Visual evaluation method and device for gas-water flow law in horizontal well fracturing fracture

Abstract

This invention provides a method for visually evaluating the gas-water flow patterns within fractured horizontal wells. The method includes: preparing an experimental physical model; weighing and recording the first weight of the physical model under dry conditions; the physical model is used to simulate fractured horizontal wells; pumping a colored displacement solution into the physical model to completely displace the air within the model; weighing and recording the second weight of the physical model at this point; injecting gas and water into the physical model under different experimental conditions; recording the gas-water distribution and flow state within the physical model; and calculating the critical water saturation for gas-water flow. This invention can simulate the flow and distribution of the gas and water phases within fractures under different conditions, such as fracture width, proppant size, proppant wetting properties, gas-water flow velocity, and gas-water ratio.

Description

Technical Field

[0001] This invention relates to the field of oil and gas field development technology, and more specifically, to a method and apparatus for visually evaluating the flow patterns of gas and water within fractures in horizontal wells. Background Technology

[0002] Two-phase gas-water flow is widespread in shale and tight sandstone gas reservoirs during post-fracturing flowback and production stages, directly determining reservoir stimulation and development effectiveness. The Sulige and Dongsheng gas fields in Ordos are both water-bearing gas reservoirs, with large, widespread water-rich areas in the horizontal plane and complex gas-water relationships vertically. Post-fracturing gas wells generally exhibit high water production, severely impacting normal well production and the overall development plan of the blocks. To improve post-fracturing production efficiency and economic benefits, and to identify the development potential and technical strategies for water-bearing gas reservoirs, it is necessary to focus on studying the gas-water flow relationship within fracturing fractures, clarifying the adaptability of fracturing processes, and developing differentiated fracturing stimulation technologies for gas reservoirs with different water saturation levels.

[0003] Currently, research on gas-water two-phase flow within fractures has involved several methods. Some scholars employ numerical simulations, considering gas-water slippage and the water film effect at the fracture surface, to establish gas-water two-phase fluid flow models. Others have developed devices to evaluate the conductivity of fractures using gas-water two-phase flow, employing small core samples to investigate the impact of aqueous fracturing fluid intrusion on the conductivity of shale fractures and its seepage patterns (CN207379891U). However, effective research methods are lacking regarding the gas-water flow state within fractures, the flow patterns of the gas-water two phases within the fractures, and the influence of fracture morphology on gas-water two-phase flow. Furthermore, the conclusions of numerical simulation studies lack necessary laboratory experimental verification. Therefore, directly observing the gas-water flow state within fractures and clarifying the flow patterns under different gas-water ratios and fracture morphologies is of great significance for the efficient development of water-bearing gas reservoirs and improving post-fracturing production.

[0004] To address the problems of existing technologies, this invention provides a method and apparatus for visually evaluating the gas-water flow patterns within fractures in horizontal wells. Summary of the Invention

[0005] To address the technical problem that existing experimental methods cannot observe the gas-water flow state within fractures, thus failing to effectively verify the accuracy of numerical simulations of gas-water flow within fractures, this invention provides a method for visually evaluating the gas-water flow patterns within horizontal well fracturing fractures. The method includes the following steps:

[0006] S1. Prepare an experimental physical model, weigh and record the first weight of the physical model under dry conditions, the physical model is used to simulate horizontal well fracturing fractures;

[0007] S2. Pump a colored displacing solution into the physical model to completely displace the air in the physical model. At this time, weigh and record the second weight of the physical model.

[0008] S3. Under different experimental conditions, gas and water are injected into the physical model, the distribution and flow state of gas and water in the physical model are recorded, and the critical water saturation of gas and water flow is calculated.

[0009] According to an embodiment of the present invention, the preparation of the experimental physical model in step S1 includes:

[0010] Take two transparent experimental plates;

[0011] Based on the simulated fracturing fracture size requirements, the two transparent experimental plates were adjusted to the required fracture width and then filled with proppant.

[0012] The two transparent experimental plates were sealed around their sides, leaving only the liquid inlet channels on both sides of the plates.

[0013] According to one embodiment of the present invention, step S2 includes: staining water with methylene blue dye to prepare the colored displacement solution.

[0014] According to an embodiment of the present invention, the method includes the following steps: calculating the pore volume of the physical model based on the first weight and the second weight.

[0015] According to an embodiment of the present invention, step S3 includes:

[0016] Keeping the total gas-water flow rate constant, the gas-water two-phase ratio is changed, and gas and water are injected into the physical model.

[0017] Record the pressure difference and gas-water flow rate at both ends of the physical model under different gas-water two-phase ratio conditions and the stable pressure at both ends of the physical model, and take pictures to record the gas-water distribution and flow state in the crack.

[0018] According to an embodiment of the present invention, step S3 includes:

[0019] While keeping the gas-water two-phase ratio constant, the total gas-water flow rate is changed, and gas and water are injected into the physical model.

[0020] Record the pressure difference and gas-water flow rate at both ends of the physical model under different total gas-water flow rate conditions and the stable pressure at both ends of the physical model. Also, take pictures to record the gas-water distribution and flow state within the crack.

[0021] According to an embodiment of the present invention, the method includes the following steps:

[0022] Record the weight of the physical model under stable pressure at both ends, and denote it as the third weight;

[0023] Based on the third weight and combined with the first weight, the water saturation of the physical model is calculated.

[0024] Record the pressure difference between the two ends of the physical model under stable pressure conditions, and calculate the critical water saturation for gas-water flow by combining the water saturation.

[0025] According to another aspect of the invention, a storage medium is also provided, which includes a series of instructions for performing the steps of the method described in any of the preceding claims.

[0026] According to another aspect of the present invention, a visualization and evaluation device for the gas-water flow pattern within a horizontal well fracturing fracture is also provided, which performs the method described in any of the preceding claims, the device comprising:

[0027] The preparation module is used to prepare an experimental physical model, weigh and record the first weight of the physical model under dry conditions, and the physical model is used to simulate horizontal well fracturing fractures.

[0028] The displacement module is used to pump a colored displacement solution into the physical model to completely displace the air in the physical model. At this time, the second weight of the physical model is weighed and recorded.

[0029] The experimental module is used to inject gas and water into the physical model under different experimental conditions, record the distribution and flow state of gas and water in the physical model, and calculate the critical water saturation of gas and water flow.

[0030] According to another aspect of the present invention, a visualization and evaluation system for the gas-water flow pattern within fractured fractures in a horizontal well is also provided, which performs the method described in any of the preceding claims, the system comprising:

[0031] Liquid tank, used to hold experimental water;

[0032] A horizontal flow pump, which is connected to the liquid tank;

[0033] An oil tank, connected to the advection pump, is used to hold experimental oil;

[0034] A staining solution container, connected to the oil tank, is used to prepare a colored displacement solution;

[0035] Nitrogen cylinders are used to store nitrogen gas for laboratory use.

[0036] A gas buffer tank, which is connected to the nitrogen cylinder;

[0037] A physical model, which is connected to the staining solution container and the gas buffer tank;

[0038] A gas-liquid separator, which is connected to the physical model;

[0039] A gas meter is connected to the gas-water separator.

[0040] This invention provides a method and apparatus for visually evaluating the gas-water flow patterns within fractures in horizontal well fracturing. It can simulate the flow and distribution of the gas and water phases within fractures under conditions such as different fracture widths, proppant sizes, proppant wetting properties, gas-water flow velocities, and gas-water ratios. The experiment allows for visual observation of the gas-water flow process within the fractures. By accurately observing the gas-water flow state within the fractures and recording the gas-water ratio, the influence of fracture morphology and displacement pressure on the gas-water flow within the fractures can be clarified, providing a theoretical basis for fracture morphology design and production system optimization in fracturing stimulation.

[0041] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the description, claims, and drawings. Attached Figure Description

[0042] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with the embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0043] Figure 1 A flowchart of a method for visually evaluating the gas-water flow pattern within a horizontal well fracturing fracture, according to an embodiment of the present invention, is shown.

[0044] Figure 2 This diagram shows a schematic representation of a system for visualizing and evaluating the flow patterns of gas and water within a fractured horizontal well, according to an embodiment of the present invention.

[0045] Figure 3 A schematic diagram of a transparent plate without proppant is shown according to an embodiment of the present invention;

[0046] Figure 4 A schematic diagram showing a displacement pressure difference of 2.5 kPa and a water saturation of 24% in a plate according to an embodiment of the present invention is shown.

[0047] Figure 5 A schematic diagram showing a displacement pressure difference of 7 kPa and a water saturation of 20% in a plate according to an embodiment of the present invention is shown.

[0048] Figure 6The graph showing the relationship between displacement pressure difference and water saturation in a plate according to an embodiment of the present invention is shown.

[0049] Figure 7 A schematic diagram showing an air-to-water ratio of 1:0 and a water saturation of 21% in a plate according to an embodiment of the present invention is displayed.

[0050] Figure 8 A schematic diagram showing an air-to-water ratio of 1:1 and a water saturation of 51.5% in a plate according to an embodiment of the present invention is displayed.

[0051] Figure 9 A schematic diagram showing an air-to-water ratio of 0:1 and a water saturation of 80% in a plate according to an embodiment of the present invention is displayed.

[0052] Figure 10 A schematic diagram showing an air-to-water ratio of 0:1 and a water saturation of 71.6% in a plate according to an embodiment of the present invention is displayed.

[0053] In the accompanying drawings, the same parts use the same reference numerals. Also, the drawings are not drawn to scale.

[0054] The meanings of the reference numerals in the attached figures are as follows: 1—liquid tank, 2—parallel flow pump, 3—nitrogen cylinder, 4—flow controller, 5—gas buffer tank, 6—dyeing solution container, 7—oil tank, 8—six-way valve, 9—camera, 10—physical model, 11—fracturing proppant, 12—light source, 13—gas-liquid separator, 14—gas meter, 15—one-way valve, 16—valve, 17—pressure gauge, 18—pipeline. Detailed Implementation

[0055] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0056] Figure 1 A flowchart of a method for visually evaluating the flow patterns of gas and water within fractures in a horizontal well, according to an embodiment of the present invention, is shown.

[0057] In one embodiment, before the experiment begins, the required gas and water flow rates and gas-water ratios under the experimental conditions are calculated based on the actual on-site scale of the fracture after fracturing, the gas production rate, and the water production rate.

[0058] like Figure 1 As shown, in step S1, an experimental physical model is prepared, and its first weight under dry conditions is weighed and recorded. The physical model is used to simulate horizontal well fracturing fractures. Specifically, the physical model is made of PMMA material and is used to simulate fracturing fractures, which are filled with fracturing proppant. The fracture width and proppant type can be set manually.

[0059] In one embodiment, preparing the experimental physical model includes the following steps:

[0060] S11. Take two transparent experimental plates. Specifically, transparent PMMA material is used to make transparent experimental plates, which allow for real-time observation of the gas and water flow within the simulated fracturing fracture during the experiment.

[0061] S12. Based on the simulated fracturing fracture size requirements, adjust the two transparent experimental plates to the required fracture width and then fill them with proppant. Specifically, the fracturing fracture size requirements refer to the actual fracture size at the field scale after fracturing.

[0062] S13. Seal the two transparent experimental plates around their perimeter, leaving only the liquid inlet channels on the sides. Specifically, seal the two transparent experimental plates around their perimeter with silicone sealant, leaving only the liquid inlet channels on the sides of the transparent plates. Figure 3 As shown.

[0063] like Figure 1 As shown, in step S2, a colored displacing solution is pumped into the physical model to completely displace the air within the model. At this point, the second weight of the physical model is weighed and recorded. In one embodiment, step S2 includes: staining water / distilled water / pure water with methylene blue dye to prepare the colored displacing solution.

[0064] In one embodiment, a method for visually evaluating the gas-water flow pattern within a horizontal well fracturing fracture includes the following steps: calculating the pore volume of a physical model based on a first weight and a second weight. Specifically, the pore volume within the physical model under proppant-filled fracture conditions can be calculated based on the difference between the first weight M1 and the second weight M2.

[0065] like Figure 1 As shown, in step S3, under different experimental conditions, gas and water are injected into the physical model, the distribution and flow state of gas and water in the physical model are recorded, and the critical water saturation of gas and water flow is calculated.

[0066] In one embodiment, step S3 includes: keeping the total gas-water flow rate constant, changing the gas-water two-phase ratio, and injecting gas and water into the physical model; recording the pressure difference and gas-water flow rate at both ends of the physical model under different gas-water two-phase ratio conditions and with the pressure at both ends of the physical model stable, and taking pictures to record the gas-water distribution and flow state within the crack. Specifically, keeping the total gas-water flow rate constant, injecting gas and water into the physical model under different gas-water two-phase ratio conditions, waiting for the pressure at both ends of the physical model to stabilize, taking pictures to record the gas-water distribution and flow state within the crack, and calculating the water saturation based on the pore volume.

[0067] In one embodiment, step S3 includes: keeping the gas-water two-phase ratio constant, changing the total gas-water flow rate, and injecting gas and water into the physical model; recording the pressure difference and gas-water flow rate at both ends of the physical model under different total gas-water flow rate conditions and with the pressure at both ends of the physical model stable, and taking pictures to record the gas-water distribution and flow state within the crack. Specifically, keeping the gas-water two-phase ratio constant, injecting gas and water into the physical model under different total gas-water flow rate conditions, waiting for the pressure at both ends of the physical model to stabilize, taking pictures to record the gas-water distribution and flow state within the crack, and calculating the water saturation based on the pore volume, thereby obtaining the critical water saturation for gas-water flow within the crack of the physical model.

[0068] In one embodiment, calculating the critical water saturation for gas-water flow includes the following steps: recording the weight of the physical model under stable pressure at both ends, denoted as the third weight M3; calculating the water saturation of the physical model based on the third weight and the first weight; and recording the pressure difference between the two ends of the physical model under stable pressure, and calculating the critical water saturation for gas-water flow based on the water saturation. Specifically, by plotting the experimental data points of the pressure difference (displacement pressure) versus water saturation, the critical water saturation for gas-water flow within the crack of the physical model at the current crack width can be obtained, such as... Figure 6 .

[0069] In one embodiment, a method for visually evaluating the gas-water flow pattern within a horizontal well fracture includes the following steps: changing the fracture width and proppant type in the physical model, and repeating step S3, which can simulate the gas-water two-phase flow state within the fracture under different fracture widths and proppant performance conditions.

[0070] This invention can clarify the gas-water flow pattern within fracturing fractures, guide the design of fracturing and stimulation processes for water-bearing gas reservoirs, achieve efficient development of water-bearing gas reservoirs, and enable effective observation of the gas-water two-phase flow state within fractures.

[0071] Figure 2 A schematic diagram of a visualization and evaluation system for the flow patterns of gas and water within a fractured horizontal well, according to an embodiment of the present invention, is shown.

[0072] like Figure 2 The system shown is a visualization evaluation system for the flow law of gas and water in fractures of horizontal wells. It simulates the two-phase flow of gas and water in fractures and aims to determine the critical water saturation of gas and water flow in fractures and clarify the flow law of gas and water in fractures.

[0073] A visualization evaluation system for the flow pattern of gas and water within fractures in a horizontal well is composed of a liquid tank 1, a horizontal flow pump 2, a nitrogen cylinder 3, a flow controller 4, a gas buffer tank 5, a dyeing solution container 6, an oil tank 7, a six-way valve 8, a camera 9, a physical model 10, fracturing proppant 11, a light source 12, a gas-water separator 13, a gas meter 14, a one-way valve 15, a valve 16, a pressure gauge 17, and pipelines 18.

[0074] like Figure 2 As shown, liquid tank 1 is used to hold experimental water, which can be water, distilled water, or purified water. A horizontal flow pump 2 is connected to liquid tank 1. Oil tank 7 is connected to horizontal flow pump 2 and is used to hold experimental oil. Staining solution container 6 is connected to oil tank 7 and is used to prepare colored displacement solutions.

[0075] like Figure 2 As shown, nitrogen cylinder 3 is used to hold experimental nitrogen. A pressure gauge 17 is installed at the outlet of nitrogen cylinder 3. The other end of pressure gauge 17 is connected to valve 16. The other end of valve 16 is connected to flow controller 4. Flow controller 4 is used to control the flow rate of nitrogen output from nitrogen cylinder 3. The other end of flow controller 4 is connected to the inlet of gas buffer tank 5 through pipeline 18. The outlet of gas buffer tank 5 is connected to check valve 15 through valve.

[0076] like Figure 2 As shown, the physical model 10 is connected to the dye solution container 6 and the one-way valve 15 at the outlet of the gas buffer tank 5 via a six-way valve 8. A light source 12 and a camera 9 for taking pictures are located near the physical model 10. Fracturing proppant 11 was used when making the physical model 10.

[0077] like Figure 2 As shown, the outlet of the physical model 10 is connected to a gas-water separator 13, which is also connected to a gas meter 14.

[0078] Utilize Figure 2 The visualization and evaluation system for gas-water flow within fractures in a horizontal well fracturing operation, as shown, includes the following steps when simulating two-phase gas-water flow within the fracture:

[0079] (1) Calculate the required gas and water flow rates and gas-water ratio under the experimental conditions based on the actual fracture size, gas production rate and water production rate at the field scale after fracturing.

[0080] (2) Fill the liquid container 1 with experimental water, fill the oil container 7 with experimental oil, fill the staining solution container 6 with experimental water, and stain with methylene blue dye to prepare a colored displacement solution.

[0081] (3) Prepare an experimental physical model 10 based on the width of the hydraulic fracturing crack and the type of proppant during on-site construction.

[0082] (4) Place the experimental light source 12 on one side of the physical model 10 so that the light is facing the physical model 10. At the same time, place the camera 9 on the other side to record the air and water flow phenomenon in the physical model 10 in real time during the experiment.

[0083] (5) Weigh the physical model 10 filled with proppant 11 to obtain the experimental mold weight under dry conditions in the crack of the physical model 10, and record it as the first weight M1.

[0084] (6) Place the physical model 10 in the experimental procedure, keep the nitrogen cylinder 3 closed, start the horizontal flow pump 2, and completely displace the air in the physical model 10 by continuously pumping the methylene blue staining solution into the physical model 10.

[0085] (7) Remove the physical model 10 and weigh it again to obtain the weight of the experimental mold under the condition that the water saturation in the crack of the physical model 10 is 100%, which is recorded as the second weight M2. The pore volume in the crack of the physical model 10 under the condition of being filled with proppant can be calculated based on the difference between M1 and M2.

[0086] (8) Place the physical model 10 back into the experimental process, start the horizontal flow pump 2, and pump water according to the designed liquid flow rate. After the water flow rate stabilizes, open the nitrogen cylinder 3 and set the gas flow rate through the gas flow controller 4, while pumping gas and liquid into the physical model 10.

[0087] (9) Camera 9 records the gas-water flow process in physical model 10. When the gas flow rate at the outlet end and the inlet end of physical model 10 are equal, it indicates that the gas-water state in the crack is stable (the pressure at both ends of the physical model is stable). At this time, the gas-water distribution state, gas-water flow rate, and inlet end pressure P in physical model 10 are recorded, and the displacement pressure difference at both ends of physical model 10 can be obtained.

[0088] (10) Remove the physical model 10 and weigh it to obtain the weight of the physical model 10 at this time, which is recorded as the third weight M3. Combined with M1, the water content in the physical model 10 can be calculated, and the water saturation in the crack of the physical model 10 can be calculated based on the pore volume.

[0089] (11) By keeping the gas-water two-phase ratio constant and changing the total gas-water flow velocity, the water saturation within the fracture under different displacement pressure differentials can be obtained. By plotting the experimental data points of the pressure difference (displacement pressure) versus water saturation, the critical water saturation for gas-water flow within the fracture at the current fracture width can be obtained, such as... Figures 4-6 As shown.

[0090] (12) By changing the gas-water two-phase ratio at the inlet of physical model 10, the gas-water flow pattern within the filled fracture at different scales can be simulated under different gas-water production conditions, such as... Figures 7-10 As shown.

[0091] The present invention provides a visualization evaluation system for the gas-water flow pattern in horizontal well fracturing fractures, which can simulate the gas-water two-phase flow in fractures under different gas-water flow velocities, gas-water ratios, fracture widths, proppant properties, etc., and can visualize the gas-water flow process in fractures during the experiment.

[0092] The present invention provides a method and apparatus for visually evaluating the gas-water flow patterns within fractured fractures in horizontal wells. This method and apparatus can also be used in conjunction with a computer-readable storage medium. The storage medium stores a computer program, which is executed to run the method for visually evaluating the gas-water flow patterns within fractured fractures in horizontal wells. The computer program is capable of executing computer instructions, which include computer program code. The computer program code can be in the form of source code, object code, executable files, or some intermediate form.

[0093] Computer-readable storage media may include: any entity or device capable of carrying computer program code, recording media, USB flash drives, portable hard drives, magnetic disks, optical disks, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signals, telecommunication signals, and software distribution media, etc.

[0094] It should be noted that the contents of computer-readable storage media may be appropriately added to or subtracted from the contents according to the requirements of legislation and patent practice in a jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, computer-readable storage media may not include electrical carrier signals and telecommunication signals.

[0095] The present invention also provides a visualization evaluation device for the gas-water flow pattern in fractured horizontal wells, which implements a visualization evaluation method for the gas-water flow pattern in fractured horizontal wells, comprising: a preparation module, a displacement module, and an experimental module.

[0096] Specifically, the preparation module is used to prepare the physical model for the experiment, weigh and record the first weight of the physical model under dry conditions, and the physical model is used to simulate the fracturing fractures in a horizontal well; the displacement module is used to pump a colored displacement solution into the physical model to completely displace the air in the physical model, and at this time, the second weight of the physical model is weighed and recorded; the experimental module is used to inject gas and water into the physical model under different experimental conditions, record the distribution and flow state of gas and water in the physical model, and calculate the critical water saturation of gas and water flow.

[0097] In summary, this invention provides a method and apparatus for visually evaluating the gas-water flow patterns within fractures in horizontal well fracturing. This method can simulate the flow and distribution of the gas and water phases within fractures under various conditions, including fracture width, proppant size, proppant wetting properties, gas-water flow velocity, and gas-water ratio. The experiment allows for visual observation of the gas-water flow process within the fracture. By accurately observing the gas-water flow state within the fracture and recording the gas-water ratio, the influence of fracture morphology and displacement pressure on the gas-water flow within the fracture can be clarified, providing a theoretical basis for fracture morphology design and production system optimization in fracturing.

[0098] It should be understood that the embodiments disclosed herein are not limited to the specific structures, processing steps, or materials disclosed herein, but should be extended to equivalent substitutions of these features as understood by those skilled in the art. It should also be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting.

[0099] In the description of this invention, unless otherwise stated, "a plurality of" means two or more; the terms "upper," "lower," "left," "right," "inner," "outer," "front end," "rear end," "head," "tail," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0100] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0101] The phrase "an embodiment" or "an embodiment" used in this specification means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. Therefore, the phrase "an embodiment" or "an embodiment" appearing in various places throughout the specification does not necessarily refer to the same embodiment.

[0102] The embodiments of the present invention are given for illustrative and descriptive purposes only, and are not intended to be exhaustive or to limit the invention to the forms disclosed. Many modifications and variations will be apparent to those skilled in the art. The embodiments were chosen and described in order to better illustrate the principles and practical application of the invention, and to enable those skilled in the art to understand the invention and to design various embodiments with various modifications suitable for a particular purpose.

[0103] While the embodiments disclosed in this invention are as described above, the content is merely for the purpose of facilitating understanding of the invention and is not intended to limit the invention. Any person skilled in the art to which this invention pertains may make any modifications and variations in form and detail of the implementation without departing from the spirit and scope disclosed herein; however, the scope of patent protection for this invention shall still be determined by the scope defined in the appended claims.

Claims

1. A method for visualizing and evaluating gas-water flow law in a horizontal well fracture, characterized in that, The method comprises the following steps: S1, preparing a physical model for experiment, weighing and recording a first weight of the physical model under dry conditions, the physical model being used to simulate a fracturing fracture of a horizontal well; S2, pumping a colored displacement solution into the physical model to completely displace air in the physical model, at this time, weighing and recording a second weight of the physical model; S3, under different experimental conditions, injecting gas and water into the physical model, recording the distribution and flow state of gas and water in the physical model, and calculating a gas-water flow critical water saturation; Step S3 comprises: keeping the total gas-water flow rate unchanged, changing the gas-water two-phase ratio, injecting gas and water into the physical model; recording the pressure difference between the two ends of the physical model and the gas-water flow rate under the stable state of the pressure difference between the two ends of the physical model and the gas-water distribution and flow state in the fracture under different gas-water two-phase ratio conditions, and taking a photo; Step S3 comprises: keeping the gas-water two-phase ratio unchanged, changing the total gas-water flow rate, injecting gas and water into the physical model; recording the pressure difference between the two ends of the physical model and the gas-water flow rate under the stable state of the pressure difference between the two ends of the physical model under different total gas-water flow rate conditions, and taking a photo to record the gas-water distribution and flow state in the fracture; The method comprises the following steps: recording the weight of the physical model under the stable state of the pressure difference between the two ends of the physical model, denoted as a third weight; based on the third weight, the first weight is combined to calculate the water saturation of the physical model; The pressure difference between the two ends of the physical model under the stable state of the pressure difference between the two ends of the physical model is recorded, and the gas-water flow critical water saturation is calculated combined with the water saturation, wherein a curve graph of the pressure difference between the two ends and the water saturation is drawn to obtain the gas-water flow critical water saturation.

2. The method for visualizing and evaluating gas-water flow law in the fracture of horizontal well according to claim 1, characterized in that, Step S1 of preparing a physical model for experiment comprises: Take two transparent experimental plates; According to the size requirements of the simulated fracturing fracture, adjust the two transparent experimental plates to the required fracture width, and then fill them with proppants; Seal the four sides of the two transparent experimental plates, and only leave the liquid inlet channels on both sides of the two transparent experimental plates.

3. The method of visualizing and evaluating gas-water flow law in hydraulic fractures of horizontal wells according to claim 1, characterized in that, Step S2 comprises: dyeing water with methyl blue dye to prepare the colored displacement solution.

4. The method of visualizing and evaluating gas-water flow law in hydraulic fractures of horizontal wells according to claim 1, characterized in that, The method comprises the following steps: based on the first weight and the second weight, the pore volume of the physical model is calculated.

5. A storage medium, characterized by It comprises instructions for executing the horizontal well fracturing fracture gas-water flow rule visualization evaluation method as claimed in any one of claims 1-4.

6. A device for visualizing and evaluating gas-water flow law in a horizontal well fracturing fracture, characterized in that, The device comprises: a preparation module for preparing a physical model for experiment, weighing and recording a first weight of the physical model under dry conditions, the physical model being used to simulate a fracturing fracture of a horizontal well; a displacement module for pumping a colored displacement solution into the physical model to completely displace air in the physical model, at this time, weighing and recording a second weight of the physical model; An experimental module is used to inject gas and water into the physical model under different experimental conditions, record the distribution and flow state of gas and water in the physical model, and calculate the critical water saturation of gas and water flow.

7. A system for visualizing and evaluating gas-water flow rules in a horizontal well fracture, characterized in that, The system comprises: A liquid tank is used to store experimental water. A horizontal pump is connected to the liquid tank. An oil tank is connected to the horizontal pump and used to store experimental oil. A dye solution container is connected to the oil tank and used to prepare colored displacement solution. A nitrogen cylinder is used to store experimental nitrogen. A gas buffer tank is connected to the nitrogen cylinder. A physical model is connected to the dye solution container and the gas buffer tank. A gas-water separator is connected to the physical model. A gas meter is connected to the gas-water separator.

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