Shale saturation device and shale saturation experimental method

Abstract

The invention relates to the technical field of oilfield development, and discloses a shale saturation device for experimental shale, which comprises a sleeve mechanism, a liquid injection mechanism and an air exhaust mechanism. The casing mechanism comprises an upper cylinder, a liquid storage assembly and a lower cylinder, the upper cylinder is provided with a first cavity, the liquid storage assembly is provided with a second cavity, the second cavity is used for being communicated with the first cavity and forming a drawing channel used for containing experimental shale, and a butt joint port used for being connected with the experimental shale in a sealed mode can be formed between the first cavity and the second cavity. A third cavity used for containing the liquid storage assembly is formed in the lower barrel, and the third cavity can communicate with or be isolated from the second cavity. The liquid injection mechanism is used for communicating with the third cavity when the air pressure in the sleeve mechanism is smaller than the preset air pressure, so that the experiment shale is saturated by the degassed crude oil. And the liquid injection mechanism enables the gas-containing live oil to saturate the experimental shale under the condition that the first cavity is filled with the degassed crude oil. And the air exhaust mechanism is used for vacuumizing the sleeve mechanism and upwards drawing the degassed crude oil or the gas-containing live oil through the drawing channel.

Description

Technical Field

[0001] The present application belongs to the technical field of oilfield development, and specifically relates to a shale saturation device and a shale saturation experimental method. Background Art

[0002] The primary problem faced in core experiments is how to inject brine or crude oil into the experimental shale core to saturate the core with oil (or water).

[0003] Currently, there are two main methods for saturating shale cores both domestically and internationally. One method uses conventional sandstone saturation: placing the shale core in a core holder, applying confining pressure, and then evacuating the core. Oil is then injected from the core end using a displacement method, creating a pressure differential across the core to achieve saturation. However, this method has the disadvantage of a very small contact surface between the oil and the core, resulting in poor saturation and a very long saturation time.

[0004] Another method involves directly pressurizing and saturating the entire core, using a saturation method that combines step-by-step pressurization and weighing. This involves saturating the core with crude oil at a certain high pressure, then removing the core after depressurization and weighing it. The weighed core is then returned to the high-pressure vessel, where it is further pressurized and saturated, and then removed and weighed again. Saturation is considered complete when the core weights at the two pressures no longer change. However, this method requires repeated pressurization and depressurization of the core, which can easily rupture under the pressure differential, leading to changes in core mass and impacting experimental accuracy.

[0005] In summary, pressurized saturation is a process of injecting crude oil into the core from the outside to the inside. In addition to overcoming the problem of poor flow caused by capillary pressure, it is also necessary to overcome the problems of insufficient core saturation and poor saturation caused by the expansion force of gas squeezed in the ink bottle-shaped pore throat. Summary of the Invention

[0006] The purpose of this application is to provide a shale saturation device and a shale saturation experimental method, which improves the flow capacity of degassed crude oil and gas-containing live oil through the experimental shale and increases the saturation of the experimental shale.

[0007] In order to achieve the above objectives, the present application provides a shale saturation device for testing shale, the shale saturation device comprising:

[0008] The casing mechanism includes an upper cylinder, a liquid storage assembly, and a lower cylinder. The upper cylinder is provided with a first cavity, and the liquid storage assembly is provided with a second cavity. The second cavity is used to communicate with the first cavity and form a pull-out channel. The pull-out channel is used to accommodate experimental shale. A docking port can be formed between the first cavity and the second cavity. The docking port is used to be sealed with the experimental shale. The lower cylinder is formed with a third cavity for accommodating the liquid storage assembly, and the third cavity can communicate with or isolate the second cavity.

[0009] The liquid injection mechanism is used to connect the third cavity when the air pressure in the casing mechanism is less than a preset air pressure, and saturate the test shale with the degassed crude oil; the liquid injection mechanism is also used to saturate the test shale with the live oil when the first cavity is filled with the degassed crude oil; and

[0010] The pumping mechanism is used to draw a vacuum to the casing mechanism and to draw the degassed crude oil or gas-containing live oil upward through the pumping channel.

[0011] In an embodiment of the present invention, the air extraction mechanism comprises:

[0012] Vacuum pump;

[0013] a first vacuum assembly, whose two ends are respectively connected to the first cavity and the vacuum pump, and the first vacuum assembly connects the first cavity and the vacuum pump when the air pressure in the sleeve mechanism is greater than the first preset air pressure, so that the vacuum pump vacuums the sleeve mechanism;

[0014] The second air pumping assembly has two ends connected to the third cavity and the air pump respectively. The second air pumping assembly is used to connect the third cavity and the air pump when the air pressure in the casing mechanism is greater than the first preset air pressure, or to connect the third cavity and the air pump in the case of gas-containing live oil saturated experimental shale, and to isolate the third cavity and the air pump when the injection mechanism injects degassed crude oil into the third cavity.

[0015] In an embodiment of the present invention, the second air extraction assembly includes:

[0016] An oil-gas separation container, the third cavity and the air pump are connected via an oil-gas pipeline, the oil-gas separation container is arranged on the oil-gas pipeline, and the oil-gas separation container is used to connect to the third cavity when the experimental shale is saturated with gas-containing active oil, or to isolate the third cavity when the gas pressure in the casing mechanism is greater than a first preset gas pressure;

[0017] The flow meter is connected to the oil-gas separation container and is used to detect the gas flow in the oil-gas separation container.

[0018] In an embodiment of the present invention, the liquid storage component includes:

[0019] An external liquid storage tube, wherein the second cavity is arranged in the external liquid storage tube;

[0020] The inner support tube is arranged in the second cavity and connected to the cavity wall of the second cavity. The inner support tube is provided with a support cavity for accommodating experimental shale. The cavity wall of the support cavity is connected to the second cavity, and the upper end of the support cavity is open and used to communicate with the first cavity.

[0021] In an embodiment of the present invention, the upper end surface of the inner support tube is flush with the upper end surface of the outer liquid storage tube, the lower end surface of the inner support tube is recessed in the second cavity, and the lower end surface of the outer liquid storage tube is provided with an exhaust port for communicating with the third cavity.

[0022] In an embodiment of the present invention, the cross-sectional size of the support cavity is larger than that of the experimental shale. When the injection mechanism injects oil into the experimental shale, an oil immersion channel can be formed between the cavity wall of the support cavity and the experimental shale.

[0023] In an embodiment of the present invention, a liquid inlet and a liquid outlet are further provided on the side wall of the lower cylinder. The liquid inlet is used to communicate with the liquid injection mechanism and is located at an end close to the upper cylinder. The liquid outlet is used to communicate with the gas extraction mechanism and discharge the degassed crude oil in the third cavity and is located at an end away from the upper cylinder.

[0024] In an embodiment of the present invention, a shale saturation test method is proposed, which is applied to the shale saturation device described above. The shale saturation test method includes the following steps:

[0025] The sleeve mechanism is vacuumed by using the vacuum mechanism until the air pressure in the sleeve mechanism is lower than the second preset air pressure;

[0026] Isolating the vacuum mechanism from the third cavity and stopping vacuuming the third cavity;

[0027] Connect the injection mechanism, the second cavity and the third cavity;

[0028] injecting degassed crude oil into the third cavity through the liquid injection mechanism;

[0029] The first cavity is evacuated by using a pumping mechanism, and the degassed crude oil is drawn upward through the pumping channel until the degassed crude oil saturates the experimental shale;

[0030] The gas-extraction mechanism and the liquid-injection mechanism are used to displace the gas-containing active oil into the third cavity until the gas-containing active oil saturates the experimental shale;

[0031] Calculate the saturation of the experimental shale.

[0032] In an embodiment of the present invention, displacing gas-containing active oil into the third cavity by cooperating with the gas extraction mechanism and the liquid injection mechanism until the gas-containing active oil saturates the experimental shale further includes:

[0033] Isolate the second cavity and the third cavity, and stop evacuating the first cavity;

[0034] connecting the liquid injection mechanism to the third cavity;

[0035] Injecting gas-containing active oil into the third cavity through the liquid injection mechanism;

[0036] displacing the degassed crude oil from the third cavity;

[0037] Until the amount of degassed crude oil displaced is consistent with the amount of gas and oil in the gas-containing live oil.

[0038] In an embodiment of the present invention, the shale saturation experimental method further includes:

[0039] Stop displacement when the gas-oil ratio of the displaced degassed crude oil is consistent with that of the live gas oil;

[0040] connecting the second cavity to the third cavity;

[0041] The first cavity is evacuated by an air extraction mechanism and the gas-containing active oil is extracted upward through the extraction channel;

[0042] The injection mechanism continuously injects the gas-containing live oil into the third cavity until the gas-oil ratio of the mixture of the degassed crude oil extracted from the first cavity by the gas extraction mechanism and the gas-containing live oil is consistent with the gas-oil ratio of the gas-containing live oil.

[0043] Through the above technical solutions, the shale saturation device and shale saturation experimental method provided by the embodiments of the present invention have the following beneficial effects:

[0044] The shale saturation device of the present invention includes a casing mechanism, a liquid injection mechanism, and an air extraction mechanism. The casing mechanism includes an upper cylinder, a liquid storage assembly, and a lower cylinder. The first cavity of the upper cylinder is connected to the second cavity of the liquid storage assembly and forms a pulling channel for accommodating the experimental shale. A docking port for sealingly connecting the experimental shale is formed between the first cavity and the second cavity. The lower cylinder forms a third cavity for accommodating the liquid storage assembly, and the second cavity and the third cavity can be connected or disconnected. When the air pressure in the casing mechanism is less than the preset air pressure, the liquid injection mechanism is connected to the third cavity and saturates the experimental shale with degassed crude oil; or when the first cavity is filled with degassed crude oil, the experimental shale is saturated with live gas oil. The air extraction mechanism is used to evacuate the casing mechanism and draw the degassed crude oil or live gas oil upward through the pulling channel. The shale saturation device of the present invention draws degassed crude oil or gas-containing live oil upward through a pumping mechanism, so that the degassed crude oil or gas-containing live oil enters the second cavity through the third cavity, and then enters the first cavity through the experimental shale, so that the experimental shale is fully saturated after the degassed crude oil and gas-containing live oil seep through. The setting of the pumping mechanism effectively improves the flow capacity of the degassed crude oil and gas-containing live oil through the experimental shale, thereby improving the saturation of the experimental shale.

[0045] Other features and advantages of the embodiments of the present application will be described in detail in the subsequent detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] The accompanying drawings are used to provide a further understanding of the embodiments of the present application and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the embodiments of the present application, but do not constitute a limitation on the embodiments of the present application. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without inventive work. In the drawings:

[0047] Figure 1 is a schematic structural diagram of a shale saturation device according to the present application;

[0048] Figure 2 is a structural schematic diagram of the installation cover according to the present application;

[0049] Figure 3 Schematic diagram of the structure of the upper cylinder body according to the present application;

[0050] Figure 4 Schematic diagram of the structure of the liquid storage assembly according to the present application;

[0051] Figure 5 Schematic diagram of the structure of the liquid storage assembly and the lower cylinder according to the present application;

[0052] Figure 6 This is a schematic diagram of the cross-sectional structure of the experimental shale after saturation according to the present application;

[0053] Figure 7 This is a schematic diagram of the cross-sectional structure of experimental shale after saturation in the prior art.

[0054] Description of Reference Numerals

[0055] 1 Upper cylinder 31 Third cavity

[0056] 11 First cavity 32 Liquid injection port

[0057] 12 Upper cylinder body 4 Vacuum pump

[0058] 13 Install cover 51 First exhaust pipe

[0059] 14 Docking port 52 First air extraction valve

[0060] 2 Liquid storage component 61 Oil and gas separation container

[0061] 21 Second cavity 62 Flow meter

[0062] 22 External liquid storage pipe 63 Second air extraction pipe

[0063] 221 Exhaust port 64 Second exhaust valve

[0064] 222 Control valve 8 piston cylinder

[0065] 23 Inner support tube 9 Pressure pump

[0066] 231 Support chamber 10 injection valve

[0067] 3 Lower cylinder 100 experimental shale DETAILED DESCRIPTION

[0068] The following describes the specific embodiments of the present application in detail with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present application and are not intended to limit the present application.

[0069] The shale saturation device and shale saturation experimental method according to the present application are described below with reference to the accompanying drawings.

[0070] like Figure 1 As shown, in an embodiment of the present invention, a shale saturation device is provided for use with experimental shale 100. The shale saturation device includes a casing mechanism, a liquid injection mechanism, and a gas extraction mechanism. The casing mechanism comprises an upper cylinder 1, a liquid storage assembly 2, and a lower cylinder 3. The upper cylinder 1 is provided with a first cavity 11, and the liquid storage assembly 2 is provided with a second cavity 21. The second cavity 21 is connected to the first cavity 11 and forms a gas extraction channel for accommodating the experimental shale 100. A docking port 14 is formed between the first cavity 11 and the second cavity 21, and the docking port 14 is sealed to the experimental shale 100. The lower cylinder 3 is formed with a third cavity 31 for accommodating the liquid storage assembly 2, and the third cavity 31 can be connected to or isolated from the second cavity 21. The liquid injection mechanism is used to connect the third cavity 31 when the air pressure within the casing mechanism is less than a preset pressure, and saturate the experimental shale 100 with degassed crude oil. When the first cavity 11 is filled with degassed crude oil, the liquid injection mechanism saturates the experimental shale 100 with live oil. The pumping mechanism is used to evacuate the casing mechanism and draw the degassed crude oil or gas-containing live oil upward through the pumping channel.

[0071] The shale saturation device of the present invention includes a casing mechanism, a liquid injection mechanism, and a gas extraction mechanism. The casing mechanism comprises an upper cylinder 1, a liquid storage assembly 2, and a lower cylinder 3. The first cavity 11 of the upper cylinder 1 communicates with the second cavity 21 of the liquid storage assembly 2, forming a withdrawal channel for accommodating the test shale 100. A docking port is formed between the first cavity 11 and the second cavity 21 for sealingly connecting the test shale 100. The lower cylinder 3 defines a third cavity 31 for accommodating the liquid storage assembly 2. The second cavity 21 and the third cavity 31 can be connected or disconnected. When the pressure within the casing mechanism is less than a preset pressure, the liquid injection mechanism communicates with the third cavity 31 and saturates the test shale 100 with degassed crude oil. Alternatively, when the first cavity 11 is filled with degassed crude oil, the liquid injection mechanism saturates the test shale 100 with live oil. The gas extraction mechanism is used to evacuate the casing mechanism and draw degassed crude oil or live oil upward through the withdrawal channel. It should be noted that, compared with the saturation of conventional sandstone in the prior art, the experimental shale 100 in the present invention is in sufficient contact with the degassed crude oil or gas-containing live oil, and the degassed crude oil or gas-containing live oil in the second cavity 21 can only seep into the first cavity 11 through the experimental shale 100, and the saturation is high; compared with the method of directly pressurizing and saturating the entire core in the prior art, the experimental shale 100 in the present invention continuously absorbs air on one side and pressurizes the other side, so that the degassed crude oil or gas-containing live oil in the second cavity 21 can only seep into the first cavity 11 through the experimental shale 100, the experimental shale 100 can be fully saturated, and the present invention as a whole does not have a process of repeated pressurization and decompression.

[0072] The shale saturation device of the present invention draws degassed crude oil or gas-containing live oil upward through a pumping mechanism, so that the degassed crude oil or gas-containing live oil enters the second cavity 21 through the third cavity 31, and then enters the first cavity 11 from the second cavity 21 through the experimental shale 100, so that the experimental shale 100 is fully saturated in the process of the degassed crude oil and gas-containing live oil seeping into the first cavity 11. The setting of the pumping mechanism effectively improves the flow capacity of the degassed crude oil and gas-containing live oil through the experimental shale 100 and increases the saturation of the experimental shale 100.

[0073] like Figure 1 As shown, the injection mechanism includes a piston cylinder 8, an injection pipe, and a pressure pump 9. In this embodiment of the present invention, two piston cylinders 8 are provided, each containing degassed crude oil and live oil. One end of the injection pipe is connected to the lower cylinder 3, and the other end of the injection pipe is connected to the two piston cylinders 8. The degassed crude oil or live oil in the piston cylinder 8 is injected into the third cavity 31 through the injection pipe. The degassed crude oil or live oil is pressurized by the pressure pump 9 connected to both piston cylinders 8. This improves the circulation of the degassed crude oil and live oil within the casing mechanism, enhances the flow capacity of the degassed crude oil and live oil in the micro-nano pores of the experimental shale 100, and reduces the seepage resistance of the degassed crude oil and live oil. The injection pipe is also provided with an injection valve 10 to open and close the injection pipe.

[0074] like Figure 2 and Figure 3 As shown, the upper cylinder 1 also includes an upper cylinder body 12 and a mounting cover. The outer peripheral wall of the top of the upper cylinder body 12 is provided with an external thread, and the inner wall of the mounting cover 13 is provided with an internal thread that cooperates with the external thread of the upper cylinder body 12. The setting of the mounting cover 13 enables the upper cylinder body 12 to be easily cleaned.

[0075] like Figure 1 、 Figure 2 and Figure 3 As shown, in an embodiment of the present invention, the upper cylinder 1 and the lower cylinder 3 are connected by bolts, and a seal is provided between the upper cylinder 1 and the lower cylinder 3. The seal adopts a copper washer and an O-ring, which can effectively ensure the sealing of the connection between the upper cylinder 1 and the lower cylinder 3.

[0076] like Figure 1 As shown, in an embodiment of the present invention, the air extraction mechanism includes an air pump 4, a first air extraction component, and a second air extraction component. The two ends of the first air extraction component are respectively connected to the first cavity 11 and the air extraction pump 4. When the air pressure in the casing mechanism is greater than the first preset air pressure, the first air extraction component connects the first cavity 11 and the air extraction pump 4, so that the air extraction pump 4 vacuums the casing mechanism. The two ends of the second air extraction component are respectively connected to the third cavity 31 and the air extraction pump 4. The second air extraction component is used to connect the third cavity 31 and the air extraction pump 4 when the air pressure in the casing mechanism is greater than the first preset air pressure, or to connect the third cavity 31 and the air extraction pump 4 in the case of gas-containing live oil saturated experimental shale 100, and to isolate the third cavity 31 and the air extraction pump 4 when the injection mechanism injects degassed crude oil into the third cavity 31.

[0077] like Figure 1 As shown, in an embodiment of the present invention, the second gas extraction assembly includes an oil-gas separation container 61 and a flowmeter 62. The third chamber 31 and the gas extraction pump 4 are connected by an oil-gas pipeline. The oil-gas separation container 61 is installed on the oil-gas pipeline. The oil-gas separation container 61 is used to connect to the third chamber 31 when the experimental shale 100 is saturated with gas-live oil, or to isolate the third chamber 31 when the pressure within the casing mechanism exceeds a first preset pressure. The flowmeter 62 is connected to the oil-gas separation container 61 and is used to detect the flow rate of gas separated by the oil-gas separation container 61. The oil-gas separation container 61 is used to measure the crude oil volume of the degassed crude oil and the live oil volume after oil-gas separation of the live oil. The oil-gas separation container 61 is used to separate the crude oil and gas, and the crude oil volume is read. The flowmeter 62 then reads the gas volume. The gas volume is then divided by the crude oil volume to obtain the gas-to-oil ratio. The flowmeter 62 is a conventional air flow meter.

[0078] like Figure 1As shown, the first air extraction assembly includes a first air extraction pipe 51 and a first air extraction valve 52 provided on the first air extraction pipe 51. The first air extraction pipe 51 is used to connect the first cavity 11 with the air extraction pump 4 or the oil-gas separation container 61. The second air extraction assembly also includes a second air extraction pipe 63 and a second air extraction valve 64 provided on the second air extraction pipe 63. The second air extraction pipe 63 is used to connect the third cavity 31 with the air extraction pump 4 or the oil-gas separation container 61. Two three-way valves are provided between the first air extraction pipe 51 and the second air extraction pipe 63, and the two three-way valves are used to disconnect the oil in the first air extraction pipe 51 and the second air extraction pipe 63 from the oil-gas separation container 61 or the air extraction pump 4. The vacuum pump 4 is connected to both the first vacuum pipe 51 and the second vacuum pipe 63 and can evacuate the casing mechanism through the first vacuum pipe 51 and the second vacuum pipe 63. The oil-gas separation container 61 is also connected to both the first vacuum pipe 51 and the second vacuum pipe 63 and is controlled by the first vacuum valve 52, the second vacuum valve 64, and two three-way valves. Under the action of the vacuum pump 4, the degassed crude oil or live oil in the first cavity 11 can enter the oil-gas separation container 61 through the first vacuum pipe 51. Under the action of the vacuum pump 4, the degassed crude oil in the third cavity 31 can enter the oil-gas separation container 61 through the second vacuum pipe 63. A third vacuum pipe is also provided between the two three-way valves, and a third vacuum valve is provided on the third vacuum pipe. The third vacuum valve is used to open and close the third vacuum pipe. The first vacuum pipe 51 is a transparent tube. When the first vacuum pipe 51 is observed to extract degassed crude oil or a mixture of degassed crude oil and live oil, it can be determined that the first cavity 11 is full. The control valve 222 , the first air extraction pipe 51 , the second air extraction pipe 63 and the liquid injection valve 10 are all on-off valves in the prior art.

[0079] In an embodiment of the present invention, the upper cylinder 1, the liquid storage assembly 2, and the lower cylinder 3 are first assembled, and the experimental shale 100 is placed in the pull-out channel formed between the first cavity 11 and the second cavity 21. The upper end surface of the experimental shale 100 is extended into the first cavity 11 through the docking port, ensuring a sealed connection between the docking port and the experimental shale 100, so that the degassed crude oil and gas-containing live oil in the second cavity 21 can only flow into the first cavity 11 through the experimental shale 100.

[0080] The Fuling area is rich in shale oil and gas resources. Taking the Fuxing Oilfield as an example, a short shale plunger adapted to the docking port was used as an experimental core. Before the experiment, the porosity and permeability of the experimental shale 100 were measured according to the national standards GB / T 34533-2017 "Porosity of Shale by Helium Gas Method" and GB / T 34533-2017 "Determination of Porosity of Shale by Helium Gas Method and Permeability by Pulse Attenuation Method". The porosity and permeability of the experimental shale 100 were 3.64% and 0.00343 mD, respectively. The porosity and permeability of the experimental shale 100 were low, and the rock was dense. The shale saturation device of the present invention was used to saturate the experimental shale 100 with crude oil:

[0081] To assemble the shale saturation device of the present invention, first thread the liquid storage assembly 2 onto the top wall of the lower barrel 3. Place the test shale 100 in the inner support tube 23, allowing the lower end of the test shale 100 to extend into the second cavity 21. Bolt the lower barrel 3 to the upper barrel 1, allowing the upper end of the test shale 100 to pass through the docking port 14 and into the first cavity 11. Ensure that the upper end of the test shale 100 is higher than the bottom of the first cavity 11, ensuring that the degassed crude oil or live oil in the second cavity 21 can only seep through the test shale 100. After assembly, the casing mechanism is tested for leaks using nitrogen.

[0082] like Figure 1 and Figure 5 As shown, the experimental shale 100 is first saturated with degassed crude oil, and the first air extraction valve 52 and the second air extraction valve 64 are opened at the same time, so that the first air extraction pipe 51 and the second air extraction pipe 63 are connected to the air extraction pump 4 at the same time, and the casing mechanism is vacuumed by the air extraction pump 4. When the internal pressure of the casing mechanism drops to 0.001 Pa, the second air extraction valve 64 is closed, so that the second air extraction pipe 63 is disconnected from the third cavity 31. At this time, the control valve 222 is opened to connect the second cavity 21 with the third cavity 31 and connect the injection pipe with the third cavity 31. Under the action of the pressure pump 9, the degassed crude oil in the piston cylinder 8 is injected into the third cavity 31. Under the suction force of the air extraction pump 4 and the high pressure of the pressure pump 9, the degassed crude oil in the third cavity 31 enters the second cavity 21 and seeps into the first cavity 11 through the experimental shale 100. When the first cavity 11 is filled with degassed crude oil, the first air extraction valve 52 and the second air extraction valve 64 are closed, the first air extraction pipe 51 and the second air extraction pipe 63 are disconnected from the air extraction pump 4 at the same time, the injection valve 10 and the first air extraction valve 52 are opened, and the live oil in the piston cylinder 8 is injected into the third cavity 31 under the action of the pressure pump 9. Under the suction force of the air extraction pump 4 and the high pressure of the pressure pump 9, the live oil in the third cavity 31 enters the second cavity 21 and seeps into the first cavity 11 through the experimental shale 100. At this time, the mixed degassed crude oil and live oil in the first cavity 11 can enter the oil-gas separation container 61 through the first injection pipe. When the gas-oil ratio of the degassed crude oil and live oil extracted from the first cavity 11 is consistent with the gas-oil ratio of the live oil, the experimental shale 100 is fully saturated with the live oil.

[0083] like Figure 1As shown, in an embodiment of the present invention, the liquid storage assembly 2 includes an outer liquid storage tube 22 and an inner support tube 23. A second cavity 21 is disposed within the outer liquid storage tube 22. The inner support tube 23 is disposed within the second cavity 21 and connected to the wall of the second cavity 21. The inner support tube 23 is provided with a support cavity 231 for accommodating the test shale 100. The wall of the support cavity 231 communicates with the second cavity 21, and the upper end of the support cavity 231 is open and communicates with the first cavity 11. The wall of the support cavity 231 communicates with the second cavity 21, and the inner support tube 23 is configured as a mesh structure to facilitate the flow of degassed crude oil or live oil. If the height of the test shale 100 placed in the support cavity 231 is lower than that of the inner support tube 23, a gasket is added to the bottom of the inner support tube 23 to ensure that the height of the test shale 100 meets the experimental requirements after the gasket is added, which can accommodate test shale 100 of different heights.

[0084] like Figure 1 and Figure 4 As shown, in an embodiment of the present invention, the upper end surface of the inner support tube 23 is flush with the upper end surface of the outer liquid storage tube 22, the lower end surface of the inner support tube 23 is recessed in the second cavity 21, and the lower end surface of the outer liquid storage tube 22 is provided with an exhaust port 221 for communicating with the third cavity 31. The outer wall surface of the exhaust port 221 is provided on an exchange tube connected to the exhaust port 221. The exchange tube allows the liquid in the third cavity 31 to flow into the second cavity 21. A control valve 222 is provided on the exchange tube. The control valve 222 is used to connect or isolate the second cavity 21 and the third cavity 31.

[0085] like Figure 1 As shown, in an embodiment of the present invention, the cross-sectional dimensions of the support cavity 231 are larger than those of the experimental shale 100. When the injection mechanism injects oil into the experimental shale 100, an oil-immersed channel is formed between the wall of the support cavity 231 and the experimental shale 100. The provision of the oil-immersed channel in the present invention prevents the wall of the support cavity 231 from partially covering the experimental shale 100 when the cross-sectional dimensions of the experimental shale 100 and the support cavity 231 are the same, thereby affecting sufficient contact between the experimental shale 100 and the degassed crude oil or live oil, and causing a decrease in the saturation of the experimental shale 100.

[0086] like Figure 1As shown, in the embodiment of the present invention, a liquid injection port 32 and a liquid outlet are further provided on the side wall of the lower cylinder 3. The liquid injection port 32 is used to communicate with the liquid injection mechanism and is located at one end close to the upper cylinder 1. The liquid outlet is used to communicate with the gas extraction mechanism and discharge the degassed crude oil in the third cavity 31. The liquid outlet is located at one end away from the upper cylinder 1. The liquid injection port 32 is connected to a liquid injection pipe. The live oil is lighter than the degassed crude oil. During the process of the live oil displacing the degassed crude oil, the live oil is injected into the third cavity 31 filled with degassed crude oil through the liquid injection pipe. The live oil will first fill the top of the third cavity 31 and connect the liquid outlet to the oil-gas separation container 61, gradually discharging the degassed crude oil from the liquid outlet to the oil-gas separation container 61.

[0087] In an embodiment of the present invention, a shale saturation test method is provided, which is applied to the shale saturation device described above. The shale saturation test method includes the following steps:

[0088] The sleeve mechanism is vacuumed by using the vacuum mechanism until the air pressure in the sleeve mechanism is less than a second preset air pressure;

[0089] Isolating the vacuum mechanism from the third cavity 31 and stopping vacuuming the third cavity 31;

[0090] Connect the injection mechanism, the second cavity 21 and the third cavity 31;

[0091] Inject degassed crude oil into the third cavity 31 through the liquid injection mechanism;

[0092] The first cavity 11 is evacuated by a pumping mechanism, and the degassed crude oil is drawn upward through the pumping channel until the degassed crude oil saturates the experimental shale 100;

[0093] By cooperating with the gas extraction mechanism and the liquid injection mechanism, the gas-containing active oil is displaced into the third cavity 31 until the gas-containing active oil saturates the experimental shale 100;

[0094] Calculate the saturation of the experimental shale 100.

[0095] In an embodiment of the present invention, displacing the live oil into the third cavity 31 includes: isolating the second cavity 21 and the third cavity 31 and stopping the vacuum pumping of the first cavity 11; connecting the liquid injection mechanism with the third cavity 31; injecting the live oil into the third cavity 31 through the liquid injection mechanism; and displacing the degassed crude oil from the third cavity 31 until the amount of the displaced degassed crude oil is the same as that of the live oil.

[0096] In an embodiment of the present invention, the shale saturation experimental method also includes: stopping displacement when the gas-oil ratio of the displaced degassed crude oil is consistent with that of the gas-containing live oil; connecting the second cavity 21 with the third cavity 31; using a pumping mechanism to pump air from the first cavity 11 and pulling the gas-containing live oil upward through the pumping channel; and continuously injecting the gas-containing live oil into the third cavity 31 by the injection mechanism until the gas-oil ratio of the mixture of the degassed crude oil and the gas-containing live oil extracted from the first cavity 11 by the pumping mechanism is consistent with the gas-oil ratio of the gas-containing live oil.

[0097] The shale saturation test method of the present invention first evacuates the casing structure using a pumping mechanism, connecting the second chamber 21 with the third chamber 31. Simultaneously, the first chamber 11, the second chamber 21, and the third chamber 31 are evacuated until the internal pressure of the casing structure drops to 0.001 Pa. The pumping mechanism is then isolated from the third chamber 31, and the evacuation of the third chamber 31 is stopped. The pumping mechanism continues to evacuate the first chamber 11, allowing the degassed crude oil in the third chamber 31 to flow into the second chamber 21 and seep from the test shale 100 into the first chamber 11. The second and third chambers 21 and 31 are disconnected until the first chamber 11 is filled with degassed crude oil. Live oil is injected into the third cavity 31 through the injection mechanism, displacing the degassed crude oil in the third cavity 31 until the amount of gas and oil in the displaced degassed crude oil matches that in the live oil. The second cavity 21 is then connected to the third cavity 31, allowing the live oil in the third cavity 31 to flow into the second cavity 21 and seep from the experimental shale 100 into the first cavity 11 until the gas-oil ratio of the degassed crude oil and live oil extracted from the first cavity 11 by the gas extraction mechanism matches that of the live oil, and the experimental shale 100 is fully saturated with the live oil. The experimental method of the present invention improves the saturation of the experimental shale 100 by double saturation with degassed crude oil and live oil through the technical means of extracting gas from the first cavity 11, thereby solving the problem of poor saturation of the experimental shale 100 in the prior art.

[0098] It should be noted that once the test shale 100 is saturated, the pressure in the third chamber 31 is slowly reduced using the pressure pump 9. After a period of stagnation, the test shale 100 is removed to prevent it from fracturing due to the pressure differential, which could cause changes in its mass and affect the accuracy of the experiment. The oil film on the surface of the test shale 100 is then wiped clean and weighed. The saturated test shale 100 is then scanned using a nuclear magnetic resonance scanner to determine its saturation.

[0099] By comparing the ratio of saturated oil volume to total pore volume under the two saturation methods, as shown in the following table, the ratio of saturated oil volume to total pore volume in the saturation method of this patent is 87.4%, while the ratio of saturated oil volume to total pore volume obtained by the method of the prior art is only 62.2%. By comparison, it can be seen that the saturation effect of the method of this patent is better, and the amount of saturated oil in the pore volume of shale is higher.

[0100] Figure 6 and Figure 7 The following are NMR images of the core saturated using the patented method and the prior art method, respectively. Comparing the images, we can see that after saturating the experimental shale 100 using the patented method, the saturation degree of the experimental shale 100 is higher than that achieved using the prior art method, and the crude oil concentration in the experimental shale 100 is higher. However, after saturating the core using the prior art method, the crude oil is more dispersed, the saturation degree is low, and the saturation effect is significantly inferior to that achieved using the patented method. Figure 6 The longitudinal section and the horizontal middle section of the experimental shale 100 after saturation of the experimental method of this patent are shown. Figure 7 The longitudinal section and the horizontal middle section of the experimental shale 100 after saturation using the prior art method are shown.

[0101]

[0102] In the description of this application, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of such features. In the description of this application, "plurality" means at least two, for example, two, three, etc., unless otherwise specifically defined.

[0103] In this application, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection, or communication; direct connection or indirect connection through an intermediate medium; internal communication between two elements or interaction between two elements, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0104] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" 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 application. 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 can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

[0105] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A shale saturation device for testing shale (100), characterized in that: The shale saturation device includes: A casing mechanism comprises an upper cylinder (1), a liquid storage assembly (2) and a lower cylinder (3), wherein the upper cylinder (1) is provided with a first cavity (11), the liquid storage assembly (2) is provided with a second cavity (21), the second cavity (21) is used to communicate with the first cavity (11) and form a drawing channel, the drawing channel is used to accommodate the experimental shale (100), a docking port (14) can be formed between the first cavity (11) and the second cavity (21), the docking port (14) is used to be sealed and connected to the experimental shale (100), the lower cylinder (3) is formed with a third cavity (31) for accommodating the liquid storage assembly (2), and the third cavity (31) can communicate with or isolate the second cavity (21); The liquid injection mechanism is used to connect the third cavity (31) when the air pressure in the casing mechanism is less than a preset air pressure, and saturate the experimental shale (100) with the degassed crude oil; the liquid injection mechanism is also used to saturate the experimental shale (100) with the gas-containing live oil when the first cavity (11) is filled with the degassed crude oil; and The air extraction mechanism is used to extract a vacuum from the casing mechanism and to draw the degassed crude oil or the gas-containing live oil upward through the drawing channel.

2. The shale saturation device according to claim 1, characterized in that: The air extraction mechanism comprises: Air pump (4); a first air extraction component, the two ends of which are respectively connected to the first cavity (11) and the air extraction pump (4); the first air extraction component connects the first cavity (11) and the air extraction pump (4) when the air pressure in the sleeve mechanism is greater than a first preset air pressure, so that the air extraction pump (4) evacuates the sleeve mechanism; A second air extraction component has two ends connected to the third cavity (31) and the air extraction pump (4), respectively. The second air extraction component is used to connect the third cavity (31) and the air extraction pump (4) when the air pressure in the casing mechanism is greater than a first preset air pressure, or to connect the third cavity (31) and the air extraction pump (4) when the gas-containing active oil saturates the experimental shale (100), and to isolate the third cavity (31) and the air extraction pump (4) when the injection mechanism injects degassed crude oil into the third cavity (31).

3. The shale saturation device according to claim 2, characterized in that: The second air extraction component includes: An oil-gas separation container (61), the third cavity (31) and the air pump (4) are connected via an oil-gas pipeline, the oil-gas separation container (61) is provided on the oil-gas pipeline, and the oil-gas separation container (61) is used to connect the third cavity (31) when the gas-containing active oil saturates the experimental shale (100), or to isolate the third cavity (31) when the gas pressure in the casing mechanism is greater than a first preset gas pressure; A flow meter (62) is connected to the oil-gas separation container (61) and is used to detect the gas flow in the oil-gas separation container (61).

4. The shale saturation device according to claim 1, characterized in that: The liquid storage component (2) comprises: an external liquid storage tube (22), wherein the second cavity (21) is arranged in the external liquid storage tube (22); An inner support tube (23) is arranged in the second cavity (21) and connected to the cavity wall of the second cavity (21); the inner support tube (23) is provided with a support cavity (231) for accommodating the experimental shale (100); the cavity wall of the support cavity (231) is communicated with the second cavity (21), and the upper end of the support cavity (231) is open and is used to communicate with the first cavity (11).

5. The shale saturation device according to claim 4, characterized in that: The upper end surface of the inner support tube (23) is flush with the upper end surface of the outer liquid storage tube (22); the lower end surface of the inner support tube (23) is recessed in the second cavity (21); and the lower end surface of the outer liquid storage tube (22) is provided with an exhaust port (221) for communicating with the third cavity (31).

6. The shale saturation device according to claim 4, characterized in that: The cross-sectional size of the support cavity (231) is larger than the cross-sectional size of the experimental shale (100). When the injection mechanism injects oil into the experimental shale (100), an oil-immersed channel can be formed between the cavity wall of the support cavity (231) and the experimental shale (100).

7. The shale saturation device according to any one of claims 1 to 6, characterized in that: A liquid injection port (32) and a liquid outlet are also provided on the side wall of the lower cylinder (3); the liquid injection port (32) is used to communicate with the liquid injection mechanism and is located at one end close to the upper cylinder (1); the liquid outlet is used to communicate with the gas extraction mechanism and discharge the degassed crude oil in the third cavity (31); the liquid outlet is located at one end away from the upper cylinder (1).

8. A shale saturation test method, characterized in that: Applied to the shale saturation device according to any one of claims 1 to 7, the shale saturation experimental method comprises: The sleeve mechanism is vacuumed by the vacuum mechanism until the air pressure in the sleeve mechanism is less than a second preset air pressure; Isolating the vacuum mechanism and the third cavity (31) and stopping vacuuming the third cavity (31); connecting the liquid injection mechanism, the second cavity (21) and the third cavity (31); injecting the degassed crude oil into the third cavity (31) through the liquid injection mechanism; The first cavity (11) is evacuated using the evacuation mechanism, and the degassed crude oil is drawn upward through the extraction channel until the degassed crude oil saturates the experimental shale (100); The gas extraction mechanism and the liquid injection mechanism cooperate to displace the gas-containing active oil into the third cavity (31) until the gas-containing active oil saturates the experimental shale (100); The saturation of the experimental shale (100) is calculated.

9. The shale saturation test method according to claim 8, characterized in that: The method further comprises: displacing the gas-containing active oil into the third cavity (31) by cooperating with the gas extraction mechanism and the liquid injection mechanism until the gas-containing active oil saturates the experimental shale (100); Isolating the second cavity (21) and the third cavity (31), and stopping vacuuming the first cavity (11); connecting the liquid injection mechanism to the third cavity (31); injecting the gas-containing active oil into the third cavity (31) through the liquid injection mechanism; displacing the degassed crude oil out of the third cavity (31); Until the amount of gas and oil in the degassed crude oil displaced is consistent with that in the gas-containing live oil.

10. The shale saturation test method according to claim 9, characterized in that: The shale saturation experimental method further includes: Stop displacement when the gas-oil ratio of the displaced degassed crude oil is consistent with that of the live gas oil; connecting the second cavity (21) and the third cavity (31); The air extraction mechanism is used to extract air from the first cavity (11) and to draw the gas-containing oil upward through the drawing channel; The injection mechanism continuously injects the gas-containing live oil into the third cavity (31) until the gas-oil ratio of the mixture of the degassed crude oil and the gas-containing live oil extracted from the first cavity (11) by the extraction mechanism is consistent with the gas-oil ratio of the gas-containing live oil.

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