Device and method for testing deformation and damage in salt rock creep process

Abstract

The invention provides a deformation and damage testing device in a salt rock creep process. The deformation and damage testing device comprises a confining pressure loading device, an axial pressure loading device, a first temperature adjusting device, a second temperature adjusting device and a signal acquisition system. The confining pressure loading device is used for simulating horizontal ground stress of a stratum where salt rock is located, the axial pressure loading device is used for simulating axial pressure applied to the salt rock by stratum fluid, the first temperature adjusting device is used for simulating the temperature of the stratum where the salt rock is located, and the second temperature adjusting device is used for simulating the temperature of the stratum fluid. The signal acquisition system is used for acquiring acoustic emission signals and displacement signals. According to the deformation and damage testing device in the salt rock creep process, only one of the confining pressure, the axial pressure, the formation temperature and the formation fluid temperature can serve as a variable, other parameters are fixed, and the relation between deformation and damage and the confining pressure, the axial pressure, the formation temperature and the formation fluid temperature in the salt rock creep process is obtained through experimental data.

Description

Technical Field

[0001] The invention relates to the technical field of oil and gas engineering, and in particular to a device and method for testing deformation and damage in a salt rock creep process. Background Art

[0002] As a rock mass with good air tightness, strong damage recovery ability, and stable chemical and mechanical properties, salt rock is often used as an important storage place for deep energy reservoirs and underground nuclear waste. In the field of oil and gas engineering, salt rock is usually used as the cap rock of oil and gas reservoirs.

[0003] Since salt rock has strong creep characteristics, and the creep rate of salt rock is closely related to formation temperature, horizontal ground stress, overburden pressure, formation fluid temperature, etc. In addition, the creep process of salt rock is also accompanied by the evolution and repair process of internal damage of the rock mass. However, there is no device or method in the prior art that can derive the relationship between salt rock creep and various influencing factors. Summary of the invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention provides a deformation and damage testing device and a testing method during the creep process of salt rock, aiming to solve the problem that there is no device or method in the related art that can derive the relationship between the creep process of salt rock formations and various influencing factors.

[0005] The present invention provides a device for testing deformation and damage during creep of salt rock, comprising:

[0006] A confining pressure loading device, the confining pressure loading device comprising a pressure vessel and a hydraulic oil supply device, the pressure vessel is provided with a first pressure chamber, the salt rock sample is used to be placed in the first pressure chamber, and the hydraulic oil supply device is used to supply hydraulic oil into the first pressure chamber;

[0007] An axial pressure loading device, the axial pressure loading device comprising two pressure heads and a formation fluid supply device, the two pressure heads are connected to the pressure vessel, and the two pressure heads are respectively connected to the two ends of the salt rock sample, a second pressure chamber is provided between the pressure heads and the salt rock sample, and the formation fluid supply device is used to supply formation fluid into the second pressure chamber;

[0008] a first temperature regulating device, the first temperature regulating device being arranged on the pressure vessel and being used for regulating the temperature of the hydraulic oil in the first pressure chamber;

[0009] a second temperature regulating device, the second temperature regulating device being arranged on the formation fluid supply device and being used for regulating the temperature of the formation fluid supplied into the second pressure chamber;

[0010] A signal acquisition system, the signal acquisition system at least includes an acoustic emission sensor, a displacement sensor and a signal collector, the acoustic emission sensor and the displacement sensor are both electrically connected to the signal collector, the acoustic emission sensor is arranged on the pressure vessel, and is used to collect acoustic emission signals, and the displacement sensor is arranged around the salt rock sample, and is used to collect radial displacement of the salt rock sample.

[0011] According to the deformation and damage testing device for salt rock creep provided by the present invention, the hydraulic oil supply device includes a hydraulic oil pump, a confining pressure sensor and a confining pressure controller. The confining pressure sensor is arranged in the first pressure chamber, and the hydraulic oil pump and the confining pressure sensor are both electrically connected to the confining pressure controller.

[0012] According to the deformation and damage testing device for salt rock creep provided by the present invention, the formation fluid supply device includes a liquid pump, an axial pressure sensor and an axial pressure controller, the axial pressure sensor is arranged in the liquid supply pipeline of the formation fluid supply device, and the liquid pump and the axial pressure sensor are both electrically connected to the axial pressure controller.

[0013] According to the deformation and damage testing device for salt rock creep provided by the present invention, the first temperature regulating device includes a heating wire, a first temperature controller and a first temperature sensor, the heating wire is arranged on the outside of the pressure vessel, the first temperature sensor is arranged in the first pressure chamber, and the heating wire and the first temperature sensor are both electrically connected to the first temperature controller.

[0014] According to the deformation and damage testing device for salt rock creep provided by the present invention, the second temperature regulating device includes a heating device, a second temperature controller and a second temperature sensor, the heating device is arranged on the liquid supply pipeline of the formation fluid supply device, the second temperature sensor is arranged in the liquid supply pipeline of the formation fluid supply device, and the heating device and the second temperature sensor are both electrically connected to the second temperature controller.

[0015] According to the device for testing deformation and damage during creep of rock salt provided by the present invention, the outer side of the pressure vessel is also coated with a thermal insulation layer, and the heating wire is located between the pressure vessel and the thermal insulation layer.

[0016] According to the device for testing deformation and damage during creep of salt rock provided by the present invention, the edge of one end of the pressure head connected to the salt rock sample is in sealing contact with the end face of the salt rock sample, a plurality of mutually connected grooves are arranged on the inner side of the one end of the pressure head connected to the salt rock sample, and the plurality of grooves form the second pressure chamber, and the pressure head is also provided with a fluid channel connecting the inside and outside of the second pressure chamber, and the end of the fluid channel away from the second pressure chamber is connected to the liquid outlet end of the formation fluid supply device.

[0017] According to the device for testing deformation and damage during creep of rock salt provided by the present invention, the outer sides of the pressure head and the rock salt sample are covered with an oil-isolating sleeve.

[0018] The present invention also provides a method for testing deformation and damage during creep of salt rock. Based on the above-mentioned device for testing deformation and damage during creep of salt rock, the testing method comprises the following steps:

[0019] The hydraulic oil supply device is adjusted to inject hydraulic oil into the first pressure chamber until the oil pressure in the first pressure chamber reaches a preset confining pressure, the formation fluid supply device is adjusted to inject formation fluid into the second pressure chamber until the liquid pressure in the second pressure chamber reaches a preset axial pressure, and the first temperature adjustment device is adjusted to heat the hydraulic oil in the first pressure chamber to a preset temperature, wherein the preset confining pressure and the preset axial pressure are determined according to the pressure conditions of the formation where the salt rock is located, and the preset temperature is determined according to the temperature conditions of the formation where the salt rock is located;

[0020] The preset confining pressure, the preset axial pressure and the preset temperature are maintained unchanged, the second temperature regulating device is adjusted to change the temperature of the formation fluid supplied to the second pressure chamber, and the acoustic emission signal and displacement signal of the salt rock sample in the creep process under different formation fluid temperatures are recorded by the signal acquisition system;

[0021] After reaching the target test time, the displacement signal is used to determine whether the salt rock sample has entered the accelerated creep stage to determine whether the salt rock sample has been damaged, and the following steps are performed based on the result of whether the salt rock sample has been damaged:

[0022] Confirm that the salt rock sample has not been damaged, and determine whether it is necessary to continue to increase the axial loading stress based on the existing data;

[0023] If it is determined that the axial loading stress needs to be further increased, the axial pressure is increased by adjusting the fluid supply pressure of the formation fluid supply device, and the loading time is set. The acoustic emission signal and displacement signal of the salt rock sample during the creep process at different formation fluid temperatures are recorded through the signal acquisition system;

[0024] If there is no need to continue increasing the axial loading stress or the salt rock sample has been destroyed, the experiment ends;

[0025] The obtained experimental data are analyzed to determine the interaction law between confining pressure, axial pressure, formation fluid temperature, formation environment temperature and salt rock damage and deformation.

[0026] According to the method for testing deformation and damage of salt rock during creep provided by the present invention, before the hydraulic oil supply device is opened to inject hydraulic oil into the first pressure chamber until the oil pressure in the first pressure chamber reaches a preset confining pressure, and the formation fluid supply device is opened to inject formation fluid into the second pressure chamber until the liquid pressure in the second pressure chamber reaches a preset axial pressure, the following steps are also included:

[0027] Assemble the hydraulic oil supply device and the pressure vessel into a confining pressure loading device;

[0028] Connect two pressure heads to the two ends of the salt rock sample respectively, connect the displacement sensor around the salt rock sample, then put the salt rock sample into the first pressure chamber of the pressure vessel, then connect the pressure head to the pressure vessel, and finally connect the formation fluid supply device to the pressure head to form an axial pressure loading device;

[0029] Connecting a first temperature regulating device to the pressure vessel, and connecting a second temperature regulating device to the formation fluid supply device;

[0030] The acoustic emission sensor is connected to the pressure vessel, and the acoustic emission sensor and the displacement sensor are connected to the signal collector.

[0031] The present invention adopts the above technical solution, which has the following advantages:

[0032] The deformation and damage testing device for salt rock during creep provided by the present invention comprises a confining pressure loading device, an axial pressure loading device, a first temperature regulating device, a second temperature regulating device and a signal acquisition system. The confining pressure loading device comprises a pressure vessel and a hydraulic oil supply device, a first pressure chamber is arranged in the pressure vessel, the salt rock sample is used to be placed in the first pressure chamber, and the hydraulic oil supply device is used to supply hydraulic oil to the first pressure chamber. The axial pressure loading device comprises two pressure heads and a formation fluid supply device, both of which are connected to the pressure vessel, and the two pressure heads are respectively connected to the two ends of the salt rock sample, a second pressure chamber is arranged between the pressure heads and the salt rock sample, and the formation fluid supply device is used to supply formation fluid to the second pressure chamber. The first temperature regulating device is arranged on the pressure vessel, and is used to adjust the temperature of the hydraulic oil in the first pressure chamber. The second temperature regulating device is arranged on the formation fluid supply device, and is used to adjust the temperature of the formation fluid supplied to the second pressure chamber. The signal acquisition system at least includes an acoustic emission sensor, a displacement sensor and a signal collector. The acoustic emission sensor and the displacement sensor are both electrically connected to the signal collector. The acoustic emission sensor is arranged on the pressure vessel for collecting acoustic emission signals. The displacement sensor is arranged around the salt rock sample for collecting radial displacement of the salt rock sample. Before the test, two pressure heads are respectively installed at both ends of the salt rock sample, and the displacement sensor is installed around the salt rock sample. Then the salt rock sample installed with the pressure head and the displacement sensor is placed in the first pressure chamber, and the pressure head is connected to the pressure vessel, and then the hydraulic oil supply device is connected to the pressure vessel, and the formation fluid supply device is connected to the pressure head. Then the first temperature regulating device is connected to the pressure vessel, and the second temperature regulating device is connected to the formation fluid supply device. Then the acoustic emission sensor is installed on the pressure vessel, and the acoustic emission sensor and the displacement sensor are connected to the signal collector. During the test, one of the confining pressure, axial pressure, the temperature of the hydraulic oil in the first pressure chamber, and the temperature of the formation fluid is changed as a variable, and the other parameters are fixed to collect the acoustic emission signal collected by the acoustic emission sensor and the radial displacement of the salt rock sample collected by the displacement sensor. Finally, based on the collected data, the relationship between the deformation and damage during the creep process of salt rock and the formation pressure, formation fluid temperature, and formation temperature can be obtained.

[0033] Furthermore, in the method for testing deformation and damage during creep of salt rock provided by the present invention, since it is implemented based on the device for testing deformation and damage during creep of salt rock as described above, it has the same advantages as described above. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0035] Figure 1 It is a structural schematic diagram of a device for testing deformation and damage of salt rock during creep provided by one embodiment of the present invention;

[0036] Figure 2 is a bottom view of a pressure head provided by an embodiment of the present invention;

[0037] Figure 3 is a side cross-sectional view of a pressure head provided in one embodiment of the present invention;

[0038] Figure 4 FIG. 1 is a top view of a pressure vessel with a salt rock sample disposed therein according to an embodiment of the present invention.

[0039] Reference numerals:

[0040] 110: pressure vessel; 111: first pressure chamber; 121: hydraulic oil pump; 122: confining pressure sensor; 123: confining pressure controller; 200: salt rock sample; 310: pressure head; 311: second pressure chamber; 321: liquid pump; 322: axial pressure sensor; 323: axial pressure controller; 324: liquid supply pipeline; 410: acoustic emission sensor; 420: displacement sensor; 430: signal collector; 510: heating wire; 520: first temperature controller; 530: first temperature sensor; 610: heating device; 620: second temperature controller; 630: second temperature sensor; 700: insulation layer; 800: oil isolation sleeve. DETAILED DESCRIPTION

[0041] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are 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 creative work are within the scope of protection of the present invention.

[0042] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0043] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is more than two, unless otherwise clearly and specifically defined.

[0044] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0045] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0046] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0047] The present invention provides a deformation and damage testing device during the creep process of salt rock, comprising a confining pressure loading device, an axial pressure loading device, a first temperature regulating device, a second temperature regulating device and a signal acquisition system. The confining pressure loading device is used to simulate the horizontal ground stress of the stratum in which the salt rock is located for the salt rock sample, the axial pressure loading device is used to simulate the axial pressure exerted on the salt rock by the formation fluid for the salt rock sample, the first temperature regulating device is used to simulate the temperature of the stratum in which the salt rock is located for the salt rock sample, the second temperature regulating device is used to simulate the temperature of the formation fluid for the salt rock sample, and the signal acquisition system is used to collect acoustic emission signals and displacement signals to judge the damage degree and radial displacement of the salt rock sample according to the data. The deformation and damage testing device during the creep process of salt rock provided by the present invention can only use one of the confining pressure, axial pressure, formation temperature and formation fluid temperature as a variable, and the other parameters are fixed, and the relationship between the deformation and damage during the creep process of salt rock and the confining pressure, axial pressure, formation temperature and formation fluid temperature is obtained through experimental data.

[0048] Combine the following Figures 1 to 4 The invention describes a device for testing deformation and damage during creep of salt rock.

[0049] An embodiment of the present invention provides a device for testing deformation and damage during creep of salt rock, comprising a confining pressure loading device, an axial pressure loading device, a first temperature regulating device, a second temperature regulating device and a signal acquisition system.

[0050] The confining pressure loading device includes a pressure vessel 110 and a hydraulic oil supply device. The pressure vessel 110 is provided with a first pressure chamber 111 . The salt rock sample 200 is used to be placed in the first pressure chamber 111 . The hydraulic oil supply device is used to supply hydraulic oil to the first pressure chamber 111 .

[0051] Specifically, the first pressure chamber 111 of the pressure vessel 110 is used to place the salt rock sample 200. When the hydraulic oil supply device supplies hydraulic oil to the first pressure chamber 111, the oil pressure in the first pressure chamber 111 increases, and the oil pressure in the first pressure chamber 111 is adjusted by adjusting the oil supply pressure of the hydraulic oil supply device. The hydraulic oil in the first pressure chamber 111 is wrapped around the outer peripheral surface of the salt rock sample 200. The oil pressure is used to provide confining pressure for the salt rock sample 200, so as to simulate the horizontal ground stress of the stratum where the salt rock is located.

[0052] The axial pressure loading device includes two pressure heads 310 and a formation fluid supply device. The two pressure heads 310 are both connected to the pressure vessel 110, and the two pressure heads 310 are respectively connected to the two ends of the salt rock sample 200. A second pressure chamber 311 is arranged between the pressure heads 310 and the salt rock sample 200. The formation fluid supply device is used to supply formation fluid into the second pressure chamber 311.

[0053] Specifically, the axial pressure loading device includes two pressure heads 310 and a formation fluid supply device. When in use, the two pressure heads 310 are first connected to the two ends of the salt rock sample 200 along the axial direction, respectively, to form a closed second pressure chamber 311 at the position where the pressure heads 310 are connected to the salt rock sample 200, and then the salt rock sample 200 connected with the pressure heads 310 is placed in the first pressure chamber 111 of the pressure vessel 110, and then the two pressure heads 310 are connected to the pressure vessel 110. Then, the two liquid supply ends of the formation fluid supply device are connected to the two pressure heads 310 respectively, so that the formation fluid supply device is connected to the second pressure chamber 311.

[0054] When the formation fluid supply device supplies formation pressure into the second pressure chamber 311 , axial pressure is formed at both ends of the salt rock sample 200 to simulate the axial pressure of the formation fluid on the salt rock.

[0055] The first temperature regulating device is disposed on the pressure container 110 and is used to regulate the temperature of the hydraulic oil in the first pressure chamber 111 .

[0056] Specifically, the temperature of the hydraulic oil in the first pressure chamber 111 can be adjusted by the first temperature adjustment device to simulate the temperature of the stratum where the salt rock is located.

[0057] The second temperature regulating device is disposed on the formation fluid supply device, and is used to regulate the temperature of the formation fluid supplied to the second pressure chamber 311 .

[0058] Specifically, the second temperature regulating device is used to change the temperature of the formation fluid supplied to the second pressure chamber 311 to simulate the temperature of the formation fluid in the formation where the salt rock sample 200 is located.

[0059] The signal acquisition system at least includes an acoustic emission sensor 410, a displacement sensor 420 and a signal collector 430, and the acoustic emission sensor 410 and the displacement sensor 420 are both electrically connected to the signal collector 430. The acoustic emission sensor 410 is disposed on the pressure vessel 110 to collect acoustic emission signals. The displacement sensor 420 is disposed around the salt rock sample 200 to collect radial displacement of the salt rock sample 200.

[0060] Specifically, the acoustic emission sensor 410 is used to collect acoustic emission signals to determine the damage of the salt rock sample 200 , and the displacement sensor 420 is used to collect radial displacement of the salt rock sample 200 to determine the deformation of the salt rock sample 200 .

[0061] The deformation and damage testing device for the creep process of salt rock provided in the present embodiment can adjust the oil supply pressure of the hydraulic oil supply device according to the pressure and temperature conditions of the formation in which the salt rock is to be simulated, so that the oil pressure in the first pressure chamber 111 of the pressure vessel 110 reaches a preset confining pressure to simulate the horizontal ground stress to which the salt rock is subjected in the formation, adjust the fluid supply pressure of the formation fluid supply device to make the pressure of the formation fluid in the second pressure chamber 311 reach a preset axial pressure to simulate the axial stress to which the salt rock is subjected in the formation, adjust the first temperature regulating device to heat the hydraulic oil in the first pressure chamber 111 to make the temperature of the hydraulic oil in the first pressure chamber 111 reach a preset temperature to simulate the ambient temperature of the salt rock in the formation, and adjust the second temperature regulating device to change the temperature of the formation fluid.

[0062] During the test, the acoustic emission signal of the acoustic emission sensor 410 and the displacement signal of the displacement sensor 420 can be collected when one of the confining pressure, axial pressure, the temperature of the hydraulic oil in the first pressure chamber 111, and the temperature of the formation fluid in the second pressure chamber 311 is used as an independent variable and the other parameters remain fixed. The relationship between the deformation and damage in the process of salt rock creep and the confining pressure, axial pressure, ambient temperature, and formation fluid temperature is obtained through the collected data.

[0063] For example, during the test, the confining pressure, axial pressure of the salt rock sample 200 and the temperature of the hydraulic oil in the first pressure chamber 111 are kept unchanged, and only the temperature of the formation fluid is changed. The acoustic emission signal of the acoustic emission sensor 410 and the displacement signal of the displacement sensor 420 are collected, and finally the relationship between the deformation and damage during the creep process of the salt rock and the formation fluid temperature is obtained.

[0064] In some embodiments of the present invention, the hydraulic oil supply device includes a hydraulic oil pump 121, a confining pressure sensor 122 and a confining pressure controller 123. The confining pressure sensor 122 is arranged in the first pressure chamber 111, and the hydraulic oil pump 121 and the confining pressure sensor 122 are both electrically connected to the confining pressure controller 123.

[0065] Specifically, the hydraulic oil pump 121 is used to provide power for the hydraulic oil so that the hydraulic oil can be supplied to the first pressure chamber 111. The confining pressure sensor 122 is arranged in the first pressure chamber 111 to collect the oil pressure of the hydraulic oil in the first pressure chamber 111. The confining pressure controller 123 can adjust the power of the hydraulic oil pump 121 according to the input pressure value and the pressure value collected by the confining pressure sensor 122 to achieve the purpose of regulating the oil pressure.

[0066] In some embodiments of the present invention, the formation fluid supply device includes a liquid pump 321, an axial pressure sensor 322 and an axial pressure controller 323. The axial pressure sensor 322 is arranged in a liquid supply pipeline 324 of the formation fluid supply device. The liquid pump 321 and the axial pressure sensor 322 are both electrically connected to the axial pressure controller 323.

[0067] Specifically, the liquid pump 321 is used to provide power for the formation fluid so that the formation fluid can be supplied to the second pressure chamber 311. The axial pressure sensor 322 is arranged in the liquid supply pipeline 324 of the formation fluid supply device and is used to collect the pressure of the formation fluid in the liquid supply pipeline 324. The pressure of the formation fluid in the liquid supply pipeline 324 is the same as the pressure of the formation fluid in the second pressure chamber 311. The axial pressure controller 323 can adjust the power of the liquid pump 321 according to the input pressure value and the pressure value collected by the axial pressure sensor 322 to achieve the purpose of adjusting the axial pressure.

[0068] In some embodiments of the present invention, the first temperature regulating device includes a heating wire 510, a first temperature controller 520 and a first temperature sensor 530. The heating wire 510 is arranged on the outside of the pressure vessel 110, and the first temperature sensor 530 is arranged in the first pressure chamber 111. The heating wire 510 and the first temperature sensor 530 are both electrically connected to the first temperature controller 520.

[0069] Specifically, the heating wire 510 is used to be wound around the outside of the pressure vessel 110, and the first temperature sensor 530 is arranged in the first pressure chamber 111 to collect the temperature of the hydraulic oil in the first pressure chamber 111. The first temperature controller 520 can adjust the heating power of the heating wire 510 according to the input temperature value and the collected temperature of the hydraulic oil to achieve the purpose of regulating the temperature of the hydraulic oil.

[0070] In some embodiments of the present invention, the second temperature regulating device includes a heating device 610, a second temperature controller 620 and a second temperature sensor 630. The heating device 610 is arranged on the liquid supply pipeline 324 of the formation fluid supply device, and the second temperature sensor 630 is arranged in the liquid supply pipeline 324 of the formation fluid supply device. The heating device 610 and the second temperature sensor 630 are both electrically connected to the second temperature controller 620.

[0071] Specifically, the heating device 610 is used to heat the formation fluid in the liquid supply pipeline 324 of the formation fluid supply device. The second temperature sensor 630 is arranged in the liquid supply pipeline 324, and the temperature of the formation fluid in the liquid supply pipeline 324 is the same as the temperature of the formation fluid in the second pressure chamber 311. The second temperature controller 620 can adjust the heating power of the heating device 610 according to the input temperature value and the collected temperature value of the formation fluid, so as to achieve the purpose of adjusting the temperature of the formation circulation.

[0072] In some embodiments of the present invention, a heat-insulating layer 700 is coated on the outside of the pressure vessel 110 , and the heating wire 510 is located between the pressure vessel 110 and the heat-insulating layer 700 to slow down the heat exchange between the pressure vessel 110 and the environment.

[0073] In some embodiments of the present invention, the salt rock sample 200 may be cylindrical, the outer edge of one end of the pressure head 310 connected to the end face of the salt rock sample 200 is in sealing contact with the end face of the salt rock sample 200, and a plurality of mutually connected grooves are provided on the inner side of the end of the pressure head 310 connected to the end face of the salt rock sample 200, and the plurality of grooves are connected to each other to form a second pressure chamber 311. A fluid channel connecting the inside and outside of the second pressure chamber 311 is also provided on the pressure head 310, and the end of the fluid channel away from the second pressure chamber 311 is used to be connected to the liquid supply end of the formation fluid supply device.

[0074] Such an arrangement can increase the contact area between the formation fluid and the end surface of the salt rock sample 200, making the force more uniform.

[0075] In some embodiments of the present invention, the outer sides of the pressure head 310 and the salt rock sample 200 are covered with an oil isolation sleeve 800 to prevent the hydraulic oil in the first pressure chamber 111 from contacting the salt rock sample 200 .

[0076] An embodiment of the present invention further provides a method for testing deformation and damage during creep of salt rock, which is implemented based on the above-mentioned device for testing deformation and damage during creep of salt rock. The method comprises the following steps:

[0077] Step S100, adjusting the hydraulic oil supply device to inject hydraulic oil into the first pressure chamber 111 until the oil pressure in the first pressure chamber 111 reaches a preset confining pressure, adjusting the formation fluid supply device to inject formation fluid into the second pressure chamber 311 until the liquid pressure in the second pressure chamber 311 reaches a preset axial pressure, and adjusting the first temperature adjustment device to heat the hydraulic oil in the first pressure chamber 111 to a preset temperature, wherein the preset confining pressure and the preset axial pressure are determined according to the pressure conditions of the formation where the salt rock is located, and the preset temperature is determined according to the temperature conditions of the formation where the salt rock is located;

[0078] Step S200, keeping the preset confining pressure, the preset axial pressure and the preset temperature unchanged, adjusting the second temperature adjustment device to change the temperature of the formation fluid supplied to the second pressure chamber 311, and recording the acoustic emission signal and displacement signal of the salt rock sample 200 during the creep process at different formation fluid temperatures through the signal acquisition system;

[0079] Step S300: After reaching the target experimental time, determine whether the salt rock sample 200 has entered the accelerated creep stage by using the displacement signal to determine whether the salt rock sample 200 has been damaged, and perform the following steps based on the result of whether the salt rock sample 200 has been damaged:

[0080] Determine that the salt rock sample 200 is not damaged, and determine whether it is necessary to continue to increase the axial loading stress based on the existing data;

[0081] If it is determined that the axial loading stress needs to be further increased, the axial pressure loading stress is increased by adjusting the oil supply pressure of the hydraulic oil supply device, and the loading time is set, and the acoustic emission signal and displacement signal of the salt rock sample 200 during the creep process at different temperatures are recorded by the signal acquisition system;

[0082] If there is no need to continue increasing the axial loading stress or the salt rock sample 200 has been damaged, the experiment ends;

[0083] Step S400: Analyze the obtained experimental data to determine the interaction law among salt rock stress, damage, formation fluid and temperature.

[0084] The method for testing deformation and damage during creep of salt rock provided by the present invention is implemented based on the above-mentioned device for testing deformation and damage during creep of salt rock, and therefore has the same advantages as described above.

[0085] In some embodiments of the present invention, before the hydraulic oil supply device is opened to inject hydraulic oil into the first pressure chamber 111 until the oil pressure in the first pressure chamber 111 reaches a preset confining pressure, and the formation fluid supply device is opened to inject formation fluid into the second pressure chamber 311 until the liquid pressure in the second pressure chamber 311 reaches a preset axial pressure, the following steps are also included:

[0086] Step S500, assembling the hydraulic oil supply device and the pressure vessel 110 into a confining pressure loading device;

[0087] Step S600, connecting two pressure heads 310 to the two ends of the salt rock sample 200 respectively, and connecting the displacement sensor 420 around the salt rock sample 200, then placing the salt rock sample 200 into the first pressure chamber 111 of the pressure vessel 110, then connecting the pressure head 310 to the pressure vessel 110, and finally connecting the bottom fluid supply device to the pressure head 310 to form an axial pressure loading device;

[0088] Step S700, connecting a first temperature regulating device to the pressure vessel 110, and connecting a second temperature regulating device to the formation fluid supply device;

[0089] Step S800 , connecting the acoustic emission sensor 410 to the pressure vessel 110 , and connecting the acoustic emission sensor 410 and the displacement sensor 420 to the signal collector 430 .

[0090] The above steps are used to assemble the deformation and damage testing device during the creep process of salt rock before testing.

[0091] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A device for testing deformation and damage during creep of salt rock, characterized in that: include: A confining pressure loading device, the confining pressure loading device comprising a pressure vessel (110) and a hydraulic oil supply device, the pressure vessel (110) being provided with a first pressure chamber (111), the salt rock sample (200) being used to be placed in the first pressure chamber (111), and the hydraulic oil supply device being used to supply hydraulic oil into the first pressure chamber (111); An axial pressure loading device, the axial pressure loading device comprising two pressure heads (310) and a formation fluid supply device, the two pressure heads (310) are both connected to the pressure container (110), and the two pressure heads (310) are respectively connected to two ends of the salt rock sample (200), a second pressure chamber (311) is provided between the pressure heads (310) and the salt rock sample (200), and the formation fluid supply device is used for supplying formation fluid into the second pressure chamber (311); a first temperature regulating device, the first temperature regulating device being arranged on the pressure container (110) and being used for regulating the temperature of the hydraulic oil in the first pressure chamber (111); a second temperature regulating device, the second temperature regulating device being arranged on the formation fluid supply device and being used for regulating the temperature of the formation fluid supplied to the second pressure chamber (311); A signal acquisition system, the signal acquisition system comprising at least an acoustic emission sensor (410), a displacement sensor (420) and a signal collector (430), the acoustic emission sensor (410) and the displacement sensor (420) both being electrically connected to the signal collector (430), the acoustic emission sensor (410) being arranged on the pressure vessel (110) for collecting acoustic emission signals, and the displacement sensor (420) being arranged around the salt rock sample (200) for collecting radial displacement of the salt rock sample (200).

2. The device for testing deformation and damage during creep of salt rock according to claim 1, characterized in that: The hydraulic oil supply device comprises a hydraulic oil pump (121), a confining pressure sensor (122) and a confining pressure controller (123); the confining pressure sensor (122) is arranged in the first pressure chamber (111); and the hydraulic oil pump (121) and the confining pressure sensor (122) are both electrically connected to the confining pressure controller (123).

3. The device for testing deformation and damage during creep of salt rock according to claim 1, characterized in that: The formation fluid supply device comprises a liquid pump (321), an axial pressure sensor (322) and an axial pressure controller (323); the axial pressure sensor (322) is arranged in a liquid supply pipeline (324) of the formation fluid supply device; the liquid pump (321) and the axial pressure sensor (322) are both electrically connected to the axial pressure controller (323).

4. The device for testing deformation and damage during creep of salt rock according to claim 1, characterized in that: The first temperature regulating device comprises a heating wire (510), a first temperature controller (520) and a first temperature sensor (530); the heating wire (510) is arranged on the outside of the pressure container (110); the first temperature sensor (530) is arranged in the first pressure chamber (111); the heating wire (510) and the first temperature sensor (530) are both electrically connected to the first temperature controller (520).

5. The device for testing deformation and damage during creep of salt rock according to claim 1, characterized in that: The second temperature regulating device includes a heating device (610), a second temperature controller (620) and a second temperature sensor. The heating device (610) is arranged on the liquid supply pipeline (324) of the formation fluid supply device, and the second temperature sensor is arranged in the liquid supply pipeline (324) of the formation fluid supply device. The heating device (610) and the second temperature sensor are both electrically connected to the second temperature controller (620).

6. The device for testing deformation and damage during creep of salt rock according to claim 4, characterized in that: The outer side of the pressure container (110) is also coated with a thermal insulation layer (700), and the heating wire (510) is located between the pressure container (110) and the thermal insulation layer (700).

7. The device for testing deformation and damage during creep of salt rock according to claim 1, characterized in that: The edge of one end of the pressure head (310) connected to the salt rock sample (200) is in sealing contact with the end face of the salt rock sample (200), and a plurality of mutually connected grooves are arranged on the inner side of the end of the pressure head (310) connected to the salt rock sample (200), and the plurality of grooves form the second pressure chamber (311). The pressure head (310) is also provided with a fluid channel connecting the inside and outside of the second pressure chamber (311), and the end of the fluid channel away from the second pressure chamber (311) is connected to the liquid outlet end of the formation fluid supply device.

8. The device for testing deformation and damage during creep of salt rock according to claim 7, characterized in that: The outer sides of the pressure head (310) and the salt rock sample (200) are covered with an oil isolation sleeve (800).

9. A method for testing deformation and damage during creep of salt rock, characterized in that: Based on the deformation and damage testing device during creep of salt rock according to any one of claims 1 to 8, the testing method comprises the following steps: The hydraulic oil supply device is adjusted to inject hydraulic oil into the first pressure chamber (111) until the oil pressure in the first pressure chamber (111) reaches a preset confining pressure, the formation fluid supply device is adjusted to inject formation fluid into the second pressure chamber (311) until the liquid pressure in the second pressure chamber (311) reaches a preset axial pressure, and the first temperature adjustment device is adjusted to heat the hydraulic oil in the first pressure chamber (111) to a preset temperature, wherein the preset confining pressure and the preset axial pressure are determined according to the pressure conditions of the formation in which the salt rock is located, and the preset temperature is determined according to the temperature conditions of the formation in which the salt rock is located; The preset confining pressure, the preset axial pressure and the preset temperature are maintained unchanged, a second temperature regulating device is adjusted to change the temperature of the formation fluid supplied to the second pressure chamber (311), and an acoustic emission signal and a displacement signal of the salt rock sample (200) during creep at different formation fluid temperatures are recorded through a signal acquisition system; After reaching the target experimental time, the displacement signal is used to determine whether the salt rock sample (200) has entered the accelerated creep stage to determine whether the salt rock sample (200) has been damaged, and the following steps are performed based on the result of whether the salt rock sample (200) has been damaged: Determine that the salt rock sample (200) is not damaged, and determine whether it is necessary to continue to increase the axial loading stress based on the existing data; If it is determined that the axial loading stress needs to be further increased, the axial pressure is increased by adjusting the fluid supply pressure of the formation fluid supply device, and the loading time is set, and the acoustic emission signal and displacement signal of the salt rock sample (200) during the creep process at different formation fluid temperatures are recorded through the signal acquisition system; If there is no need to continue increasing the axial loading stress or the salt rock sample (200) has been damaged, the experiment ends; The obtained experimental data are analyzed to determine the interaction law between confining pressure, axial pressure, formation fluid temperature, formation environment temperature and salt rock damage and deformation.

10. The method for testing deformation and damage during creep of salt rock according to claim 9, characterized in that: Before the hydraulic oil supply device is opened to inject hydraulic oil into the first pressure chamber (111) until the oil pressure in the first pressure chamber (111) reaches a preset confining pressure, and the formation fluid supply device is opened to inject formation fluid into the second pressure chamber (311) until the liquid pressure in the second pressure chamber (311) reaches a preset axial pressure, the method further comprises the following steps: Assembling a hydraulic oil supply device and a pressure container (110) into a confining pressure loading device; Two pressure heads (310) are respectively connected to two ends of a salt rock sample (200), and a displacement sensor (420) is connected around the salt rock sample (200), and then the salt rock sample (200) is placed in a first pressure chamber (111) of the pressure vessel (110), and then the pressure head (310) is connected to the pressure vessel (110), and finally a formation fluid supply device is connected to the pressure head (310) to form an axial pressure loading device; Connecting a first temperature regulating device to the pressure vessel (110), and connecting a second temperature regulating device to the formation fluid supply device; The acoustic emission sensor (410) is connected to the pressure vessel (110), and the acoustic emission sensor (410) and the displacement sensor (420) are connected to the signal collector (430).

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