An experimental device and method for visualizing and automatically determining a thermal connection plane between thermal recovery wells for thick oil

Abstract

This invention discloses an automated experimental device for visually determining inter-well thermal connectivity in heavy oil thermal recovery, comprising a sand-filling system, an injection system, a production system, a well network system, a thermal imaging module, and a determination module. An automated determination method is also disclosed. The beneficial effects of this invention are: by arranging a well network in the sand-filling system to simulate heavy oil thermal recovery, acquiring horizontal temperature field images using an infrared thermal imager, and automatically calculating and determining the inter-well thermal connectivity status based on temperature field characteristics, it achieves planar visual observation of the inter-well thermal connectivity morphology during the physical simulation experiment of heavy oil thermal recovery. This allows for automatic and objective determination of the degree of thermal connectivity, providing experimental basis and decision-making reference for optimizing heavy oil thermal recovery process parameters.

Description

Technical Field

[0001] This invention relates to the field of physical simulation experiment technology for heavy oil thermal recovery, and in particular to an experimental device and method for automatically determining the plane of thermal connectivity between heavy oil wells. Background Technology

[0002] Heavy oil, also known as heavy crude oil, is characterized by high density (>0.92 g / cm³), high viscosity (>50 mPa·s), and poor fluidity. It is widely distributed in the Bohai Bay Basin, Junggar Basin, and Qaidam Basin in my country, and is an unconventional energy source with abundant resources. Due to its unique properties, conventional waterflooding is difficult to effectively extract it. The industry commonly employs thermal recovery methods, including steam injection (CSS), steam flooding (SF), steam-assisted gravity drainage (SAGD), and in-situ combustion (ISC). In various thermal recovery processes, the degree of connectivity of the thermal energy field between the injection well and the production well directly determines the heavy oil production efficiency—only when the inter-well region is effectively heated to the viscosity-reducing temperature (usually >150℃) and a continuous flow channel is formed can crude oil be produced at an economical flow rate.

[0003] However, in the early stages of thermal recovery pilot experiments and field production, how to efficiently, accurately, and intuitively determine the thermal connectivity between injection and production wells has always been a technical challenge for the industry. Existing monitoring methods have the following limitations: the production data inversion method relies on data such as field production volume and wellhead temperature to indirectly infer thermal connectivity, resulting in a lag of several days to several weeks, making it impossible to grasp the downhole thermal field distribution in real time, leading to a serious lag in control measures compared to the thermal field evolution. The numerical simulation prediction method is based on geological static data and production parameters, but the heavy oil reservoir has strong heterogeneity and complex vapor cavity morphology, resulting in large uncertainty in simulation results. It requires a large amount of field data for repeated correction, and its reliability is extremely low in the early stages of pilot experiments when historical fitting data is lacking. The downhole measuring point monitoring method obtains discrete point temperatures by deploying thermocouples or optical fibers in the wellbore, but it is limited by the number of wellbores and cannot form a continuous temperature field in the inter-well region, making it difficult to identify local unconnected "cold zones" or dominant channel "thermal cross-contamination".

[0004] At the level of physical simulation experiments, existing visualization devices also have structural defects. Three-dimensional physical simulation devices mostly insert electrode arrays inside the sand-filled cavity and rely on resistivity interpolation to indirectly invert the temperature field. The spatial resolution is limited by the electrode spacing (usually >50mm), and it cannot intuitively display the morphology of the steam cavity. Two-dimensional visualization devices generally adopt a side-view structure, observing the vertical cross-section through an plexiglass window. However, this type of structure has a fundamental limitation: it can only observe the vertical expansion height of the steam cavity and cannot observe the planar expansion morphology, lateral symmetry, and multi-well interference effects of the steam cavity on the horizontal plane.

[0005] From the perspective of thermal recovery mechanism analysis, the horizontal thermal connectivity is more critical than the vertical expansion. Taking SAGD as an example, once the steam chamber touches the top cap vertically, the subsequent oil drainage efficiency mainly depends on whether the steam chamber expands uniformly to the entire well control area in the horizontal plane. If there are local unconnected areas in the horizontal plane, "dead oil zones" will be formed, leading to a decrease in the final recovery rate. During steam drive, the degree of thermal connectivity of the injection and production well groups in the horizontal plane directly determines whether the displacement front advances uniformly. Premature breakthrough or local stagnation will significantly reduce the oil displacement efficiency. Therefore, obtaining an overall thermal field image of the horizontal plane and quantitatively evaluating the uniformity of thermal connectivity are core requirements for optimizing thermal recovery control strategies. Existing side profile devices cannot meet the above requirements: their observation angle is parallel to the direction of gravity, and they can only capture one-dimensional vertical expansion information; while the thermal connectivity processes of multiple wells and multiple directions in the horizontal plane (such as the four corner connections of a five-point well network) overlap and cannot be distinguished in the side projection.

[0006] In summary, the existing technology lacks an experimental device that can directly observe the overall thermal field evolution from a horizontal top-down perspective and quantitatively and automatically determine the thermal connectivity status. This gap leads to a lack of real-time basis for the regulation and optimization during the thermal cycling stage or the SAGD start-up stage, making it impossible to identify local unconnected areas in a timely manner and implement differentiated steam injection, increasing experimental risks and costs, and prolonging the evaluation cycle. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of the prior art and provide an experimental device and method for automatically determining the planar thermal connectivity between heavy oil thermal recovery wells.

[0008] The objective of this invention is achieved through the following technical solution: an experimental device for automatically determining the planar thermal connectivity between heavy oil thermal recovery wells, comprising a sand-filling system, an injection system, a production system, a well network system, a thermal imaging module, and a determination module;

[0009] Sand-filling systems are used to lay out well patterns and simulate heavy oil thermal recovery.

[0010] The injection system injects steam, water, and oil into the well through injection pipelines, which are equipped with control valve assemblies to regulate flow rate, pressure, and temperature.

[0011] The production system is used to monitor the temperature of the produced fluid, the production pressure differential, and to collect the production fluid and oil production.

[0012] The well network system includes at least one steam injection well and one production well, with the steam injection well and production well vertically penetrating the sand-filling system;

[0013] The thermal imaging module includes an infrared thermal imager, the optical axis of which is perpendicular to the sand filling system, and is used to acquire the two-dimensional temperature field distribution of the sand filling system in the horizontal plane.

[0014] The determination module is used to determine and output the planar thermal connectivity status.

[0015] Preferably, the sand filling system includes a stainless steel frame, the bottom surface of which is sealed and bonded to tempered glass to form a square sand filling cavity, and the top surface of the stainless steel frame is provided with a tempered glass window, which is fixed by clamping cover plates and bolts.

[0016] Preferably, the injection system includes a steam generator, a constant speed and constant pressure pump, intermediate container a, intermediate container b, and sensor measuring line a. The steam generated by the steam generator is injected into the steam injection well through the injection pipeline. The constant speed and constant pressure pump replenishes fluid into the well through intermediate containers a and b. The sensor measuring line a includes a temperature sensor a and a pressure sensor a. The temperature sensor a is installed on the injection pipeline and near the wellhead of the steam injection well to monitor the temperature of the injected steam. The pressure sensor a is installed on the injection pipeline to monitor the injection pressure.

[0017] Preferably, the production system includes a production pipeline, a back pressure valve, a cooler, an oil-water separator, a measuring cylinder, and an electronic balance. The production pipeline is connected to the wellhead of the production well and is connected in series with the back pressure valve, the cooler, and the oil-water separator. The measuring cylinder is used to measure the amount of fluid produced, and the electronic balance is used to measure the amount of oil produced. A control valve group b is installed on the production pipeline to regulate the bottom hole pressure and the fluid production rate.

[0018] Preferably, the production system also includes sensor line b, which includes temperature sensor b, pressure sensor b, and data acquisition unit. Temperature sensor b is installed on the production pipeline and near the wellhead of the production well to monitor the temperature of the produced fluid. Pressure sensor b is installed before and after the back pressure valve to monitor the production pressure difference. Data acquisition unit is used to collect metering data in real time.

[0019] Preferably, the thermal imaging module also includes an industrial camera and a temperature calibration probe. The industrial camera is coaxially arranged with the infrared thermal imager. The industrial camera is used to acquire planar images to assist in the identification of the steam leading edge. The temperature calibration probe is set in the sand-filled cavity and is used to calibrate the temperature measurement of the infrared thermal imager.

[0020] Preferably, the processing steps of the determination module are as follows:

[0021] S1: Establish a mapping relationship between physical coordinates and pixel coordinates based on the temperature field data collected by the infrared thermal imager (17);

[0022] S2: Delineate the inter-well analysis area based on the planar coordinates of the steam injection well and the production well;

[0023] S3: Extract the temperature field characteristics within the inter-well analysis area;

[0024] S4: Calculate the thermal connectivity distance index, which characterizes the extent of thermal front extension, based on the aforementioned temperature field characteristics. Thermal symmetry index, which characterizes the symmetry of the thermal front. The drag coefficient characterizing the flow resistance in thermal recovery and the production efficiency coefficient characterizing thermal recovery efficiency ;

[0025] S5: Based on calculations value, value, Value and The thermal connectivity coefficient I is calculated using the AHP (Analytical Hierarchical Analysis) method, and the planar thermal connectivity state is determined and output.

[0026] Preferably, in step S4, the thermal connectivity distance index The calculation formula is:

[0027] ;

[0028] ;

[0029] ;

[0030] in, For the influence factor of thermal connection temperature, The thermal connectivity distance is an influencing factor. Intensity factor This refers to the proportion of high-temperature zones within the control area between injection and production wells. The distance between the highest temperature pixel and the injection well. This refers to the spacing between injection and production wells;

[0031] , and The calculation formula is:

[0032] ;

[0033] ;

[0034] ;

[0035] in, This represents the sum of the temperatures of all pixels within the pixel area of ​​the infrared thermal imager that have a temperature greater than 150 degrees Celsius. This represents the number of pixels with a temperature greater than 150 degrees Celsius across all pixel ranges. The steam injection temperature. The initial temperature of the experimental setup. The x-coordinate of the pixel is The ordinate of the pixel;

[0036] Thermal symmetry index The calculation formula is:

[0037] ;

[0038] in, This refers to the number of pixels in the high-temperature zone located to the left of the center line of the injection-sampling line where the temperature exceeds 150 degrees Celsius. This refers to the number of pixels in the high-temperature zone whose temperature exceeds 150 degrees Celsius to the right of the center line of the injection-sampling connection.

[0039] drag coefficient The calculation formula is:

[0040] ;

[0041] in, This refers to the injection-production pressure difference during the steam injection process. This refers to the initial pressure difference during the steam injection process;

[0042] Production efficiency coefficient The calculation formula is:

[0043] ;

[0044] in, For cumulative oil production, This represents the cumulative injection amount.

[0045] Preferably, in step S5, the formula for calculating the thermal connectivity coefficient I is:

[0046] ;

[0047] in, , , , These are the thermal connectivity distance indices. Thermal symmetry index drag coefficient Production efficiency coefficient Weights calculated using the AHP method;

[0048] when When the value is ≥0.75, it is considered fully connected; when 0.45≤ When the value is less than 0.75, the connection is considered unconnected. When <0.45, it is determined to be partially connected;

[0049] Weights calculated using the AHP method , , and The specific steps are as follows:

[0050] A1: Constructing the Criterion Layer Matrix Characterizing the importance of temperature field features relative to flow field features:

[0051] ;

[0052] in, This serves as a scale for the importance of temperature field characteristics relative to flow field characteristics. , which is the importance scale of flow field characteristics relative to temperature field characteristics;

[0053] A2: Constructing the temperature field feature matrix Characterizing thermal connectivity distance index Relative to thermal symmetry index Importance:

[0054] ;

[0055] in, Thermal connectivity distance index Relative to thermal symmetry index Importance scale , which is relative to the production efficiency coefficient Importance scale, when thermal connectivity distance index With thermal symmetry index When equally important, =1;

[0056] A13: Constructing the flow field characteristic matrix Characterizing the drag coefficient Relative to the production efficiency coefficient Importance:

[0057] ;

[0058] in, drag coefficient Relative to the production efficiency coefficient Importance scale , is the production efficiency coefficient Relative to drag coefficient Importance scale;

[0059] A14: Calculate the matrix The geometric mean of the elements in each row.

[0060] ;

[0061] ;

[0062] Normalization yields the criterion layer weights.

[0063] ;

[0064] ;

[0065] in, For the characteristic weights of the temperature field, For the characteristic weights of the flow field;

[0066] Similarly, calculate the matrix. Normalized weights and and matrix Normalized weights and ;

[0067] A15: Calculate the combined weights of each indicator for the target layer:

[0068] ;

[0069] ;

[0070] ;

[0071] ;

[0072] A16: Calculate the consistency ratio :

[0073] ;

[0074] ;

[0075] in, To determine the largest eigenvalue of a matrix, Let be the order of the matrix. It is a random consistency index; when each judgment matrix is When the value is less than 0.1, the weight is accepted. , , and .

[0076] An experimental method for automatically determining the thermal connectivity plane between heavy oil thermal recovery wells through visualization, comprising the aforementioned experimental device for automatically determining the thermal connectivity plane between heavy oil thermal recovery wells through visualization, and further comprising the following steps:

[0077] B1: The sand filling cavity of the sand filling system is filled with quartz sand and saturated simulated oil, and steam injection wells and production wells are arranged.

[0078] B2: Steam is injected into the injection well according to the set parameters. At the same time, the back pressure valve is set to control the production of the production well. The infrared thermal imager continuously collects the temperature field data of the horizontal surface of the sand-filled cavity at set time intervals. The production volume and oil production are recorded in real time through a measuring cylinder and an electronic balance.

[0079] B3: The determination module executes steps S1 to S5, processes each frame of temperature field data, and outputs the thermal connectivity status determination result in real time.

[0080] B4: Real-time overlay display of planar temperature field map, well location mark, high temperature isotherm and current thermal connectivity determination result on the display terminal.

[0081] The present invention has the following advantages: By arranging a well network in a sand-filling system to simulate heavy oil thermal recovery, the present invention acquires horizontal temperature field images through an infrared thermal imager, and automatically calculates and determines the thermal connectivity status between wells based on the temperature field characteristics. This enables planar visualization observation of the thermal connectivity morphology between wells during the physical simulation experiment of heavy oil thermal recovery, and can automatically and objectively determine the degree of thermal connectivity, providing experimental basis and decision-making reference for optimizing the process parameters of heavy oil thermal recovery. Attached Figure Description

[0082] Figure 1 This is a schematic diagram of a sand-filling system;

[0083] Figure 2 A schematic diagram showing the connection between the injection system and the extraction system;

[0084] Figure 3 This is a schematic diagram of a planar temperature field and the principle for determining thermal connectivity;

[0085] In the diagram, 1-bolt, 3-stainless steel frame, 4-clamping cover plate, 5-tempered glass, 8-constant speed and pressure pump, 10-intermediate container a, 11-intermediate container b, 12-steam generator, 17-infrared thermal imager, 18-industrial camera, 19-sand filling system, 20-temperature calibration probe, 21-measuring cylinder, 22-electronic balance, 23-oil-water separator, 24-cooler, 26-backpressure valve, 27-sensor line a, 28-sensor line b. Detailed Implementation

[0086] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0087] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0088] It should be noted that, unless otherwise specified, the embodiments and features described in this invention can be combined with each other.

[0089] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0090] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use, or the orientation or positional relationship commonly understood by those skilled in the art. They are only used for the convenience of describing this 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 this invention. In addition, the terms "first," "second," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0091] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" 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; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0092] In this embodiment, as Figure 1 and Figure 2 As shown, an experimental device for automatic visual determination of thermal connectivity between heavy oil thermal recovery wells includes a sand filling system, an injection system 19, a production system, a well network system, a thermal imaging module, and a determination module.

[0093] Sand filling system 19 is used to arrange the well network and simulate heavy oil thermal recovery;

[0094] The injection system injects steam, water, and oil into the well through injection pipelines, which are equipped with control valve assemblies to regulate flow rate, pressure, and temperature.

[0095] The production system is used to monitor the temperature of the produced fluid, the production pressure differential, and to collect the production fluid and oil production.

[0096] The well network system includes at least one steam injection well and one production well, which vertically penetrate the sand-filled system 19. Specifically, the steam injection well and the production well vertically penetrate the sand-filled cavity, and the steam injection well and the production well are located diagonally opposite each other in the sand-filled cavity. Their projected positions on the horizontal plane of the sand-filled cavity are at a predetermined distance, with a planar projection spacing of 636 mm. Here, both the steam injection well and the production well are stainless steel screen pipes with an outer diameter of 6 mm, a screen aperture density of 100 holes / meter, and are covered with 100-mesh wire mesh. The upper end of the steam injection well is connected to the injection system, and the lower end is closed; the lower end of the production well is connected to the production system, and the upper end is closed.

[0097] The thermal imaging module includes an infrared thermal imager 17, the optical axis of which is perpendicular to the sand filling system 19, and is used to acquire the two-dimensional temperature field distribution of the sand filling system 19 in the horizontal plane.

[0098] The determination module is used to determine and output the planar thermal connectivity status. By arranging a well network in the sand-filling system 19, heavy oil thermal recovery simulation is carried out. The horizontal temperature field image is acquired by the infrared thermal imager 17, and the inter-well thermal connectivity status is automatically calculated and determined based on the temperature field characteristics. This realizes the planar visualization observation of the inter-well thermal connectivity morphology during the physical simulation experiment of heavy oil thermal recovery. It can automatically and objectively determine the degree of thermal connectivity, providing experimental basis and decision-making reference for optimizing heavy oil thermal recovery process parameters.

[0099] Furthermore, the sand-filling system 19 includes a stainless steel frame 3. The bottom surface of the stainless steel frame 3 is sealed and bonded to the tempered glass 5 to form a square sand-filling cavity. A tempered glass window is provided on the top surface of the stainless steel frame 3. The tempered glass window is clamped and fixed by a clamping cover plate 4 and bolts 1. Specifically, the horizontal dimension of the square sand-filling cavity is 450mm × 450mm, and the vertical thickness is 50mm. Preferably, the 50mm vertical thickness is the typical thickness of a single-layer reservoir, resulting in low heat loss, short experimental cycle, and meeting the detection depth requirements of the infrared thermal imager 17 for sandstone reservoirs. The size of the tempered glass window is 450mm × 450mm, completely covering the horizontal projection surface of the sand-filling cavity 19, and the bolt spacing is 80mm.

[0100] Furthermore, the injection system includes a steam generator 12, a constant speed and constant pressure pump 8, an intermediate container a10, an intermediate container b11, and a sensor measuring line a27. The steam generated by the steam generator 12 is injected into the steam injection well through the injection pipeline. The constant speed and constant pressure pump 8 replenishes fluid into the well through the intermediate containers a10 and b11. The sensor measuring line a27 includes a temperature sensor a and a pressure sensor a. The temperature sensor a is installed on the injection pipeline and near the wellhead of the steam injection well to monitor the temperature of the injected steam. The pressure sensor a is installed on the injection pipeline to monitor the injection pressure. Specifically, the constant speed and pressure pump 8 is an ISCO 100DX model with a flow rate of 0.01-50 mL / min and a pressure of 0-20 MPa; intermediate containers a10 and b11 are 500 mL piston-type intermediate containers, with intermediate container a10 containing water and intermediate container b11 containing oil; the steam generator 12 is a controllable dryness steam generator with a maximum temperature of 300°C, a maximum pressure of 10 MPa, and a dryness of 0-100%; the control valve group is a needle valve; and the injection pipeline is connected to the upper end of the steam injection well through a wellhead sealing joint.

[0101] In this embodiment, the production system includes a production pipeline, a back pressure valve 26, a cooler 24, an oil-water separator 23, a measuring cylinder 21, and an electronic balance 22. The production pipeline connects to the wellhead of the production well and is connected in series with the back pressure valve 26, the cooler 24, and the oil-water separator 23. The measuring cylinder 21 is used to measure the produced fluid volume, and the electronic balance 22 is used to measure the produced oil volume. A control valve group b is installed on the production pipeline to regulate the bottom hole pressure and the production rate. Furthermore, the production system also includes a sensor line b28, which includes a temperature sensor b, a pressure sensor b, and a data acquisition unit. The temperature sensor b is installed on the production pipeline near the wellhead of the production well to monitor the temperature of the produced fluid. The pressure sensor b is installed before and after the back pressure valve 26 to monitor the production pressure differential. The data acquisition unit is used to collect metering data in real time. Specifically, the production pipeline is connected to the bottom end of the production well through a wellhead sealing joint. The back pressure valve 26 sets the bottom pressure of the production well. The back pressure valve 26 is a precision back pressure valve with a control range of 0-10MPa and an accuracy of ±0.01MPa. The cooler 24 is a shell-and-tube cooler.

[0102] Furthermore, the thermal imaging module also includes an industrial camera 18 and a temperature calibration probe 20. The industrial camera 18 is coaxially arranged with the infrared thermal imager 17. The industrial camera 18 is used to acquire planar images to assist in identifying the steam leading edge. The temperature calibration probe 20 is set inside the sand-filled cavity and is used to calibrate the temperature measurement of the infrared thermal imager 17. Specifically, the infrared thermal imager 17 is a FLIR A700 model with a resolution of 640×512, thermal sensitivity <0.03°C, and a temperature measurement range of -20°C to 2000°C. It is set 400mm directly above the tempered glass viewing window, with its optical axis vertically downward. The industrial camera 18 has 5 megapixels and is coaxially arranged with the infrared thermal imager 17. The temperature calibration probe 20 is a K-type thermocouple calibration probe, that is, two K-type thermocouple calibration probes are set diagonally in the sand-filled cavity, buried at a depth of 25mm.

[0103] In this embodiment, as Figure 3 As shown, the processing steps of the determination module are as follows:

[0104] S1: Establish the mapping relationship between physical coordinates and pixel coordinates based on the temperature field data collected by the infrared thermal imager 17;

[0105] S2: Delineate the inter-well analysis area based on the planar coordinates of the steam injection well and the production well;

[0106] S3: Extract temperature field characteristics within the inter-well analysis area;

[0107] S4: Calculation of the thermal connectivity distance index, which characterizes the extent of thermal front extension, based on temperature field characteristics. Thermal symmetry index, which characterizes the symmetry of the thermal front. The drag coefficient characterizing the flow resistance in thermal recovery and the production efficiency coefficient characterizing thermal recovery efficiency ;

[0108] S5: Based on calculations value, value, Value and The thermal connectivity coefficient I is calculated using the AHP (Analytic Hierarchy Process) method to determine and output the planar thermal connectivity state. Specifically, the thermal connectivity distance index is extracted based on the planar temperature field. and thermal symmetry index It can objectively evaluate the extent and uniformity of the thermal front, and can better reflect the actual quality of inter-well connectivity than side observation.

[0109] Furthermore, in step S4, the thermal connectivity distance index... The calculation formula is:

[0110] ;

[0111] ;

[0112] ;

[0113] in, For the influence factor of thermal connection temperature, The thermal connectivity distance is an influencing factor. The intensity factor is the ratio of the actual achievable temperature rise in the high-temperature region to the theoretical maximum possible temperature. This refers to the proportion of high-temperature zones within the control area between injection and production wells. The distance between the highest temperature pixel and the injection well. This refers to the spacing between injection and production wells;

[0114] , and The calculation formula is:

[0115] ;

[0116] ;

[0117] ;

[0118] in, This represents the sum of the temperatures of all pixels within the pixel area of ​​the infrared thermal imager that have a temperature greater than 150 degrees Celsius. This represents the number of pixels with a temperature greater than 150 degrees Celsius across all pixel ranges. The steam injection temperature. The initial temperature of the experimental setup. The x-coordinate of the pixel is The ordinate of the pixel;

[0119] Thermal symmetry index The calculation formula is:

[0120] ;

[0121] in, This refers to the number of pixels in the high-temperature zone located to the left of the center line of the injection-sampling line where the temperature exceeds 150 degrees Celsius. This refers to the number of pixels in the high-temperature zone whose temperature exceeds 150 degrees Celsius to the right of the center line of the injection-sampling connection.

[0122] drag coefficient The calculation formula is:

[0123] ;

[0124] in, This refers to the injection-production pressure difference during the steam injection process. This refers to the initial pressure difference during the steam injection process;

[0125] Production efficiency coefficient The calculation formula is:

[0126] ;

[0127] in, For cumulative oil production, This represents the cumulative injection amount.

[0128] Furthermore, in step S5, the formula for calculating the thermal connectivity coefficient I is:

[0129] ;

[0130] in, , , , These are the thermal connectivity distance indices. Thermal symmetry index drag coefficient Production efficiency coefficient Weights calculated using the AHP method;

[0131] when When the value is ≥0.75, it is considered fully connected; when 0.45≤ When the value is less than 0.75, the connection is considered unconnected. When <0.45, it is determined to be partially connected;

[0132] Weights calculated using the AHP method , , and The specific steps are as follows:

[0133] A1: Constructing the Criterion Layer Matrix Characterizing the importance of temperature field features relative to flow field features:

[0134] ;

[0135] in, This serves as a scale for the importance of temperature field characteristics relative to flow field characteristics. , which is the importance scale of flow field characteristics relative to temperature field characteristics;

[0136] A2: Constructing the temperature field feature matrix Characterizing thermal connectivity distance index Relative to thermal symmetry index Importance:

[0137] ;

[0138] in, Thermal connectivity distance index Relative to thermal symmetry index Importance scale , which is relative to the production efficiency coefficient Importance scale, when thermal connectivity distance index With thermal symmetry index When equally important, =1;

[0139] A13: Constructing the flow field characteristic matrix Characterizing the drag coefficient Relative to the production efficiency coefficient Importance:

[0140] ;

[0141] in, drag coefficient Relative to the production efficiency coefficient Importance scale , is the production efficiency coefficient Relative to drag coefficient Importance scale;

[0142] A14: Calculate the matrix The geometric mean of the elements in each row.

[0143] ;

[0144] ;

[0145] Normalization yields the criterion layer weights.

[0146] ;

[0147] ;

[0148] in, For the characteristic weights of the temperature field, For the characteristic weights of the flow field;

[0149] Similarly, calculate the matrix. Normalized weights and and matrix Normalized weights and ;

[0150] A15: Calculate the combined weights of each indicator for the target layer:

[0151] ;

[0152] ;

[0153] ;

[0154] ;

[0155] A16: Calculate the consistency ratio :

[0156] ;

[0157] ;

[0158] in, To determine the largest eigenvalue of a matrix, Let be the order of the matrix. It is a random consistency index; when each judgment matrix is When the value is less than 0.1, the weight is accepted. , , and .

[0159] An experimental method for automatically determining the thermal connectivity plane between heavy oil thermal recovery wells through visualization, comprising the aforementioned experimental device for automatically determining the thermal connectivity plane between heavy oil thermal recovery wells through visualization, and further comprising the following steps:

[0160] B1: The sand filling cavity of the sand filling system 19 is filled with quartz sand and saturated simulated oil, and steam injection wells and production wells are arranged.

[0161] B2: Steam is injected into the injection well according to the set parameters. At the same time, the back pressure valve 26 is set to control the production of the production well. The infrared thermal imager 17 continuously collects the temperature field data of the horizontal plane of the sand-filled cavity at set time intervals. The production volume and oil production are recorded in real time through the measuring cylinder 21 and the electronic balance 22.

[0162] B3: The determination module executes steps S1 to S5, processes each frame of temperature field data, and outputs the thermal connectivity status determination result in real time.

[0163] B4: The planar temperature field map, well location markers, high-temperature isotherms, and current thermal connectivity determination results are overlaid and displayed in real time on the display terminal. Specifically, simulated heavy oil with 80-12 mesh quartz sand, controlled porosity of 38%, and saturated viscosity of 5000 mPa·s is used to establish initial reservoir conditions at 50°C and atmospheric pressure.

[0164] Connect the injection system to the steam injection well and the production system to the production well. Check the air tightness. Specifically, purge with nitrogen at 2MPa and maintain the pressure for 30 minutes until the pressure drop is <0.05MPa.

[0165] Set the injection rate to 30 mL / min, steam temperature to 250°C, dryness to 70%, and injection pressure to 2 MPa; set the back pressure valve to 1.5 MPa to establish a production pressure differential of 0.5 MPa.

[0166] Turn on the infrared thermal imager 17, set the sampling interval to 30 seconds, and connect the injection and extraction systems to begin the SAGD simulation experiment.

[0167] The judgment module processes one frame of temperature field image every 30 seconds and calculates... Value and The value is used to determine the thermal connection status and to record the liquid production volume and water content.

[0168] The experiment continued until the liquid production dropped to 10% of the initial level, outputting the complete thermal connectivity evolution process and production dynamic curves. In this embodiment, the injection-extraction system and the judgment module data are fused to achieve real-time control based on thermal field feedback. When full connectivity is determined, the injection parameters can be automatically optimized or the production regime adjusted to improve experimental efficiency and data value.

[0169] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An experimental device for automatically determining the planar thermal connectivity between heavy oil thermal recovery wells, characterized in that: It includes a sand filling system, an injection system (19), a production system, a well network system, a thermal imaging module, and a judgment module; The sand-filling system (19) is used to arrange the well network and simulate heavy oil thermal recovery; The injection system injects steam, water and oil into the well through an injection pipeline, which is equipped with a control valve group to regulate flow rate, pressure and temperature. The production system is used to monitor the temperature of the produced fluid, the production pressure differential, and to collect the amount of produced fluid and oil. The well network system includes at least one steam injection well and one production well, wherein the steam injection well and the production well penetrate the sand filling system (19) vertically. The thermal imaging module includes an infrared thermal imager (17), the optical axis of which is perpendicular to the sand filling system (19), and is used to acquire the two-dimensional temperature field distribution of the sand filling system (19) in the horizontal plane; The determination module is used to determine and output the planar thermal connectivity status.

2. The experimental device for automatic visual determination of thermal connectivity between heavy oil thermal recovery wells according to claim 1, characterized in that: The sand filling system (19) includes a stainless steel frame (3), the bottom surface of which is sealed and bonded to tempered glass (5) to form a square sand filling cavity, and the top surface of the stainless steel frame (3) is provided with a tempered glass window, which is pressed and fixed by a clamping cover plate (4) and bolts (1).

3. The experimental device for automatically determining the planar visualization of thermal connectivity between heavy oil thermal recovery wells according to claim 2, characterized in that: The injection system includes a steam generator (12), a constant speed and constant pressure pump (8), an intermediate container a (10), an intermediate container b (11), and a sensor measuring line a (27). The steam generated by the steam generator (12) is injected into the steam injection well through the injection pipeline. The constant speed and constant pressure pump (8) replenishes fluid into the well through the intermediate container a (10) and the intermediate container b (11). The sensor measuring line a (27) includes a temperature sensor a and a pressure sensor a. The temperature sensor a is installed on the injection pipeline and close to the wellhead of the steam injection well to monitor the temperature of the injected steam. The pressure sensor a is installed on the injection pipeline to monitor the injection pressure.

4. The experimental device for automatically determining the planar visualization of thermal connectivity between heavy oil thermal recovery wells according to claim 3, characterized in that: The production system includes a production pipeline, a back pressure valve (26), a cooler (24), an oil-water separator (23), a measuring cylinder (21), and an electronic balance (22). The production pipeline is connected to the wellhead of the production well and is connected in series with the back pressure valve (26), the cooler (24), and the oil-water separator (23). The measuring cylinder (21) is used to measure the amount of fluid produced, and the electronic balance (22) is used to measure the amount of oil produced. A control valve group b is installed on the production pipeline to regulate the bottom hole pressure and the fluid production rate.

5. The experimental device for automatic visual determination of thermal connectivity between heavy oil thermal recovery wells according to claim 4, characterized in that: The production system also includes sensor line b (28), which includes a temperature sensor b, a pressure sensor b, and a data acquisition unit. The temperature sensor b is installed on the production pipeline and near the wellhead of the production well to monitor the temperature of the produced fluid. The pressure sensor b is installed at the front and rear ends of the back pressure valve (26) to monitor the production pressure difference. The data acquisition unit is used to collect metering data in real time.

6. The experimental device for automatically determining the planar visualization of thermal connectivity between heavy oil thermal recovery wells according to claim 5, characterized in that: The thermal imaging module also includes an industrial camera (18) and a temperature calibration probe (20). The industrial camera (18) is coaxially arranged with the infrared thermal imager (17). The industrial camera (18) is used to acquire planar images to assist in the identification of the steam leading edge. The temperature calibration probe (20) is set in the sand-filled cavity and is used to calibrate the temperature measurement of the infrared thermal imager (17).

7. The experimental device for automatic visual determination of thermal connectivity between heavy oil thermal recovery wells according to claim 6, characterized in that: The processing steps of the determination module are as follows: S1: Establish a mapping relationship between physical coordinates and pixel coordinates based on the temperature field data collected by the infrared thermal imager (17); S2: Delineate the inter-well analysis area based on the planar coordinates of the steam injection well and the production well; S3: Extract the temperature field characteristics within the inter-well analysis area; S4: Calculate the thermal connectivity distance index, which characterizes the extent of thermal front extension, based on the aforementioned temperature field characteristics. Thermal symmetry index, which characterizes the symmetry of the thermal front. The drag coefficient characterizing the flow resistance in thermal recovery and the production efficiency coefficient characterizing thermal recovery efficiency ; S5: Based on calculations value, value, Value and The thermal connectivity coefficient I is calculated using the AHP (Analytical Hierarchy Process) method, and the planar thermal connectivity state is determined and output.

8. The experimental device for automatic visual determination of thermal connectivity between heavy oil thermal recovery wells according to claim 7, characterized in that: In step S4, the thermal connectivity distance index The calculation formula is: ； ； ； in, For the influence factor of thermal connection temperature, The thermal connectivity distance is an influencing factor. Intensity factor This refers to the proportion of high-temperature zones within the control area between injection and production wells. The distance between the highest temperature pixel and the injection well. This refers to the spacing between injection and production wells; , and The calculation formula is: ； ； ； in, This represents the sum of the temperatures of all pixels within the pixel area of ​​the infrared thermal imager that have a temperature greater than 150 degrees Celsius. This represents the number of pixels with a temperature greater than 150 degrees Celsius across all pixel ranges. The steam injection temperature. The initial temperature of the experimental setup. The x-coordinate of the pixel is The ordinate of the pixel; Thermal symmetry index The calculation formula is: ； in, This refers to the number of pixels in the high-temperature zone located to the left of the center line of the injection-sampling line where the temperature exceeds 150 degrees Celsius. This refers to the number of pixels in the high-temperature zone whose temperature exceeds 150 degrees Celsius to the right of the center line of the injection-sampling connection. drag coefficient The calculation formula is: ； in, This refers to the injection-production pressure difference during the steam injection process. This refers to the initial pressure difference during the steam injection process; Production efficiency coefficient The calculation formula is: ； in, For cumulative oil production, This represents the cumulative injection amount.

9. The experimental device for automatic visual determination of thermal connectivity between heavy oil wells according to claim 8, characterized in that: In step S5, the formula for calculating the thermal connectivity coefficient I is: ； in, , , , These are the thermal connectivity distance indices. Thermal symmetry index drag coefficient Production efficiency coefficient Weights calculated using the AHP method; when When the value is ≥0.75, it is considered fully connected; when 0.45≤ When the value is less than 0.75, the connection is considered unconnected. When <0.45, it is determined to be partially connected; Weights calculated using the AHP method , , and The specific steps are as follows: A1: Constructing the Criterion Layer Matrix Characterizing the importance of temperature field features relative to flow field features: ； in, This serves as a scale for the importance of temperature field characteristics relative to flow field characteristics. , which is the importance scale of flow field characteristics relative to temperature field characteristics; A2: Constructing the temperature field feature matrix Characterizing the thermal connectivity distance index Relative to thermal symmetry index Importance: ； in, Thermal connectivity distance index Relative to thermal symmetry index Importance scale , which is relative to the production efficiency coefficient Importance scale, when thermal connectivity distance index With thermal symmetry index When equally important, =1; A13: Constructing the flow field characteristic matrix Characterizing the drag coefficient Relative to the production efficiency coefficient Importance: ； in, drag coefficient Relative to the production efficiency coefficient Importance scale , is the production efficiency coefficient Relative to drag coefficient Importance scale; A14: Calculate the matrix The geometric mean of the elements in each row. ； ； Normalization yields the criterion layer weights. ； ； in, For the characteristic weights of the temperature field, For the characteristic weights of the flow field; Similarly, calculate the matrix. Normalized weights and and matrix Normalized weights and ; A15: Calculate the combined weights of each indicator for the target layer: ； ； ； ； A16: Calculate the consistency ratio : ； ； in, To determine the largest eigenvalue of a matrix, Let be the order of the matrix. It is a random consistency index; when each judgment matrix is When the value is less than 0.1, the weight is accepted. , , and .

10. An experimental method for automatically determining the planar visualization of thermal connectivity between heavy oil thermal recovery wells, comprising the experimental device for automatically determining the planar visualization of thermal connectivity between heavy oil thermal recovery wells as described in any one of claims 7 to 9, characterized in that: It also includes the following steps: B1: The sand filling cavity of the sand filling system (19) is filled with quartz sand and saturated simulated oil, and the steam injection well and the production well are arranged there. B2: Steam is injected into the steam injection well according to the set parameters, and the pressure of the back pressure valve (26) is set to control the production of the production well. The infrared thermal imager (17) continuously collects the temperature field data of the horizontal plane of the sand filling cavity at set time intervals. The production volume and oil production are recorded in real time by the measuring cylinder (21) and the electronic balance (22). B3: The determination module executes steps S1 to S5, processes each frame of temperature field data, and outputs the thermal connectivity status determination result in real time. B4: Real-time overlay display of planar temperature field map, well location mark, high temperature isotherm and current thermal connectivity determination result on the display terminal.

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