Wellbore non-homogeneous formation fluid migration visualization simulation and characterization device and method

Abstract

The application discloses a device and method for visualizing simulation and characterization of fluid migration in wellbore heterogeneous formation. The device comprises a wellbore simulation unit for simulating wellbore structure and lateral pumping channel; a heterogeneous formation simulation unit for simulating wellbore heterogeneous formation structure; a boundary sealing unit for limiting tracer fluid from entering the heterogeneous formation simulation unit from upper and lower boundaries; a peripheral fluid supply unit for providing tracer fluid to the heterogeneous formation simulation unit and maintaining the liquid level of the tracer fluid within a preset height range; an observation recording unit for recording the migration state of the tracer fluid and corresponding time information during the extraction process of the tracer fluid; a profile acquisition and characterization unit for acquiring the distribution pattern of the tracer fluid in the heterogeneous formation simulation unit and quantitatively characterizing the distribution pattern. The application can realize dynamic visual observation, stratified profile reconstruction and quantitative characterization of the fluid migration process in the wellbore heterogeneous formation.

Description

Technical Field

[0001] This invention relates to the field of formation fluid migration simulation and experimental characterization technology, and in particular to a device and method for visual simulation and characterization of fluid migration in heterogeneous formations around wells. Background Technology

[0002] The fluid migration processes and dynamic characteristics within the surrounding formations are of great significance for oil and gas development, hydrogeology, and the study of underground fluid migration. Under conditions such as wellbore suction, injection-production disturbances, or pressure changes, formation fluids are influenced by factors such as pressure gradients, formation heterogeneity, layered structure, and local flow boundaries, often resulting in complex migration paths and non-uniform dynamic patterns. Significant differences exist in fluid responses between different regions, different stratigraphic levels, and different orientations within the wellbore.

[0003] Currently, research on wellbore fluid transport mainly employs numerical simulation, theoretical analysis, and laboratory experiments. Numerical simulation can calculate and analyze fluid transport processes, but its results typically depend on formation parameters, boundary conditions, and model assumptions, making it difficult to intuitively reflect the true spatial distribution and dynamic evolution of fluids under complex heterogeneous conditions. Theoretical analysis methods are mostly based on idealized models, which are suitable for deriving laws under simplified conditions, but cannot accurately describe the complex flow behavior in actual wellbore formations. Existing laboratory experimental methods mostly use homogeneous media or simplified filling models, making it difficult to effectively simulate radial, longitudinal, and composite heterogeneous layered structures around the wellbore, and also difficult to simultaneously reflect the lateral flow characteristics of the wellbore and the continuous replenishment conditions of the surrounding fluid.

[0004] Furthermore, existing experimental studies primarily focus on overall flow rate and pressure changes or macroscopic seepage patterns. They lack intuitive, continuous, and quantifiable experimental observation and characterization methods for the fluid's movement range, spatial distribution, dynamic expansion process, and potential asymmetric flow phenomena in the areas in front of, behind, and around the wellbore's lateral connections. Simultaneously, existing methods struggle to correlate visualized fluid distribution results with changes in geometric parameters, movement boundaries, resistivity, and other electrical parameters. They also fail to reconstruct fluid distribution profiles and dynamic evolution patterns based on results from different strata or at different time points, thus limiting the understanding and experimental evaluation of complex wellbore fluid migration mechanisms.

[0005] Therefore, there is an urgent need for a visualization simulation and characterization device and method for fluid transport in heterogeneous formations around wells, which can be used to simulate the fluid transport process in heterogeneous formations around wells and realize the visualization observation of fluid transport dynamics, reconstruction of layered profiles, reconstruction of dynamic evolution morphology and quantitative characterization. Summary of the Invention

[0006] To address the shortcomings of existing wellbore fluid transport experimental methods in simulating heterogeneous stratified structures, controlling lateral flow boundaries in the wellbore, characterizing continuous external fluid supply conditions, visualizing fluid transport dynamics, and quantitatively characterizing fluid mobility range, spatial distribution, dynamic evolution process, and electrical response characteristics, this invention provides a device and method for visualizing and simulating fluid transport in heterogeneous strata around wells.

[0007] The technical solution adopted by this invention to overcome its technical problems is: This invention discloses a visualization simulation and characterization device for fluid transport in heterogeneous formations around wells, comprising: A wellbore simulation unit is used to simulate the wellbore structure and the wellbore lateral suction channel. The wellbore simulation unit includes a vertically arranged hollow tube body. The lower end of the hollow tube body is sealed, and at least one fluid communication port or tap simulation structure is provided on the side wall. The heterogeneous strata simulation unit is located around the wellbore simulation unit and includes at least two media layers with different seepage characteristics. The media layers are distributed in a radial, longitudinal, or combined radial and longitudinal manner to simulate the heterogeneous strata structure around the well. Boundary sealing units are disposed above and below the heterogeneous stratum simulation unit to restrict the tracer fluid from entering the heterogeneous stratum simulation unit from the upper and lower boundaries, so that the fluid moves from the outside of the heterogeneous stratum simulation unit toward the wellbore simulation unit. An external fluid supply unit is located around the heterogeneous layer simulation unit and is used to provide tracer fluid to the heterogeneous layer simulation unit and maintain the liquid level of the tracer fluid within a preset height range. The suction control unit is connected to the wellbore simulation unit and is used to extract tracer fluid from the wellbore simulation unit, adjust the tracer fluid extraction speed, and measure the volume of tracer fluid extracted. The observation and recording unit is used to record the migration status of the tracer fluid and the corresponding time information during the tracer fluid extraction process. The profile acquisition and characterization unit is used to acquire the distribution pattern of the tracer fluid in the heterogeneous stratum simulation unit after the experiment, and to quantitatively characterize the distribution pattern.

[0008] Furthermore, the heterogeneous layer simulation unit is a radially layered structure, a longitudinally layered structure, or a combination of radially and longitudinally layered structures; The radial layered structure includes multiple annular media layers arranged sequentially around the wellbore simulation unit, with each annular media layer distributed in a concentric ring shape in the top view direction; The vertical layered structure includes multiple dielectric layers stacked sequentially along the vertical direction; The combined structure of radial and longitudinal layering includes both the radial layering structure and the longitudinal layering structure.

[0009] Furthermore, the components of the heterogeneous strata simulation unit include sponge, quartz sand, sand and gravel particles, clay, sand-clay mixture, soil sample, artificially proportioned strata materials or combinations thereof, and each medium layer has different pore structure, permeability, fluid retention capacity or electrical parameters.

[0010] Furthermore, a separation structure is provided between adjacent dielectric layers of the heterogeneous layer simulation unit.

[0011] Furthermore, when the heterogeneous stratum simulation unit uses sponge material, the partition structure is non-woven fabric; when the heterogeneous stratum simulation unit uses quartz sand, gravel particles, clay, sand-clay mixture, soil sample, or artificially proportioned stratum material, the partition structure is a porous partition.

[0012] Furthermore, the boundary sealing unit includes a sealing cover disposed above the heterogeneous layer simulation unit and a sealing base disposed below the heterogeneous layer simulation unit.

[0013] Furthermore, the peripheral fluid supply unit includes a liquid supply chamber disposed outside the heterogeneous layer simulation unit, a replenishment container connected to the liquid supply chamber, and a liquid level control structure.

[0014] Furthermore, the suction control unit includes a suction pump, a flow regulator, and a fluid collection container, wherein the fluid collection container is used to measure the volume of the extracted tracer fluid corresponding to different extraction times.

[0015] Furthermore, the observation and recording unit includes at least a camera device for continuously recording the experimental process.

[0016] Furthermore, the profile acquisition and characterization unit includes an image acquisition device, a scale, a gridded recording template, an image processing module, and a fluid distribution reconstruction module, used to acquire the length, width, area, center position, boundary morphology, and distribution range of the tracer fluid in each medium layer, and to reconstruct the tracer fluid distribution morphology corresponding to different medium layer profiles.

[0017] As a preferred embodiment, the system further includes an electrical parameter measurement unit, which includes electrodes, probes, a resistivity measurement module, or other electrical parameter measurement modules, for measuring the resistivity changes or other electrical parameter changes in the tracer fluid distribution region or its central region in the heterogeneous stratum simulation unit.

[0018] This invention also discloses a method for visualizing, simulating, and characterizing fluid transport in heterogeneous formations around wells, using the aforementioned apparatus and comprising the following steps: S1. Construct a vertically arranged wellbore simulation unit with a sealed lower end, and set a fluid communication port or tap simulation structure on the side wall of the wellbore simulation unit; S2. Construct a heterogeneous strata simulation unit around the wellbore simulation unit. The heterogeneous strata simulation unit includes at least two media layers with different seepage characteristics. The media layers are distributed in a radial, longitudinal, or combined radial and longitudinal manner. S3. Construct a boundary sealing unit to seal the top and bottom of the heterogeneous layer simulation unit; S4. Construct an external fluid supply unit around the heterogeneous layer simulation unit, add tracer fluid to the outside of the heterogeneous layer simulation unit, and maintain the liquid level of the tracer fluid within a preset height range. S5. The tracer fluid is extracted from the wellbore simulation unit at a preset extraction speed by the suction control unit, and the extraction time and the volume of the extracted tracer fluid are recorded. S6. During the extraction of tracer fluid, the tracer fluid transport process and corresponding time information are continuously recorded by the observation and recording unit. S7. After the tracer fluid extraction is completed, the heterogeneous layer simulation unit is unfolded, dissected or sampled layer by layer to obtain the spatial distribution pattern of the tracer fluid in each medium layer. S8. Extract and quantitatively characterize the spatial distribution morphology of the tracer fluid using geometric parameters to obtain the tracer fluid's operational range, distribution boundary, morphological characteristics, and the differences in tracer fluid response between different media layers.

[0019] Further, in step S8, the spatial distribution pattern of the tracer fluid is processed by meshing, pixelation or image segmentation to identify the tracer fluid distribution area and tracer fluid distribution boundary, and the length, width, area, center position, boundary shape and distribution range of the tracer fluid distribution area are obtained. The two-dimensional or three-dimensional tracer fluid distribution profile is reconstructed based on the characterization results of different medium layer profiles.

[0020] Furthermore, in step S8, under the same conditions of layered structure, medium type, tracer fluid type, peripheral fluid supply conditions, fluid connection shape, and extraction speed, different extraction times are set and the tracer fluid extraction, profile acquisition, and quantitative characterization steps are repeatedly executed to obtain fluid distribution reconstruction results corresponding to multiple extraction time nodes. Based on the fluid distribution reconstruction results corresponding to multiple time nodes, the dynamic evolution of fluid migration in heterogeneous formations around the well is analyzed.

[0021] As a preferred embodiment, after step S8, the method further includes: measuring the resistivity change or other electrical parameter changes in the tracer fluid distribution area or its central area in the heterogeneous layer simulation unit, and performing corresponding analysis on the resistivity change or other electrical parameter changes in relation to the tracer fluid distribution range, extraction time, extraction speed, and layer structure parameters.

[0022] As a preferred option, after step S8, the method further includes: conducting controlled variable experiments by changing the layered structure, medium type, extraction speed, extraction time, tracer fluid type, peripheral fluid supply conditions, or fluid communication port shape, in order to analyze the fluid migration law of the heterogeneous formation around the well under different conditions.

[0023] Compared with the prior art, the present invention has at least the following beneficial effects: 1) By setting fluid communication ports or tap simulation structures on the sidewall of the wellbore simulation unit, this invention can simulate the process of fluid moving from a heterogeneous stratum to the wellbore under lateral suction conditions, which is more in line with the local flow characteristics around the well.

[0024] 2) By setting up heterogeneous strata simulation units and distributing the medium layer in a radial, longitudinal, or combined radial and longitudinal manner, this invention can simulate the radial heterogeneity, longitudinal heterogeneity, and composite heterogeneity of the strata around the well, thereby improving the simulation capability of the indoor experimental model for complex strata structures.

[0025] 3) By setting a sealing cover and a sealing base, the present invention restricts the tracer fluid from entering the heterogeneous stratum simulation unit from the top and bottom directions, and makes the fluid move from the outside of the heterogeneous stratum simulation unit towards the wellbore simulation unit, which is conducive to forming a controlled lateral flow boundary and improving the controllability and repeatability of the test process.

[0026] 4) The present invention maintains the liquid level of the tracer fluid within a preset height range through the peripheral fluid supply unit, which can simulate the continuous replenishment conditions of the peripheral fluid and is beneficial to reflecting the replenishment and migration process of the fluid around the well.

[0027] 5) This invention extracts tracer fluid through a suction control unit, adjusts the extraction speed, and measures the volume of extracted tracer fluid, thereby establishing a correspondence between extraction speed, extraction time, volume of extracted tracer fluid, and the range of tracer fluid application.

[0028] 6) This invention continuously records the tracer fluid transport state and corresponding time information during the experiment through the observation and recording unit, which enables dynamic and visual observation of the tracer fluid transport process.

[0029] 7) By unfolding, dissecting or sampling layer by layer after the experiment, this invention can obtain the spatial distribution pattern of tracer fluid in different media layers, thereby realizing the reconstruction of the layered profile of the tracer fluid's range of movement, distribution boundary and irregular shape.

[0030] 8) This invention uses gridding, pixelation or image segmentation to quantitatively characterize the distribution morphology of tracer fluids, and can obtain length, width, area, center position, boundary morphology and distribution range, thereby improving the quantitative analysis capability of tracer fluid transport experimental results.

[0031] 9) By setting different extraction times under the same experimental conditions and repeatedly carrying out profile acquisition and quantitative characterization experiments, this invention can obtain the tracer fluid distribution reconstruction results corresponding to multiple extraction time nodes, thereby reflecting the process of the tracer fluid's mobilization range and spatial distribution changing with extraction time.

[0032] 10) This invention obtains the resistivity change or other electrical parameter change of the tracer fluid distribution area or its central area through an electrical parameter measurement unit, which enables joint analysis between the tracer fluid visualization distribution results and electrical response parameters.

[0033] 11) This invention can conduct controlled variable experiments by changing the layered structure, medium type, extraction speed, extraction time, tracer fluid type, peripheral fluid supply conditions or fluid communication port shape, providing an experimental basis for studying the fluid migration law of heterogeneous formations around the well under different conditions. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the overall structure of the wellbore heterogeneous formation fluid transport visualization simulation and characterization device described in an embodiment of the present invention.

[0035] Figure 2 This is a top view schematic diagram of the heterogeneous layer simulation unit with a radially layered structure according to an embodiment of the present invention.

[0036] Figure 3 This is a cross-sectional schematic diagram of the heterogeneous layer simulation unit described in this embodiment of the invention, which has a longitudinally layered structure.

[0037] Figure 4 This is a schematic diagram of the partition structure and dielectric layer arrangement in the heterogeneous layer simulation unit according to an embodiment of the present invention.

[0038] Figure 5 This is a schematic diagram illustrating the post-experiment layered profile acquisition, gridded characterization, and fluid distribution reconstruction as described in an embodiment of the present invention.

[0039] Figure 6 This is a side view schematic diagram showing the restored boundary shape and distribution range of the pump extraction section according to an embodiment of the present invention.

[0040] Figure 7 This is a three-dimensional reconstruction diagram of the boundary shape and distribution range of the pump extraction section as described in an embodiment of the present invention.

[0041] In the figure: 1 is the wellbore simulation unit, 11 is the hollow tube, 12 is the fluid communication port, 13 is the lower sealing structure, 2 is the heterogeneous stratum simulation unit, 21 is the medium layer, 211 is the first radial medium layer, 212 is the second radial medium layer, 213 is the third radial medium layer, 221 is the first longitudinal medium layer, 222 is the second longitudinal medium layer, 223 is the third longitudinal medium layer, 31 is the sealing cap, 32 is the sealing base, 4 is the peripheral fluid supply unit, 41 is the liquid supply chamber, 42 is the liquid replenishment container, 43 is the overflow port, 44 is the liquid level gauge, 51 is the suction pump, 52 is the flow regulator, 53 is the fluid collection container, 6 is the observation and recording unit, 71 is the transverse porous baffle, 72 is the vertical porous baffle, 73 is the through hole, 81 is the tracer fluid distribution area, 82 is the tracer fluid distribution boundary, 83 is the gridded recording template, and 84 is the fluid distribution reconstruction result. Detailed Implementation

[0042] To better understand the above technical solutions, exemplary embodiments of the present invention will be described in detail below with reference to the accompanying drawings. These are merely exemplary embodiments of the present invention; however, it should be understood that the present invention can be implemented in various forms and is not limited to the embodiments described herein. These embodiments are provided to enable those skilled in the art to understand the present invention more clearly and thoroughly.

[0043] Example 1

[0044] This invention provides a visualization simulation and characterization device for fluid transport in heterogeneous formations around wells, the overall structure of which is as follows: Figure 1 As shown, it includes a wellbore simulation unit 1, a heterogeneous strata simulation unit 2, a boundary sealing unit, an external fluid supply unit 4, a suction control unit, an observation and recording unit 6, and a profile acquisition and characterization unit.

[0045] In this embodiment, the wellbore simulation unit 1 is used to simulate the wellbore structure and the wellbore lateral suction channel. Specifically, the wellbore simulation unit 1 includes a vertically arranged hollow tube 11, the lower end of which is sealed, specifically by a lower end sealing structure 13; at least one fluid communication port 12 or tap simulation structure is provided on the side wall of the hollow tube 11. The fluid communication port 12 is used to simulate the wellbore lateral suction channel, allowing fluid in the heterogeneous stratum simulation unit 2 to enter the hollow tube 11 through the fluid communication port 12 under suction. Alternatively, a tap simulation structure can be installed on the side wall of the hollow tube 11 to simulate different wellbore lateral communication conditions.

[0046] In one optional embodiment, the hollow tube is made of UPVC, PVC, acrylic, glass, or other corrosion-resistant materials, wherein the UPVC, PVC, acrylic, or glass tubes are transparent or semi-transparent. Using transparent or semi-transparent tubes facilitates observation of the fluid state inside the wellbore simulation unit; using opaque, corrosion-resistant tubes does not affect the device's ability to simulate wellbore fluid transport and perform quantitative profile characterization.

[0047] In this embodiment, the fluid communication port 12 is a circular hole, an elliptical hole, a rectangular hole, a slit-shaped hole, or other non-circular opening. In an optional embodiment, the fluid communication port 12 is located on the side wall of the hollow tube 11 near the lower part, for example, in the shape of a circular hole with a diameter of about 1 cm, used to simulate a local suction port on the side wall of the wellbore. The specific size of the fluid communication port 12 should also be determined according to the overall proportion of the visualization simulation and characterization device for fluid migration in heterogeneous formations around the well, and is not limited to the shape and size described above.

[0048] In this embodiment, the heterogeneous formation simulation unit 2 is disposed around the wellbore simulation unit 1 to simulate the heterogeneous formation structure around the well. Specifically, it simulates heterogeneous formation structures with different pore structures, permeability, fluid retention capacity, or electrical parameters. The heterogeneous formation simulation unit 2 includes at least two media layers 21 with different seepage characteristics, thereby simulating the heterogeneous differences between different layers, different radial regions, or different physical property regions in actual formations.

[0049] To more realistically simulate heterogeneous layer structures, this embodiment distributes the dielectric layer 21 in three ways: radial, longitudinal, or a combination of radial and longitudinal directions.

[0050] In one optional embodiment, the heterogeneous strata simulation unit 2 is constructed as a radially layered structure. The radially layered structure includes multiple annular media layers arranged sequentially around the wellbore simulation unit 1, with each annular media layer distributed concentrically in a top-view orientation. For example, as... Figure 2 As shown, the medium layer 21 of the heterogeneous formation simulation unit 2 includes, from the inside out, a first radial medium layer 211, a second radial medium layer 212, and a third radial medium layer 213. The first radial medium layer 211, the second radial medium layer 212, and the third radial medium layer 213 are concentrically ring-shaped in the top view. By setting radial medium layers with different seepage characteristics, the heterogeneous changes of the formation around the well along the radial direction can be simulated.

[0051] In another alternative embodiment, the heterogeneous layer simulation unit 2 is constructed as a vertically layered structure. The vertically layered structure includes multiple dielectric layers stacked sequentially along the vertical direction. For example, as... Figure 3As shown, the medium layer 21 of the heterogeneous formation simulation unit 2 includes, from top to bottom, a first longitudinal medium layer 221, a second longitudinal medium layer 222, and a third longitudinal medium layer 223. By setting longitudinal medium layers with different seepage characteristics, the heterogeneous changes of the formation around the well along the vertical direction can be simulated.

[0052] In a further optional embodiment, the heterogeneous strata simulation unit 2 is constructed as a combination of radial and vertical layering. This combination includes both radial and vertical layering, meaning the medium layer 21 is distributed radially and stacked vertically, forming a composite heterogeneous strata model combining radial and vertical heterogeneity. This structure more closely approximates the actual situation where seepage capacity varies significantly across different orientations, layers, and distances in complex well-perimeter formations.

[0053] In this embodiment, the heterogeneous stratum simulation unit 2 can be composed of sponge, quartz sand, gravel particles, clay, sand-clay mixture, soil sample, artificially proportioned stratum materials, or combinations thereof. Each medium layer has different pore structures, permeability, fluid retention capacity, or electrical parameters. In one optional embodiment, the heterogeneous stratum simulation unit 2 is constructed using sponge materials with different pore structures or different liquid absorption capacities, so that the tracer fluid distribution can be directly observed layer by layer after the experiment. In another embodiment, the heterogeneous stratum simulation unit 2 is made of white quartz sand, clay, and other artificially proportioned stratum materials to form a seepage environment similar to the pore media of the stratum. Different medium layers 21 can have different permeability and fluid retention capacities by changing the quartz sand particle size, clay content, compaction degree, or proportioning method.

[0054] In this embodiment, a separation structure is provided between adjacent dielectric layers of the heterogeneous layer simulation unit.

[0055] In one optional embodiment, when the heterogeneous layer simulation unit 2 uses sponge material, the separation structure between adjacent medium layers 21 can be made of non-woven fabric, preferably high-density non-woven fabric, to isolate adjacent sponge layers and regulate the fluid exchange capacity between medium layers.

[0056] In another optional embodiment, when the heterogeneous stratum simulation unit 2 uses quartz sand, gravel particles, clay, sand-clay mixture, soil sample, or artificially proportioned stratum materials, the separation structure between adjacent media layers 21 can be a porous partition. The porous partition serves as a support and connectivity control structure, maintaining the stability of the layered structure while avoiding complete blockage of fluid communication. Specifically, when the heterogeneous stratum simulation unit has a radially layered structure, a vertical porous partition 72 is provided between adjacent media layers 21; when the heterogeneous stratum simulation unit has a longitudinally layered structure, a transverse porous partition 71 is provided between adjacent media layers 21; when the heterogeneous stratum simulation unit has a combined radial and longitudinally layered structure, both a transverse porous partition 71 and a vertical porous partition 72 are provided between adjacent media layers 21. Figure 4 As shown, Figure 4 The left sub-figure shows the arrangement structure of the medium layers separated by vertical porous baffles. That is, vertical porous baffles 72 are provided between adjacent medium layers 21 to maintain the relative positions of different medium layers 21 in the lateral or radial direction and to regulate the fluid communication between adjacent medium layers. Figure 4 The right-hand sub-figure shows the arrangement of the media layers separated by horizontal porous baffles, that is, a horizontal porous baffle 71 is provided between adjacent media layers 21. The porous baffles are provided with multiple through holes 73, that is, multiple through holes 73 are provided on both the horizontal porous baffle 71 and the vertical porous baffle 72. The through holes 73 are used to allow controlled communication between adjacent media layers while maintaining the layering stability of adjacent media layers 21.

[0057] In this embodiment, the boundary sealing unit is disposed above and below the heterogeneous stratum simulation unit 2. Specifically, the boundary sealing unit includes a sealing cap 31 disposed above the heterogeneous stratum simulation unit 2 and a sealing base 32 disposed below the heterogeneous stratum simulation unit 2. The sealing cap 31 and the sealing base 32 are used to restrict the tracer fluid from entering the heterogeneous stratum simulation unit 2 from the upper and lower boundaries, allowing the fluid to move from the outside of the heterogeneous stratum simulation unit 2 towards the wellbore simulation unit 1. The sealing cap 31 and the sealing base 32 can cooperate with the heterogeneous stratum simulation unit 2 to form a seal through sealant, sealing ring, clamping member, or clamping structure.

[0058] In a preferred embodiment, the sealing cover 31 further includes a pressure structure or an upper weighting component above it, for applying a predetermined pressure to the heterogeneous formation simulation unit 2, the peripheral tracer fluid, or both, to simulate the pressurized formation environment or seepage conditions under different compaction states.

[0059] In this embodiment, the peripheral fluid supply unit 4 is disposed around the heterogeneous layer simulation unit 2, and is used to provide tracer fluid to the heterogeneous layer simulation unit 2 and maintain the liquid level of the tracer fluid within a preset height range. The peripheral fluid supply unit 4 includes a supply chamber 41 disposed outside the heterogeneous layer simulation unit, a replenishment container 42 connected to the supply chamber, and a liquid level control structure for maintaining the liquid level of the tracer fluid within the preset height range. Specifically, the supply chamber 41 is used to contain the tracer fluid located around the heterogeneous layer simulation unit 2. The replenishment container 42 is used to replenish the tracer fluid to the supply chamber 41. The liquid level control structure can be an overflow port 43 or a liquid level gauge 44. Specifically, if the liquid level control structure uses an overflow port 43, the overflow port 43 is used to limit the liquid level from being too high. When the liquid level exceeds the position of the overflow port, the tracer fluid flows out through the overflow port. If the liquid level control structure uses a liquid level gauge 44, the liquid level gauge 44 is used to observe and record the liquid level of the tracer fluid during the experiment. When the liquid level reaches a preset height range, an alert can be issued. Through the cooperation of the replenishment container 42 and the liquid level control structure, the liquid level of the external tracer fluid can be kept basically constant during the experiment, thereby forming a stable external replenishment condition.

[0060] In this embodiment, the tracer fluid can be one or more combinations of fluids with identifiable differences in color, electrical properties, density, or other physical properties. Specifically, the tracer fluid can be selected from one or more combinations of color-labeled brine, dyed water, simulated oil, and crude oil. In one specific embodiment, the tracer fluid is color-labeled brine or dyed water, allowing its distribution pattern in quartz sand, clay mixtures, or sponge materials to be directly observed and image-identified after the experiment. When electrical response analysis is required, brine with resistivity differences or other fluids with identifiable electrical parameters can be used. The choice of tracer fluid depends on the specific circumstances.

[0061] In this embodiment, the suction control unit is connected to the wellbore simulation unit 1 and is used to extract tracer fluid from the wellbore simulation unit 1, adjust the tracer fluid extraction speed, and measure the volume of extracted tracer fluid. Specifically, the suction control unit includes a suction pump 51, a flow regulator 52, and a fluid collection container 53. The suction pump 51 can be an adjustable-speed suction pump, a peristaltic pump, a vacuum suction device, or other device capable of generating stable suction. The flow regulator 52 is used to adjust the tracer fluid extraction speed. The fluid collection container 53 is used to collect and measure the volume of extracted fluid corresponding to different extraction times. The suction control unit is connected to the wellbore simulation unit 1 via a pipeline. Preferably, one end of the pipeline is connected to the top of the wellbore simulation unit 1, and the other end of the pipeline is connected to the fluid collection container 53. The suction pump 51 and the flow regulator 52 are installed on the pipeline. The suction control unit can establish a correspondence between the extraction speed, extraction time, volume of extracted tracer fluid, and the range of tracer fluid movement.

[0062] In this embodiment, the observation and recording unit 6 is used to record the tracer fluid migration state and corresponding time information during the tracer fluid extraction process. The observation and recording unit 6 includes at least a camera device for continuously recording the experimental process. Preferably, the observation and recording unit 6 further includes a time display device for displaying the extraction time information during recording. In one embodiment, the camera device can be arranged outside the wellbore heterogeneous formation fluid migration visualization simulation and characterization device to continuously record tracer fluid level changes, the extraction process, and the fluid migration state within the visible area; alternatively, it can be combined with a stopwatch, electronic time display, or data recording system to synchronously record the extraction time.

[0063] In this embodiment, the profile acquisition and characterization unit is used to acquire the distribution pattern of the tracer fluid in the heterogeneous layer simulation unit after the experiment, and to quantitatively characterize the distribution pattern. Specifically, the profile acquisition and characterization unit includes an image acquisition device, a scale, a gridded recording template 83, an image processing module, and a fluid distribution reconstruction module. It is used to acquire the length, width, area, center position, boundary morphology, and distribution range of the tracer fluid in each medium layer, and to reconstruct the tracer fluid distribution pattern corresponding to different medium layer profiles. The image processing module and the fluid distribution reconstruction module are software modules. After the experiment, the medium layers of the heterogeneous layer simulation unit 2 can be unfolded, dissected, or sampled layer by layer, and the tracer fluid distribution images in each medium layer can be acquired by taking pictures, scanning, or recording videos using the image acquisition device. A scale can be set in the image to establish the proportional relationship between the image pixel size and the actual size. The gridded recording template 83 is used to assist in statistically analyzing the length, width, area, center position, boundary morphology, and distribution range of the tracer fluid distribution area 81.

[0064] like Figure 5 As shown, during the process of obtaining layered profiles and reconstructing fluid distribution after the experiment, the tracer fluid distribution patterns corresponding to different layered profiles can be obtained. Figure 5 In the diagram, a, b, c, and d represent the tracer fluid distribution patterns obtained from different layered profiles. The tracer fluid distribution region 81 has a tracer fluid distribution boundary 82. By meshing using a meshed recording template 83 and performing pixelation or image segmentation processing through an image processing module, the outer contour of the tracer fluid distribution region 81 can be identified, and parameters such as its length, width, area, center position, boundary morphology, and distribution range can be extracted. Furthermore, based on the characterization results corresponding to multiple layered profiles, a fluid distribution reconstruction result 84 can be generated through a fluid distribution reconstruction module to characterize the fluid boundary morphology and distribution range in the heterogeneous strata around the well.

[0065] In a further embodiment, under the same layered structure, medium type, tracer fluid type, peripheral fluid supply conditions, fluid connection shape, and extraction speed, different extraction times can be set and the tracer fluid extraction, profile acquisition, and quantitative characterization steps can be repeatedly executed to obtain fluid distribution reconstruction results 84 corresponding to multiple extraction time nodes. By comparing the fluid distribution reconstruction results 84 corresponding to multiple extraction time nodes, the dynamic evolution process of the fluid mobilization range of the heterogeneous formation around the well can be analyzed as a function of extraction time.

[0066] In one implementation, when quantitatively characterizing an image, pixel size can first be calibrated using a scale in the image. Then, the tracer fluid distribution region 81 can be extracted using color thresholding, grayscale thresholding, manual contour drawing, or semi-automatic image segmentation. Subsequently, the number of pixels corresponding to the tracer fluid distribution region 81 can be counted and converted to the actual area. Simultaneously, the tracer fluid distribution boundary 82, maximum length, maximum width, center position, and boundary irregularity can be extracted. Multiple fluid distribution reconstruction results 84 obtained from repeated experiments under different extraction time conditions can be arranged according to the extraction time sequence, forming a dynamic evolution of the fluid movement range over time. Results obtained from multiple layered profiles can be overlaid or reconstructed according to the actual layer relationships to form two-dimensional or three-dimensional fluid distribution reconstruction results 84.

[0067] In a preferred embodiment, the wellbore heterogeneous formation fluid migration visualization simulation and characterization device further includes an electrical parameter measurement unit. Specifically, the electrical parameter measurement unit includes electrodes, probes, resistivity measurement modules, or other electrical parameter measurement modules, used to measure the resistivity changes or other electrical parameter changes in the tracer fluid distribution region 81 or its central region in the heterogeneous formation simulation unit 2. During measurement, the background resistivity of the medium layer 21 and the resistivity after tracer fluid distribution can be measured before and after the experiment, respectively. Alternatively, electrical parameters can be measured in the tracer fluid distribution region 81, the area near the tracer fluid distribution boundary 82, and the unexploded area after dissection. By analyzing the resistivity changes or other electrical parameter changes in relation to the tracer fluid distribution range, extraction time, extraction speed, and layered structure parameters, the relationship between fluid migration morphology and electrical response characteristics can be further revealed.

[0068] Example 2

[0069] Based on the apparatus described in Example 1, this embodiment of the invention also discloses a method for visualizing, simulating, and characterizing fluid transport in heterogeneous formations around wells, comprising the following steps: S1. Construct a vertically arranged and sealed wellbore simulation unit 1, and provide a fluid communication port 12 or a tap simulation structure on the side wall of the wellbore simulation unit 1. Specifically, a transparent UPVC pipe can be selected as the hollow pipe body 11, a lower end sealing structure 13 is provided at the lower end of the hollow pipe body 11, and a round hole is opened on its side wall near the lower part as a fluid communication port 12.

[0070] S2. Construct a heterogeneous strata simulation unit 2 around the wellbore simulation unit 1. The heterogeneous strata simulation unit 2 includes at least two media layers 21 with different seepage characteristics. The media layers are distributed radially, longitudinally, or in a combination of radial and longitudinal directions. Specifically, the hollow tube 11 can be filled with different proportions of quartz sand, clay, and artificially proportioned formation materials. Alternatively, sponges or other porous materials can be used as needed for the experiment.

[0071] S3. Construct a boundary sealing unit to seal the top and bottom of the heterogeneous stratum simulation unit. Specifically, the boundary sealing unit includes a sealing cap 31 disposed above the heterogeneous stratum simulation unit 2 and a sealing base 32 disposed below the heterogeneous stratum simulation unit, used to restrict the tracer fluid from entering the heterogeneous stratum simulation unit 2 from the upper and lower boundaries, so that the fluid moves from the outside of the heterogeneous stratum simulation unit 2 towards the wellbore simulation unit 1.

[0072] S4. Construct an external fluid supply unit around the heterogeneous layer simulation unit 2, add tracer fluid to the outside of the heterogeneous layer simulation unit, and maintain the tracer fluid level within a preset height range through the supply chamber 41, replenishment container 42, and level control structure. The tracer fluid may be one or more combinations of color-coded brine, dyed water, simulated oil, and crude oil.

[0073] S5. The tracer fluid is extracted from the wellbore simulation unit 1 at a preset extraction speed by the suction control unit, and the extraction time and the volume of the extracted tracer fluid are recorded. Specifically, the suction pump 51 provides suction power, the flow regulator 52 adjusts the tracer fluid extraction speed, and the fluid collection container 53 collects and measures the volume of extracted fluid corresponding to different extraction times.

[0074] S6. During the extraction of the tracer fluid, the observation and recording unit 6 continuously records the tracer fluid's migration process and corresponding time information. The observation and recording unit 6 can continuously record the experimental process and can also synchronously record the extraction time in conjunction with a time display device.

[0075] S7. After the tracer fluid extraction is completed, the heterogeneous stratum simulation unit 2 is unfolded, dissected, or sampled layer by layer to obtain the spatial distribution pattern of the tracer fluid in each medium layer. When the heterogeneous stratum simulation unit 2 is made of sponge material, each sponge layer can be unfolded layer by layer and the tracer fluid distribution pattern can be recorded; when the heterogeneous stratum simulation unit 2 is made of quartz sand, gravel particles, clay, sand-clay mixture, soil sample, or artificially proportioned stratum material, each layer can be dissected, shoveled, or sampled layer by layer and the tracer fluid distribution pattern can be recorded.

[0076] S8. Geometric parameters are extracted and quantitatively characterized for the spatial distribution morphology of the tracer fluid to obtain the tracer fluid's operational range, distribution boundary, morphological characteristics, and differences in tracer fluid response between different media layers. Specifically, the tracer fluid distribution region 81 and tracer fluid distribution boundary 82 can be identified through meshing, pixelation, or image segmentation processing to obtain the area, length, width, center position, boundary morphology, and distribution range of the tracer fluid distribution region 81. Based on the characterization results corresponding to multiple layered profiles, a fluid distribution reconstruction result 84 is formed, which can specifically reconstruct two-dimensional or three-dimensional tracer fluid distribution profiles. When repeated experiments are conducted under different extraction time conditions, a dynamic evolution result of the fluid operational range changing over time can also be formed based on the characterization results corresponding to multiple extraction time nodes.

[0077] The following two figures illustrate the specific distribution profile of the tracer fluid in the heterogeneous formation simulation unit 2 after the tracer fluid is extracted from the wellbore simulation unit 1 by the suction pump 51. Figure 6This is a side view diagram showing the restored boundary morphology and distribution range of the pump extraction section, specifically a side view section in the YZ plane direction. Figure 7 This is a three-dimensional reconstruction diagram of the boundary shape and distribution range of the pump extraction section, specifically a three-dimensional reconstruction diagram of the unfolded elliptical section rolled back into a cylinder. Figure 6 and Figure 7 In the diagram, the colored lines represent the cross-section of the tracer fluid in the medium layer after pumping. Figure 6 and Figure 7 It can be explained that as the pumping proceeds, the fluid from a distance is gradually drawn in, and the tracer fluid distribution profile eventually presents this shape. Not only can the specific medium layer profile shape be obtained through the experiment of the well-perimeter heterogeneous stratum fluid migration visualization simulation and characterization device described in this embodiment, but it can also be restored from the three-dimensional model for subsequent simulation analysis, etc.

[0078] In a further embodiment, under the same conditions of layered structure, medium type, tracer fluid type, peripheral fluid supply conditions, fluid connection shape, and extraction speed, different extraction times are set and the tracer fluid extraction, profile acquisition, and quantitative characterization steps are repeatedly executed to obtain fluid distribution reconstruction results corresponding to multiple extraction time nodes. Based on the fluid distribution reconstruction results corresponding to multiple time nodes, the dynamic evolution of fluid migration in heterogeneous formations around the well is analyzed.

[0079] As a preferred embodiment, the method for visualizing and characterizing fluid migration in heterogeneous formations around a well further includes: measuring the resistivity changes or other electrical parameter changes in the tracer fluid distribution area or its central area in the heterogeneous formation simulation unit, and performing corresponding analysis on the resistivity changes or other electrical parameter changes in relation to the tracer fluid distribution range, extraction time, extraction speed, and layered structure parameters.

[0080] As a preferred embodiment, the method for visualizing and characterizing fluid migration in heterogeneous formations around wells further includes: conducting controlled variable experiments by changing the layered structure, medium type, extraction rate, extraction time, tracer fluid type, peripheral fluid supply conditions, or the shape of the fluid connection port 12, to analyze the fluid migration patterns in heterogeneous formations around wells under different conditions. By comparing and analyzing the changes in the tracer fluid distribution area 81, tracer fluid distribution boundary 82, extracted tracer fluid volume, extraction time, extraction rate, and electrical parameters under different experimental conditions, the fluid migration patterns, differences in the range of movement, and asymmetric flow characteristics under different heterogeneous formation conditions around wells can be studied.

[0081] Below, we will conduct a comparative verification through a controlled variable experiment. Specifically, a controlled variable experiment was conducted with different extraction times while keeping other variables (layer structure, medium type, extraction rate, tracer fluid type, peripheral fluid supply conditions, and fluid connection shape) the same. As shown in Table 1, the parameters of each medium layer profile under different extraction times are presented. The extraction times were set to 20 minutes and 40 minutes, and the length and width were used to represent the size of the extracted profile area. As can be seen from Table 1, when other experimental conditions remain consistent, after the extraction time is increased from 20 minutes to 40 minutes, the height or width of the tracer fluid distribution area in most medium layers tends to increase. This indicates that extending the extraction time can expand the fluid mobility range in the heterogeneous formations around the well. The local parameters of some medium layers fluctuate, which may be related to the heterogeneity of the medium, the sampling location of the profile, and the irregularity of the tracer fluid distribution boundary.

[0082] Table 1. Parameters of various medium layer profiles at different extraction times.

[0083] This invention, through the visualization simulation and characterization device for fluid migration in heterogeneous formations around wells described in Example 1 and the visualization simulation and characterization method for fluid migration in heterogeneous formations around wells described in Example 2, can simulate the migration process of fluid in heterogeneous formations around wells under controlled indoor conditions. Through dynamic observation, layered profile acquisition, gridded or pixelated characterization, electrical parameter measurement, and fluid distribution reconstruction, it can achieve a comprehensive characterization of the fluid's movement range, spatial distribution morphology, dynamic evolution process, and electrical response characteristics.

[0084] The above description only outlines the basic principles and preferred embodiments of the present invention. Those skilled in the art can make many changes and modifications based on the above description, and these changes and modifications should fall within the protection scope of the present invention.

Claims

1. A device for visualizing, simulating, and characterizing fluid transport in heterogeneous formations around a well, characterized in that, include: A wellbore simulation unit is used to simulate the wellbore structure and the wellbore lateral suction channel. The wellbore simulation unit includes a vertically arranged hollow tube body. The lower end of the hollow tube body is sealed, and at least one fluid communication port or tap simulation structure is provided on the side wall. The heterogeneous strata simulation unit is located around the wellbore simulation unit and includes at least two media layers with different seepage characteristics. The media layers are distributed in a radial, longitudinal, or combined radial and longitudinal manner to simulate the heterogeneous strata structure around the well. Boundary sealing units are disposed above and below the heterogeneous stratum simulation unit to restrict the tracer fluid from entering the heterogeneous stratum simulation unit from the upper and lower boundaries, so that the fluid moves from the outside of the heterogeneous stratum simulation unit toward the wellbore simulation unit. An external fluid supply unit is located around the heterogeneous layer simulation unit and is used to provide tracer fluid to the heterogeneous layer simulation unit and maintain the liquid level of the tracer fluid within a preset height range. The suction control unit is connected to the wellbore simulation unit and is used to extract tracer fluid from the wellbore simulation unit, adjust the tracer fluid extraction speed, and measure the volume of tracer fluid extracted. The observation and recording unit is used to record the migration status of the tracer fluid and the corresponding time information during the tracer fluid extraction process. The profile acquisition and characterization unit is used to acquire the distribution pattern of the tracer fluid in the heterogeneous stratum simulation unit after the experiment, and to quantitatively characterize the distribution pattern.

2. The apparatus according to claim 1, characterized in that, The heterogeneous layer simulation unit is a radially layered structure, a longitudinally layered structure, or a combination of radial and longitudinal layers. The radial layered structure includes multiple annular media layers arranged sequentially around the wellbore simulation unit, with each annular media layer distributed in a concentric ring shape in the top view direction; The vertical layered structure includes multiple dielectric layers stacked sequentially along the vertical direction; The combined structure of radial and longitudinal layering includes both the radial layering structure and the longitudinal layering structure.

3. The apparatus according to claim 1, characterized in that, The components of the heterogeneous strata simulation unit include sponge, quartz sand, sand and gravel particles, clay, sand-clay mixture, soil sample, artificially proportioned strata materials or combinations thereof, and each medium layer has different pore structure, permeability, fluid retention capacity or electrical parameters.

4. The apparatus according to claim 3, characterized in that, The adjacent dielectric layers of the heterogeneous layer simulation unit are separated by a partition structure.

5. The apparatus according to claim 4, characterized in that, When the heterogeneous layer simulation unit uses sponge material, the partition structure is non-woven fabric; When the heterogeneous stratum simulation unit uses quartz sand, gravel particles, clay, sand-clay mixture, soil sample, or artificially proportioned stratum materials, the partition structure is a porous partition.

6. The apparatus according to claim 1, characterized in that, The boundary sealing unit includes a sealing cover disposed above the heterogeneous layer simulation unit and a sealing base disposed below the heterogeneous layer simulation unit.

7. The apparatus according to claim 1, characterized in that, The peripheral fluid supply unit includes a liquid supply chamber located outside the heterogeneous layer simulation unit, a replenishment container connected to the liquid supply chamber, and a liquid level control structure.

8. The apparatus according to claim 1, characterized in that, The suction control unit includes a suction pump, a flow regulator, and a fluid collection container. The fluid collection container is used to measure the volume of tracer fluid extracted at different extraction times.

9. The apparatus according to claim 1, characterized in that, The observation and recording unit includes at least a camera device for continuously recording the experimental process.

10. The apparatus according to claim 1, characterized in that, The profile acquisition and characterization unit includes an image acquisition device, a scale, a gridded recording template, an image processing module, and a fluid distribution reconstruction module. It is used to acquire the length, width, area, center position, boundary morphology, and distribution range of the tracer fluid in each medium layer, and to reconstruct the tracer fluid distribution morphology corresponding to different medium layer profiles.

11. The apparatus according to any one of claims 1-10, characterized in that, It also includes an electrical parameter measurement unit, which includes electrodes, probes, resistivity measurement modules or other electrical parameter measurement modules, for measuring the resistivity changes or other electrical parameter changes in the tracer fluid distribution area or its central area in the heterogeneous stratum simulation unit.

12. A method for visualizing, simulating, and characterizing fluid transport in heterogeneous formations around a well, using the apparatus described in any one of claims 1-11, characterized in that, Includes the following steps: S1. Construct a vertically arranged wellbore simulation unit with a sealed lower end, and set a fluid communication port or tap simulation structure on the side wall of the wellbore simulation unit; S2. Construct a heterogeneous strata simulation unit around the wellbore simulation unit. The heterogeneous strata simulation unit includes at least two media layers with different seepage characteristics. The media layers are distributed in a radial, longitudinal, or combined radial and longitudinal manner. S3. Construct a boundary sealing unit to seal the top and bottom of the heterogeneous layer simulation unit; S4. Construct an external fluid supply unit around the heterogeneous layer simulation unit, add tracer fluid to the outside of the heterogeneous layer simulation unit, and maintain the liquid level of the tracer fluid within a preset height range. S5. The tracer fluid is extracted from the wellbore simulation unit at a preset extraction speed by the suction control unit, and the extraction time and the volume of the extracted tracer fluid are recorded. S6. During the extraction of tracer fluid, the tracer fluid transport process and corresponding time information are continuously recorded by the observation and recording unit. S7. After the tracer fluid extraction is completed, the heterogeneous layer simulation unit is unfolded, dissected or sampled layer by layer to obtain the spatial distribution pattern of the tracer fluid in each medium layer. S8. Extract and quantitatively characterize the spatial distribution morphology of the tracer fluid using geometric parameters to obtain the tracer fluid's operational range, distribution boundary, morphological characteristics, and the differences in tracer fluid response between different media layers.

13. The method according to claim 12, characterized in that, In step S8, the spatial distribution pattern of the tracer fluid is processed by meshing, pixelation or image segmentation to identify the tracer fluid distribution area and tracer fluid distribution boundary, and the length, width, area, center position, boundary shape and distribution range of the tracer fluid distribution area are obtained. The two-dimensional or three-dimensional tracer fluid distribution profile is reconstructed based on the characterization results of different medium layer profiles.

14. The method according to claim 12, characterized in that, In step S8, under the same conditions of layered structure, medium type, tracer fluid type, peripheral fluid supply conditions, fluid connection shape and extraction speed, different extraction times are set and the tracer fluid extraction, profile acquisition and quantitative characterization steps are repeatedly executed to obtain fluid distribution reconstruction results corresponding to multiple extraction time nodes. Based on the fluid distribution reconstruction results corresponding to multiple time nodes, the dynamic evolution of fluid migration in heterogeneous formations around the well is analyzed.

15. The method according to claim 12, characterized in that, Step S8 is followed by: measuring the resistivity change or other electrical parameter changes in the tracer fluid distribution area or its central area in the heterogeneous layer simulation unit, and performing corresponding analysis on the resistivity change or other electrical parameter changes in relation to the tracer fluid distribution range, extraction time, extraction speed and layer structure parameters.

16. The method according to any one of claims 12-15, characterized in that, Step S8 and beyond also includes: conducting controlled variable experiments by changing the layered structure, medium type, extraction speed, extraction time, tracer fluid type, peripheral fluid supply conditions, or fluid communication port shape, in order to analyze the fluid migration law of the heterogeneous formation around the well under different conditions.

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