CN212432591U - Split double-wall fidelity corer pressure loading experiment structure and experiment platform - Google Patents

Abstract

The utility model relates to a split type double-wall fidelity corer pressure loading experiment structure and an experiment platform, which comprises a pressure experiment chamber for simulating a fidelity corer fidelity chamber, wherein the outer barrel of the chamber body of the pressure experiment chamber comprises a first test piece, a second test piece and an intermediate connecting piece, the first test piece and the second test piece are connected together by the intermediate connecting piece, the intermediate connecting piece is provided with a side hole, and the inner wall of the intermediate connecting piece is provided with an electric heating structure; the wall of the first test piece and/or the second test piece is/are provided with an annular vacuum interlayer. The utility model adopts the middle connecting piece to join the test piece to jointly form a cabin body, and the liquid injection hole is designed on the middle connecting piece, thereby avoiding drilling on the test piece and preventing the test piece from being damaged, thereby reducing the pressure environment of the test piece and ensuring that the test result is more reliable; the utility model discloses a pressure maintaining thermal insulation performance in this bilayer structure pressure test cabin can be verified to double-walled structure and internal heating mode to improve the coring drilling machine from structural.

Description

Split double-wall fidelity corer pressure loading experiment structure and experiment platform

Technical Field

The utility model relates to a core device test system technical field especially relates to split type double-walled fidelity corer pressure loading experiment structure and experiment platform.

Background

The mineral resources in the shallow part of the earth are gradually exhausted, and the marching to the deep part of the earth is an important direction of scientific and technological innovation in China in the near term and in the future. The in-situ rock mechanical behavior law of different deep occurrence terranes is the guiding science and theoretical basis of deep drilling, deep resource development and utilization and earth application science.

The characteristics of deep rock such as physical mechanics, chemical biology and the like are closely related to the in-situ environmental conditions, the in-situ environmental loss in the coring process can cause the distortion and the irreversible change of the physicochemical property and the mechanical property of the rock core, and the key of the attack is how to obtain the in-situ rock core under the deep environmental conditions and carry out real-time loading test and analysis under the in-situ fidelity state.

At present, in-situ fidelity coring devices store rock cores in a core storage tube after the rock cores are drilled by a drilling tool, and realize the simulation of the in-situ environment of the rock cores through a pressure maintaining device, a heat preserving device and a moisture preserving device which are connected with the core storage tube. Before core drilling, the pressure maintaining capacity needs to be verified, so that a pressure resistance testing platform of the pressure maintaining cabin is produced.

The pressure resistance test platform of the pressure holding chamber generally comprises a pressure holding experiment chamber, a hydraulic system and the like, and the pressure holding performance of the pressure holding experiment chamber is verified by injecting high-pressure liquid into the pressure holding experiment chamber through the hydraulic system. The existing pressure maintaining experiment cabin is connected with a hydraulic pipeline by drilling holes in the cylinder wall, and the drilling holes of a drilling machine can damage the pressure maintaining experiment cabin, so that the experiment result is unreliable.

SUMMERY OF THE UTILITY MODEL

The utility model aims at providing split type double-walled fidelity corer pressure loading experiment structure and experiment platform can avoid haring the test piece, enables the test result more reliable.

In order to achieve the above purpose, the utility model adopts the following technical scheme:

the pressure loading experiment structure of the split double-wall fidelity corer comprises a pressure experiment chamber used for simulating a fidelity chamber of the fidelity corer, wherein an outer barrel of a chamber body of the pressure experiment chamber comprises a first test piece, a second test piece and an intermediate connecting piece, the second test piece is positioned below the first test piece, the intermediate connecting piece connects the first test piece and the second test piece together, the intermediate connecting piece is provided with a side hole, and the inner wall of the intermediate connecting piece is provided with an electric heating structure; and the wall of the first test piece and/or the second test piece is/are provided with an annular vacuum interlayer.

Furthermore, the pressure experiment chamber also comprises a center rod, a core barrel and a lower end sealing device, wherein the lower end sealing device is arranged on the second test piece and used for sealing the lower end of the pressure experiment chamber, and the core barrel is arranged in the outer barrel of the chamber body;

the lower end of the central rod extends into the core barrel, the lower end of the central rod is provided with an outer step, the upper end of the core barrel is provided with an inner step matched with the outer step, and when the central rod is lifted upwards until the outer step is abutted against the inner step, the central rod can drive the core barrel to synchronously move upwards;

when the central rod is lifted to the stroke end, the outer wall of the upper end of the core barrel is in sealing fit with the inner wall of the first test piece.

The lower sealing device is a sealing end cover, and the sealing end cover is in threaded connection with the lower port of the second test piece.

Further, the lower end sealing device is a flap valve, the flap valve comprises a valve seat, a valve clack and an elastic part, the valve seat is installed on the inner wall of the second test piece, one end of the valve clack is movably connected with the outer side wall of the upper end of the valve seat, and a valve port sealing surface matched with the valve clack is arranged at the top of the valve seat;

when the core barrel is positioned in the valve seat, the valve clack is opened by 90 degrees and is positioned between the core barrel and the second test piece; when the core barrel is lifted to a certain height by the central rod, the valve clack returns to the top surface of the valve seat under the action of the elastic element and gravity to be in sealing contact with the valve port sealing surface.

Furthermore, the inner wall of the first test piece is provided with a first limiting step for axially limiting the core barrel, and when the upper end face of the core barrel abuts against the first limiting step, the center rod is lifted to the stroke end point.

Preferably, the electrical heating structure comprises a graphene membrane or a helical thermal coil.

Furthermore, an annular vacuum interlayer is arranged on the wall of the middle connecting piece cylinder.

A split double-wall fidelity corer pressure loading experiment platform comprises the pressure experiment cabin and a pressure supply system, wherein the pressure supply system is connected with a side hole in a middle connecting piece through a pipeline.

Further, pressure feed system includes liquid tank and frequency conversion superhigh pressure plunger pump, and the export of liquid tank passes through the pipeline and links to each other with the entry of frequency conversion superhigh pressure plunger pump, the export of frequency conversion superhigh pressure plunger pump passes through the pipeline and links to each other with the one end of high-pressure pipe, and the other end of high-pressure pipe links to each other with the side opening of intermediate junction spare.

Further, split type double-walled fidelity corer pressure loading experiment platform still includes linear drive mechanism, linear drive mechanism's output member with well core rod links to each other in order to drive well core rod axial rectilinear movement.

Compared with the prior art, the utility model discloses following beneficial effect has:

1, the utility model adopts the middle connecting piece to join the test piece to jointly form a cabin body, and designs the liquid injection hole on the middle connecting piece, thereby avoiding drilling on the test piece and preventing the test piece from being damaged, thereby reducing the pressure environment of the test piece and ensuring that the test result is more reliable;

2, the utility model discloses a withstand voltage, the thermal insulation performance in this bilayer structure pressure test cabin can be verified to double-walled structure and interior heating method to improve coring drilling machine from structure and material.

Drawings

FIG. 1 is a schematic view of the pressure experiment chamber with the central pole not lifted;

FIG. 2 is a schematic view of the configuration of the holding pressure test chamber when the center pole is lifted to the end of travel;

FIG. 3 is a cross-sectional view of an intermediate linkage member according to one embodiment;

FIG. 4 is a schematic structural diagram of a split double-wall fidelity corer pressure loading experiment platform;

FIG. 5 is a schematic structural view of a quick-connect structure;

FIG. 6 is a cross-sectional view of an intermediate connecting member in a second embodiment;

FIG. 7 is a schematic view showing the structure of the third embodiment in which the lower end sealing means is opened;

fig. 8 is a schematic structural view of the third embodiment in which the lower end seal device is closed.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings.

Implementation mode one

As shown in fig. 1 and 2, the utility model discloses a split type double-walled fidelity corer pressure loading experiment structure, including the pressure experiment cabin that is used for simulating the fidelity corer fidelity cabin, the pressure experiment cabin includes cabin body urceolus, well core rod 2, core barrel 3 and lower extreme sealing device 5.

The outer barrel of the cabin body of the pressure experiment cabin comprises a first test piece 11, a second test piece 12 and an intermediate connecting piece 13, wherein the second test piece 12 is positioned below the first test piece 11, and the intermediate connecting piece 13 connects the first test piece 11 and the second test piece 12 together to form a split cabin body structure.

As shown in fig. 3, the middle connector 13 has two side holes on its wall, one of which is used as a liquid injection hole 14 for externally connecting a hydraulic source. The other side hole is used as a watertight connector mounting hole 18, and the side hole can be designed into a threaded hole for convenient connection and fixation.

And two ends of the middle connecting piece 13 are provided with connecting threads so as to be connected with a test piece conveniently. The connecting thread can be external thread or internal thread, and the specific situation is determined according to the test piece. The utility model discloses an intermediate junction spare links up the test piece and constitutes the cabin body jointly, with the design of liquid filling hole 14 on the intermediate junction spare to can avoid drilling on the test piece, prevent to cause the harm to the test piece, therefore the pressure environment of reducible test piece, make the test result more reliable.

The inner wall of the middle connecting piece 13 is provided with an electric heating structure and a temperature sensor, so that the medium in the pressure experiment chamber can be rapidly heated and the temperature in the feedback chamber can be implemented, and the experiment efficiency can be improved. The electrical heating structure in this embodiment comprises a helical thermal coil 17. The spiral heat coil 17 is fitted in an annular groove 19 in the inner wall of the intermediate connecting member 13.

The cylinder wall of the first test piece and/or the second test piece is/are provided with an annular vacuum interlayer so as to improve the heat insulation effect of the pressure experiment chamber, and simultaneously, the heat insulation capability and the pressure resistance of the vacuum wall structure can be verified so as to improve the coring drilling machine structurally and materially.

The lower end sealing device 5 is arranged on the second test piece and used for sealing the lower end of the pressure test chamber, and in the embodiment, the lower end sealing device 5 is a sealing end cover which is in threaded connection with the lower end opening of the second test piece 12 to seal the lower end of the outer cylinder of the chamber body.

The core barrel 3 is arranged in the outer barrel of the cabin body, the lower end of the central rod 2 extends into the core barrel 3, the lower end of the central rod 2 is provided with an outer step 23, the upper end of the core barrel 3 is provided with an inner step 32 matched with the outer step, and when the central rod 2 is lifted upwards until the outer step 23 abuts against the inner step 32, the central rod 2 can drive the core barrel 3 to move upwards synchronously. Meanwhile, due to the abutting of the outer step 23 and the inner step 32, sealing can be formed between the outer wall of the central rod 2 and the inner wall of the core barrel 3 at the abutting part.

The inner wall of the outer barrel of the cabin body is provided with a first limiting step 16 for axially limiting the core barrel 3, and when the upper end surface 21 of the core barrel abuts against the first limiting step 16, the center rod 2 is lifted to the stroke end point. When the central rod 2 is lifted to the stroke end, the outer wall of the upper end of the core barrel 3 is in sealing fit with the inner wall of the first test piece 11. In the present embodiment, two seal rings 22 are installed on the outer wall of the upper end of the core barrel 3 to seal the barrel wall of the first test piece 11. At this time, the outer wall of the central rod 2 and the inner wall of the core barrel 3 form sealing at the abutting part of the outer step 23 and the inner step 32, so that the sealing at the upper end of the outer barrel of the cabin body is completed. The lower end of the outer barrel of the cabin body is sealed by a lower end sealing device 5, so that a sealed space for storing the rock core is formed in the outer barrel of the cabin body.

As shown in fig. 4, the utility model discloses a split type double-walled fidelity corer pressure loading experiment platform, including pressure experiment cabin, pressure feed system 6 and linear drive mechanism 8, linear drive mechanism 8's output member links to each other with 2 axial rectilinear movement in order to drive well core rod in the pressure experiment cabin.

In this embodiment, the pressure supply system 6 includes a liquid tank 61 and a variable-frequency ultrahigh-pressure plunger pump 64, an outlet of the liquid tank 61 is connected to an inlet of the variable-frequency ultrahigh-pressure plunger pump 64 through a first pipeline, an outlet of the variable-frequency ultrahigh-pressure plunger pump 64 is connected to one end of a high-pressure pipe 612 through a second pipeline 610, and the other end of the high-pressure pipe 612 is in threaded connection with the liquid injection hole 14 of the intermediate connector 13.

The inlet and outlet of the variable-frequency ultrahigh-pressure plunger pump 64 are respectively provided with a first valve 62 and a second valve 66. The liquid filter 63 is installed at the inlet of the variable-frequency ultrahigh-pressure plunger pump 64, and the liquid filter 63 is also installed on the second pipeline 610 and used for filtering impurities in liquid and preventing the impurities from entering the cabin body. Two discharge pipes are branched from the second pipeline 610, the two discharge pipes are respectively connected with the second pipeline 610 side through a tee joint, one of the discharge pipes is provided with a third valve 68, and the other discharge pipe is provided with a fourth valve 69. The third valve 68 and the fourth valve 69 are normally closed valves.

Of course, the variable frequency ultra-high pressure plunger pump 64 is provided with an oil return line, and the oil return line is provided with a sixth valve 65. The utility model discloses well first valve 62 is manual ball valve, and second valve 66, third valve 68 and sixth valve 65 are pneumatic stop valve, and fourth valve 69 is manual valve.

The second pipeline 610 is provided with a safety valve 611, and when the pressure is too high, the safety valve 611 is automatically opened to release the pressure, so that the experimental safety is ensured. Pressure sensors 613 are installed at the outlet of the variable-frequency ultrahigh-pressure plunger pump 64 and the outlet of the pressure supply system 6, and are used for measuring the pressure in the system.

The linear driving mechanism 8 may be a conventional linear driving device such as a hydraulic cylinder or an air cylinder.

Taking the linear driving mechanism 8 as an example of a hydraulic cylinder, the pressure supply system 6 is also responsible for providing a power source for the hydraulic cylinder. The hydraulic cylinder is a double-acting hydraulic cylinder, a branch pipe is connected to the upstream of the variable-frequency ultrahigh-pressure plunger pump 64 and connected with one oil hole of the hydraulic cylinder, a branch pipe is connected to the downstream of the variable-frequency ultrahigh-pressure plunger pump 64 and connected with the other oil hole of the hydraulic cylinder, a fifth valve 67 is mounted on the second pipeline 610, and the fifth valve 67 is located at the downstream of the liquid supply branch pipe of the hydraulic cylinder. The action of the hydraulic cylinder is controlled by pushing and pulling the variable-frequency ultrahigh-pressure plunger pump 64, so that the lifting and resetting of the central rod 2 are realized.

As shown in fig. 4, in order to verify the sealing performance of the holding pressure test chamber under different tension conditions, a tension testing device 10 is arranged on the output part of the linear driving mechanism 8 and the central rod 2. The tension testing device 10 can be a tension meter, and two ends of the tension meter are provided with connecting threads.

In order to achieve a quick connection of the linear drive 8 to the central rod 2, a quick plug-in connection can be used in another embodiment to achieve a quick connection of the linear drive 8 to the central rod 2.

As shown in fig. 4 and 5, the quick-plugging structure includes a plug portion 24, a socket portion 71 adapted to the plug portion 24, and at least two spring latches 9, and the plug portion 24 and the socket portion 71 can be axially clamped and fixed by the spring latches 9.

For example, the male portion 24 is connected to the center rod 2 and the female portion 71 is connected to the pull rod 7, where connection means that two separate components are connected together or integrally manufactured.

One end of the pull rod 7 is in threaded connection with the tension testing device 10, and the other end of the pull rod 7 is provided with an inserting hole part 71. The spring buckle 9 is mounted on the plug part 24 in the embodiment; the spring catch 9 includes a latch 91 and a radially disposed spring 92. The outer side wall of the plug part 24 is provided with a groove 25 for avoiding the fixture block 91, one end of the spring 92 is fixedly connected with the groove wall of the groove 25, and the other end of the spring 92 is fixedly connected with the fixture block 91; under the action of spring 92, a portion of latch 91 is located in recess 25, and another portion of latch 91 protrudes from the outer sidewall of plug portion 24.

The outer side of the clamping block 91 is provided with an inclined surface 93, so that when the plug part 24 is inserted into the insertion hole part 71, the insertion hole part 71 acts on the inclined surface 93 to generate a radial component force, and the clamping block 91 is further pushed to move radially to be completely immersed into the groove 25; the socket portion 71 is provided with a socket 76, a hole wall 74 of the socket 76 is coaxially provided with an annular groove 75, and the cross section of the annular groove 75 is matched with the convex portion of the latch 91 exposed out of the plug portion 24.

The cross-sectional shape of the annular groove 75 may be a triangle, the first groove wall 73 of the annular groove 75 fits the inclined surface 93 of the latch 91, and the second groove wall 74 of the annular groove 75 fits the inclined surface 93 of the latch 91.

For ease of insertion, the outer side wall of the plug portion 24 is an outer tapered surface 26, and the wall 74 of the receptacle 76 of the receptacle portion 71 is an inner tapered surface matching the outer tapered surface 26. The connection between the plug portion 24 and the central rod 2 forms a stop step 27 for abutting against the end surface 72 of the plug portion.

As shown in fig. 5, when the pull rod 7 and the central rod 2 need to be connected together, the pull rod 7 is butted with the central rod 2, the axial force of the insertion hole portion 71 acting on the inclined surface 93 generates a radial component force to push the latch 91 to gradually and radially move to be completely submerged into the groove 25, and when the annular groove 75 moves to be opposite to the latch 91, the latch 91 loses the acting external force of the insertion hole portion 71 and radially moves to a part to be clamped into the annular groove 75 under the action of the spring 92; at this time, the end surface 72 of the plug portion also just abuts against the limit step 27 and is inserted in place.

Because the latch 91 is partially located in the groove 25 of the plug portion 24 and partially located in the annular groove 75 of the socket portion 71, the pull rod 7 and the central rod 2 are prevented from moving relative to each other in the axial direction, and the pull rod 7 and the central rod 2 are quickly clamped and fixed in the axial direction. The number of the spring buckles 9 is set according to the requirement, and can be set to be 2, 3 or more. To ensure a balanced force, the spring catches 9 are arranged at equal intervals in the circumferential direction.

Of course, in another embodiment, the plug portion 24 may be connected to the drawbar 7 and the socket portion 71 connected to the central rod 2.

When the device is used, the fifth valve 67 is closed, the variable-frequency ultrahigh-pressure plunger pump 64 supplies liquid medium to the hydraulic cylinder, the hydraulic cylinder lifts the central rod 2 to the stroke end point, the inner wall of the core barrel 3 and the central rod 2 are sealed, the outer wall of the core barrel 3 and the first test piece 11 are in sealing fit, and therefore a closed environment is formed in the pressure maintaining experiment cabin; then, closing valves at two oil holes of the hydraulic cylinder to keep the central rod 2 at the end point of the upper stroke;

then, the fifth valve 67 is opened, and the oil or water in the liquid tank 61 is pumped to the high-pressure pipe 612 through the variable-frequency ultrahigh-pressure plunger pump 64 and enters the annular space between the outer cylinder of the cabin body and the core barrel 3 through the liquid injection hole 14 on the pressurizing intermediate member 13, so that the whole closed environment is gradually filled, and the simulation of the in-situ pressure environment is realized; meanwhile, an electric heating structure on the middle connecting piece 13 is heated inwards, so that the temperature in the cabin is increased to a preset temperature, and an in-situ temperature environment is simulated.

After the specified time of pressurize, the system carries out safe pressure release and cooling, and the specified time of pressurize sets up according to the experiment needs. In the process, the deformation conditions of the first test piece 11 and the second test piece 12 and the heat insulation performance of the cabin body can be monitored, and the strength design and the heat insulation performance of the cylinder wall of the pressure holding experiment cabin are verified, so that the fidelity core drilling machine is structurally and materially improved. And the pressure failure reason of the pressure maintaining cabin can be further detected and analyzed, and an experiment support is provided for improving the pressure resistance of the pressure maintaining cabin. The utility model discloses a frequency conversion superhigh pressure plunger pump 64 can carry out 0-140 MPa's continuous pressure test to pressurize experiment cabin.

Second embodiment

The electrical heating structure in this embodiment comprises a graphene film. Specifically, as shown in fig. 6, in order to facilitate mounting of the graphene film 21, the electrical heating structure is fabricated by plating the graphene film 21 on the aluminum can 20. An annular groove 19 for installing an aluminum cylinder 20 is formed in the inner wall of the intermediate connecting piece 13, and the aluminum cylinder 20 plated with the graphene film 21 is embedded in the annular groove 19 in the inner wall of the intermediate connecting piece 13. The depth of the annular groove 19 is set according to the thickness of the aluminum cylinder 20, for example, the depth of the annular groove 19 and the wall thickness of the aluminum cylinder 20 are set to be 3 mm.

It should be noted that the mounting position of the aluminum barrel 20 should be kept away from the liquid injection hole 14 or a through hole should be opened at the position of the aluminum barrel 20 corresponding to the liquid injection hole 14 for passing the medium.

Third embodiment

This embodiment differs from the first or second embodiment in that: as shown in fig. 7 and 8, in the present embodiment, the lower end sealing device 5 is a flap valve 5, and includes a valve seat 51, a flap 52 and an elastic member 53, the valve seat 51 is installed on the inner wall of the second test piece 12, one end of the flap 52 is movably connected with the outer side wall of the upper end of the valve seat 51, and the top of the valve seat 51 has a valve port sealing surface matched with the flap 52. The elastic member 53 is a spring or a torsion spring.

As shown in fig. 7, in the initial state, the core barrel 3 is located at the lower end of the outer barrel of the cabin and in the valve seat 51. When the core barrel 3 is positioned in the valve seat 51, the valve flap 52 is opened by 90 degrees and is positioned between the core barrel 3 and the outer barrel of the cabin body; as shown in fig. 8, when the core barrel 3 is lifted up to a certain height by the center rod 2, the valve flap 52 returns to the top surface of the valve seat 51 to be in sealing contact with the valve port sealing surface by the elastic member 53 and gravity, and the valve is closed.

In order to increase the sealing specific pressure of the flap valve 5, the pressure maintaining experiment chamber further comprises a trigger mechanism 4, the trigger mechanism 4 comprises a trigger inner cylinder 41, a trigger block 42 and a trigger spring 43, a through hole is formed in the side wall of the trigger inner cylinder 41, the trigger block 42 is placed in the through hole, and a protruding portion 31 matched with the trigger block 42 is arranged on the outer side wall of the bottom of the core cylinder 3; the inner wall of the outer barrel of the cabin body is provided with an avoiding opening 15 matched with the trigger block 42, the trigger block 42 is positioned above the valve clack 52, and the avoiding opening 15 is positioned above the trigger block 42. The bottom of the avoiding opening 15 is provided with a guiding inclined plane which is convenient for the trigger block 42 to slide into the avoiding opening 15 from bottom to top and is also convenient for the trigger block 42 to slide out of the avoiding opening 15 from top to bottom.

The trigger spring 43 is sleeved outside the trigger inner cylinder 41, the outer wall of the trigger inner cylinder 41 is provided with a shoulder 44, the trigger spring 43 is compressed between the shoulder 44 and the step surface of the inner wall of the outer cylinder of the cabin body, and the trigger spring 43 is positioned above the trigger block 42;

when the core barrel 3 is positioned in the valve seat 51, the trigger inner barrel 41 is positioned between the core barrel 3 and the cabin outer barrel, the lower end of the trigger inner barrel 41 is matched with a spigot of the valve seat 51, and the trigger block 42 protrudes out of the inner side wall of the trigger inner barrel 41;

when the core barrel 3 is lifted upwards to the first height, the convex part 31 of the core barrel 3 supports against the trigger block 42, so that the trigger inner barrel 41 can be driven to move upwards synchronously;

when the core barrel 3 is continuously lifted upwards to the second height, the trigger block 42 is pushed into the avoidance port 15 by the convex portion 31, so that the trigger block 42 avoids the convex portion 31;

when the core barrel 3 is lifted up to the bottom of the core barrel 3 to cross the avoidance port 15, the trigger block 42 loses the acting force of the core barrel 3, and the trigger inner cylinder 41 drives the trigger block 42 to fall back to press the closed valve clack 52 under the action of gravity and the trigger spring 43.

The embodiment can test the action reliability of the flap valve so as to structurally improve the flap valve.

Of course, the present invention can be embodied in many other forms without departing from the spirit or essential attributes thereof, and it should be understood that various changes and modifications can be made by one skilled in the art without departing from the spirit or essential attributes thereof, and that such changes and modifications are intended to be included within the scope of the appended claims.

Claims (10)

1. Split type double-wall fidelity corer pressure loading experiment structure, including the pressure experiment cabin that is used for simulating the fidelity cabin of fidelity corer, its characterized in that: the outer barrel of the pressure experiment chamber comprises a first test piece, a second test piece and an intermediate connecting piece, wherein the second test piece is positioned below the first test piece, the intermediate connecting piece connects the first test piece and the second test piece together, the intermediate connecting piece is provided with a side hole, and the inner wall of the intermediate connecting piece is provided with an electric heating structure; the wall of the first test piece and/or the second test piece is/are provided with an annular vacuum interlayer.

2. The split double-wall fidelity corer pressure loading experimental structure of claim 1, characterized in that: the pressure experiment cabin also comprises a center rod, a core barrel and a lower end sealing device, wherein the lower end sealing device is arranged on the second test piece and used for sealing the lower end of the pressure experiment cabin, and the core barrel is arranged in the outer barrel of the cabin body;

the lower end of the central rod extends into the core barrel, the lower end of the central rod is provided with an outer step, the upper end of the core barrel is provided with an inner step matched with the outer step, and when the central rod is lifted upwards until the outer step is abutted against the inner step, the central rod can drive the core barrel to synchronously move upwards;

when the central rod is lifted to the stroke end, the outer wall of the upper end of the core barrel is in sealing fit with the inner wall of the first test piece.

3. The split double-wall fidelity corer pressure loading experimental structure of claim 2, characterized in that: the lower end sealing device is a sealing end cover, and the sealing end cover is in threaded connection with the lower end opening of the second test piece.

4. The split double-wall fidelity corer pressure loading experimental structure of claim 2, characterized in that: the lower end sealing device is a flap valve, the flap valve comprises a valve seat, a valve clack and an elastic part, the valve seat is installed on the inner wall of the second test piece, one end of the valve clack is movably connected with the outer side wall of the upper end of the valve seat, and a valve port sealing surface matched with the valve clack is arranged at the top of the valve seat;

when the core barrel is positioned in the valve seat, the valve clack is opened by 90 degrees and is positioned between the core barrel and the second test piece; when the core barrel is lifted to a certain height by the central rod, the valve clack returns to the top surface of the valve seat under the action of the elastic element and gravity to be in sealing contact with the valve port sealing surface.

5. The split double-walled fidelity coring device pressure loading experimental structure of claim 2, 3 or 4, wherein: the inner wall of the first test piece is provided with a first limiting step for axially limiting the core barrel, and when the upper end face of the core barrel abuts against the first limiting step, the center rod is lifted to a stroke end point.

6. The split double-wall fidelity corer pressure loading experimental structure of claim 1, characterized in that: the electrical heating structure comprises a graphene membrane or a helical thermal coil.

7. The split double-wall fidelity corer pressure loading experimental structure of claim 1, characterized in that: the cylinder wall of the middle connecting piece is provided with an annular vacuum interlayer.

8. The utility model provides a split type double-wall fidelity corer pressure loading experiment platform which characterized in that: the split double-wall fidelity corer pressure loading experimental structure comprises a pressure supply system and the split double-wall fidelity corer pressure loading experimental structure as claimed in any one of claims 1 to 7, wherein the pressure supply system is connected with a side hole on an intermediate connecting piece through a pipeline.

9. The split double-walled fidelity corer pressure loading experiment platform of claim 8, characterized in that: the pressure supply system comprises a liquid tank and a variable-frequency ultrahigh-pressure plunger pump, wherein an outlet of the liquid tank is connected with an inlet of the variable-frequency ultrahigh-pressure plunger pump through a pipeline, an outlet of the variable-frequency ultrahigh-pressure plunger pump is connected with one end of a high-pressure pipe through a pipeline, and the other end of the high-pressure pipe is connected with a side hole of an intermediate connecting piece.

10. The split double-walled fidelity corer pressure loading experiment platform of claim 8 or 9, characterized in that: the output part of the linear driving mechanism is connected with the central rod to drive the central rod to axially and linearly move.

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