Oil-water displacement simulation experiment device and method for constructing artificial dominant channel through electric field excitation

Abstract

The invention discloses a water-oil displacement simulation experiment device and method for constructing an artificial dominant channel through electric field excitation. The device comprises a water phase driving-in assembly, an oil phase driving-in assembly, a visual displacement assembly, an electric field assembly and a metering assembly. The visual displacement assembly comprises a visual rock plate structure, an experimental rock plate with cracks is packaged in the visual rock plate structure, and a liquid inlet and a liquid outlet which are communicated with the experimental rock plate are formed in the visual rock plate structure; the water phase driving-in assembly and the oil phase driving-in assembly are both connected with a liquid inlet of the visual rock plate structure and used for driving a water phase and an oil phase into the visual rock plate structure. The electric field assembly is used for applying an electric field to the visual rock plate structure; the metering assembly is used for measuring the content of a water phase and the content of an oil phase of liquid flowing out of the liquid outlet of the visual rock plate structure. According to the invention, the water-oil displacement fluid flow rule under the excitation action of different electric fields can be simulated, and the guiding effect of different electric field intensities on the advancing direction of the water-oil displacement front edge can be evaluated.

Description

Technical Field

[0001] The invention relates to the technical field of electric field enhanced oil recovery, and in particular to a water-drive oil simulation experimental device for constructing an artificial superior channel by electric field excitation. Background Art

[0002] At present, oil fields at home and abroad will use water injection to improve crude oil recovery in the later stages of production. However, due to process technology limitations and complex formation conditions, nearly 50% to 70% of reserves are still unexploited at the end of water drive oil production, making it difficult to fully utilize oil and gas resources. With the development of new energy, electric field-related technologies are gradually gaining attention in the oil and gas industry due to their coupling with new energy technologies. Among them, electric field enhanced oil recovery technology refers to the introduction of electric fields into conventional oil production technology to improve fluid flow capacity and increase water drive efficiency. The integration of electric field enhanced oil recovery technology and new energy technology is expected to help the deep coupling of oil and gas extraction and new energy power generation, and accelerate the pace of electrification and cleaning of oil fields.

[0003] Carbonate reservoirs usually have high permeability zones or fracture zones of varying degrees. When high permeability zones or fracture zones connect water injection wells and production wells, the water drive front advances too fast during water injection, and the injected water quickly passes through the high permeability zones into the oil wells, thereby reducing the water drive oil swept area. The electric field helps to reduce the oil-water interfacial tension, and the oil-water seepage capacity is stronger along the direction of the electric field, which means that by applying an electric field at a specific location in the reservoir and controlling the direction of the electric field, a favorable high permeability zone can be artificially created to drive oil and water to flow in the designed flow direction, thereby achieving the purpose of improving the water drive oil front and avoiding the high permeability zone in advance, thereby increasing the water drive oil swept area and water drive oil efficiency.

[0004] In order to deeply study the water-to-oil driving mechanism under the coupling of electric field and seepage field and provide an experimental basis for the development of electric field enhanced oil recovery technology, it is necessary to design a simulation experimental device. Summary of the invention

[0005] The purpose of the present invention is to provide a water-drive-oil simulation experimental device and method for constructing an artificial dominant channel by electric field excitation in order to deeply study the water-drive-oil mechanism under the coupling effect of electric field seepage field, so as to simulate the flow law of water-drive-oil fluid under different electric field excitations and evaluate the guiding effect of different electric field strengths on the advancing direction of the water-drive-oil front.

[0006] The present invention is achieved through the following technical solutions:

[0007] In the first aspect, the present invention provides a water-oil driving simulation experimental device for constructing an artificial dominant channel by electric field excitation, comprising a water phase driving component, an oil phase driving component, a visualization driving component, an electric field component and a metering component; the visualization driving component comprises a visualization rock plate structure, in which an experimental rock plate with cracks is encapsulated, and a liquid inlet and a liquid outlet communicated with the experimental rock plate are provided; the water phase driving component and the oil phase driving component are both connected to the liquid inlet of the visualization rock plate structure, and are used to drive the water phase and the oil phase into the visualization rock plate structure respectively; the electric field component is used to apply an electric field to the visualization rock plate structure; the metering component is used to measure the content of the water phase and the oil phase in the liquid flowing out of the liquid outlet of the visualization rock plate structure.

[0008] As a preferred embodiment of the present invention, the visualization rock plate structure includes two acrylic plates arranged opposite to each other, the experimental rock plate sealing clamp is arranged between the two acrylic plates, and the liquid inlet and the liquid outlet penetrate into the experimental rock plate from the surface of the acrylic plate.

[0009] As a preferred embodiment of the present invention, the visualized rock plate structure further includes a plurality of conductive nails, and the plurality of conductive nails are all inserted into the experimental rock plate from the surface of the acrylic plate, and the conductive nails are used to connect to a computer to measure changes in electric potential.

[0010] As a preferred embodiment of the present invention, the water phase driving component includes a motor, a fluid pump, a water phase intermediate container and a graduated water phase container. The motor rotates forward to suck the water phase in the graduated water phase container into the water phase intermediate container, and the motor rotates reversely to drive the water phase sucked into the water phase intermediate container into the visualized rock plate structure.

[0011] As a preferred embodiment of the present invention, the oil phase driving component includes a motor, a fluid pump, an oil phase intermediate container and a graduated oil phase container. The motor rotates forward to suck the oil phase in the graduated oil phase container into the oil phase intermediate container, and the motor rotates reversely to drive the oil phase sucked into the oil phase intermediate container into the visualized rock plate structure.

[0012] As a preferred embodiment of the present invention, the visualization displacement assembly also includes an insulating bracket, a sliding mechanism and a microscope, the insulating bracket is supported on the lower side of the visualization rock plate structure, the sliding mechanism is arranged on the upper side of the visualization rock plate structure, the microscope is installed on the sliding mechanism to achieve left and right movement, and the microscope is connected to a computer.

[0013] As a preferred embodiment of the present invention, the electric field component includes a DC power supply, a knife switch, an ammeter and a voltmeter. The DC power supply and the knife switch are used in conjunction to apply or disconnect the electric field to the visualized rock plate structure, and the ammeter and the voltmeter are used to monitor changes in circuit voltage and current.

[0014] As a preferred embodiment of the present invention, the metering component includes a measuring cup and an oil-water level detector, the measuring cup is used to hold the liquid flowing out from the liquid outlet of the visual rock plate structure, and the oil-water level detector reads the position of the oil-water interface in the measuring cup.

[0015] As a preferred solution of the present invention, the metering component further includes an insertion thermometer, which is arranged in the measuring cup and is used to monitor changes in the temperature of the fluid.

[0016] In a second aspect, the present invention provides a water-displacement-oil simulation experimental method for constructing an artificial dominant channel by electric field excitation, and the water-displacement-oil simulation experimental device for constructing an artificial dominant channel by electric field excitation described in the first aspect comprises the following steps:

[0017] Step 1: Prepare an experimental rock plate with cracks, use CT scanning to test the pore crack distribution map of the experimental rock plate, and use nuclear magnetic resonance to test the pore distribution curve of the experimental rock plate;

[0018] Step 2: After the manufactured experimental rock plate is loaded into the visualized rock plate structure, the oil phase is driven into the visualized rock plate structure through the oil phase driving component until a continuous oil flow appears at the liquid outlet;

[0019] Step 3: Drive the water phase into the visualized rock plate structure through the water phase drive component to carry out a water drive oil experiment, take samples from the liquid outlet at a certain time interval, and measure the water phase and oil phase content in the sampled liquid through the metering component. After no oil is produced, remove the experimental rock plate, test the pore and crack distribution map of the experimental rock plate through CT scanning, test the pore distribution curve of the experimental rock plate using nuclear magnetic resonance, and use a pipette to absorb the oil phase at the upper end of the mixed liquid, and test the mineralization by evaporating the remaining water phase;

[0020] Step 4. Install the experimental rock plate back into the visualized rock plate structure, apply an electric field to the visualized rock plate structure through the electric field component, drive the water phase into the visualized rock plate structure through the water phase driving component to continue the water drive oil experiment, take samples from the liquid outlet at a certain time interval again, and calculate the water phase and oil phase content in the sampled liquid through the metering component. After no oil is produced, remove the experimental rock plate, test the pore and crack distribution map of the experimental rock plate through CT scanning, use nuclear magnetic resonance to test the pore distribution curve of the experimental rock plate, and use a pipette to absorb the oil phase at the upper end of the mixed liquid, and test the mineralization by evaporating the remaining water phase.

[0021] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0022] The present invention builds a water-drive-oil simulation experimental device for constructing an artificial advantageous channel by electric field excitation in the laboratory, which can simulate the flow law of water-drive-oil fluid under different electric field excitations, evaluate the guiding effect of different electric field strengths on the advancing direction of the water-drive-oil front, and at the same time, understand the water-drive-oil mechanism under the coupling of electric field seepage field, verify the feasibility of constructing an artificial favorable advantageous channel by electric field excitation, and provide an experimental basis for the development of electric field enhanced oil recovery technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and should not be regarded as limiting the scope. For those of ordinary skill in the art, other relevant drawings can be obtained based on these drawings without creative work. In the drawings:

[0024] Figure 1 Schematic diagram of a water-to-oil simulation experimental device for constructing an artificial dominant channel for electric field excitation in the present invention;

[0025] Figure 2 This is a schematic diagram of the visualized rock plate structure in the present invention;

[0026] Figure 3 It is a schematic diagram of the location of the high permeability zone in the experimental rock plate in the present invention;

[0027] Figure 4 It is a schematic diagram of the area affected by water-driven oil displacement with a high permeability zone in the present invention;

[0028] Figure 5 It is a schematic diagram of the area affected by water-driven oil after the artificial superior channel is established in the present invention where a high permeability zone exists;

[0029] Figure 6 It is the test result before the electric field excitation in the present invention;

[0030] Figure 7 The test results after constructing the artificial channel for electric field excitation in the present invention;

[0031] Figure 8 The following are example curves of different mineralization changes under the action of electric field and without electric field in the present invention;

[0032] Fig. 9 It is a schematic diagram of the water-to-oil drive result when the electric field excitation point is BC in the present invention;

[0033] Fig.10 It is a schematic diagram of water-to-oil displacement results when the electric field excitation point is BF in the present invention;

[0034] Fig.11 It is a schematic diagram of the nuclear magnetic resonance test results of the experimental rock plate in the present invention.

[0035] Marks and corresponding parts names in the attached drawings:

[0036] 1. 16-motor; 2. 15-fluid pump; 3. 9, 14, 17-mechanical pressure gauge; 4. 13, 30-needle valve; 5-oil phase intermediate container; 6-oil phase container with scale; 7, 8, 11-three-way valve; 10-water phase container with scale; 12-water phase intermediate container; 18-computer; 19-oil-water level detector; 20-insertion thermometer; 21-measuring cup; 22-visualized rock plate structure; 23-insulating bracket; 24-microscope; 25-sliding mechanism; 26-knife switch; 27-DC power supply; 28-ammeter; 29-voltmeter. DETAILED DESCRIPTION

[0037] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments and drawings. The exemplary embodiments of the present invention and their description are only used to explain the present invention and are not intended to limit the present invention.

[0038] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0039] In the description of the embodiments of the present application, technical terms such as "first" and "second" are only used to distinguish different objects and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features.

[0040] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0041] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent: A exists, A and B exist at the same time, and B exists. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0042] In the embodiments of the present application, the same reference numerals represent the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width and other dimensions of various components in the embodiments of the present application shown in the drawings, as well as the overall thickness, length, width and other dimensions of the integrated device are only exemplary descriptions and should not constitute any limitation to the present application.

[0043] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces), unless otherwise clearly and specifically defined.

[0044] In the description of the embodiments of the present application, the technical 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. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the embodiments of the present application 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 a limitation on the embodiments of the present application.

[0045] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "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, and it can be the internal connection of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0046] Please refer to Figures 1 to 11A water-oil driving simulation experimental device for constructing an artificial dominant channel by electric field excitation provided in an embodiment of the present application includes a water phase driving component, an oil phase driving component, a visualization driving component, an electric field component and a metering component; the visualization driving component includes a visualization rock plate structure 22, in which an experimental rock plate with cracks is encapsulated, and a liquid inlet and a liquid outlet communicated with the experimental rock plate are provided; the water phase driving component and the oil phase driving component are both connected to the liquid inlet of the visualization rock plate structure 22, and are used to drive the water phase and the oil phase into the visualization rock plate structure 22 respectively; the electric field component is used to apply an electric field to the visualization rock plate structure 22; the metering component is used to measure the content of the water phase and the oil phase in the liquid flowing out of the liquid outlet of the visualization rock plate structure 22.

[0047] According to some embodiments of the present application, the visualization rock plate structure 22 includes two acrylic plates arranged opposite to each other, the experimental rock plate sealing clamp is arranged between the two acrylic plates, and the liquid inlet and the liquid outlet penetrate into the experimental rock plate from the surface of the acrylic plate.

[0048] The visualization rock plate structure 22 is made of an experimental rock plate sandwiched between two high-transmittance and high-strength acrylic plates (applicable experimental rock plate size is 500mm×500mm×50mm). The size of the two acrylic plates is larger than the size of the experimental rock plate. Holes are drilled around the two acrylic plates and multiple bolts are installed. A compression rubber ring is set between the inner edges of the two acrylic plates for sealing. After being tightened by the bolts, the compression rubber ring is compressed to achieve a sealing effect on the edges around.

[0049] Highly transparent resin is used to seal the upper and lower sides of the experimental rock plate and the two acrylic plates to prevent the fluid from flowing through the gap between the experimental rock plate and the two acrylic plates. Holes are drilled on the left and right ends of the experimental rock plate for inflow and outflow. Specifically, holes can be drilled from the acrylic plate into the experimental rock plate, or directly from the left and right ends of the experimental rock plate to form a liquid inlet and a liquid outlet for injecting liquid into the experimental rock plate, or for liquid to flow out of the experimental rock plate.

[0050] According to some embodiments of the present application, the visualization rock plate structure 22 also includes a plurality of conductive nails, which are inserted into the experimental rock plate from the surface of the acrylic plate, and the conductive nails are used to connect to a computer to measure potential changes. Specifically, holes can be drilled in the middle of the experimental rock plate according to the potential test positions to install conductive nails for testing points, and the conductive nails are connected to the computer to test the potential changes between different conductive nails in real time.

[0051] The appearance of the visualized rock plate structure 22 is as follows Figure 2As shown. An experimental rock plate with cracks was made to simulate a reservoir with a high permeability zone. The cracks parallel to the injection well-oil production well connection line were taken as the research object. The position of the high permeability zone (the dotted line position in the figure) in the experimental rock plate is shown in Figure 3 When no artificial dominant channel is established, due to the existence of a high permeability zone, water flooding oil will quickly advance along the high permeability zone after water is injected into the fracture zone. The actual water flooding oil affected area is as follows Figure 4 As shown. Figure 5 A DC electric field is connected in the direction shown to establish an artificial advantageous channel. Since the channel is closer to the water injection well, the injected water preferentially flows upward along the artificial advantageous channel, away from the high permeability zone, and then displaces from above toward the oil production well, and the water-driven oil affected area is significantly increased.

[0052] According to some embodiments of the present application, the water phase driving component includes a motor 16, a fluid pump 15, a water phase intermediate container 12 and a graduated water phase container 10. The motor 16 rotates forward to suck the water phase in the graduated water phase container 10 into the water phase intermediate container 12, and the motor 16 rotates reversely to drive the water phase sucked into the water phase intermediate container 12 into the visualized rock plate structure 22.

[0053] Considering that the water phase driving component in the experiment needs to be energized as a whole, the commonly used pressure pump cannot be used with power due to the problem of precision components therein, so a motor 16 is used to connect the roller through a belt, and then drive the fluid pump 15 to achieve displacement. A mechanical pressure gauge 14 is installed behind the fluid pump 15 for monitoring the water phase outlet pressure. The fluid pump 15 is connected to the water phase intermediate container 12 through a needle valve 13, and the three-way valve 11 is connected to the water phase intermediate container 12 and the scaled water phase container 10.

[0054] According to some embodiments of the present application, the oil phase driving component includes a motor 1, a fluid pump 2, an oil phase intermediate container 5 and a scaled oil phase container 6. The motor 1 rotates forward to suck the oil phase in the scaled oil phase container 6 into the oil phase intermediate container 5, and the motor 1 rotates reversely to drive the oil phase sucked into the oil phase intermediate container 5 into the visualized rock plate structure 22.

[0055] Specifically, a motor 1 is connected to a rolling wheel through a belt, thereby driving a fluid pump 2 to achieve displacement. A mechanical pressure gauge 3 is installed behind the fluid pump 2 for monitoring the oil phase outlet pressure. The fluid pump 2 is connected to an oil phase intermediate container 5 through a needle valve 4. The three-way valve 7 is connected to the oil phase intermediate container 5 and a scaled oil phase container 6.

[0056] According to some embodiments of the present application, the visualization displacement assembly also includes an insulating bracket 23, a sliding mechanism 25 and a microscope 24, the insulating bracket 23 is supported on the lower side of the visualization rock plate structure 22, the sliding mechanism 25 is arranged on the upper side of the visualization rock plate structure 22, the microscope 24 is installed on the sliding mechanism 25 to achieve left and right movement, and the microscope 24 is connected to a computer 28.

[0057] The visualization displacement assembly is supported by an insulating bracket 23 to support the visualization rock plate structure 22, and the microscope 24 is installed on the sliding mechanism 25. Specifically, the sliding mechanism 25 can adopt a structure in which a motor and a screw nut drive a cross slide rail, as long as the microscope 24 can be moved left and right above the visualization rock plate structure 22 to observe the experimental rock plate condition.

[0058] According to some embodiments of the present application, the electric field assembly includes a DC power supply 27, a knife switch 26, an ammeter 28 and a voltmeter 29. The DC power supply 27 and the knife switch 26 are used to apply or disconnect the electric field to the visual rock plate structure 22, and the ammeter 28 and the voltmeter 29 are used to monitor the changes in the circuit voltage and current. Specifically, an adjustable DC power supply 27 can be used to provide power input, and the DC power supply 27 can be controlled by the knife switch 26.

[0059] According to some embodiments of the present application, the metering component includes a measuring cup 21 and an oil-water level detector 19, the measuring cup 21 is used to hold the liquid flowing out from the liquid outlet of the visual rock plate structure 22, and the oil-water level detector 19 reads the oil-water interface position in the measuring cup 21. Specifically, the measuring cup 21 is used to receive the liquid flowing out from the liquid outlet of the visual rock plate structure 22, the measuring cup 21 is replaced at regular intervals, and then the received liquid is passed through the oil-water level detector 19 to read the interface position, and the content of the water phase and the oil phase can be calculated in combination with the diameter of the measuring cup 21.

[0060] According to some embodiments of the present application, the metering assembly further comprises an insertion thermometer 20, which is disposed in the measuring cup 21 and is used to monitor the change in fluid temperature. It should be noted that all instruments in the water-displacement-oil simulation experimental device are installed with insulating pads to be isolated from the ground.

[0061] The present application provides a water-displacement-oil simulation experimental method for constructing an artificial dominant channel by electric field excitation. The method uses the water-displacement-oil simulation experimental device described above. The specific experimental process is as follows:

[0062] (1) Experimental preparation

[0063] The experimental water was prepared according to the formation water composition of the test block. The experimental rock plate with horizontal high permeability zone was prepared using outcrop rock, and the pore and crack distribution diagram of the experimental rock plate was tested by CT scanning (Fig0). The pore distribution curve Curve0 of the experimental rock plate was tested by saturated water through nuclear magnetic resonance.

[0064] The volume of the pipeline between the liquid outlet of the visual rock plate structure 22 and the measuring cup 21 is calibrated as V b .

[0065] Before the experiment, check that all valves are closed and that there is sufficient suction margin in the intermediate container. Figure 1 The middle three-way valve is named A end, B end, C end and D end according to the four directions of up, down, left and right. At the same time, it is ensured that the motor rotates forward for the intermediate container to suck in, and reverses for the intermediate container to expel, and ensures that the fluid in the scaled oil phase and water phase containers is filled to more than 85% to ensure that the suction volume requirements of the intermediate container can be met.

[0066] Water phase preparation process: open the C end and B end of the three-way valve 11, open the needle valve 13, rotate the motor 16 forward to allow the water phase intermediate container 12 to absorb the water phase, read the scaled water phase container 10, and when the volume of the absorbed water phase reaches 80% of the water phase intermediate container 12, turn off the motor 16, let it stand and observe the pressure of the mechanical pressure gauge 14 until it stabilizes, and then close the C end, B end and needle valve 13 of the three-way valve 11.

[0067] Oil phase preparation process: open the C end and B end of the three-way valve 7, open the needle valve 4, rotate the motor 1 forward to allow the oil phase intermediate container 5 to absorb the oil phase, read the scaled oil phase container 6, and when the volume of the absorbed oil phase reaches 80% of the oil phase intermediate container 5, turn off the motor 1, let it stand and observe the pressure of the mechanical pressure gauge 3 until it stabilizes, and then close the C end, B end and needle valve 4 of the three-way valve 7.

[0068] Experimental rock plate saturated with oil: install the prepared experimental rock plate into the visual rock plate structure 22, tighten the bolts, and ensure that all valves are closed before the experiment. Open the B and D ends of the three-way valve 8 and the A and B ends of the three-way valve 7, open the needle valve 4 and the needle valve 30, start the motor 1 to reverse and slowly drive the oil, wait for continuous oil flow and no bubbles to appear in the measuring cup 21, stop the test, and close all valves.

[0069] During the whole experiment, the mechanical pressure gauges 3, 9, 14, and 17 can be used to observe whether the pressure is abnormal, and determine whether the experimental device is leaking (the reading drops sharply) or is blocked (the reading increases suddenly).

[0070] (2) Water drive oil experimental test

[0071] After the experimental rock plate is saturated with oil, open the A end and D end of the three-way valve 8 and the C end and D end of the three-way valve 11, open the needle valve 13 and the needle valve 30, start the motor 16 to reverse the constant speed to perform the water-to-oil experiment, replace the measuring cup 21 at the end of the measuring cup 21 at a time interval of Δt to take samples, and the outflow volume taken out is numbered in sequence and then placed in a static layer. The oil-water interface position is tested by the oil-water level detector 19, and the oil and water volumes are calculated. The measured oil phase volume is greater than V b As the starting point of the water-to-oil experiment.

[0072] An empty measuring cup is placed on the table, and the distance between the probe and the bottom of the measuring cup is measured as H, and the distance between the interface position and the test point is measured as L. Then the height of the water phase in the measuring cup is HL, and the total liquid level in the measuring cup is measured as h. Then the height of the oil phase in the measuring cup is h-(HL), and the unit is m. According to the conversion of the oil phase and water phase density, the oil-water two-phase flow rate at the time interval is:

[0073]

[0074] Δq w =q w t -q w t-1

[0075]

[0076] Δq o =q o t -q o t-1

[0077] Where r is the radius of the bottom of the measuring cup, m; q w is the water flow rate, m 3 / s;q o is the oil phase flow rate, m 3 / s;

[0078] After observing that there is basically no oil coming out of the outflow end, turn off the motor 16, close all valves, remove the experimental rock plate, remove the bolts, conductive nails and other metal parts on the experimental rock plate, and use CT scanning to test the pore crack distribution diagram Fig1 of the experimental rock plate, and use nuclear magnetic resonance to test the pore distribution curve Curve1 of the experimental rock plate. Let each sample obtained at this time stand and stratify, use a pipette to absorb the oil phase at the top of the mixture, and take 1 / 2 of the remaining water phase to evaporate and test the mineralization to obtain the K at each time i t , plot tK i t After the test is completed, the remaining water phase is mixed and evaporated to dryness and the mineralization is tested to be K1.

[0079] After that, the experimental rock plate is reinstalled into the visualization rock plate structure 22, the bolts are tightened, the adjustable DC power supply 27 is adjusted to the set value, the knife switch 26 is turned off to energize, and the above-mentioned water displacement process is continued. The outflow water volume is measured again at the measuring cup 21 at the time Δt'. Plot tq w Relationship curve and tq o After observing that there is basically no oil coming out of the outflow end, open the knife switch 26, turn off the motor 16, close all valves, remove the experimental rock plate, and test the pore and crack distribution diagram of the experimental rock plate by CT scanning Fig2, and use nuclear magnetic resonance to test the pore distribution curve Curve2 of the experimental rock plate. Let each sample obtained at this time stand and separate, use a pipette to absorb the oil phase at the top of the mixture, and take 1 / 2 of the remaining water phase to evaporate and test the mineralization to obtain the draw After the test is completed, the remaining water phase is mixed and evaporated to dryness and the mineralization is tested to be K2.

[0080] The parameters obtained through the above test process can be analyzed as follows:

[0081] 1. Comparative analysis of the results of the artificial dominant channel established by electric field and conventional water flooding experiments w and q o The size and change trend of the electric field are used to quantify the water-to-oil improvement effect of establishing an artificial dominant channel; the test results before electric field excitation are as follows: Figure 6 The test results of constructing artificial channels by electric field excitation are shown in Figure 7 As shown in the figure, the water content rise after electric field excitation will slow down and the breakthrough speed of the water flooding front will decrease.

[0082] 2. Superimpose Fig.0, Fig.1 and Fig.2 of the experimental results of establishing artificial advantageous channel by electric field and conventional water-drive oil, and analyze the differences in the affected areas of water-drive oil in establishing artificial advantageous channel by electric field.

[0083] 3. Through tK i t Curve and The curve can be used to analyze the destructive effect of fluid on rock slabs, and the mutual comparison can be used to analyze the destructive effect of fluid on the experimental rock slab after the electric field is introduced. Example curves of different mineralization changes are as follows: Figure 8 As shown, under the action of the electric field, the reaction between the mineral ions in the experimental rock plate and the injected water increases, and the mineralization of the produced water increases.

[0084] 4. Connect to different points, different DC electric field strengths, and different electric field types (DC / AC) to analyze the effect of electric field direction, strength and type on water-to-oil improvement. Examples of water-to-oil results at different electric field excitation points are as follows: Fig. 9 and Fig.10As shown in the figure, when the excitation point is selected as BC, the water injection breakthrough speed increases. It is particularly important to select the appropriate excitation direction in practical application.

[0085] 5. Through Curve0, Curve1, and Curve2, we can analyze the distribution characteristics of residual oil in different pore sizes, as well as the distribution changes of residual oil in different pore sizes after charging. Fig.11 As shown, by comparison, the residual oil is significantly reduced after the artificial dominant channel is constructed by electric field excitation.

[0086] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A water-to-oil simulation experimental device for constructing an artificial dominant channel by electric field excitation, characterized in that: It includes a water phase driving component, an oil phase driving component, a visual displacement component, an electric field component and a metering component; the visual displacement component includes a visual rock plate structure, in which an experimental rock plate with cracks is encapsulated, and a liquid inlet and a liquid outlet communicated with the experimental rock plate are provided; the water phase driving component and the oil phase driving component are both connected to the liquid inlet of the visual rock plate structure, and are used to drive the water phase and the oil phase into the visual rock plate structure respectively; The electric field component is used to apply an electric field to the visualized rock plate structure; The metering component is used to measure the content of water phase and oil phase in the liquid flowing out from the liquid outlet of the visualization rock plate structure.

2. The water-displacement simulation experimental device for constructing an artificial dominant channel by electric field excitation according to claim 1 is characterized in that: The visualization rock plate structure includes two acrylic plates arranged opposite to each other, the experimental rock plate sealing clamp is arranged between the two acrylic plates, and the liquid inlet and the liquid outlet penetrate into the experimental rock plate from the surface of the acrylic plate.

3. The water-displacement simulation experimental device for constructing an artificial dominant channel by electric field excitation according to claim 2 is characterized in that: The visualization rock plate structure also includes a plurality of conductive nails, and the plurality of conductive nails are inserted into the experimental rock plate from the surface of the acrylic plate. The conductive nails are used to connect to a computer to measure changes in electric potential.

4. The water-displacement simulation experimental device for constructing an artificial dominant channel by electric field excitation according to claim 1 is characterized in that: The water phase driving component includes a motor, a fluid pump, a water phase intermediate container and a graduated water phase container. The motor rotates forward to suck the water phase in the graduated water phase container into the water phase intermediate container, and the motor rotates reversely to drive the water phase sucked into the water phase intermediate container into the visualized rock plate structure.

5. The water-displacement simulation experimental device for constructing an artificial dominant channel by electric field excitation according to claim 1 is characterized in that: The oil phase driving component includes a motor, a fluid pump, an oil phase intermediate container and a graduated oil phase container. The motor rotates forward to suck the oil phase in the graduated oil phase container into the oil phase intermediate container, and the motor rotates reversely to drive the oil phase sucked into the oil phase intermediate container into the visualized rock plate structure.

6. The water-displacement simulation experimental device for constructing an artificial dominant channel by electric field excitation according to claim 1 is characterized in that: The visualization displacement assembly also includes an insulating bracket, a sliding mechanism and a microscope. The insulating bracket is supported on the lower side of the visualization rock plate structure, the sliding mechanism is arranged on the upper side of the visualization rock plate structure, and the microscope is installed on the sliding mechanism to achieve left and right movement. The microscope is connected to a computer.

7. The water-displacement simulation experimental device for constructing an artificial dominant channel by electric field excitation according to claim 1 is characterized in that: The electric field component includes a DC power supply, a knife switch, an ammeter and a voltmeter. The DC power supply and the knife switch are used in conjunction to apply or disconnect the electric field to the visualized rock plate structure. The ammeter and the voltmeter are used to monitor changes in circuit voltage and current.

8. The water-displacement simulation experimental device for constructing artificial dominant channels by electric field excitation according to claim 1 is characterized in that: The metering component includes a measuring cup and an oil-water level detector. The measuring cup is used to contain the liquid flowing out from the liquid outlet of the visual rock plate structure, and the oil-water level detector reads the position of the oil-water interface in the measuring cup.

9. The water-displacement simulation experimental device for constructing artificial dominant channels by electric field excitation according to claim 8 is characterized in that: The metering component also includes an insertion thermometer, which is arranged in the measuring cup and is used to monitor changes in the temperature of the fluid.

10. A water-displacement-oil simulation experimental method for constructing an artificial dominant channel by electric field excitation, using the water-displacement-oil simulation experimental device for constructing an artificial dominant channel by electric field excitation according to claim 1, characterized in that: The following steps are involved: Step 1: Prepare an experimental rock plate with cracks, use CT scanning to test the pore crack distribution map of the experimental rock plate, and use nuclear magnetic resonance to test the pore distribution curve of the experimental rock plate; Step 2: After the manufactured experimental rock plate is loaded into the visualized rock plate structure, the oil phase is driven into the visualized rock plate structure through the oil phase driving component until a continuous oil flow appears at the liquid outlet; Step 3: Drive the water phase into the visualized rock plate structure through the water phase drive component to carry out a water drive oil experiment, take samples from the liquid outlet at a certain time interval, and measure the water phase and oil phase content in the sampled liquid through the metering component. After no oil is produced, remove the experimental rock plate, test the pore and crack distribution map of the experimental rock plate through CT scanning, test the pore distribution curve of the experimental rock plate using nuclear magnetic resonance, and use a pipette to absorb the oil phase at the upper end of the mixed liquid, and test the mineralization by evaporating the remaining water phase; Step 4. Install the experimental rock plate back into the visualized rock plate structure, apply an electric field to the visualized rock plate structure through the electric field component, drive the water phase into the visualized rock plate structure through the water phase driving component to continue the water drive oil experiment, take samples from the liquid outlet at a certain time interval again, and calculate the water phase and oil phase content in the sampled liquid through the metering component. After no oil is produced, remove the experimental rock plate, test the pore and crack distribution map of the experimental rock plate through CT scanning, use nuclear magnetic resonance to test the pore distribution curve of the experimental rock plate, and use a pipette to absorb the oil phase at the upper end of the mixed liquid, and test the mineralization by evaporating the remaining water phase.

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