Displacement test device and method

Abstract

The invention discloses a displacement test device and method, and relates to the technical field of displacement tests, a displacement fluid system, a rock core holder and a nuclear magnetic resonance spectrometer, a fluid outlet of the displacement fluid system is communicated with a fluid inlet of the rock core holder, a rock core is arranged in the rock core holder, and the nuclear magnetic resonance spectrometer is arranged in the rock core holder. The displacement fluid system can convey displacement fluid into the rock core holder, the rock core holder can replace target fluid from the rock core, and the rock core holder is arranged in a detection cavity of the nuclear magnetic resonance spectrometer. According to the displacement test device and method, shale can be detected in the shale displacement test process, and the displacement test effect is well evaluated.

Description

Technical Field

[0001] The invention relates to the technical field of displacement test, and in particular to a displacement test device and method. Background Art

[0002] The displacement device is a test device that uses displacement fluid to displace the target fluid based on osmosis under a certain temperature and pressure. However, most displacement devices currently only detect the results of the displacement, and there are relatively few studies on the changes in various parameters and indicators during the shale displacement process, and the effect of the displacement test cannot be well evaluated. Therefore, there is an urgent need for a displacement test device and method that can detect shale during the shale displacement test and well evaluate the effect of the displacement test. Summary of the invention

[0003] The purpose of the present invention is to provide a displacement test device and method to solve the problems existing in the above-mentioned prior art, so as to detect shale during the shale displacement test and well evaluate the displacement test effect.

[0004] To achieve the above object, the present invention provides the following solutions: The present invention provides a displacement test device, comprising: a displacement fluid system, a core holder and a nuclear magnetic resonance instrument, wherein a fluid outlet of the displacement fluid system is connected to a fluid inlet of the core holder, a core is arranged in the core holder, the core holder can use the displacement fluid to displace a target fluid from the core, and the core holder is arranged in a detection chamber of the nuclear magnetic resonance instrument.

[0005] Preferably, the displacement fluid system includes a power pump and a material storage, a heating device, a purifier, a first container and a power pump which are sequentially connected and communicated with each other. The output end of the power pump is communicated with the first container, and a first pressure gauge is provided on the first container.

[0006] Preferably, the core clamp includes a clamp body, a temperature detection device and a pressure control component, the pressure control component is connected to the clamp body, the clamp body is used to set the core, the clamp body can apply axial pressure and confining pressure to the core in the clamp body, the pressure control component can control the magnitude of the confining pressure and axial pressure of the clamp body on the core, the detection end of the temperature detection device is located in the clamp body, and the temperature detection device can detect the temperature inside the clamp body.

[0007] Preferably, the pressure control assembly includes a pressure control pump, a first valve, a second valve, a main pipeline, a first branch pipe and a second branch pipe, one end of the main pipeline is connected to the output end of the pressure control pump, one end of the first branch pipe is connected to the main pipeline, and the other end is connected to the confining pressure regulating port of the clamp body, one end of the second branch pipe is connected to an end of the main pipeline away from the pressure control pump, and the other end is connected to the axial pressure regulating port of the clamp body, the first valve is arranged on the first branch pipe, and the second valve is arranged on the second branch pipe.

[0008] Preferably, the pressure-controlled pump is a manual pump.

[0009] Preferably, the pressure control assembly further includes a first pressure relief pipeline and a second pressure relief pipeline, one end of the first pressure relief pipeline is connected to the first branch pipe between the first valve and the clamp body, and the other end is provided with a first pressure relief valve, and one end of the second pressure relief pipeline is connected to the second branch pipe between the second valve and the clamp body, and the other end is provided with a second pressure relief valve.

[0010] Preferably, the pressure control assembly further includes a second container, a third branch pipe and a third valve, one end of the third branch pipe is connected to the main pipeline, and the other end is connected to the second container, and the third valve is arranged on the third branch pipe.

[0011] Preferably, it also includes a fluid processing system, which includes a gas-liquid separator, a fourth valve and a gas flow meter, the fluid output end of the core clamp is connected to the gas-liquid separator, the gas output end of the gas-liquid separator is connected to the fourth valve, and the fourth valve is connected to the gas flow meter.

[0012] Preferably, the fluid processing system further comprises a back pressure valve, the fluid output end of the core holder is in communication with the back pressure valve, and the back pressure valve is in communication with the fluid inlet of the gas-liquid separator.

[0013] The present invention also provides a displacement test method, comprising the following steps: Initial testing: Place the treated core in a core holder and use a nuclear magnetic resonance instrument to test the pore size distribution of the core that has not been subjected to the displacement test; Test phase: The fluid is displaced into the core holder by a displacement fluid system, the target fluid is displaced from the core by the displacement fluid, and the pore size distribution of the core is detected by a nuclear magnetic resonance instrument.

[0014] Compared with the prior art, the present invention has achieved the following technical effects: In the displacement test device provided by the present invention, during the test, the gas in the displacement fluid system enters the core holder, and the core holder uses the displacement fluid to displace the target fluid from the core to complete the displacement work. During the displacement process, the nuclear magnetic resonance instrument can continuously detect the core, thereby obtaining the pore size distribution data of the core during the displacement test, and better evaluating the effect of the displacement test.

[0015] Furthermore, in the present invention, by respectively arranging the first pressure relief valve and the second pressure relief valve on the first pressure relief pipeline and the second pressure relief pipeline, the control of the confining pressure and the axial pressure is made more convenient. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 A schematic diagram of the structure of the displacement test device provided by the present invention; In the figure: 1. Nuclear magnetic resonance instrument; 2. Material warehouse; 3. Heating device; 4. Purifier; 5. First container; 6. Power pump; 7. First pressure gauge; 8. Clamp body; 9. Temperature detection device; 10. Pressure control pump; 11. First valve; 12. Second valve; 13. Main pipeline; 14. First branch pipe; 15. Second branch pipe; 16. First pressure relief valve; 17. Second pressure relief valve; 18. Second container; 19. Third valve; 20. Gas-liquid separator; 21. Fourth valve; 22. Gas flow meter; 23. Back pressure valve; 24. Second pressure gauge; 25. Fifth valve; 26. Computer. DETAILED DESCRIPTION

[0018] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] The purpose of the present invention is to provide a displacement test device and method to solve the problems existing in the above-mentioned prior art, so as to detect shale during the shale displacement test and well evaluate the displacement test effect.

[0020] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0021] Embodiment 1 This embodiment provides a displacement test device, such as Figure 1 As shown, it includes: a displacement fluid system, a core holder and a nuclear magnetic resonance instrument 1, the fluid outlet of the displacement fluid system is connected to the fluid inlet of the core holder, the core holder is used to set the core, the displacement fluid system can transport the displacement fluid to the core holder, the core holder can displace the target fluid from the core, and the core holder is set in the detection chamber of the nuclear magnetic resonance instrument 1.

[0022] The displacement test device provided in this embodiment, during the test, the fluid in the displacement fluid system enters the core holder, the core holder applies axial pressure and confining pressure to the core, and uses the displacement fluid to displace the target fluid from the core to complete the displacement work. During the displacement process, the nuclear magnetic resonance instrument 1 can continuously detect the core, thereby obtaining the pore size distribution data of the core during the displacement test, and better evaluate the effect of the displacement test. Among them, the nuclear magnetic resonance instrument 1 is connected to the computer 26 signal, and the nuclear magnetic resonance instrument 1 can perform T2 spectrum testing on the core and output the data to the computer 26; the displacement fluid is preferably CO2, and light hydrocarbons or water can also be used.

[0023] In a preferred implementation of the present embodiment, the displacement fluid system includes a power pump 6 and a material storehouse 2, a heating device 3, a purifier 4 and a first container 5 which are connected and communicated in sequence. The output end of the power pump 6 is communicated with the first container 5, and a first pressure gauge 7 is provided on the first container 5. The fluid inlet of the core holder has two states: open and closed. When the displacement fluid is introduced into the core holder, the fluid inlet of the core holder is first closed, and the displacement fluid is introduced into the heating device 3. The displacement fluid is heated to the temperature required by the test by the heating device 3. Then, the heated displacement fluid is introduced into the purifier 4. The displacement fluid is purified and impurities are removed by the purifier 4 to ensure the purity of the displacement fluid. Then, the impurity-removed gas is introduced into the first container 5, and the first pressure gauge 7 on the first container 5 is observed. If there is a digital display on the first pressure gauge 7, it means that there is no damage or leakage in each component. At this time, the fluid inlet of the core holder is opened, and the fluid is introduced into the core holder by the power pump 6 for use in the displacement test. Among them, the power pump 6 is preferably a constant pressure and constant speed pump; a fifth valve 25 is provided between the material storage 2 and the heating device 3.

[0024] In a preferred implementation of the present embodiment, the core holder includes a holder body 8, a temperature detection device 9 and a pressure control assembly. The pressure control assembly is connected to the holder body 8. The holder body 8 is used to set the core. The holder body 8 can apply axial pressure and confining pressure to the core in the holder body 8. The pressure control assembly can control the size of the confining pressure and axial pressure of the holder body 8 on the core. The detection end of the temperature detection device 9 is located in the holder body 8. The temperature detection device 9 can detect the temperature in the holder body 8. After opening the fluid inlet of the displacement system, observe whether the temperature on the temperature detection device 9 reaches the temperature of the displacement fluid heated by the heating device 3. If it reaches, it indicates that the fluid volume of the displacement fluid in the holder body 8 has reached the test requirements (if not, continue to introduce the displacement fluid). Then open the core holder, adjust the pressure control assembly, apply the axial pressure and confining pressure required by the test to the core, and perform the displacement work.

[0025] It should be noted that the clamp body in the present invention is a prior art known to the inventor, and the application of axial pressure and confining pressure is achieved by means of existing fluid pressurization.

[0026] In a preferred implementation manner of the present embodiment, the pressure control assembly includes a pressure control pump 10, a first valve 11, a second valve 12, a main pipeline 13, a first branch pipe 14 and a second branch pipe 15. One end of the main pipeline 13 is connected to the output end of the pressure control pump 10, one end of the first branch pipe 14 is connected to the main pipeline 13, and the other end is connected to the confining pressure regulating port of the clamp body 8. One end of the second branch pipe 15 is connected to the main pipeline 13 and one end away from the pressure control pump 10, and the other end is connected to the axial pressure regulating port of the clamp body 8. The first valve 11 is arranged on the first branch pipe 14, and the second valve 12 is arranged on the second branch pipe 15. When adjusting the pressure, if the confining pressure needs to be adjusted, the first valve 11 is opened, the second valve 12 is closed, and the fluid is introduced into the main pipe and the first branch pipe through the pressure control pump 10 until the preset confining pressure value is reached; when adjusting the axial pressure, the second valve 12 is opened, the first valve 11 is closed, and the fluid is injected into the main pipe and the second branch pipe 15 through the pressure control pump 10 until the preset axial pressure value is reached. The control of the axial pressure and the confining pressure is more convenient through the pressure control pump 10, the first valve 11 and the second valve 12. Among them, the pressure control pump 10 can introduce gas or water into the confining pressure regulating port and the axial pressure regulating port of the clamp body 8, as long as the filling pressure and the requirements of the displacement test can be met.

[0027] In a preferred implementation of this embodiment, the pressure control pump 10 is a manual pump. The pressure control pump 10 is preferably a manual air pump. Compared with devices such as hydraulic oil pumps, manual pumps are easy to operate and can reduce the failure rate of machinery.

[0028] In a preferred implementation of the present embodiment, the pressure control assembly further includes a first pressure relief pipeline and a second pressure relief pipeline. One end of the first pressure relief pipeline is connected to the first branch pipe 14 between the first valve 11 and the clamp body 8, and the other end is provided with a first pressure relief valve 16. One end of the second pressure relief pipeline is connected to the second branch pipe 15 between the second valve 12 and the clamp body 8, and the other end is provided with a second pressure relief valve 17. During the test, it is sometimes necessary to adjust the axial pressure and the surrounding pressure during the displacement process. For example, the initial axial pressure and the surrounding pressure are both 8MPa. After 5 minutes of the test, the axial pressure and the surrounding pressure need to be reduced to 5MPa. At this time, the first pressure relief valve 16 and the second pressure relief valve 17 can be opened, and the pressure relief valve can be closed after the axial pressure and the surrounding pressure are reduced to 5MPa. By setting the first pressure relief valve 16 and the second pressure relief valve 17, the control of the surrounding pressure and the axial pressure is more convenient. Among them, the clamp body 8 is built with a pressure sensor, and the magnitude of the axial pressure and the surrounding pressure can be detected by the pressure sensor.

[0029] In a preferred implementation of this embodiment, the pressure control component also includes a second container 18, a third branch pipe and a third valve 19. One end of the third branch pipe is connected to the main pipeline 13, and the other end is connected to the second container 18. The third valve 19 is arranged on the third branch pipe. Before adjusting the axial pressure and the surrounding pressure, the first valve 11 and the second valve 12 are closed first, and the third valve 19 is opened. The fluid is introduced into the second container 18 through the pressure control pump 10. When the fluid in the second container 18 is full, the third valve 19 is closed, and the axial pressure and the surrounding pressure are adjusted by the first valve 11, the second valve 12 and the pressure control pump 10. By setting the second container 18, the unstable pressure during the initial ventilation of the pressure control pump 10 is buffered, the pressure fluctuation is prevented during the test, and the accuracy of the test is improved.

[0030] In a preferred implementation of this embodiment, the displacement test device provided by the present invention further includes a fluid processing system, the displacement fluid is carbon dioxide, the fluid processing system includes a gas-liquid separator 20, a fourth valve 21 and a gas flow meter 22, the fluid output end of the core holder is connected to the gas-liquid separator 20, the gas output end of the gas-liquid separator 20 is connected to the fourth valve 21, and the fourth valve 21 is connected to the gas flow meter 22. After the displacement system completes the displacement work, the displacement fluid is introduced into the gas-liquid separator 20, the gas-liquid separator 20 separates the gas and liquid in the displacement fluid, the liquid is retained in the gas-liquid separator 20, and the gas enters the gas flow meter 22. When the value in the gas flow meter 22 no longer changes, it indicates that the displacement work is completed (if the test stipulates the specific time for the displacement work, the specific time for the displacement work shall prevail). Among them, when the fluid processing system is not set, other containers can be used to collect the displacement fluid, and gas-liquid separation and metering can be performed in other devices.

[0031] In a preferred implementation of this embodiment, the fluid processing system further includes a back pressure valve 23, the fluid output end of the core clamp is connected to the back pressure valve 23, and the back pressure valve 23 is connected to the fluid inlet of the gas-liquid separator 20. When the fluid pressure at the back pressure valve 23 is low, the gas can pass through the back pressure valve 23 and flow into the gas-liquid separation device. When the fluid pressure is high, the back pressure valve 23 opens to discharge the fluid, reduce the pressure, and improve the safety of the device. Among them, a second pressure gauge 24 is provided on the back pressure valve 23.

[0032] Embodiment 2 This embodiment provides a displacement test method, comprising the following steps: Initial testing: Place the treated core in a core holder and use a nuclear magnetic resonance instrument to test the pore size distribution of the core that has not been subjected to the displacement test; Experimental phase: The fluid is displaced into the core holder through the displacement fluid system, and the target fluid is replaced from the core by the displacement fluid. At the same time, the pore size distribution of the core is detected by a nuclear magnetic resonance instrument.

[0033] In the displacement test method provided in this embodiment, the nuclear magnetic resonance instrument 1 can detect the pore size distribution of the core during the displacement test, and can better evaluate the effect of the displacement test.

[0034] Specifically, when conducting the test, you can follow the following steps: Preparation steps: drying the core at 120° in an oven for 72 hours to evaporate the water in the core, evacuating the core with a vacuum pressure saturation device and saturating the core with oil for 48 hours, and measuring the core with a test nuclear magnetic resonance instrument 1 to obtain an initial T2 spectrum curve; Pressure regulation: place the core in the holder body 8, close the first valve 11 and the second valve 12, open the third valve 19, use the pressure control pump 10 to pressurize the second container 18 until the pressure is full (the handle of the manual pump cannot continue to rotate), then close the third valve 19, then open the first valve 11, close the second valve 12, apply the confining pressure through the pressure control pump 10 to reach the set value, then close the first valve 11, open the second valve 12, and apply the axial pressure through the pressure control pump 10 to reach the set value.

[0035] Fluid entry: Open the fifth valve 25, CO2 gas enters the heating device 3 for heating. The setting temperature of the heating device 3 is the formation temperature of the study area. After the gas is heated, it enters the purifier 4 for purification, and then enters the first container 5. At this time, observe whether the first pressure gauge 7 on the first container 5 displays a pressure value (if the pipeline is damaged and leaking, the pressure value cannot be displayed); when the pressure value of the first pressure gauge 7 no longer changes, according to the test design, the power pump 6 is used to push the gas in the first container 5 into the core holder, and the temperature detection device 9 (temperature probe) is inserted into the core, and the temperature is detected to be close to the temperature in the heating device 3, so as to determine whether the gas has entered the cavity in the core holder. If the temperature on the temperature detection device 9 is close to or equal to the temperature of the heating device 3, it indicates that the gas has entered the cavity.

[0036] Displacement test: Use CO2 gas to carry out displacement test, displace the displacement fluid (the displacement fluid includes CO2 and shale oil), and pass the displacement fluid generated by displacement in the core holder into the gas-liquid separator 20 for gas-liquid separation, and open the fourth valve 21 to observe whether there is a value in the gas flow meter 22. If there is a value, it means that the displacement test is carried out normally. When the displacement work is carried out for 5 minutes, 10 minutes, and 15 minutes respectively, turn on the nuclear magnetic resonance instrument 1 to carry out T2 spectrum test on the core in the core holder (if the pressure needs to be reduced, adjust the first pressure relief valve 16 and the second pressure relief valve 17). When the value in the gas flow meter 22 no longer changes, it indicates that the displacement test is over. At this time, stop the power pump 6, close the first valve 11, the second valve 12, the fourth valve 21 and the fifth valve 25, read the value of the gas flow meter 22, remove the gas-liquid separator 20 and measure the liquid in the gas-liquid separator 20.

[0037] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the method and core ideas of the present invention. At the same time, for those skilled in the art, according to the ideas of the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A displacement test device, characterized in that: include: A displacement fluid system, a core holder and a nuclear magnetic resonance instrument, wherein the fluid outlet of the displacement fluid system is communicated with the fluid inlet of the core holder, the core holder is used to set the core, the displacement fluid system can transport the displacement fluid to the core holder, the core holder can displace the target fluid from the core, and the core holder is arranged in the detection chamber of the nuclear magnetic resonance instrument; the displacement fluid system includes a power pump and a material storehouse, a heating device, a purifier, a first container and a power pump which are connected and communicated in sequence, the output end of the power pump is communicated with the first container, and the first container is provided with a first pressure gauge; the core holder includes a holder body, a temperature detection device and a pressure control component, the pressure control component is connected to the holder body, the core is set in the holder body, the holder body can apply axial pressure and confining pressure to the core in the holder body, the pressure control component can control the size of the confining pressure and axial pressure of the holder body on the core, the temperature The detection end of the temperature detection device is located in the clamp body, and the temperature detection device can detect the temperature in the clamp body; the pressure control component includes a pressure control pump, a first valve, a second valve, a main pipeline, a first branch pipe and a second branch pipe, one end of the main pipeline is connected to the output end of the pressure control pump, one end of the first branch pipe is connected to the main pipeline, and the other end is connected to the confining pressure regulating port of the clamp body, one end of the second branch pipe is connected to the end of the main pipeline away from the pressure control pump, and the other end is connected to the axial pressure regulating port of the clamp body, the first valve is arranged on the first branch pipe, and the second valve is arranged on the second branch pipe; the pressure control component also includes a first pressure relief pipeline and a second pressure relief pipeline, one end of the first pressure relief pipeline is connected to the first branch pipe between the first valve and the clamp body, and the other end is provided with a first pressure relief valve, one end of the second pressure relief pipeline is connected to the second branch pipe between the second valve and the clamp body, and the other end is provided with a second pressure relief valve.

2. The displacement test device according to claim 1, characterized in that: The pressure control pump is a manual pump.

3. The displacement test device according to claim 1, characterized in that: The pressure control assembly further includes a second container, a third branch pipe and a third valve. One end of the third branch pipe is connected to the main pipeline, and the other end is connected to the second container. The third valve is arranged on the third branch pipe.

4. The displacement test device according to claim 1, characterized in that: It also includes a fluid processing system, which includes a gas-liquid separator, a fourth valve and a gas flow meter. The fluid output end of the core clamp is connected to the gas-liquid separator, the gas output end of the gas-liquid separator is connected to the fourth valve, and the fourth valve is connected to the gas flow meter.

5. The displacement test device according to claim 4, characterized in that: The fluid processing system further comprises a back pressure valve, the fluid output end of the core holder is in communication with the back pressure valve, and the back pressure valve is in communication with the fluid inlet of the gas-liquid separator.

6. A displacement test method, characterized in that: Using the displacement test device in claim 1 comprises the following steps: Initial testing: Place the treated core in a core holder and use a nuclear magnetic resonance instrument to test the pore size distribution of the core that has not been subjected to the displacement test; Test phase: The fluid is displaced into the core holder by a displacement fluid system, the target fluid is displaced from the core by the displacement fluid, and the pore size distribution of the core is detected by a nuclear magnetic resonance instrument.

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