transfer system, and a ball valve is closed to maintain the sample's high pressure environment. A tube-removing piston removes the sample from the tube and transfers it into the triaxial testing system, where triaxial testing is performed within a rubber cylinder to determine the mechanical properties of deep-sea energy soil reservoir samples. This device is easily transported on scientific research vessels and docks with existing natural gas hydrate sample pressure-maintaining transfer systems. Fidelity triaxial testing can be performed immediately upon acquisition of the natural gas hydrate sample, providing significant scientific research benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0019] FIG1 is a schematic diagram of the overall structure of a deep-sea fidelity core triaxial test apparatus suitable for a shipboard laboratory;

[0020] FIG2 is a schematic structural diagram of a sample transfer system;

[0021] Figure 3 is a schematic diagram of the structure of the three-axis host system;

[0022] Reference numerals in the figure: 1 sample transfer system; 1-1 sample cylinder; 1-2 tube removal piston; 1-3 sample; 1-4 ball valve; 1-5 clamp; 2 three-axis host system; 2-1 bottom interface; 2-2 rubber cylinder; 2-3 fixing ring; 2-4 three-axis inner wall; 2-5 three-axis outer wall; 2-6 top interface. DETAILED DESCRIPTION

[0023] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0024] The purpose of the present invention is to provide a deep-sea fidelity core triaxial testing device suitable for shipboard laboratories, which is used for the study of the mechanical properties of deep-sea energy soil reservoirs. It can well solve the triaxial testing problems of deep-sea energy soil reservoirs, provide an effective safety design scheme for the safe mining of deep-sea energy soil, and provide corresponding theoretical support for reducing the environmental risks caused by energy mining.

[0025] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0026] As shown in Figures 1-3, the present invention provides a deep-sea, high-fidelity core triaxial testing apparatus suitable for use in shipboard laboratories. The apparatus comprises a sample transfer system 1 and a triaxial host system 2. The sample transfer system 1 is responsible for removing the natural gas hydrate sample from the tube and transferring it to the triaxial host system. The triaxial host system 2 is responsible for completing triaxial testing of the natural gas hydrate sample under high-fidelity conditions.

[0027] The sample transfer system 1 is responsible for removing the natural gas hydrate sample from the tube and sending it into the three-axis host system 2. First, it connects to the existing natural gas hydrate sample pressure-maintaining transfer system on the market, and stores the authentic sample that has been cut to a certain length into the sample tube 1-1. At this time, the plastic tube attached to the outside of the sample 1-3 is still there; then the ball valve 1-4 in the sample transfer system 1 is closed, and the connection with the three-axis host system 2 is completed under the action of the clamp 1-5 device; finally, the tube removal piston 1-2 in the sample transfer system 1 pushes the natural gas hydrate sample 1-3 forward under the action of high-pressure seawater until it reaches the bottom interface 2-1 of the three-axis host system 2. The diameter of the bottom interface 2-1 is designed to be slightly smaller than the outer diameter of the plastic tube, and the diameter of the tube removal piston 1-2 is designed to be slightly smaller than the inner diameter of the plastic tube. Under the push of the tube removal piston 1-2, the natural gas hydrate sample 1-3 is removed from the tube and enters the three-axis host system 2.

[0028] As shown in Figure 2, the sample transfer system 1 includes a sample cylinder 1-1, a tube removal piston 1-2, a sample 1-3, a ball valve 1-4, and a clamp 1-5. The sample cylinder 1-1 and ball valve 1-4 are connected by bolts. The ball valve 1-4 is opened and closed to store the high-pressure natural gas hydrate sample 1-3. The sample 1-3 is pushed out of the tube by the tube removal piston 1-2 and enters the three-axis host system 2. The clamp 1-5 connects the sample transfer system 1 to the three-axis host system 2.

[0029] In one embodiment, the tail end of the tube-ejecting piston 1-2 is provided with vertically symmetrical triangular grooves, which act as a buffer. When the natural gas hydrate sample pressure-maintaining transfer system deposits the authentic sample into the sample tube 1-1, the oil between the tube-ejecting piston 1-2 and the sample tube 1-1 must flow out through the axial triangular grooves, thereby braking the tube-ejecting piston 1-2. The triangular throttling area of ​​this buffer device gradually decreases as the buffer stroke increases, thereby ensuring a uniform change in buffer pressure and reducing impact pressure.

[0030] The triaxial host system 2 is responsible for completing the triaxial test of the natural gas hydrate sample. It consists of an inner and outer double-layer structure, in which the triaxial inner wall is responsible for maintaining the high pressure in the deep sea, and the triaxial outer wall is responsible for maintaining the low temperature in the deep sea. Specifically, as shown in Figure 3, the triaxial host system 2 includes a bottom interface 2-1, a rubber cylinder 2-2, a fixing ring 2-3, a triaxial inner wall 2-4, a triaxial outer wall 2-5, and a top interface 2-6. The bottom interface 2-1 and the top interface 2-6 are both provided with confining pressure holes, which can provide confining pressure for the natural gas hydrate sample with the cooperation of an external pressure device; the top interface 2-6 is separately designed with a pore pressure hole, which can test the pore pressure of the natural gas hydrate sample during the triaxial test; the rubber cylinder 2-2 and the fixing ring 2-3 are combined to form a triaxial test reaction chamber; the triaxial inner wall 2-4 is filled with high-pressure seawater to maintain the high pressure in the deep sea, and the triaxial outer wall 2-5 is provided with a water inlet and outlet, and the circulating cold water is responsible for maintaining the low temperature in the deep sea.

[0031] Instructions for use of the present invention:

[0032] After the present invention carries the scientific research vessel to the vicinity of the target area of ​​the deep-sea energy soil reservoir, the staff on the scientific research vessel obtains deep-sea energy soil reservoir samples through pressure-maintaining drilling tools, and stores samples 1-3 in the existing pressure-maintaining transfer system. The natural gas hydrate pressure-maintaining transfer system cuts and transfers the samples 1-3, and stores the samples 1-3 that meet the triaxial test length requirements in the sample transfer system 1. The ball valve 1-4 is closed to preserve the high-pressure environment of the samples 1-3. The sample transfer system 1 is docked with the triaxial host system 2 under the action of the clamp 1-5; the tube-detaching piston 1-2 detaches the sample 1-3 and sends it into the triaxial host system 2, and performs a triaxial test in the rubber cylinder 2-2, thereby obtaining the mechanical properties of the deep-sea energy soil reservoir sample.

[0033] The deep-sea fidelity core triaxial testing device of the present invention, which is suitable for shipboard laboratories, has the following characteristics:

[0034] 1. This device uses a specially designed detachable piston 1-2 structure. After obtaining the authentic natural gas hydrate sample, the plastic tube attached to the outside of the sample 1-3 can be removed and placed into the reaction chamber, facilitating subsequent triaxial testing of the sample. The piston structure also serves as the axial pressure source for the triaxial test, simplifying the operation process and improving test efficiency.

[0035] 2. This device adopts a specially designed axial triangular throttling groove structure. The triangular throttling area of ​​the buffer device gradually decreases as the buffer stroke increases, so that the buffer pressure changes evenly during the transfer process of samples 1-3, reducing the impact pressure.

[0036] 3. This device adopts a specially designed inner and outer double-layer triaxial host system 2 structure, in which the inner layer is filled with high-pressure seawater to maintain the high pressure in the deep sea, and the outer layer is equipped with water inlets and outlets, and circulating cold water is responsible for maintaining the low temperature in the deep sea, so as to maintain the temperature and pressure of the sample during the triaxial test and prevent the adverse effects of hydrate decomposition on the mechanical properties of the test sample.

[0037] 4. This device adopts a specially designed rubber tube 2-2 plus a fixed ring 2-3 structure. Under the premise of ensuring the transmission of the confining pressure required for the triaxial test, it maintains a certain strength to facilitate the transfer of natural gas hydrate samples.

[0038] 5. The present invention is convenient to be carried on scientific research vessels and docked with the existing natural gas hydrate sample pressure-maintaining transfer system. After obtaining the natural gas hydrate sample, the triaxial test can be carried out immediately, which has strong scientific research benefits.

[0039] It should be noted that it is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention. Therefore, from all perspectives, the embodiments should be regarded as illustrative and non-restrictive, and the scope of the present invention is defined by the appended claims rather than the foregoing description. It is intended that all changes that fall within the meaning and range of equivalents of the claims be included in the present invention, and any reference signs in the claims should not be construed as limiting the claims to which they relate.

[0040] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only intended to help understand the method and core concept of the present invention. At the same time, those skilled in the art will find that the specific implementation methods and application scopes may vary based on the concept of the present invention. In summary, the contents of this specification should not be construed as limiting the present invention.

Claims

1. A deep-sea fidelity core triaxial test device suitable for shipboard laboratories, characterized by: include A sample transfer system, the sample transfer system is used to remove the natural gas hydrate sample from the tube and send it into the three-axis host system, the sample transfer system includes a sample barrel, a tube removal piston, a ball valve and a connector, the sample barrel and the ball valve are connected by bolts, the sample is placed in the sample barrel, and the tube removal piston arranged in the sample barrel is used to push the sample into the three-axis host system; and A three-axis main engine system, the three-axis main engine system is used to complete the triaxial test of natural gas hydrate samples under vacuum conditions, the three-axis main body system includes a bottom interface, a rubber cylinder, a three-axis inner wall, a three-axis outer wall and a top interface, the bottom interface and the sample cylinder are sealed and connected through the connecting piece, the bottom interface is communicated with the rubber cylinder arranged in the inner cavity of the three-axis inner wall, and the sample is sent into the rubber cylinder for triaxial compression test; the three-axis inner wall is filled with seawater for ensuring the test pressure, and the three-axis outer wall located on the outer periphery of the three-axis inner wall is provided with a water inlet and outlet, and the circulating cold water is connected with the water inlet and outlet on the three-axis outer wall.

2. The deep-sea fidelity core triaxial test device suitable for shipboard laboratories according to claim 1 is characterized in that: The connecting piece is a clamp, and the bottom interface and the sample tube are sealed and connected via the clamp.

3. The deep-sea fidelity core triaxial test device suitable for shipboard laboratories according to claim 1 is characterized in that: The tail end of the tube-ejecting piston is provided with a triangular groove symmetrical in the upper and lower directions. When the sample is stored in the sample cylinder, the oil between the tube-ejecting piston and the sample cylinder flows out through the axial triangular groove.

4. The deep-sea fidelity core triaxial test device suitable for shipboard laboratories according to claim 1 is characterized in that: A plastic tube is attached to the outside of the sample put into the sample cylinder, and the diameter of the tube removal piston is smaller than the inner diameter of the plastic tube.

5. The deep-sea fidelity core triaxial test device suitable for shipboard laboratories according to claim 4 is characterized in that: The diameter of the bottom interface is smaller than the outer diameter of the plastic tube; the tube-detaching piston in the sample transfer system pushes the sample forward under the action of seawater until it reaches the bottom interface of the three-axis host system, and the sample is detached from the plastic tube and enters the three-axis host system under the push of the tube-detaching piston.

6. The deep-sea fidelity core triaxial test device suitable for shipboard laboratories according to claim 1 is characterized in that: The bottom interface and the top interface are both provided with confining pressure holes, and the confining pressure holes on the bottom interface and the top interface provide confining pressure for the sample in cooperation with an external pressure device.

7. The deep-sea fidelity core triaxial test device suitable for shipboard laboratories according to claim 1 is characterized in that: The top interface is provided with a pore pressure hole, and the pore pressure hole is used to test the pore pressure of the sample during the triaxial test.

8. The deep-sea fidelity core triaxial test device suitable for shipboard laboratories according to claim 1 is characterized in that: The rubber tube is fixedly installed in the inner cavity of the inner wall of the three shafts through a fixing ring.

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