Support migration and settlement simulation experiment device capable of adjusting crack width in real time

Abstract

The invention belongs to the technical field of fracturing, and discloses a crack width real-time adjustable support migration settlement simulation experiment device, which comprises: an adapter seat, two ends of which are provided with mounting surfaces; the two groups of simulation assemblies are arranged, n simulation assemblies form one group, and the two groups of simulation assemblies are symmetrically mounted on the mounting surface by taking the adapter as the center; in each group, n simulation components are connected in sequence, and n is greater than or equal to 1; the simulation assembly is used for simulating different reservoir fractures and migration and sedimentation of a propping agent in the reservoir fractures. By arranging the simulated crack and the pressure-bearing air bag, in the using process, the width of the simulated crack is adjusted in a stepless mode by injecting air into the pressure-bearing air bag, so that the migration and sedimentation simulation experiment of the propping agent with different crack widths is completed, after actual inspection, the obtained result conforms to the expectation, it is indicated that the device is effective, and the device is suitable for popularization and application. And a brand-new thought and method are provided for exploring the migration and settlement rule of the fracturing proppant in fracturing development.

Description

Technical Field

[0001] The invention belongs to the technical field of fracturing, and in particular relates to a support migration and settlement simulation experimental device with real-time adjustable crack width. Background Art

[0002] At present, fracturing technology is commonly used to develop unconventional oil and gas reservoirs with low permeability and low porosity. With the widespread application of hydraulic fracturing technology, the proppant used to support the cracks that have been opened during hydraulic fracturing has become a research hotspot for scientific researchers. Hydraulic fracturing technology mixes a certain concentration of proppant into the fracturing fluid, so that the cracks that have been opened are closed on the proppant particles, improving the conductivity of the fracture network, thereby achieving the effect of increasing the production of the reservoir; while the cracks that have been opened without the entry of proppant will be closed again due to reservoir stress, which will have a great impact on the conductivity of the fractures and the post-fracturing production. Therefore, mastering the migration and sedimentation laws of proppants in the wellbore and fractures is of great guiding significance for the application of fracturing technology.

[0003] Patent CN113027409A proposes an experimental device for simulating the migration of proppant in a horizontal well hydraulic fracturing network, which simulates the network topology of the horizontal well hydraulic fracturing network under actual conditions to the greatest extent. However, due to the complexity of the simulated situation and the limitation of the device size, it will inevitably cause large errors in the experimental results. In addition, the simulation scale of the experimental device cannot be adjusted, and the simulation situation is also very limited. Summary of the invention

[0004] In order to solve at least one problem in the background technology, the present invention proposes a proppant migration and settlement simulation experimental device with real-time adjustable fracture width. The experimental device can simulate the migration and distribution characteristics of the proppant during injection and backflow at different fracture widths, and then derive the migration and settlement law of the proppant between fractures.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A support migration and settlement simulation experimental device with real-time adjustable crack width, comprising:

[0007] The adapter seat has mounting surfaces at both ends;

[0008] The simulation components are provided in two groups, with n components in one group, and the two groups of simulation components are symmetrically mounted on the mounting surface with the adapter as the center;

[0009] In each group of simulation components, n simulation components are connected in sequence, n≥1;

[0010] The simulation component is used to simulate different reservoir fractures and the migration and settlement of proppants in the reservoir fractures.

[0011] Preferably, the simulation component includes a front fixing frame, a visualization glass plate, a rear support plate, a pressure-bearing airbag, and a rear baffle plate that are stacked in sequence;

[0012] A simulated crack is reserved between the rear support plate and the visualization glass plate, and the width of the simulated crack is 2 mm to 10 mm;

[0013] Both ends of the rear support plate are connected with connecting blocks, and the connecting blocks are located between the simulated crack and the rear baffle plate.

[0014] Preferably, the front fixing frame is in a "mouth" shape.

[0015] Preferably, one side surface of the front fixing frame and the connecting block at one end of the rear support plate are both bolted to one mounting surface of the adapter base.

[0016] Preferably, it further includes a first interface support in a rectangular column shape. The inside of the first interface support is a hollow structure. A first discharge interface communicating with the inside is provided at the end, and a fixing interface is provided on one side surface. And the first interface support communicates with the simulated crack;

[0017] One side surface of the first interface support is fixedly connected to one end of the simulation component away from the adapter base.

[0018] Preferably, it further includes a second interface support in a rectangular column shape. The inside of the second interface support is a hollow structure. A second discharge interface communicating with the inside is provided at the end, and the second interface support communicates with the simulated crack;

[0019] The other side surface of the second interface support is fixedly connected to one end of the simulation component away from the adapter base.

[0020] Preferably, a filling pipe is also connected to the pressure-bearing airbag, and the filling pipe passes through the rear baffle plate and extends to the outside of the simulation component.

[0021] Preferably, the rear support plate is fixedly connected with n×n upright rods, n≥2. The upright rods are centered on the center point of the rear support plate, pass through the pressure-bearing airbag and the rear baffle plate and extend to the outside of the simulation component, and are arranged in an n×n rectangular manner.

[0022] Preferably, a transparent wellbore is also installed on the adapter base, and the transparent wellbore communicates with the simulated crack.

[0023] Preferably, both the front fixing frame and the rear support plate are made of plastic materials.

[0024] Preferably, several of the support migration and sedimentation simulation experimental devices with real-time adjustable fracture widths are arranged in parallel to simulate multiple parallel reservoir fractures and the migration and sedimentation of proppants in the reservoir fractures; or, several of the support migration and sedimentation simulation experimental devices with real-time adjustable fracture widths are arranged in series to simulate continuous reservoir fractures and the migration and sedimentation of proppants in the reservoir fractures.

[0025] Preferably, the support migration and settlement simulation experimental device is used to simulate the distribution of fracturing fluid / sand-carrying fluid entering reservoir fractures when reservoir fractures are opened under constant closing pressure conditions, and observe real-time changes in fracture width.

[0026] Preferably, the support migration and settlement simulation experimental device is used to simulate the gradual change of reservoir fracture width under different pressure conditions, including gradual increase in width and gradual decrease in width.

[0027] Beneficial effects of the present invention:

[0028] The present invention sets up simulated cracks and pressure-bearing air bags. During use, the width of the simulated cracks is steplessly adjusted by injecting air into the pressure-bearing air bags, thereby completing a simulation experiment of proppant migration and settlement of different crack widths. After actual testing, the present invention has obtained results that are consistent with expectations, indicating that the present invention is effective and provides a new idea and method for exploring the laws of proppant migration and settlement in hydraulic fracturing.

[0029] Other features and advantages of the present invention will be described in the following description, and partly become obvious from the description, or be understood by implementing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures pointed out in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0031] Figure 1 A structural schematic diagram of a support migration and settlement simulation experimental device with real-time adjustable crack width according to the present invention is shown;

[0032] Figure 2 Shows Figure 1 The cross-sectional view of the AA plane of the support migration and settlement simulation experimental device with real-time adjustable middle crack width;

[0033] Figure 3Shows Figure 1 Front view of the support migration and settlement simulation experimental device with real-time adjustable middle crack width;

[0034] Figure 4 The working flow chart of the support migration and settlement simulation experimental device with real-time adjustable crack width is shown;

[0035] Figure 5 The crack structure diagram of the support migration and settlement simulation experimental device with real-time adjustable crack width under constant pressure is shown;

[0036] Figure 6 The crack structure diagram of the support migration and settlement simulation experimental device with real-time adjustable crack width under different pressures is shown.

[0037] In the figure: 1. Transparent shaft; 2. Adapter; 3. Front fixed frame; 4. Rear baffle; 5. Rear support plate; 6. Pressure airbag; 7. Righting rod; 8. Filling pipe; 9. Visual glass plate; 10. First interface support; 1001. First discharge interface; 1002. Fixed interface; 11. Second interface support; 1101. Second discharge interface; 12. Connecting block. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0039] A support migration settlement simulation experimental device with real-time adjustable crack width includes: an adapter 2, with mounting surfaces at both ends; two groups of simulation components, with n components in one group, and the two groups of simulation components are symmetrically mounted on the mounting surfaces with the adapter 2 as the center. In each group of simulation components, n simulation components are connected in sequence, and n≥1.

[0040] A support migration and settlement simulation experimental device with real-time adjustable crack width, such as Figure 1As shown in the figure, when n = 1, it includes a transparent wellbore 1, an adapter base 2, a simulation component, a first interface support 10, and a second interface support 11. Among them, the transparent wellbore 1 is installed on the adapter base 2 and passes through the adapter base 2. The adapter base 2 is a symmetric structure, and mounting surfaces are provided at both ends. There are two simulation components in total, which are symmetrically installed on the mounting surfaces with the adapter base 2 as the center. Each simulation component can simulate different reservoir fractures and the migration and settlement of proppants in the reservoir fractures, and the simulated reservoir fractures are all connected to the transparent wellbore 1. In addition, the first interface support 10 and the second interface support 11 are respectively installed on both sides of the entire experimental device.

[0041] It should be noted that in Figure 1 , proppant fluid can be injected into the simulation component through the transparent wellbore 1. The proppant fluid can migrate and settle in the simulation component and finally be discharged through the first interface support 10 and the second interface support 11. In addition, both the transparent wellbore 1 and the visualization glass plate 9 are made of special materials to improve their structural strength.

[0042] Furthermore, as shown in Figure 2 , the simulation component includes a front fixing frame 3, a visualization glass plate 9, a rear support plate 5, a pressure-bearing airbag 6, and a rear baffle 4 that are stacked in sequence; among them, a simulation fracture is reserved between the rear support plate 5 and the visualization glass plate 9, and the width of the simulation fracture is 2 mm to 10 mm; connecting blocks 12 are connected to both ends of the rear support plate 5, and the connecting blocks 12 are located between the simulation fracture and the rear baffle 4.

[0043] It should be noted that as can be seen from Figure 2 , the simulation fracture of the simulation component is equivalent to the reservoir fracture. During use, by injecting gas into the pressure-bearing airbag 6, when the pressure in the pressure-bearing airbag 6 reaches a certain value, it will squeeze the rear support plate 5, and the greater the pressure, the smaller the width of the simulation fracture, so as to achieve the effect of adjusting the width of the simulation fracture.

[0044] It should be further noted that the pressure-bearing airbag 6 is also connected to a filling pipe 8. The filling pipe 8 passes through the rear baffle 4 and extends to the outside of the simulation component. In the working state, gas can be injected into the pressure-bearing airbag 6 through the filling pipe 8, and devices such as a pressure gauge can also be added at the position of the filling pipe 8 to help the user control the internal pressure of the pressure-bearing airbag 6. In addition, in this embodiment, both the front fixing frame 3 and the rear support plate 5 are made of plastic materials, and when the pressure-bearing airbag 6 squeezes the rear support plate 5, the rear support plate 5 can be deformed to control the width of the simulation fracture.

[0045] Furthermore, the front fixing frame 3 is in a "mouth" shape. It should be noted that the main function of the front fixing frame 3 is to fix the visualization glass plate 9, and the "mouth" shape structure is used to reserve an observation area so that the user can observe the migration and settlement of the proppant fluid in the simulation fracture through the visualization glass plate 9.

[0046] Further, from Figure 2 As can be seen in the figure, the connection block 12 on one side of the front fixing frame 3 and one end of the rear support plate 5 are both bolted to a mounting surface of the adapter 2. Therefore, the connection block 12 is not only a part of the closed simulated crack, but also a structure that is bolted to the adapter 2 as an adapter structure.

[0047] Furthermore, combined with Figure 2 and Figure 3 It can be known that the support, transport and settlement simulation experimental device of the present invention also includes a first interface support 10 in the shape of a rectangular column. The first interface support 10 has a hollow structure inside, and a first discharge interface 1001 communicating with the inside is opened at the end, and a fixed interface 1002 is opened on one side, and the first interface support 10 is connected to the simulated crack. The fixed interface 1002 is used to stabilize the crack simulation device and to connect it with the ground stabilization device to prevent the crack simulation device from tipping over and shaking during the experiment; one side of the first interface support 10 is fixedly connected to one end of the simulation component away from the adapter 2. In addition, the support, transport and settlement simulation experimental device also includes a second interface support 11 in the shape of a rectangular column. The second interface support 11 has a hollow structure inside, and a second discharge interface 1101 communicating with the inside is opened at the end, and the second interface support 11 is connected to the simulated crack; the other side of the second interface support 11 is fixedly connected to one end of the simulation component away from the adapter 2.

[0048] It should be noted that the first interface support 10 and the second interface support 11 can not only connect the simulated cracks, but also serve as part of the supporting structure of the entire device to keep the entire device stable. Figure 2 In the figure, the three positions a, b and c are where sealant needs to be applied, and the specific positions include the contact surface between the connecting block 12 and the rear baffle 4 and the contact surface between the fixing interface 1002 and the second interface support 11.

[0049] Furthermore, the rear support plate 5 is fixedly connected with n×n righting rods 7, n≥2. The righting rods 7 are centered on the center point of the rear support plate 5, pass through the pressure airbag 6 and the rear baffle 4, extend to the outside of the simulation component, and are arranged in an n×n rectangular manner. The purpose is to allow the support, movement and settlement simulation experimental device to be placed on a plane to prevent tipping over.

[0050] When the present invention performs hydraulic fracturing on a reservoir, in order to prevent the already opened cracks from closing naturally under the action of reservoir stress, a large amount of proppant is injected into the hydraulic fractures, so that the already opened cracks are closed on the proppant particles under the action of external force, thereby keeping the hydraulic fractures open, improving the flow conductivity of the fracture network, and greatly reducing the resistance of the reservoir oil and gas resources to flow into the wellbore.

[0051] During use, the present invention is combined with Figure 4 It can be seen that the process is as follows:

[0052] (1) Connecting the transparent wellbore 1 to an external proppant injection device;

[0053] (2) injecting a certain amount of gas (the specific volume can be observed by a pressure gauge) into the pressure-bearing airbag 6 through an air pump to provide initial pressure for the rear support plate 5;

[0054] (3) Pump a certain amount of air into the pressure-bearing airbag 6 and the simulated crack, and check the airtightness of the device by the differential pressure test method;

[0055] (4) injecting proppant into the simulated fracture through the transparent wellbore 1;

[0056] (5) adjusting the gap (simulated crack) between the rear support plate 5 and the visualization glass plate 9 according to the experimental setting parameters to simulate different reservoir crack widths;

[0057] (6) According to the actual experimental situation, the pressure of the pressure-bearing airbag 6 is adjusted to ensure that the fluctuation of the gap size is small and the simulated fracture width remains basically unchanged during the proppant migration and settlement simulation experiment;

[0058] (7) Close the simulated wellbore interface valve, keep the pressure of the pressure-bearing air bag unchanged, open the pressure relief ports at both ends of the fracture simulation device, and discharge the proppant in the device.

[0059] It should be noted that in step (3), when pumping gas into the crack simulation device, it should be ensured that except for the valve at the inlet, all other valves should be closed, the pressure-bearing airbag should be pre-set, a certain amount of soapy water should be applied to each bolt connection of the device, and the reading of the differential pressure sensor installed in the transparent wellbore 1 should be observed and recorded. When the reading is less than 0.1 kpa and there are only a few bubbles in the soapy water near the bolt, the device is considered to be airtight. In addition, in step (5), the pressure of the pressure-bearing airbag 6 is mainly adjusted by injecting gas into the pressure-bearing airbag 6, thereby adjusting the simulated crack width.

[0060] It should be further explained that during the entire experimental process, at the beginning, the pressure-bearing airbag 6 is generally pre-loaded with 0.3-0.4MPa air pressure. When the pressure of the sand-carrying fluid increases, the rear support plate 5 compresses the pressure-bearing airbag 6 toward the rear, and the crack width increases; when the pressure of the sand-carrying fluid decreases, the rear support plate 5 moves forward under the action of the pressure-bearing airbag 6, and the crack width decreases.

[0061] Through steps (1) to (7), the present invention provides the test data shown in Table 1 and Table 2.

[0062] Table 1

[0063]

[0064] Table 2

[0065]

[0066]

[0067] Furthermore, the support migration and sedimentation simulation experimental device with real-time adjustable fracture width of the present invention can also be used in combination. For example, several support migration and sedimentation simulation experimental devices with real-time adjustable fracture width are arranged in parallel to simulate multiple parallel reservoir fractures and the migration and sedimentation of proppants in the reservoir fractures; or, several support migration and sedimentation simulation experimental devices with real-time adjustable fracture width are arranged in series to simulate continuous reservoir fractures and the migration and sedimentation of proppants in the reservoir fractures.

[0068] Furthermore, the support migration and settlement simulation experimental device is used to simulate the distribution of fracturing fluid / sand-carrying fluid entering the reservoir fracture when the reservoir fracture is opened under the condition of constant closing pressure, and observe the real-time change of the fracture width. Figure 5 As shown, the pressure on the rear support plate 5 is constant at all locations, and the width of the reservoir fracture is equal at all locations.

[0069] Furthermore, the support migration and settlement simulation experimental device is used to simulate the gradual change of reservoir fracture width under different pressure conditions, including the gradual increase of width and the gradual decrease of width. Figure 6 As shown, n=2, where two support migration and settlement simulation experimental devices are combined, the reservoir fractures of the first one are equal everywhere, and the width of the reservoir fractures of the second support migration and settlement simulation experimental device gradually decreases until it is closed, thereby simulating the situation from fracture opening to fracture closure. Of course, the combination of multiple instruments with different fracture widths can also simulate the sand-laying morphology from the fracture mouth to the fracture tip or the sand-laying morphology in the combined fractures such as the main fracture, branch fracture and micro fracture.

[0070] Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent substitutions for some of the technical features therein; and these modifications or substitutions do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A support migration and settlement simulation experimental device with real-time adjustable crack width, characterized in that: Including: An adapter (2) with mounting surfaces provided at both ends; Two groups of simulation components, with n components in each group, and the two groups of simulation components are symmetrically mounted on the mounting surfaces with the adapter (2) as the center; In each group of simulation components, the n simulation components are connected in sequence, where n≥1; The simulation components are used to simulate different reservoir fractures and the migration and settlement of proppants in the reservoir fractures.

2. The support migration and settlement simulation experimental device with real-time adjustable crack width according to claim 1 is characterized in that: The simulation component includes a front fixing frame (3), a visualization glass plate (9), a rear support plate (5), a pressure-bearing airbag (6), and a rear baffle (4) that are stacked in sequence; A simulated fracture is reserved between the rear support plate (5) and the visualization glass plate (9), and the width of the simulated fracture is 2 mm to 10 mm; Both ends of the rear support plate (5) are connected with connecting blocks (12), and the connecting blocks (12) are located between the simulated fracture and the rear baffle (4).

3. The support migration and settlement simulation experimental device with real-time adjustable crack width according to claim 2 is characterized in that: The front fixing frame (3) is in a "mouth" shape.

4. The support migration and settlement simulation experimental device with real-time adjustable crack width according to claim 2 is characterized in that: One side surface of the front fixing frame (3) and the connecting block (12) at one end of the rear support plate (5) are both bolted to one mounting surface of the adapter (2).

5. The support migration and settlement simulation experimental device with real-time adjustable crack width according to claim 4 is characterized in that: It further includes a first interface support (10) in a rectangular column shape. The interior of the first interface support (10) is a hollow structure, and a first discharge interface (1001) communicating with the interior is provided at the end, and a fixed interface (1002) is provided on one side surface, and the first interface support (10) communicates with the simulated fracture; One side surface of the first interface support (10) is fixedly connected to the end of the simulation component away from the adapter (2).

6. A support migration and settlement simulation experimental device with real-time adjustable crack width according to claim 4 or 5, characterized in that: It further includes a second interface support (11) in a rectangular column shape. The interior of the second interface support (11) is a hollow structure, and a second discharge interface (1101) communicating with the interior is provided at the end, and the second interface support (11) communicates with the simulated fracture; The other side surface of the second interface support (11) is fixedly connected to the end of the simulation component away from the adapter (2).

7. A support migration and settlement simulation experimental device with real-time adjustable crack width according to any one of claims 2 to 5, characterized in that: The pressure-bearing airbag (6) is also connected to a filling pipe (8), and the filling pipe (8) passes through the rear baffle (4) and extends to the outside of the simulation component.

8. A support migration and settlement simulation experimental device with real-time adjustable crack width according to any one of claims 2 to 5, characterized in that: The rear support plate (5) is fixedly connected with n×n扶正杆 (7), where n≥2. The扶正杆 (7) is centered on the center point of the rear support plate (5), passes through the pressure-bearing airbag (6) and the rear baffle (4) and extends to the outside of the simulation component, and is arranged in an n×n rectangular manner. (Note: The specific Chinese term '扶正杆' needs to be accurately translated according to its actual meaning in the technical context. Here, it is left untranslated for now as the accurate English term is not clear.) 9. A support migration and settlement simulation experimental device with real-time adjustable crack width according to any one of claims 2 to 5, characterized in that: A transparent wellbore (1) is also installed on the adapter (2), and the transparent wellbore (1) communicates with the simulated fracture.

10. A support migration and settlement simulation experimental device with real-time adjustable crack width according to any one of claims 2-5, characterized in that: Both the front fixing frame (3) and the rear support plate (5) are made of plastic materials.

11. The support migration and settlement simulation experimental device with real-time adjustable crack width according to claim 10, characterized in that : A number of the support migration and settlement simulation experimental devices with adjustable real-time fracture width are arranged in parallel for multiple parallel simulated reservoir fractures and the migration and settlement of proppants in the reservoir fractures: Or, a number of the support migration and settlement simulation experimental devices with adjustable real-time fracture width are arranged in series for simulating continuous reservoir fractures and the migration and settlement of proppants in the reservoir fractures.

12. According to the support migration and settlement simulation experimental device with adjustable real-time fracture width described in claim 11, characterized in that: The support migration and settlement simulation experimental device is used to simulate the distribution of fracturing fluid / sand-carrying fluid entering reservoir fractures when reservoir fractures are opened under the condition of constant closing pressure, and observe the real-time changes of fracture width.

13. The support migration and settlement simulation experimental device with real-time adjustable crack width according to claim 11, characterized in that: The support migration and settlement simulation experimental device is used to simulate the gradual change of reservoir fracture width under different pressure conditions, including the gradual increase of width and the gradual decrease of width.

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