Pressure-stabilizing and constant-temperature device, pressure-stabilizing and constant-temperature method and testing system for true triaxial permeability test

Abstract

The invention discloses a pressure-stabilizing and constant-temperature device, a pressure-stabilizing and constant-temperature method and a test system for a true triaxial permeability test, a sample bin confining pressure fluid cavity is arranged, and a preheating pipeline, a circulating pump and a heat exchange liquid storage tank are sequentially connected between a fluid inlet of the sample bin confining pressure fluid cavity and a fluid outlet of the sample bin confining pressure fluid cavity along a high-pressure pipeline; the fluid pressure in the confining pressure fluid cavity 1 of the sample bin is provided by a pressure loading pump, so that the loading of the confining pressure of the rock core is realized; the sample bin confining pressure fluid cavity is used as a carrier structure for testing the porosity and permeability of a rock sample, the pressure loading pump and the heat exchange liquid storage tank are used for providing a high-pressure environment capable of reaching 100 MPa, and meanwhile, the preheating pipeline is used for providing a high-temperature environment capable of reaching 200 DEG C at most; the device can simultaneously simulate the high-temperature state of a deep rock mass and the characteristic of a high confining pressure environment for measuring the porosity and the permeability, is simple in structure and convenient to measure, and has important significance on exploration and development of deep-ultra-deep oil gas.

Description

Technical Field

[0001] The invention belongs to the technical field of oil and gas reservoir evaluation and testing instruments, and in particular relates to a true triaxial porosity and permeability test pressure-stabilizing and temperature-constant device, a pressure-stabilizing and temperature-constant method and a testing system. Background Art

[0002] With the advancement of oil and gas exploration and development technology, the amount of recoverable shallow oil and gas resources is getting smaller and smaller, and the goal of oil and gas exploration and development has shifted to deep and ultra-deep layers.

[0003] Deep-ultra-deep oil and gas are in a high-temperature and high-pressure environment. There are complex temperature fields, stress fields and seepage fields in the rock formations. The porosity and permeability in the rock mass are quite different from those in the shallow layer. The porosity and permeability test is an important parameter and indicator for evaluating the recoverability of unconventional oil and gas reservoirs. The increase in the depth of the formation will lead to an increase in the temperature of the rock mass. It is generally believed that for every 100 meters increase in depth, the ground temperature increases by 3°C. The temperature of the deep-ultra-deep layer will reach 150-200°C, or even above 200°C.

[0004] Temperature is one of the most important factors affecting deep rock deformation and failure, and its seepage characteristics will also change significantly. Therefore, high-temperature experimental instruments must be used to accurately measure the porosity and permeability under real formation conditions.

[0005] Existing high-temperature and high-pressure true triaxial instruments usually place the true triaxial pressure vessel in a temperature control cabinet to achieve high-temperature loading through fluid convection or radiation, or set a heating plate, electric heating insulation sleeve and other devices outside the pressure vessel to achieve temperature control. For example, Chinese patent CN106596281B discloses a method for heating confining pressure fluid under triaxial stress conditions using a heating coil.

[0006] However, the above-mentioned public technical documents have the problem of heat loss due to thermal conduction, and they are unable to provide high confining pressure fluid to the rock samples, and thus are unable to inject pore fluids, resulting in the inability to measure the porosity and permeability of rocks under high temperature and high pressure conditions in real formation rocks. Summary of the invention

[0007] The purpose of the present invention is to provide a true triaxial porosity and permeability test pressure-stabilizing and constant-temperature device, a pressure-stabilizing and constant-temperature method and a test system to overcome the technical problems that the porosity and permeability of rocks under high temperature and high pressure conditions cannot be measured due to heat loss caused by thermal conduction during the existing high temperature and high pressure true triaxial test and the inability to provide high confining pressure fluid to the rock sample and thus the inability to inject pore fluid.

[0008] The present invention proposes a true triaxial porosity and permeability test pressure-stabilizing and constant-temperature device, a pressure-stabilizing and constant-temperature method and a test system, which solve the technical problems that heat is lost by heat conduction during the existing high-temperature and high-pressure true triaxial test, and high-confining pressure fluid cannot be provided to the rock sample, so pore fluid cannot be injected, resulting in the inability to measure the porosity and permeability of the rock under the high-temperature and high-pressure state of the real formation rock. The invention has the characteristics of not only simulating the high-temperature state of the deep rock mass, but also providing a high-confining pressure (100MPa) environment for the determination of porosity and permeability.

[0009] The present invention discloses a true triaxial porosity test pressure-stabilizing and temperature-constant device, comprising:

[0010] A sample chamber confining pressure fluid cavity, in which a rock sample is placed to perform a porosity and permeability test;

[0011] A preheating pipeline, the fluid outlet of which is connected to the fluid inlet of the confining pressure fluid chamber of the sample chamber;

[0012] A high-pressure circulation pump connected to the preheating pipeline;

[0013] A heat exchange liquid storage tank, one end of which is connected to the high-pressure circulation pump, and the other end of which is connected to the fluid outlet of the confining pressure fluid cavity of the sample chamber;

[0014] A pressure loading pump is connected to the fluid inlet of the sample chamber confining pressure fluid chamber through the preheating pipeline.

[0015] In some embodiments, high-pressure valves are provided on the pipeline connecting the preheating pipeline and the sample chamber confining pressure fluid cavity, the pipeline connecting the heat exchange fluid storage tank and the sample chamber confining pressure fluid cavity, and the pipeline connecting the pressure loading pump and the preheating pipeline.

[0016] In some embodiments, it also includes:

[0017] The sensor is arranged in the heat exchange liquid storage tank.

[0018] In some embodiments, it also includes:

[0019] A control system is electrically connected to the preheating pipeline and the high-pressure circulation pump.

[0020] In some of the embodiments, the sample bin confining pressure fluid chamber adopts a core clamp, including a shell, a pressurizing device, a sealing device and a flow guiding device. The shell is a hollow structure, and a plurality of through holes connecting the hollow structure to the inside are arranged on the side of the shell. The rock sample is wrapped in the hollow structure of the shell by the sealing device, the pressurizing device is arranged in the through hole on the side of the shell to pressurize the rock sample, and the flow guiding device connects the surface of the rock sample with the outside of the shell.

[0021] In some of the embodiments, the pressurizing device includes an axial pressure head and a horizontal pressure head, which are respectively arranged in the axial through hole and the horizontal through hole on the side of the shell to pressurize the side surfaces of the rock sample; the sealing device includes a casing, which is arranged outside the axial pressure head and the rock sample; the flow guide device includes an annular flow guide groove and a flow guide pipe, the annular flow guide groove is connected to the flow guide hole arranged on the axial pressure head, the flow guide hole is arranged on the contact surface between the axial pressure head and the rock sample, and the flow guide pipe is connected to the annular flow guide groove.

[0022] Another aspect of the present invention further provides a method for stabilizing pressure and maintaining constant temperature for true triaxial porosity testing, which utilizes any of the above-mentioned devices for stabilizing pressure and maintaining constant temperature for true triaxial porosity testing.

[0023] In some embodiments, the steps include:

[0024] The fluid in the heat exchange liquid storage tank is heated by the preheating pipeline, and the fluid is pumped into the sample chamber confining pressure fluid chamber through the fluid inlet of the sample chamber confining pressure fluid chamber by the high-pressure circulation pump to realize the circulation of the confining pressure fluid;

[0025] The fluid in the sample chamber confining pressure fluid cavity is transported back to the heat exchange fluid storage tank through the fluid outlet of the sample chamber confining pressure fluid cavity;

[0026] The pressure loading pump delivers the fluid to the sample chamber confining pressure fluid cavity through the preheating pipeline according to the confining pressure required for the experiment, so as to achieve the confining pressure condition in the sample chamber confining pressure fluid cavity.

[0027] In some embodiments, it also includes:

[0028] Detecting the temperature of the fluid in the heat exchange tank by a sensor;

[0029] The speed parameter of the high-pressure circulation pump and the heating temperature of the preheating pipeline are controlled by a control system.

[0030] The present invention also provides a true triaxial porosity testing system, comprising a true triaxial porosity testing voltage-stabilizing and temperature-constant device as described in any of the above technical solutions.

[0031] Compared with the prior art, the present invention has the following beneficial technical effects:

[0032] The invention provides a true triaxial porosity and permeability test pressure-stabilizing and temperature-regulating device, which provides a sample bin confining pressure fluid cavity, wherein a preheating pipeline, a circulation pump and a heat exchange liquid storage tank are sequentially connected between a fluid inlet of the sample bin confining pressure fluid cavity and a fluid outlet of the sample bin confining pressure fluid cavity along a high-pressure pipeline, and the fluid pressure in the sample bin confining pressure fluid cavity 1 is provided by a pressure loading pump to realize the loading of the core confining pressure; the confining pressure fluid in the sample bin confining pressure fluid cavity is circulated by the circulation pump to provide constant heat for the core; the confining pressure fluid temperature is provided by the preheating pipeline; the invention utilizes the sample bin confining pressure fluid cavity as a carrier structure for testing the porosity and permeability of rock samples, utilizes the pressure loading pump and the heat exchange liquid storage tank to provide a high-pressure environment of up to 100 MPa, and utilizes the preheating pipeline to provide a high-temperature environment of up to 200°C, thereby being able to simultaneously simulate the high-temperature state of deep rock mass and the characteristics of the high confining pressure environment for the determination of porosity and permeability, and having a simple structure and convenient determination, and having important significance for the exploration and development of deep-ultra-deep oil and gas.

[0033] The present invention utilizes the continuous energy supply of the circulation system and the external heating system to maintain and ensure that the temperature of the circulating fluid is at 200 degrees Celsius, thereby transferring heat to the rock sample; the pressure is stabilized by controlling the pressure with a high-pressure pump, and the confining pressure fluid will be automatically replenished or discharged as the pressure changes caused by temperature changes, maintaining a constant pressure state. The system is stable and the accuracy of the test results is ensured. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0035] Figure 1 A schematic diagram of the structure of a voltage-stabilizing and temperature-constant device for true triaxial porosity testing provided in an embodiment of the present invention.

[0036] Figure 2 This is a schematic diagram of the structure of the sample chamber confining pressure fluid chamber provided in an embodiment of the present invention.

[0037] Figure 3 A schematic structural diagram of a core holder provided in an embodiment of the present invention.

[0038] Figure 4 Another structural schematic diagram of the core holder provided in an embodiment of the present invention.

[0040] 1. Sample chamber confining pressure fluid cavity; 2. Preheating pipeline; 3. Circulation pump; 4. Heat exchange liquid storage tank; 5. Pressure loading pump; 6. High pressure valve; 7. Rock sample; 81. Axial pressure head;

[0041] 82. Horizontal pressure head; 83. Casing; 84. Annular guide groove; 85. Guide pipe; 86. Flange; 87. Shell; 88. Axial pressure block; 89. Pressure measuring hole; 90. Fastening screw. DETAILED DESCRIPTION

[0042] In order to make the purpose, technical scheme and advantages of the present invention more clearly understood, the present invention is described and illustrated below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. Based on the embodiments provided by the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the scope of protection of the present invention.

[0043] Obviously, the drawings described below are only some examples or embodiments of the present invention. For ordinary technicians in this field, the present invention can also be applied to other similar scenarios based on these drawings without creative work. In addition, it can also be understood that although the efforts made in this development process may be complicated and lengthy, for ordinary technicians in this field related to the content disclosed by the present invention, some changes in design, manufacturing or production based on the technical content disclosed by the present invention are just conventional technical means, and should not be understood as insufficient content disclosed by the present invention.

[0044] Reference to "embodiments" in the present invention means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present invention. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those of ordinary skill in the art that the embodiments described in the present invention may be combined with other embodiments without conflict.

[0045] Unless otherwise defined, the technical terms or scientific terms involved in the present invention shall have the usual meaning understood by persons with ordinary skills in the technical field to which the present invention belongs. The words "one", "a", "a", "the" and the like involved in the present invention do not indicate a quantitative limitation and may indicate the singular or plural. The terms "include", "comprise", "have" and any of their variations involved in the present invention are intended to cover non-exclusive inclusions; for example, a process, method, system, product or device comprising a series of steps or modules (units) is not limited to the listed steps or units, but may also include steps or units that are not listed, or may also include other steps or units inherent to these processes, methods, products or devices.

[0046] The words "connected", "connected", "coupled" and the like involved in the present invention are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. The "plurality" involved in the present invention refers to two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, "A and / or B" may mean: A exists alone, A and B exist at the same time, and B exists alone. The character " / " generally indicates that the objects associated before and after are in an "or" relationship.

[0047] The embodiment of the present invention provides a true triaxial porosity test pressure-stabilizing and temperature-constant device, Figure 1 It is a schematic structural diagram of a voltage-stabilizing and temperature-constant device for true triaxial porosity testing according to an embodiment of the present invention.

[0048] refer to Figure 1 As shown, the true triaxial porosity test pressure-stabilizing and temperature-regulating device provided by the present invention includes a sample bin confining pressure fluid cavity 1, a preheating pipeline 2, a circulating pump 3, a heat exchange liquid storage tank 4 and a pressure loading pump 5. The rock sample 7 is placed in the sample bin confining pressure fluid cavity 1 for porosity testing. The fluid outlet of the preheating pipeline 2 is connected to the fluid inlet of the sample bin confining pressure fluid cavity 1, the circulating pump 3 is connected to the preheating pipeline 2, one end of the heat exchange liquid storage tank 4 is connected to the circulating pump 3, and the other end of the heat exchange liquid storage tank 4 is connected to the fluid outlet of the sample bin confining pressure fluid cavity 1, and the pressure loading pump 5 is connected to the fluid inlet of the sample bin confining pressure fluid cavity 1 through the preheating pipeline 2.

[0049] In the true triaxial porosity test pressure-stabilizing and constant-temperature device provided by the present invention, a preheating pipeline 2, a circulation pump 3 and a heat exchange liquid storage tank 4 are connected in sequence along the high-pressure pipeline between the fluid inlet of the sample chamber confining pressure fluid cavity 1 and the fluid outlet of the sample chamber confining pressure fluid cavity 1, wherein one end of the preheating pipeline 2 is connected to a pressure loading pump 5.

[0050] Among them, the fluid pressure in the sample bin confining pressure fluid cavity 1 is provided by the pressure loading pump 5, which can reach up to 100MPa, so as to realize the loading of the core confining pressure; the confining pressure fluid in the sample bin confining pressure fluid cavity 1 is circulated by the circulation pump 3 to provide constant heat for the core; the confining pressure fluid temperature is provided by the preheating pipeline 2, which can reach up to 200℃.

[0051] The present invention utilizes the sample bin confining pressure fluid cavity 1 as the carrier structure for testing the porosity and permeability of the rock sample 7, utilizes the pressure loading pump 5 and the heat exchange liquid storage tank 4 to provide a high-pressure environment of up to 100 MPa, and utilizes the preheating pipeline 2 to provide a high-temperature environment of up to 200°C, which can simultaneously simulate the high-temperature state of the deep rock mass and the characteristics of the high confining pressure environment for the determination of porosity and permeability, has a simple structure and is convenient for determination, and is of great significance to the exploration and development of deep and ultra-deep oil and gas.

[0052] like Figure 2 As shown, the sample chamber confining pressure fluid chamber 1 is surrounded by a rock sample 7 and a core holder, and specifically, is surrounded by a heat shrink sleeve outside the rock sample 7 and a pressure head.

[0053] In one embodiment of the present application, Figure 3 , Figure 4 As shown, the core holder is used for porosity and permeability testing under high temperature and high pressure true triaxial stress, and includes a housing 87, a pressurizing device, a sealing device, and a flow guide device. The pressurizing device further includes an axial pressure head 81 and a horizontal pressure head 82.

[0054] Preferably, the axial pressure head 81 includes two axial pressure heads 81 abutting against the top and bottom surfaces of the rock sample 7 .

[0055] Each side surface of the rock sample 7 is abutted against a horizontal pressure head 82 , and the number of the horizontal pressure heads 82 is the same as the number of the side surfaces of the rock sample 78 .

[0056] The sealing device includes a sleeve 83, which is sleeved on the two axial pressure heads 81 and the rock sample 7. Specifically, Figure 4 As shown, the two axial pressure heads 81 and the cube-shaped core sample 7 in the middle are sealed by a sleeve after heat treatment, and cooperate with the horizontal pressure head 82 in the horizontal direction to realize true triaxial stress loading.

[0057] The flow guide device further includes an annular flow guide groove 84 and a flow guide pipe 85. The annular flow guide groove 84 is connected to a flow guide hole arranged on the axial pressure head 81. The flow guide hole is arranged on the contact surface between the axial pressure head 81 and the rock sample 7. The flow guide pipe 85 is connected to the annular flow guide groove 84. Optionally, the flow guide pipe 85 is a metal pipe used for conducting fluid inside the rock.

[0058] Optionally, the guide tube 85 and the annular guide groove 84 are disposed in the axial pressure head 81 .

[0059] The shell 87, the rock sample 7, the pressurizing device and the sealing device form a closed space, namely the sample chamber confined pressure fluid chamber 1.

[0060] Optionally, the shell 87 is provided with a fluid inlet and a fluid outlet, namely, the fluid inlet and fluid outlet of the sample chamber confining pressure fluid cavity 1, for injecting fluid.

[0061] In the embodiments of the present application, Figure 2 As shown, the rock sample 7 is in the shape of a cube with rounded corners, and the number of the horizontal pressure heads 82 is 4, which is conducive to achieving the sealing of the rock sample 7 and the axial pressure head 81 through the PEFT sleeve after heat treatment.

[0062] In order to further improve the sealing effect, one end of the axial pressure head 81 away from the rock sample 7 is provided with curved steps and grooves distributed circumferentially along the outer periphery of the axial pressure head 81 .

[0063] like Figure 3 As shown, a plurality of axial through holes and transverse through holes are provided on the shell 87, and the axial pressure head 81 and the horizontal pressure head 82 are respectively arranged in the axial through hole and the transverse through hole, and the axis of the axial through hole is perpendicular to the axis of the transverse through hole.

[0064] The present application takes the installation of the axial pressure head 81 in the axial through hole as an example, and the axial through hole is provided with the axial pressure head 81, the axial pressure block 88 and the flange 86 in sequence from the inside to the outside. The flange 86 is fixedly connected to the shell 87 by fastening screws 90, and the axial pressure head 81 and the axial pressure block 88 are pressed tightly in the axial through hole of the shell 87 by the flange 86, so as to form a high-pressure environment for the rock sample in the shell 87; through holes are provided on the axial pressure block 88 and the flange 86, and the guide tube 85 is connected to the annular guide groove 84 along the through holes on the axial pressure block 88 and the flange 86.

[0065] Optional, such as Figure 3 As shown, sealing rings are arranged between the side walls of the horizontal pressure head 82 and the side walls of the axial pressure head 81 and the inside of the through hole of the shell 87, and a two-line sealing ring structure is adopted to improve the sealing performance of the installation of the horizontal pressure head 82 and avoid the problem that the solution flows out from the side wall of the shell 87 during the true triaxial porosity test and affects the accuracy of the test.

[0066] In one embodiment of the present application, a flow guide device is provided in the axially arranged through hole of the shell 87, and a horizontal pressure head 82 is provided in the horizontally arranged through hole of the shell 87, and the horizontal pressure head 82 only provides pressure in the horizontal direction.

[0067] like Figure 3 As shown, a groove is provided at one end of the horizontal pressure head 82 away from the rock sample 7, and a reverse elastic device is provided in the groove of the horizontal pressure head 82. The end of the reverse elastic device is supported by a horizontal pressure block 91. After the outer end of the horizontal pressure block 91 is tightened by a horizontal top block 92, the flange 86 is fixed to the outside of the shell 87 by fastening screws to achieve the tightening effect.

[0068] Through holes are provided on the horizontal pressing block 91 and the horizontal top block 92, which are connected to the pressure loading pump 5 through a high-pressure conduit. The pressure loading pump 5 provides loading pressure to the reverse elastic device, and the reverse elastic device transmits the pressure to the horizontal pressing block 91, forming pressure laterally on the rock sample 7. According to the structure of the rock sample 7, a horizontal pressing block 91 is respectively provided on the lateral side thereof to form a stable pressure field around it, thereby effectively simulating the characteristics of the high confining pressure environment of the deep rock mass, which is of great significance to the exploration and development of deep and ultra-deep oil and gas.

[0069] In one embodiment of the present application, an axial pressure head 81 and a flow guide device are provided in a through hole arranged axially in the housing 87 .

[0070] like Figure 3 As shown, a groove is provided at one end of the axial pressure head 81 away from the rock sample 7, and a reverse elastic device is provided in the groove of the horizontal pressure head 82. The end of the reverse elastic device is supported by an axial pressure block 88. After the outer end of the axial pressure block 88 is tightened by a flange 86, the flange 86 is fixed to the outside of the shell 87 by a fastening screw to achieve a clamping effect.

[0071] Through holes are provided on the axial pressure head 81 and the axial pressure block 88. The guide pipe 85 of the guide device is led to the surface of the rock sample through the through hole. The annular guide groove 84 of the guide device is provided on the lower surface of the rock sample 7 and is connected to the pressure loading pump 5 through a high-pressure conduit. The pressure loading pump 5 provides loading pressure to form pressure laterally on the rock sample 7.

[0072] Optionally, an axial pressure head 81 is arranged on the upper and lower sides of the shell 87 respectively, the fluid in the heat exchange storage tank 4 is heated by the preheating pipeline 2, and the fluid is pumped into the sample bin confining pressure fluid chamber 1 through the fluid inlet of the sample bin confining pressure fluid chamber 1 by the circulating pump 3 to realize the circulation of the confining pressure fluid; the fluid in the sample bin confining pressure fluid chamber 1 is transported back to the heat exchange storage tank 4 through the fluid outlet of the sample bin confining pressure fluid chamber 1; the pressure loading pump 5 transports the fluid to the sample bin confining pressure fluid chamber 1 through the preheating pipeline 2 according to the confining pressure required for the experiment, so as to realize the confining pressure conditions in the sample bin confining pressure fluid chamber 1.

[0073] According to the structure of the rock sample 7, a horizontal pressure block 91 is set on its lateral side to form a stable pressure field around it, thereby effectively simulating the characteristics of the high confining pressure environment of the deep rock mass, which is of great significance to the exploration and development of deep and ultra-deep oil and gas.

[0074] Optional, such as Figure 3 As shown, the reverse elastic force device includes a positioning plate 94, a spring seat is arranged on the positioning plate 94, a spring 95 is arranged on the spring seat of the positioning plate 92, a spring pressure plate is arranged at the outer end of the spring 95, the outer end of the spring pressure plate is in contact with the end of the horizontal pressure block 91, the through hole on the horizontal pressure block 91 is located on one side of the horizontal pressure block 91, and the pressure provided by the pressure loading pump 5 acts on the outer side of the spring pressure plate to achieve the purpose of applying pressure.

[0075] like Figure 3As shown, a pressure measuring hole 89 is provided on the axial pressure block 88 at the lower end in the axial through hole of the shell 87, one end of the pressure measuring hole 89 is opened on the side wall of the axial pressure block 88, and the other end of the pressure measuring hole 89 is opened on the end of the axial pressure block 88. It is connected to an external pressure measuring device through a through hole on the flange 86 in contact with the axial pressure block 88, and is used to detect the sealing between the axial pressure block 88 and the inner wall of the shell 87 during the pressurization process, so as to ensure the accuracy of the measurement results in the high temperature state of the simulated deep rock mass and the high confining pressure environment for the measurement of porosity and permeability.

[0076] Preferably, a pressure measuring interface is provided on the flange 86 in contact with the axial pressure block 88 for connecting a pressure measuring device.

[0077] Specifically, in the embodiment of the present application, a plurality of spring seats are arranged circumferentially on the positioning plate 94 , and a spring 9 is arranged on each spring seat to ensure that the pressure applied by the positioning plate 92 is uniform.

[0078] Optionally, a positioning ring 92 is provided on the outer ring of the horizontal pressure block 91, and a sealing ring is provided between the outer ring of the positioning ring 92 and the inner wall of the through hole of the shell 87 to ensure the sealing between the outer ring of the positioning ring 92 and the inner wall of the through hole of the shell 87; a sealing ring is provided between the inner ring of the positioning ring 92 and the outer wall of the horizontal pressure block 91 to ensure the sealing between the inner ring of the positioning ring 92 and the outer wall of the horizontal pressure block 91.

[0079] Optionally, a high-pressure valve 6 is provided on the pipeline connecting the preheating pipeline 2 and the sample chamber confining pressure fluid chamber 1, the pipeline connecting the heat exchange liquid storage tank 4 and the sample chamber confining pressure fluid chamber 1, and the pipeline connecting the pressure loading pump 5 and the preheating pipeline 2. The circulation pump 3 adopts a high-pressure circulation pump.

[0080] In one embodiment of the present application, a sensor is further included in the heat exchange liquid storage tank 4 for obtaining the temperature in the heat exchange liquid storage tank 4 .

[0081] In one embodiment of the present application, it also includes a control system electrically connected to the preheating pipeline 2 and the circulation pump 3. The sensor is arranged in the heat exchange liquid storage tank 4 to monitor the temperature of the fluid circulating out of the sample chamber confining pressure fluid cavity 1. The control system can be used to implement parameter settings for the rotation speed of the circulation pump 3 and predict the control of the pipeline heating temperature.

[0082] This embodiment also provides a method for stabilizing pressure and maintaining constant temperature for true triaxial porosity testing, which uses a true triaxial porosity testing pressure and temperature stabilizing device listed in any of the above embodiments to perform pressure and temperature stabilization.

[0083] The specific steps include:

[0084] The fluid in the heat exchange liquid storage tank 4 is heated by the preheating pipeline 2, and the fluid is pumped into the sample chamber confining pressure fluid chamber 1 through the fluid inlet of the sample chamber confining pressure fluid chamber 1 by the circulation pump 3, so as to realize the circulation of the confining pressure fluid;

[0085] The fluid in the sample chamber confining pressure fluid chamber 1 is transported back to the heat exchange liquid storage tank 4 through the fluid outlet of the sample chamber confining pressure fluid chamber 1;

[0086] The pressure loading pump 5 delivers fluid to the sample chamber confining pressure fluid cavity 1 through the preheating pipeline 2 according to the confining pressure required for the experiment, so as to achieve the confining pressure condition in the sample chamber confining pressure fluid cavity 1.

[0087] It further includes detecting the temperature of the fluid in the heat exchange storage tank 4 through a sensor; and controlling the speed parameter of the circulation pump 3 and the heating temperature of the preheating pipeline 2 through a control system.

[0088] This embodiment also lists a true triaxial porosity testing system, which includes a true triaxial porosity testing voltage-stabilizing and temperature-constant device as listed in any of the above embodiments.

[0089] In yet another embodiment of the present invention, the true triaxial porosity test system can be used in a true triaxial porosity test pressure-stabilizing and temperature-constant device to perform a pressure-stabilizing and temperature-constant method operation.

[0090] The specific steps include:

[0091] The fluid in the heat exchange liquid storage tank 4 is controlled to be heated through the preheating pipeline 2, and a signal for controlling the circulation pump 3 is outputted, so that the fluid is pumped into the sample chamber confining pressure fluid chamber 1 through the fluid inlet of the sample chamber confining pressure fluid chamber 1 by the circulation pump 3, so as to realize the circulation of the confining pressure fluid;

[0092] Control the fluid in the sample chamber confining pressure fluid chamber 1 to be transported back to the heat exchange liquid storage tank 4 through the fluid outlet of the sample chamber confining pressure fluid chamber 1;

[0093] The pressure loading pump 5 is set to deliver fluid to the sample chamber confining pressure fluid cavity 1 through the preheating pipeline 2 according to the confining pressure required for the experiment, so as to achieve the confining pressure condition in the sample chamber confining pressure fluid cavity 1.

[0094] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0095] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A true triaxial porosity test constant temperature and pressure device, characterized in that: include: A sample chamber confining pressure fluid cavity (1), in which a rock sample (7) is placed to perform a porosity and permeability test; A preheating pipeline (2), wherein a fluid outlet of the preheating pipeline (2) is connected to a fluid inlet of the sample chamber confining pressure fluid chamber (1); A circulation pump (3), the circulation pump (3) being connected to the fluid inlet of the preheating pipeline (2); A heat exchange liquid storage tank (4), one end of the heat exchange liquid storage tank (4) is connected to the circulation pump (3), and the other end of the heat exchange liquid storage tank (4) is connected to the fluid outlet of the sample chamber confining pressure fluid cavity (1); A pressure loading pump (5) is connected to the fluid inlet of the sample chamber confining pressure fluid chamber (1) through the preheating pipeline (2).

2. A true triaxial porosity test constant pressure and temperature device according to claim 1, characterized in that: A high-pressure valve (6) is provided on the pipeline connecting the preheating pipeline (2) and the sample chamber confining pressure fluid chamber (1), the pipeline connecting the heat exchange liquid storage tank (4) and the sample chamber confining pressure fluid chamber (1), and the pipeline connecting the pressure loading pump (5) and the preheating pipeline (2).

3. A true triaxial porosity test constant temperature and pressure device according to claim 1, characterized in that: It also includes a sensor, which is arranged in the heat exchange liquid storage tank.

4. A true triaxial porosity test voltage and temperature stabilizing device according to claim 3, characterized in that: It also includes a control system, which is electrically connected to the preheating pipeline (2) and the high-pressure circulation pump (5).

5. A true triaxial porosity test voltage and temperature stabilizing device according to claim 1, characterized in that: The sample chamber confining pressure fluid chamber (1) adopts a core clamp, comprising a shell (87), a pressurizing device, a sealing device and a flow guiding device. The shell (87) is a hollow structure. The shell (87) is provided with a plurality of through holes on the side thereof that are connected to the inside of the hollow structure. The rock sample (7) is wrapped by the sealing device and arranged in the hollow structure of the shell (87). The pressurizing device is arranged in the through holes on the side of the shell (87) to pressurize the rock sample (7). The flow guiding device connects the surface of the rock sample (7) with the outside of the shell (87).

6. A true triaxial porosity test constant pressure and temperature device according to claim 5, characterized in that: The pressurizing device comprises an axial pressure head (81) and a horizontal pressure head (82), the axial pressure head (81) and the horizontal pressure head (82) being respectively arranged in the axial through hole and the horizontal through hole on the side of the shell (87) to pressurize the side surfaces of the rock sample (7); the sealing device comprises a sleeve (83), the sleeve (83) being sleeved outside the axial pressure head (81) and the rock sample (7); the flow guiding device comprises an annular flow guiding groove (84) and a flow guiding pipe (85), the annular flow guiding groove (84) being connected to a flow guiding hole arranged on the axial pressure head (81), the flow guiding hole being arranged on the contact surface between the axial pressure head (81) and the rock sample (7), and the flow guiding pipe (85) being connected to the annular flow guiding groove (84).

7. A method for constant pressure and temperature for true triaxial porosity testing, characterized in that: Based on the true triaxial porosity test pressure-stabilizing and temperature-regulating device described in claim 4, pressure-stabilizing and temperature-regulating are performed.

8. A method for stabilizing pressure and maintaining constant temperature for true triaxial porosity testing according to claim 7, characterized in that: The following steps are involved: The fluid in the heat exchange liquid storage tank is heated by the preheating pipeline, and the fluid is pumped into the sample chamber confining pressure fluid chamber through the fluid inlet of the sample chamber confining pressure fluid chamber by the high-pressure circulation pump to realize the circulation of the confining pressure fluid; The fluid in the sample chamber confining pressure fluid cavity is transported back to the heat exchange fluid storage tank through the fluid outlet of the sample chamber confining pressure fluid cavity; The pressure loading pump delivers the fluid to the sample chamber confining pressure fluid cavity through the preheating pipeline according to the confining pressure required for the experiment, so as to achieve the confining pressure condition in the sample chamber confining pressure fluid cavity.

9. A method for stabilizing pressure and maintaining constant temperature for true triaxial porosity testing according to claim 7, characterized in that: Detecting the temperature of the fluid in the heat exchange tank by a sensor; The speed parameter of the high-pressure circulation pump and the heating temperature of the preheating pipeline are controlled by a control system.

10. A true triaxial porosity test system, characterized in that: It comprises a true triaxial porosity test pressure-stabilizing and temperature-regulating device as described in any one of claims 1 to 6.

Images