Device and method for measuring penetration depth of drilling and completion fluid into rock core based on resistance test

Abstract

The invention provides a device and method for measuring the depth of drilling and completion fluid invading into a rock core based on resistance testing. The device for measuring the depth of drilling and completion fluid invading into the rock core comprises a shaft drilling and completion fluid flowing simulation module, a drilling and completion fluid invading simulation module, a temperature and pressure control module, a resistance measuring module and a recovery module. The shaft drilling and completion fluid flowing simulation module, the drilling and completion fluid invasion simulation module and the recovery module are connected in sequence; the drilling and completion fluid invasion simulation module is connected with the temperature and pressure control module and the resistance measurement module. The device can truly simulate the dynamic invasion process of the well drilling and completion fluid in the underground high-temperature and high-pressure environment to the reservoir when the well drilling and completion fluid flows, performs non-destructive measurement by using the resistance measuring instrument, realizes accurate quantitative determination of the depth of the drilling and completion fluid invading the rock core, and is suitable for deep oil and gas reservoir drilling and completion fluid pollution evaluation and reservoir protection.

Description

Technical Field

[0001] This invention relates to the field of oil and gas exploration technology, and in particular to a device and method for determining the depth of drilling and completion fluid intrusion into the core based on resistance testing. Background Technology

[0002] During oil and gas drilling and completion, drilling and completion fluids inevitably infiltrate the reservoir, causing pore blockage, decreased permeability, and impacting reservoir productivity. Therefore, accurately assessing the depth of drilling and completion fluid intrusion into the core is crucial for calculating reservoir damage and developing reservoir protection and unblocking measures.

[0003] Currently, commonly used methods for evaluating the depth of drilling and completion fluid invasion mainly include: 1. Staining method, which involves adding dye to the drilling and completion fluid and observing the color distribution after invasion by cutting sections, but this method requires core destruction and is highly subjective; 2. Nuclear magnetic resonance method, which can non-destructively detect fluid distribution, but the equipment is expensive and the operation is complex, making it difficult to popularize; 3. Resistivity method, a traditional method that only measures the overall or local resistance of the core, and cannot accurately locate the invasion boundary; 4. CT scan method, which can provide three-dimensional imaging, but it is costly, has limited resolution, and has a weak ability to distinguish between drilling and completion fluid and water.

[0004] CN118008281A discloses a method for determining reservoir fracture width when drilling fluid density is increased. The method includes determining the density change of the drilling fluid after adding weighting materials; calculating the change in formation pressure of the target well based on the drilling fluid density change; obtaining fractured rock samples through artificial fracturing using downhole rock samples, and conducting stress-sensitive experiments to obtain dynamic parameters of fractures under different pressure gradients, thus obtaining a stress sensitivity coefficient; calculating the fracture width change under drilling fluid density changes; and calculating the fracture width value under drilling fluid density changes. Starting from the change in drilling and completion fluid density, the method establishes the relationship between formation pressure and drilling and completion fluid density using the DC index method. Combined with stress-sensitive experiments, it evaluates the impact of formation pressure changes on reservoir fracture width by analyzing the changes in fracture width before and after stress damage to natural fractures, providing theoretical support for the addition of plugging agents in drilling and completion fluids and their application in reservoirs. This method is not suitable for determining the depth of drilling and completion fluid penetration into the core.

[0005] CN120214259A discloses a testing device for measuring the depth of wellbore fluid invasion into a reservoir. The device includes a dual-core holder, a formation pressure simulation mechanism, a formation temperature simulation mechanism, a fluid circulation mechanism, and a flow measurement mechanism connected to the dual-core holder via pipelines, and a data processing mechanism for receiving and processing data from the dual-core holder. This method can simulate working conditions and reservoir environments under different operational conditions during oil and gas exploration and development, and utilize microwave continuous measurement to determine the depth of wellbore fluid invasion into the reservoir. It provides a basis for optimizing wellbore fluid performance and system selection, as well as for the selection and design of engineering processes such as drilling parameters, completion methods, reservoir stimulation technologies, and reservoir protection technologies. However, this method still suffers from the problem of inaccurate measurement results of the depth of wellbore fluid invasion into the reservoir.

[0006] Therefore, it is of great significance to develop a simple and accurate device and method for measuring the depth of drilling and completion fluid invasion into the core based on resistance testing. Summary of the Invention

[0007] In view of the problems existing in the prior art, the present invention provides a device and method for determining the depth of drilling and completion fluid invasion into the core based on resistance testing. The device uses a resistance measuring instrument to measure the resistance of the core point by point before and after the drilling and completion fluid invasion, and uses the resistance-core position relationship curve to determine the depth of the drilling and completion fluid invasion into the core, thereby achieving accurate and non-destructive quantitative determination of the invasion depth.

[0008] To achieve this objective, the present invention adopts the following technical solution:

[0009] In a first aspect, the present invention provides a drilling and completion fluid invasion depth measuring device based on resistance testing, the drilling and completion fluid invasion depth measuring device comprising a wellbore drilling and completion fluid flow simulation module, a drilling and completion fluid invasion simulation module, a temperature and pressure control module, a resistance measurement module, and a recovery module;

[0010] The wellbore drilling and completion fluid flow simulation module, the drilling and completion fluid intrusion simulation module, and the recovery module are connected in sequence.

[0011] The drilling and completion fluid intrusion simulation module is connected to the temperature and pressure control module and the resistance measurement module, respectively.

[0012] The drilling and completion fluid invasion depth determination device based on resistance testing described in this invention utilizes a wellbore drilling and completion fluid flow simulation module to simulate the actual flow process of drilling and completion fluid in the wellbore and provide a stable pressure of drilling and completion fluid to the core holder; it uses a drilling and completion fluid invasion simulation module to simulate the process of drilling and completion fluid invading the core; a temperature and pressure control module provides a high-temperature and high-pressure environment consistent with formation conditions for the drilling and completion fluid invasion simulation module; a resistance measurement module acquires resistance data at various scale points before and after drilling and completion fluid invasion, generates a resistance-core position relationship curve, and finally determines the depth of drilling and completion fluid invasion into the core; and a recovery module recovers waste fluid from the drilling and completion fluid invasion core experiment. This device based on resistance testing can realistically simulate the dynamic invasion process of drilling and completion fluid into the reservoir under high-temperature and high-pressure conditions, possessing advantages such as non-destructive operation and high precision. It can be used for drilling and completion fluid pollution assessment and reservoir protection in deep oil and gas reservoirs and is suitable for widespread application.

[0013] Preferably, the wellbore drilling and completion fluid flow simulation module includes a displacement pump, an intermediate container, a first pressure gauge, a high-strength circular tube, and a first backpressure valve connected in sequence. The displacement pump is used to drive the flow of drilling and completion fluid; the high-strength circular tube is used to simulate the wellbore and is pressure-resistant to 80 MPa; the backpressure valve works with the displacement pump to adjust the pressure inside the high-strength circular tube, so that the pressure inside the high-strength circular tube is the same as and remains stable as the fluid column pressure during the actual drilling and completion process.

[0014] Preferably, a one-way valve is provided on the connecting pipeline between the displacement pump and the intermediate container to prevent liquid backflow.

[0015] Preferably, the back pressure valve is connected to the first recovery device.

[0016] Preferably, the drilling and completion fluid invasion simulation module includes a core holder, a core, a shut-off valve, a second back pressure valve, and a second pressure gauge.

[0017] Preferably, the shut-off valve, the second pressure gauge, the rock core, and the second back pressure valve are connected in sequence.

[0018] The shut-off valve of the present invention remains closed before the system pressure stabilizes. It is manually opened after the pressure inside the high-strength circular pipe is confirmed by the first pressure gauge to reach the set value, so as to start the process of drilling and completion fluid intrusion into the core. The second back pressure valve is used to regulate and maintain the displacement pressure inside the core holder. The second pressure gauge is used to assist in monitoring the pressure status before entering the core holder.

[0019] Preferably, the core is fixed by a core holder.

[0020] Preferably, the core is marked with equally spaced scale points.

[0021] Preferably, the temperature and pressure control module includes a confining pressure pump and a constant temperature chamber.

[0022] Preferably, the confining pressure pump is connected to the core holder and is used to apply confining pressure to the core holder to simulate the formation pressure environment.

[0023] Preferably, the second back pressure valve, the second pressure gauge, the core and the core holder are placed inside a constant temperature chamber to simulate a high-temperature underground environment.

[0024] Preferably, the resistance measurement module includes a resistance meter.

[0025] Preferably, the probe of the resistance measuring instrument is in contact with the outer surface of the rock core.

[0026] Preferably, the resistance measuring instrument is equipped with a data recording unit to store the resistance values ​​and corresponding scale point numbers before and after the drilling fluid enters the core, and to generate a curve showing the relationship between resistance and core position.

[0027] The resistance measuring instrument described in this invention includes a digital display resistance measuring instrument.

[0028] Preferably, the recycling module includes a second recycling device.

[0029] Preferably, the second recovery device is connected to the second back pressure valve.

[0030] Secondly, the present invention also provides a method for determining the depth of drilling and completion fluid invasion into the core based on resistance testing, wherein the method for determining the depth of drilling and completion fluid invasion into the core is performed using the drilling and completion fluid invasion into the core depth measuring device based on resistance testing described in the first aspect; the method for determining the depth of drilling and completion fluid invasion into the core includes the following steps:

[0031] (a) After the core sample is cleaned, dried and displaced in sequence, multiple scale points are marked along the axial direction to obtain the core;

[0032] (b) Use a resistance measuring instrument to measure multiple scale points of the core point by point and record the initial resistance value of each scale point to generate a curve showing the relationship between the resistance of the core before drilling and completion fluid enters the core and the core position.

[0033] (c) Place the core into the core holder and place it in the constant temperature chamber. Start the confining pressure pump to set the confining pressure. Start the displacement pump while keeping the shut-off valve closed, so that the drilling fluid enters the intermediate container and the high-strength round pipe in sequence. Maintain the pipeline pressure by adjusting the first back pressure valve and monitor the pressure inside the high-strength round pipe by the first pressure gauge until the pressure stabilizes and reaches the set value.

[0034] (d) Open the shut-off valve to allow drilling and completion fluid to enter the core holder and begin the intrusion process; stop the displacement after the preset time is reached;

[0035] (e) Remove the core and use a resistance meter to measure the resistance value at each scale point again to generate a curve showing the relationship between the resistance and the core position after the drilling fluid has invaded the core. The scale value corresponding to the intersection of the curve showing the relationship between the resistance and the core position before the drilling fluid has invaded the core described in step (b) is the depth of the drilling fluid intrusion into the core.

[0036] The method for determining the depth of drilling and completion fluid invasion into the core based on resistance testing, as described in this invention, is simple to operate and requires no expensive specialized equipment. It involves testing the resistance values ​​at multiple scale points on the core before and after fluid invasion, and plotting the relationship between the resistance and the core position. The intersection of these two curves is used as the basis for determining the invasion depth. This method overcomes the limitations of traditional single-point resistance testing, achieving quasi-distributed measurement of core resistance and accurate measurement of the depth of drilling and completion fluid invasion, avoiding misjudgments caused by core heterogeneity. Furthermore, using a resistance measuring instrument eliminates the need to cut or damage the core, allowing for multiple repeated experiments using the same core, thus saving samples. With the use of a constant temperature chamber and confining pressure pump, actual drilling and completion conditions can be simulated, resulting in highly reliable experimental results. This method is suitable for evaluating drilling and completion fluid contamination and protecting deep oil and gas reservoirs.

[0037] The present invention does not impose detailed limitations on the cleaning, drying and displacement treatment methods described in step (a), and conventional methods in the art can be used.

[0038] The present invention does not impose specific limitations on the set value of the pressure inside the high-strength circular tube in step (c) and the preset time in step (d). The values ​​can be determined based on the actual situation of the core sample and the simulation of the intrusion of drilling and completion fluid.

[0039] In step (e) of this invention, the intersection of the two curves refers to the point in the direction from the core inlet to the outlet. When the resistance value of a certain scale point after intrusion is equal to the resistance value before intrusion for the first time, the corresponding scale value is the depth of intrusion into the core.

[0040] Preferably, the displacement treatment in step (a) results in a water saturation of 50% to 60% in the core, for example, 50%, 52%, 54%, 56%, 58%, or 60%, but is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0041] Preferably, the number of scale points is not less than 10, for example, it can be 10, 11, 12, 14, 15, 16 or 18, etc., but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable to ensure that the curve trend is clear and the intersection point is accurately identified.

[0042] Preferably, the resistance measuring instrument in step (b) uses a four-electrode method or a two-electrode method to measure the resistance of the rock core, with a measurement accuracy of not less than ±1%, and the measurement process does not damage the rock core structure.

[0043] Preferably, the temperature of the constant temperature chamber in step (c) is 60~200℃, for example, it can be 60℃, 90℃, 120℃, 150℃, 180℃ or 200℃, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0044] Preferably, the pressure generated by the confining pressure pump is 10~80MPa, for example, it can be 10MPa, 25MPa, 40MPa, 55MPa, 70MPa or 80MPa, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0045] As a preferred embodiment of the present invention, the method for determining the depth of drilling and completion fluid intrusion into the core includes the following steps:

[0046] (a) After the core sample is washed, dried and displaced in sequence, multiple scale points are marked along the axial direction to obtain the core; the displacement treatment makes the water saturation of the core 50%~60%; the number of scale points is not less than 10.

[0047] (b) Use a resistance measuring instrument to measure the resistance of the core at multiple scale points and record the initial resistance value of each scale point to generate a curve showing the relationship between the resistance before drilling and completion fluid enters the core and the core position; the resistance measuring instrument uses the four-electrode method or the two-electrode method to measure the resistance of the core.

[0048] (c) Place the core into the core holder and put it in a constant temperature chamber with a temperature of 60~200℃. Start the confining pressure pump and set the confining pressure to 10~80MPa. Start the displacement pump while keeping the shut-off valve closed, so that the drilling fluid enters the intermediate container and the high-strength round pipe in sequence. Maintain the pipeline pressure by adjusting the first back pressure valve and monitor the pressure inside the high-strength round pipe by the first pressure gauge until the pressure stabilizes and reaches the set value.

[0049] (d) Open the shut-off valve to allow drilling and completion fluid to enter the core holder and begin the intrusion process; stop the displacement after the preset time is reached;

[0050] (e) Remove the core and use a resistance meter to measure the resistance value at each scale point again to generate a curve showing the relationship between the resistance and the core position after the drilling fluid has invaded the core. The scale value corresponding to the intersection of the curve showing the relationship between the resistance and the core position before the drilling fluid has invaded the core described in step (b) is the depth of the drilling fluid intrusion into the core.

[0051] Compared with the prior art, the present invention has at least the following beneficial effects:

[0052] (1) The drilling and completion fluid invasion depth measurement device based on resistance testing provided by the present invention does not require expensive special equipment. It uses a resistance measuring instrument for non-destructive measurement. The whole process does not require cutting or destroying the core. Multiple sets of repeated experiments can be carried out using the same core (such as different drilling and completion fluid systems and different pressure conditions), saving samples.

[0053] (2) The drilling and completion fluid penetration depth measurement device based on resistance testing provided by the present invention includes a wellbore drilling and completion fluid flow simulation module, a constant temperature chamber and a confining pressure pump, which can simulate the flow process and working conditions of drilling and completion fluid in the actual drilling and completion process in a real formation environment, thereby improving the reliability of experimental results.

[0054] (3) The method for determining the depth of drilling and completion fluid intrusion into the core based on resistance testing provided by the present invention is simple to operate. It uses the intersection of the resistance curve before and after drilling and completion fluid intrusion into the core and the core position curve to accurately and intuitively present the depth of intrusion, avoiding misjudgment caused by the heterogeneity of the core. Attached Figure Description

[0055] Figure 1 This is a schematic diagram of a drilling and completion fluid penetration depth measurement device based on resistance testing in a specific embodiment of the present invention.

[0056] Figure 2 This is a schematic diagram of a rock core marked with equally spaced scale points in a specific embodiment of the present invention.

[0057] Figure 3 This is a graph showing the relationship between the resistance of the drilling fluid before and after well completion and the core location in a specific embodiment of the present invention.

[0058] In the diagram: 1-First recovery device; 2-First back pressure valve; 3-High-strength circular pipe; 4-First pressure gauge; 5-Stop valve; 6-Intermediate container; 7-Resistance measuring instrument; 8-Core holder; 9-Containing pressure pump; 10-Displacement pump; 11-Check valve; 12-Constant temperature chamber; 13-Core; 14-Second back pressure valve; 15-Second pressure gauge; 16-Second recovery device. Detailed Implementation

[0059] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0060] The present invention will now be described in further detail. However, the examples described below are merely simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention is determined by the claims.

[0061] It should be understood that in the description of this invention, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0062] It should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "set," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; 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.

[0063] Those skilled in the art should understand that the present invention necessarily includes the necessary pipelines, conventional valves and general pump equipment for achieving process integrity, but the above content is not the main inventive point of the present invention. Those skilled in the art can add layouts based on process flow and equipment structure selection, and the present invention does not make any special requirements or specific limitations in this regard.

[0064] As a specific embodiment of the present invention, a device for determining the depth of drilling and completion fluid invasion into the core based on resistance testing is provided, the schematic diagram of which is shown below. Figure 1 As shown.

[0065] The drilling and completion fluid invasion depth measurement device includes a wellbore drilling and completion fluid flow simulation module, a drilling and completion fluid invasion simulation module, a temperature and pressure control module, a resistance measurement module, and a recovery module.

[0066] The wellbore drilling and completion fluid flow simulation module, the drilling and completion fluid intrusion simulation module, and the recovery module are connected in sequence.

[0067] The drilling and completion fluid intrusion simulation module is connected to the temperature and pressure control module and the resistance measurement module, respectively.

[0068] The wellbore drilling and completion fluid flow simulation module includes a displacement pump 10, an intermediate container 6, a first pressure gauge 4, a high-strength circular pipe 3, and a first back pressure valve 2 connected in sequence.

[0069] A one-way valve 11 is installed on the connecting pipeline between the displacement pump 10 and the intermediate container 6.

[0070] The back pressure valve 2 is connected to the first recovery device 1.

[0071] The drilling and completion fluid invasion simulation module includes a core holder 8, a core 13, a shut-off valve 5, a second back pressure valve 14, and a second pressure gauge 15.

[0072] In this specific embodiment, core 13 is a cylindrical sandstone core with a diameter of 2.5 cm and a length of 5 cm. A scale point is marked every 0.5 cm along the axial direction, for a total of 10 points (denoted as 1 to 10, with 1 near the entrance end). A schematic diagram is shown below. Figure 2 As shown.

[0073] The shut-off valve 5, the second pressure gauge 15, the core 13, and the second back pressure valve 14 are connected in sequence.

[0074] The core 13 is fixed by the core holder 8.

[0075] The temperature and pressure control module includes a confining pressure pump 9 and a constant temperature chamber 12.

[0076] The confining pressure pump 9 is connected to the core holder 8.

[0077] The second back pressure valve 14, the second pressure gauge 15, the core 13, and the core holder 8 are installed inside the constant temperature chamber 12.

[0078] The resistance measurement module includes a resistance meter 7. The probe of the resistance meter 7 is in contact with the outer surface of the core 13.

[0079] The resistance measuring instrument 7 is equipped with a data recording unit, which stores the resistance values ​​and corresponding scale point numbers before and after the drilling fluid invades the core, and generates a curve showing the relationship between resistance and core position.

[0080] The recycling module includes a second recycling device 16. The second recycling device 16 is connected to a second back pressure valve 14.

[0081] As a specific embodiment of the present invention, a method for determining the depth of drilling and completion fluid invasion into the core based on resistance testing is also provided. The method employs the aforementioned device for determining the depth of drilling and completion fluid invasion into the core based on resistance testing. The method includes the following steps:

[0082] (a) After the core sample was sequentially cleaned, dried and displaced, 10 scale points were marked along the axial direction to obtain core 13; the displacement treatment brought the water saturation of the core to 50%;

[0083] (b) The resistance measuring instrument 7 is used to measure the resistance of the core 13 at multiple scale points and record the initial resistance value of each scale point to generate a curve showing the relationship between the resistance before drilling and completion fluid enters the core and the core position; the resistance measuring instrument uses the four-electrode method to measure the resistance of the core.

[0084] The data results of the resistance and core location before the drilling and completion fluid invaded the core in this specific embodiment are shown in Table 1.

[0085]

[0086] Based on Table 1, plot the curves showing the relationship between the resistance before drilling and completion fluid invasion and the core location, as follows: Figure 3 The initial resistance curve is shown in the figure.

[0087] (c) Place the core 13 into the core holder 8 and place it in the constant temperature chamber 12 at a temperature of 150℃. Start the confining pressure pump 9 and set the confining pressure to 40MPa. Start the displacement pump 10 while keeping the shut-off valve 5 closed, so that the drilling fluid enters the intermediate container 6 and the high-strength circular pipe 3 in sequence. Maintain the pipeline pressure by adjusting the first back pressure valve 2 and monitor the pressure inside the high-strength circular pipe 3 by the first pressure gauge 4 until the pressure stabilizes at 3.5±0.1MPa.

[0088] (d) Open the shut-off valve 5 to allow the drilling and completion fluid to enter the core holder 8 and begin the invasion process; stop the displacement after 3 hours.

[0089] (e) Stop the displacement and wait for the system to cool to room temperature. Take out the core 13 and use the resistance measuring instrument 7 to measure the resistance value of each scale point again to generate the curve of the relationship between the resistance and the core position after the drilling fluid invades the core.

[0090] Table 2 shows the data results of resistance and core location after drilling fluid intrusion into the core in this specific embodiment.

[0091]

[0092] Based on Table 2, plot the curves showing the relationship between resistivity and core location after drilling and completion fluid intrusion, as follows: Figure 3 The pollution resistance curve is shown in the figure.

[0093] from Figure 3 It can be seen that the horizontal axis scale of the intersection point of the curve of resistance before drilling fluid intrusion into the core and the curve of resistance after drilling fluid intrusion into the core is 8cm, that is, the depth of drilling fluid intrusion into the core in this specific embodiment is 8cm.

[0094] In summary, the drilling and completion fluid invasion depth determination device based on resistance testing provided by this invention does not require expensive specialized equipment and uses a resistance measuring instrument for non-destructive measurement. Furthermore, it utilizes a wellbore drilling and completion fluid flow simulation module, a constant temperature chamber, and a confining pressure pump to simulate actual drilling and completion conditions in a real formation environment, thereby improving the reliability of the experimental results. By using the intersection of the resistance curves before and after drilling and completion fluid invasion with the core position curves, the depth of invasion into the core can be accurately and intuitively presented, avoiding misjudgments caused by core heterogeneity. It can be used for drilling and completion fluid pollution assessment and reservoir protection in deep oil and gas reservoirs.

[0095] The present invention is described in detail through the above embodiments, but the present invention is not limited to the above detailed structural features, that is, it does not mean that the present invention must rely on the above detailed structural features to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions for the components used in the present invention, additions of auxiliary components, and selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

[0096] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

Claims

1. A device for determining the depth of drilling and completion fluid invasion into the core based on resistance testing, characterized in that, The drilling and completion fluid invasion depth measuring device includes a wellbore drilling and completion fluid flow simulation module, a drilling and completion fluid invasion simulation module, a temperature and pressure control module, a resistance measurement module, and a recovery module. The wellbore drilling and completion fluid flow simulation module, the drilling and completion fluid intrusion simulation module, and the recovery module are connected in sequence. The drilling and completion fluid intrusion simulation module is connected to the temperature and pressure control module and the resistance measurement module, respectively.

2. The drilling and completion fluid invasion core depth measuring device according to claim 1, characterized in that, The wellbore drilling and completion fluid flow simulation module includes a displacement pump (10), an intermediate container (6), a first pressure gauge (4), a high-strength circular pipe (3), and a first back pressure valve (2) connected in sequence. Preferably, a check valve (11) is provided on the connecting pipeline between the displacement pump (10) and the intermediate container (6). Preferably, the back pressure valve (2) is connected to the first recovery device (1).

3. The drilling and completion fluid invasion core depth measuring device according to claim 1 or 2, characterized in that, The drilling and completion fluid invasion simulation module includes a core holder (8), a core (13), a shut-off valve (5), a second back pressure valve (14), and a second pressure gauge (15). Preferably, the shut-off valve (5), the second pressure gauge (15), the core sample (13), and the second back pressure valve (14) are connected in sequence; Preferably, the core (13) is fixed by a core holder (8); Preferably, the core (13) is marked with equally spaced scale points.

4. The drilling and completion fluid invasion core depth measuring device according to any one of claims 1 to 3, characterized in that, The temperature and pressure control module includes a confining pressure pump (9) and a constant temperature chamber (12). Preferably, the confining pressure pump (9) is connected to the core holder (8); Preferably, the second back pressure valve (14), the second pressure gauge (15), the core (13) and the core holder (8) are installed inside the constant temperature chamber (12).

5. The drilling and completion fluid invasion core depth measuring device according to any one of claims 1 to 4, characterized in that, The resistance measurement module includes a resistance meter (7); Preferably, the probe of the resistance measuring instrument (7) is in contact with the outer surface of the core (13); Preferably, the resistance measuring instrument (7) is equipped with a data recording unit to store the resistance value and corresponding scale point number before and after the drilling fluid invades the core, and to generate a curve showing the relationship between resistance and core position.

6. The drilling and completion fluid invasion core depth measuring device according to any one of claims 1 to 5, characterized in that, The recycling module includes a second recycling device (16); Preferably, the second recovery device (16) is connected to the second back pressure valve (14).

7. A method for determining the depth of drilling and completion fluid invasion into the core based on resistance testing, characterized in that, The method for determining the depth of drilling and completion fluid invasion into the core is performed using the drilling and completion fluid invasion into the core depth measurement device based on resistance testing as described in any one of claims 1 to 6; the method for determining the depth of drilling and completion fluid invasion into the core includes the following steps: (a) After the core samples were cleaned, dried and displaced in sequence, multiple scale points were marked along the axial direction to obtain the core (13). (b) Use a resistance measuring instrument (7) to measure the resistance of multiple scale points of the core (13) point by point and record the initial resistance value of each scale point to generate a curve showing the relationship between the resistance of the core before drilling and completion fluid enters the core and the core position. (c) Place the core (13) into the core holder (8) and place it in the constant temperature box (12). Start the confining pressure pump (9) to set the confining pressure. Start the displacement pump (10) while keeping the shut-off valve (5) closed, so that the drilling fluid enters the intermediate container (6) and the high-strength round pipe (3) in sequence. Maintain the pipeline pressure by adjusting the first back pressure valve (2). Monitor the pressure inside the high-strength round pipe (3) by the first pressure gauge (4) until the pressure stabilizes and reaches the set value. (d) Open the shut-off valve (5) to allow the drilling fluid to enter the core holder (8) and begin the intrusion process; stop the displacement after the preset time is reached; (e) Take out the core (13) and use a resistance measuring instrument (7) to measure the resistance value of each scale point again to generate the curve of the relationship between the resistance and the core position after the drilling fluid invades the core. The scale value corresponding to the intersection of the curve of the relationship between the resistance and the core position before the drilling fluid invades the core described in step (b) is the depth of the drilling fluid invading the core.

8. The method for determining the depth of drilling and completion fluid invasion into the core according to claim 7, characterized in that, The displacement treatment described in step (a) brings the water saturation of the core (13) to 50%~60%; Preferably, the number of scale points is not less than 10.

9. The method for determining the depth of drilling and completion fluid invasion into the core according to claim 7 or 8, characterized in that, In step (b), the resistance measuring instrument (7) measures the resistance of the core (13) using either the four-electrode method or the two-electrode method.

10. The method for determining the depth of drilling and completion fluid invasion into the core according to any one of claims 7 to 9, characterized in that, The temperature of the constant temperature chamber (12) in step (c) is 60~200℃; Preferably, the pressure generated by the confining pressure pump (9) is 10~80MPa.

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