Gas invasion simulation device, gas invasion simulation experiment method and method for judging gas invasion position

Abstract

The application discloses a kind of simulation gas invasion device and gas invasion simulation experiment method and the method for judging gas invasion position.The application utilizes the principle of pressure wave technology, simulates the gas invasion of different depth positions in wellbore, excites excitation pressure wave to wellbore by pressure excitation device, and pressure wave carries effective leakage point information in the process of propagation, is influenced by drilling fluid, well trajectory and other factors in the process of propagation, and the pressure wave is detected by the pressure sensor of inlet pipeline and outlet pipeline, and the corresponding theoretical pressure wave response spectrum curve is obtained, and by comparing it with the actually measured pressure wave response spectrum curve when gas invasion occurs, the position of actual gas invasion can be accurately determined.The application has the advantages of accurate detection, strong instantaneity, low implementation cost and simple operation, and can be widely applied to the detection of gas invasion position in various drilling processes.

Description

Technical Field

[0001] This invention relates to the field of oil and gas exploration and development technology, and in particular to a gas intrusion simulation device, a gas intrusion simulation experimental method, and a method for determining the location of gas intrusion. Background Technology

[0002] As domestic oil and gas exploration moves towards deeper and more complex reservoirs, the lithology encountered in deep drilling is intricate and complex, with multiple pressure systems developing from top to bottom. When gas layers are encountered, gas is very likely to enter the wellbore, causing frequent gas intrusion and overflow, interfering with the normal maintenance of geological logging and drilling fluid performance, and may also lead to a series of complex problems such as stuck pipe, blowout, and collapse, which seriously restrict the progress of drilling projects.

[0003] During drilling, issues such as the excitation pressure generated during drilling, low drilling fluid density, and abnormal formation pressure can cause the formation pressure to exceed the annulus pressure, leading to gas intrusion into the wellbore and resulting in gas intrusion. Under any operating conditions, a negative pressure difference forms between the annulus and the formation when gas intrusion occurs. If gas intrusion is not detected and effective measures are not taken in time, the negative pressure difference between the annulus and the formation will further increase as the gas migrates towards the wellhead, exacerbating the gas intrusion, worsening the situation, and easily inducing blowouts and other accidents. Typically, gas intrusion occurs at the bottom of the well or at the casing shoe, but in exceptionally complex formations, it can occur anywhere in the open hole. From a drilling safety perspective, the earlier gas intrusion is detected, the better. This allows for more accurate determination of the gas intrusion location, facilitates the implementation of effective measures to suppress it, fundamentally prevents blowouts, and ensures the normal progress of drilling operations.

[0004] Gas intrusion detection in the drilling industry, both domestically and internationally, is currently limited to determining whether gas intrusion has occurred. However, employing rapid and accurate methods to pinpoint the location of gas intrusion during drilling is crucial. This not only aids in analyzing complex formation structures but also allows for targeted and effective measures to suppress gas intrusion, such as increasing drilling fluid density, increasing back pressure, or using casing for isolation. Accurately determining the location of gas intrusion has become a pressing issue in drilling engineering. Therefore, providing a rapid and accurate method and device for detecting gas intrusion is essential. Summary of the Invention

[0005] In view of the above problems, the present invention is proposed to provide a device for simulating air intrusion, a method for simulating air intrusion experiments, and a method for determining the location of air intrusion in order to overcome or at least partially solve the above problems.

[0006] In a first aspect, embodiments of the present invention provide a simulated gas intrusion device, comprising: a simulated wellbore, a simulated drill string, an inlet pipe, an inlet pressure sensor, an outlet pipe, an outlet pressure sensor, a drilling pump, and a storage tank; an excitation device, multiple gas intrusion valves, an inlet valve, and an air compressor; a hydraulic throttle valve, a gas-liquid flow meter, and an industrial control computer; wherein:

[0007] The simulated drill string is installed inside the simulated wellbore; the drilling pump is connected to a storage tank, and the storage tank is connected to the simulated drill string and the simulated wellbore through an inlet pipe and an outlet pipe;

[0008] The outlet pressure sensor is located near the outlet of the outlet pipeline; the inlet pressure sensor is located near the inlet of the inlet pipeline.

[0009] The inlet pressure sensor, the outlet pressure sensor, the hydraulic throttle valve, and the gas-liquid flow meter are sequentially installed on the outlet pipeline and connected to the industrial control computer via a transmission line.

[0010] The excitation device is connected to the outlet pipeline and is positioned between the outlet pressure sensor and the gas-liquid flow meter.

[0011] Multiple gas intrusion valves are respectively installed on multiple gas intrusion simulation pipelines at different elevations. One end of each gas intrusion simulation pipeline is connected to a different depth in the wellbore, and the other end is connected to an air compressor through an air inlet valve. The multiple gas intrusion valves are used to open to simulate the occurrence of gas intrusion.

[0012] The industrial control computer is used to monitor the gas and / or drilling fluid flow signal data collected by the gas-liquid flow meter in real time, control the liquid flow in the pipeline through the hydraulic throttle valve, and obtain and process the outlet pressure wave signal data collected by the outlet pressure sensor and the inlet pressure wave signal data collected by the inlet pressure sensor when different gas intrusion valves are opened to simulate gas intrusion at different locations, so as to obtain the pressure wave response curves at different gas intrusion locations.

[0013] In one embodiment, the actuation device includes: a hydraulic gun, a hydraulic line, and a check valve;

[0014] One end of the hydraulic line is connected to the outlet line, and the other end of the hydraulic line is connected to the hydraulic gun; the one-way valve is located at the junction of the hydraulic line and the outlet line; the hydraulic gun is equipped with an excitation wrench to reset after excitation.

[0015] In one embodiment, the industrial control computer is used to continuously acquire the pressure wave signals of the inlet pressure sensor and the outlet pressure sensor after the hydraulic gun completes excitation, until the excitation pressure wave disappears and a preset time is delayed; to perform noise reduction processing on the acquired pressure wave signal data; to perform fast Fourier transform on the noise-reduced pressure wave signal data to obtain the corresponding frequency domain signal, and to derive the response spectrum curve of the gas invasion location through a pre-established simulated wellbore annular system pressure variable response function.

[0016] In one embodiment, the inlet pipe is connected to the top of the simulated drill string in the simulated wellbore, and the other end is connected to the drilling pump;

[0017] One end of the outlet pipeline is connected to the outlet of the annulus between the simulated wellbore and the simulated drill string, and the other end is connected to the storage tank.

[0018] In one embodiment, the storage tank is used to hold drilling fluid; the drilling pump is used to pump the drilling fluid out of the storage tank and circulate it until the simulated wellbore and simulated drill string are filled with the drilling fluid before the simulated gas intrusion.

[0019] Secondly, embodiments of the present invention provide a method for conducting a gas invasion simulation experiment using the aforementioned simulated gas invasion apparatus, comprising:

[0020] Start the drilling pump to pump the drilling fluid from the storage tank and circulate it in the inlet pipeline, the simulated drill string, the simulated wellbore annulus, and the outlet pipeline until the simulated wellbore and the simulated drill string are filled with the drilling fluid.

[0021] After the preset excitation conditions are met, the excitation device is pressurized until the preset pressure value is reached;

[0022] Turn on the air compressor, close all air inlet valves, and open the air intake valve;

[0023] Open the air inlet valve at the preset position and close the air inlet valves at other positions, keep the air inlet valve open, and record the flow meter reading;

[0024] The excitation device is triggered to emit an excitation pressure wave signal, and the pressure wave signals at the inlet sensor and the outlet sensor are collected until the excitation pressure wave disappears and then a preset time is delayed.

[0025] The collected pressure wave signal data is denoised.

[0026] The denoised pressure wave signal is subjected to a fast Fourier transform to convert the pressure wave time domain signal to a frequency domain signal. The response spectrum curve of the gas invasion location is derived by using the pre-established response function of the pressure variable of the simulated wellbore annulus system.

[0027] In one embodiment, if the experimental method needs to continuously simulate gas intrusion at different locations in the wellbore, after the gas intrusion simulation at the previous location is completed, all gas intrusion valves are closed, and the drilling fluid is circulated for a preset time until there is no gas in the simulated wellbore and simulated drill string; then the gas intrusion valve at the current location is opened, and the gas intrusion at the current location is simulated again.

[0028] Thirdly, embodiments of the present invention provide a method for determining the location of gas intrusion, comprising:

[0029] If gas intrusion is detected, an excitation pressure wave signal is emitted at the wellbore outlet through an excitation device, and the original pressure wave signal is collected by pressure sensors at the surface throttling manifold and riser.

[0030] The acquired raw pressure wave signal is then denoised.

[0031] The denoised signal is subjected to a fast Fourier transform to obtain the pressure wave response spectrum curve, which retains low-frequency characteristics.

[0032] By comparing the pressure wave response spectrum curve with the simulated pressure wave response spectrum curves at various locations in the wellbore during gas intrusion, the actual location of gas intrusion can be determined.

[0033] The pressure wave response spectrum curves at various locations in the wellbore obtained by simulation were obtained through the gas intrusion simulation experiment method described above.

[0034] In one embodiment, denoising the acquired raw pressure wave signal includes:

[0035] The original pressure wave signal is denoised using variational mode decomposition (VMD) or wavelet transform algorithms.

[0036] In one embodiment, the location of air intrusion is determined by comparing the pressure wave response spectrum curve with the simulated pressure wave response spectrum curves at various locations during air intrusion, including:

[0037] The measured pressure wave response spectrum curves were compared with the pressure wave response spectrum curves of simulated gas intrusion at multiple different locations in the wellbore.

[0038] Based on the peak position and trend of the curve, the actual location of the measured pressure wave response spectrum curve is determined using the bisection method.

[0039] The beneficial effects of the above-described technical solutions provided in the embodiments of the present invention include at least the following:

[0040] This invention employs the principle of pressure wave technology: a pressure excitation device generates an appropriate intensity pressure wave into the wellbore. As the excitation wave propagates downhole, it encounters an overflow point, resulting in pressure wave reflection and refraction. The reflected wave propagates from the overflow point towards the wellhead, while the original excitation wave, affected by refraction, changes its waveform and continues propagating downhole. Upon reaching the bottom of the well, it enters the drill string through the drill bit and then propagates towards the wellhead. During propagation, the pressure wave carries effective information about the leakage point. Due to the influence of drilling fluid flow and wellbore trajectory during propagation, pressure waves at the surface choke manifold and riser are detected, and characteristic information is extracted to determine the overflow layer. Using this method, gas intrusion at different depths in the wellbore is simulated, and the corresponding pressure wave response spectrum curves are obtained. By comparing these curves with the measured pressure wave response spectrum curves during actual gas intrusion, the actual location of the gas intrusion can be accurately determined. It features accurate and real-time detection, and because it does not require large-scale modifications to the well site, it generates pressure waves through a hydraulic excitation device and collects pressure wave data through a pressure sensor, achieving low cost and simple operation. It can be widely used for detecting gas intrusion locations in various drilling processes.

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

[0042] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0043] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0044] Figure 1 This is a schematic diagram of the simulated gas invasion device in an embodiment of the present invention;

[0045] Figure 2 This is a flowchart of the gas intrusion simulation experiment method in an embodiment of the present invention;

[0046] Figure 3A and 3B This is a schematic diagram of the measured pressure wave frequency domain curve and function frequency domain curve in Embodiments 1 and 2 of the present invention;

[0047] Figure 4 This is a schematic diagram of the wellbore annulus system in an embodiment of the present invention;

[0048] Figure 5This is a flowchart of a method for determining the location of gas intrusion in an embodiment of the present invention.

[0049] Explanation of reference numerals in the attached figures:

[0050] 1. Simulated wellbore; 2. Simulated drill string; 3. Inlet pressure sensor; 4. Inlet pipeline; 5. Outlet pressure sensor; 6. Drilling pump; 7. Suction pipeline; 8. Storage tank; 9. Outlet pipeline; 10. Check valve; 11. Hydraulic pipeline; 12. Hydraulic gun; 13. First gas inlet valve; 14. Second gas inlet valve; 15. Third gas inlet valve; 16. Gas pipeline; 17. Inlet valve; 18. Air compressor; 19. Transmission line of inlet sensor; 20. Transmission line of outlet sensor; 21. Signal output line; 22. Industrial control computer; 23. Computer; 24. Transmission line of gas-liquid flow meter; 25. Transmission line of hydraulic throttle valve; 26. Gas-liquid flow meter; 27. Hydraulic throttle valve. Detailed Implementation

[0051] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0052] The following detailed description, with reference to the accompanying drawings, provides a detailed explanation of the specific implementation methods of the simulated gas invasion device, the gas invasion simulation experiment method, and the method for determining the location of gas invasion provided by the present invention.

[0053] (a) Example of a simulated gas intrusion device:

[0054] This invention provides a device for simulating gas intrusion, with reference to... Figure 1 As shown, it includes: a simulated wellbore 1, a simulated drill string 2, an inlet pipe 4, an inlet pressure sensor 3, an outlet pipe 9, an outlet pressure sensor 5, a drilling pump 6, and a storage tank 8; an excitation device, multiple gas intrusion valves, an air inlet valve 17, and an air compressor 18; a hydraulic throttle valve 25, a gas-liquid flow meter 26, and an industrial control computer 22; wherein:

[0055] The simulated drill string 2 is set inside the simulated wellbore 1; the drilling pump 6 is connected to the storage tank 8, and the storage tank 8 is connected to the simulated drill string 2 and the simulated wellbore 1 through the inlet pipe 4 and the outlet pipe 9;

[0056] The outlet pressure sensor 3 is located near the outlet of the outlet pipe 9; the inlet pressure sensor 3 is located near the inlet of the inlet pipe.

[0057] Inlet pressure sensor 3, outlet pressure sensor 5, hydraulic throttle valve 25 and gas-liquid flow meter 26 are sequentially installed on outlet pipeline 9 and connected to industrial control computer 22 through transmission line;

[0058] The excitation device is connected to the outlet pipeline 9 and is located between the outlet pressure sensor 5 and the gas-liquid flow meter 26;

[0059] Multiple gas intrusion valves (e.g.) Figure 1 The first gas intrusion valve 13, the second gas intrusion valve 14, and the third gas intrusion valve 15 shown (but the embodiments of the present invention are not limited to three gas intrusion valves) are respectively installed on multiple gas intrusion simulation pipelines at different heights. One end of the multiple gas intrusion simulation pipelines is connected to different depths of the wellbore, and the other end is connected to an air compressor through an air inlet valve 17. The multiple gas intrusion valves are used to simulate the occurrence of gas intrusion when they are opened.

[0060] The industrial control computer 22 is used to monitor the gas and / or drilling fluid flow signal data collected by the gas-liquid flow meter in real time, control the liquid flow in the pipeline through the hydraulic throttle valve, and obtain the outlet pressure wave signal data collected by the outlet pressure sensor 3 and the inlet pressure wave signal data collected by the inlet pressure sensor 3 when different gas intrusion valves are opened to simulate gas intrusion at different locations, and process them to obtain the pressure wave response curves at different gas intrusion locations.

[0061] The storage tank 8 is used to hold drilling fluid (or experimental water) for subsequent recycling of drilling fluid in the simulated wellbore 1. The drilling pump 6 is used to pump the drilling fluid out of the storage tank and circulate it until the simulated wellbore 1 and simulated drill string 2 are filled with the drilling fluid before simulating gas intrusion.

[0062] Figure 1 The simulated gas intrusion device shown includes three gas intrusion valves, which are respectively set at several different preset depths of the simulated wellbore 1, such as 1 / 2, 1 / 3, 2 / 3 of the simulated wellbore 1, etc. The embodiments of the present invention are not limited to specific depths or positions, nor are they limited to the specific number of gas intrusion valves.

[0063] The inlet pipe 4 is connected to the top of the simulated drill string 2 in the simulated wellbore 1, and the other end is connected to the drilling pump 6;

[0064] One end of the outlet pipe 9 is connected to the outlet of the annulus between the simulated wellbore 1 and the simulated drill string 2, and the other end is connected to the storage tank 8.

[0065] The tubing structure inside a wellbore can be simulated using visual materials (transparent or semi-transparent). For example, concentric inner and outer casings can be used to simulate the drill string and wellbore, such as PC tubing. Drilling fluid, pressurized by the drilling pump, enters from one end of the inner casing (simulating the drill string), flows to the other end, and then flows in reverse through the annulus between the inner and outer casings until it circulates to the clean water tank. This simulated wellbore 1, using visual materials, allows for more intuitive observation of the drilling fluid circulation in the annulus between the inner and outer casings, helping to quickly eliminate interference from environmental factors and facilitating the observation and recording of the experimental process.

[0066] Provided the tubing structure inside the wellbore remains intact, each simulated tubing assembly in the simulated gas intrusion device is equipped with a quick connector. One end of the inlet pipe is installed at the top of the simulated drill string 2 inside the wellbore, and the other end is connected to the drilling pump 6. The drilling pump 6 is then connected to the storage tank 8. After completing the above pipeline connection, the drilling fluid can enter the simulated drill string 2 and annulus inside the wellbore from the storage tank 8. The annulus outlet is connected to one end of the outlet pipe 9, and the other end of the outlet pipe 9 is connected to the storage tank 8. After completing the above pipeline connection, the drilling fluid can return from the simulated drill string 2 and annulus inside the wellbore to the storage tank 8. Connecting the two parts of the pipeline completes the drilling fluid circulation.

[0067] Furthermore, the aforementioned excitation device, referring to Figure 1 As shown, it specifically includes: a hydraulic gun 12, a hydraulic line 11, and a check valve 10;

[0068] One end of the hydraulic line 11 is connected to the outlet line, and the other end of the hydraulic line 11 is connected to the hydraulic gun 12; the one-way valve 10 is located at the junction of the hydraulic line 11 and the outlet line 9; the hydraulic gun 12 is equipped with an excitation wrench to reset after excitation.

[0069] The hydraulic gun 12 is equipped with an excitation wrench, which can be reset after excitation. Before excitation, a portion of the prepared drilling fluid needs to be injected into the hydraulic gun 12. External pressurization causes the internal drilling fluid pressure to change until it reaches the pressure value required for the experiment. After reaching the required excitation pressure value, the one-way valve 10 must be opened first, and then the excitation wrench must be pulled. The internally pressurized drilling fluid enters the choke manifold through the hydraulic line 11, completing the excitation operation. This excitation device is characterized by its immediacy, low cost, and simple operation.

[0070] The specifications of the drilling pump 6 can be selected, for example, with a displacement of 0-4.5 m³ / h adjustable by frequency conversion, a head of 16 m, and inlet and outlet connections via flanges. The variable frequency motor equipped with the circulating pump can meet the experimental needs of different specifications of simulated pipe assemblies. The drilling fluid storage tank can be made of, for example, 304 stainless steel with a volume of 200L.

[0071] The industrial control computer 22 is used to continuously acquire the pressure wave signal of the inlet pressure sensor 3 and the pressure wave signal of the outlet pressure sensor 5 after the hydraulic gun 12 completes the excitation, until the excitation pressure wave disappears and then delays for a preset time; it performs noise reduction processing on the acquired pressure wave signal data; it performs fast Fourier transform on the noise-reduced pressure wave signal data to obtain the corresponding frequency domain signal, and derives the response spectrum curve of the gas invasion location through the pre-established simulated wellbore annulus system pressure variable response function.

[0072] On the industrial control computer 22, a control program can be installed. This control program can consist of measurement modules such as drilling fluid flow rate, pressure, leakage, and gas flow rate, which can monitor the changes in drilling fluid flow rate, pressure, leakage, and gas flow rate in real time during the test process.

[0073] The pressure measurement system consists of a high-precision pressure sensor and a shock-resistant pressure gauge. It primarily tests and records the process pressure during the experiment. The pressure sensor is a high-precision sensor, offering high accuracy and minimal drift. Flow measurement is achieved using a gas flow meter, while gas inflow measurement is performed using a high-precision miniature gas flow meter. A high-frequency sensor acquires pulse waveforms at a sampling rate of 14 kHz, employing dual channels, and the sampling rate can be adjusted according to experimental needs.

[0074] The program's software interface is specifically developed based on the project's experimental requirements. Exported data includes sampling rate, excitation pressure, flow rate, process pressure, leakage, and gas intrusion location. Sampling rate, excitation pressure, and gas intrusion location can be manually entered experimental information, while liquid flow rate, gas flow rate, process pressure, and leakage are data collected by sensors. Experimental data is exported as files to a specified location on the industrial computer's hard drive, with customizable filenames. The generated experimental data files are editable and can be segmented and saved separately.

[0075] (II) Examples of methods for simulating air intrusion experiments:

[0076] Based on the aforementioned simulated gas intrusion device, this embodiment of the invention also provides a method for conducting a gas intrusion simulation experiment using the aforementioned simulated gas intrusion device, referring to... Figure 2 As shown, the method includes the following steps:

[0077] S21. Start the drilling pump to pump the drilling fluid from the storage tank and circulate it in the inlet pipeline, the simulated drill string, the simulated wellbore annulus, and the outlet pipeline until the simulated wellbore and the simulated drill string are filled with the drilling fluid.

[0078] S22. After the preset excitation conditions are met, the excitation device is pressurized until the preset pressure value is reached;

[0079] S23. Turn on the air compressor, close all air inlet valves, and open the air intake valve;

[0080] S24. Open the air inlet valve at the preset position and close the air inlet valves at other positions, keep the air inlet valve open, and record the flow meter reading;

[0081] S25. Trigger the excitation device to emit an excitation pressure wave signal, and collect the pressure wave signal at the inlet sensor and the pressure wave signal at the outlet sensor until the excitation pressure wave disappears and then delay for a preset time.

[0082] S26. Denoise the collected pressure wave signal data;

[0083] S27. Perform a fast Fourier transform on the denoised pressure wave signal to convert the pressure wave time domain signal to a frequency domain signal. Using the pre-established simulated wellbore annulus system pressure variable response function, derive the response spectrum curve of the location where gas intrusion occurs.

[0084] Furthermore, if the experimental method needs to continuously simulate gas intrusion at different locations in the wellbore, after the gas intrusion simulation at the previous location is completed, all gas intrusion valves are closed, and the drilling fluid is circulated for a preset time until there is no gas in the simulated wellbore and simulated drill string; then the gas intrusion valve at the current location is opened, and the gas intrusion at the current location is simulated again.

[0085] The method of the above-mentioned gas intrusion simulation experiment is illustrated below with two examples (Example 1 and Example 2).

[0086] The specific implementation process of the two embodiments, combined with Figure 1 The structure of the simulated gas intrusion device shown is described in detail below, and the specific implementation process is as follows.

[0087] Example 1:

[0088] Step 1: Prepare experimental clean water or conventional drilling fluid in storage tank 8 for subsequent simulated wellbore drilling fluid recycling.

[0089] Step 2: Connect the hydraulic gun and hydraulic lines to the throttling manifold.

[0090] Before applying pressure with the hydraulic gun, observe whether the pressure gauge is in its initial position. If the pressure gauge pointer is not in its initial position, adjust the pressure gauge to restore it to its initial position.

[0091] Step 3: Inspect the appearance of the drilling fluid circulation system, the simulated wellbore inner column, and the annulus to check for any obvious leaks.

[0092] If there is no obvious leakage, turn on drilling pump 6 and let the drilling fluid circulate for about ten minutes. During this period, it is necessary to continuously observe whether there is gas in the drilling fluid inside the transparent wellbore.

[0093] If there is still gas in the simulated wellbore, the drilling fluid needs to be circulated continuously. Open the vent valve at the choke manifold of the simulated wellbore and use the drilling fluid circulation to completely expel the gas in the simulated wellbore through the vent valve until the simulated wellbore 1 and the simulated drill string 2 are filled with experimental clean water or conventional drilling fluid.

[0094] Step 4: Observe the flow meter and the transparent simulated wellbore. After the drilling fluid circulation flow rate remains stable and the hydraulic gun and hydraulic pipeline are connected, and there is no gas in the simulated wellbore, start the industrial control computer 22 and computer 23 and open the program control page.

[0095] After starting the industrial control computer 22 and the computer 23, check whether the industrial control computer is running normally. If it is not running normally, troubleshoot the problem in time and check whether the computer's initial page is abnormal.

[0096] Step 5: After opening the signal acquisition program control page, click the dual-channel acquisition mode, input the pressure sensor acquisition frequency of 14KHz, and click the signal acquisition button. From this moment on, pressure sensor 3 and pressure sensor 5 will start acquiring pressure wave signals at the wellbore inlet and annulus outlet.

[0097] On the signal acquisition page, observe whether the pressure wave fluctuations collected by the pressure sensor are stable and within a controllable range. If the pressure wave fluctuations are large or abnormally distorted, check in time whether the drilling fluid circulation device and the signal acquisition device are abnormal and troubleshoot the problem promptly.

[0098] Step 6: Observe the status of each instrument. If the drilling fluid circulation is normal, check whether the operation of each instrument is within the normal and controllable range.

[0099] Step 7: After the excitation conditions are met, pressurize the hydraulic gun 12, observe the changes in the hydraulic dial, and increase the pressure to the pressure value required for the experiment.

[0100] Step 8: Turn on the air compressor, close the first air inlet valve 13; the second air inlet valve 14; the third air inlet valve 15; and open the intake valve 17.

[0101] Step 9: After completing step 8, open the first gas inlet valve 13, keep the inlet valve 17 open, and record the reading of the gas flow meter.

[0102] Step 10: Open the one-way valve 10, reset the signal acquisition channel button, and start acquiring pressure wave signals from this moment. When the pressure wave signal is acquired, quickly trigger the hydraulic gun trigger device 3 to 5 seconds after the acquisition begins to generate the flow variable Δq.

[0103] Step 11: After the hydraulic gun is energized, the inlet pressure sensor 3 and the outlet sensor 5 collect the pressure wave signal through dual channels until the energized pressure wave waveform disappears 3 to 5 seconds after recording. Then click the stop button.

[0104] Step 12: After completing step 11, store the collected pressure wave signal in the corresponding folder on the computer.

[0105] Step 13: Extract the collected pressure wave signal data from the corresponding folder and process the data. Due to experimental environment factors, the collected pressure wave contains a large amount of noise signal, which makes spectrum analysis difficult. Therefore, it is necessary to denoise the signal.

[0106] Step 14: After completing step 13, the denoised signal is converted to the spectrum by Fast Fourier Transform (FFT) to transform the time-domain signal of the pressure wave for analysis.

[0107] Step 15: Establish the pressure variable response function Δh of the simulated wellbore annulus system. D (ω), derive the theoretical response curve for gas intrusion occurring at 1 / 2 of the simulated wellbore.

[0108] Analysis of the frequency domain curves shows that the pressure wave is a low-frequency signal, exhibiting a gradually decaying trend in the spectrum, with the first peak of the amplitude being the largest, and subsequent peaks decreasing sequentially.

[0109] Step 16: After completing steps 14 and 15, compare the measured pressure wave frequency domain curve with the function frequency domain curve;

[0110] Through comparison and combination Figure 3A As shown, the peak amplitude of the measured pressure wave frequency domain curve is basically consistent with the peak amplitude of the function frequency domain curve.

[0111] The system transfer function is only related to the characteristics of the annulus itself, and the operating characteristics (excitation operation) remain unchanged. Therefore, it can be determined from the pressure variable spectrum that the gas invasion occurs at 1 / 2 of the wellbore.

[0112] Example 2:

[0113] Step 1: Prepare experimental clean water or conventional drilling fluid in storage tank 8 for subsequent simulated wellbore drilling fluid recycling.

[0114] Step 2: Connect the hydraulic gun and hydraulic lines to the throttling manifold.

[0115] Step 3: Inspect the appearance of the drilling fluid circulation system, the simulated wellbore inner column, and the annulus to check for any obvious leaks.

[0116] If there is no obvious leakage, turn on drilling pump 6 and let the drilling fluid circulate for about ten minutes. During this period, it is necessary to continuously observe whether there is gas in the drilling fluid inside the transparent wellbore.

[0117] If there is still gas in the simulated wellbore, the drilling fluid needs to be circulated continuously. Open the vent valve at the choke manifold of the simulated wellbore and use the drilling fluid circulation to completely expel the gas in the simulated wellbore through the vent valve until the simulated wellbore 1 and the simulated drill string 2 are filled with experimental clean water or conventional drilling fluid.

[0118] Before applying pressure with the hydraulic gun, observe whether the pressure gauge is in its initial position. If the pressure gauge pointer is not in its initial position, adjust the pressure gauge to restore it to its initial position.

[0119] If the experiment continuously detects the location of gas intrusion in the simulated wellbore, steps 1, 2, and 3 can be skipped. All gas intrusion valves should be closed, and the drilling fluid in step 2 should be circulated for about ten minutes until there is no gas in the transparent annulus. This avoids the pressure fluctuations caused by the excitation wave in the previous experiment from affecting this group of experiments.

[0120] Step 4: Observe the flow meter and the transparent simulated wellbore. After the drilling fluid circulation flow rate remains stable and the hydraulic gun and hydraulic pipeline are connected, and there is no gas in the simulated wellbore, start the industrial control computer 22 and computer 23, and open the overflow analysis software.

[0121] After starting the industrial control computer 22 and the computer 23, check whether the industrial control computer is running normally. If it is not running normally, troubleshoot the problem in time and check whether the computer's initial page is abnormal.

[0122] Step 5: After opening the signal acquisition program control page, turn on the dual-channel acquisition mode, input the pressure sensor acquisition frequency of 14KHz, and click the signal acquisition button. From this moment on, pressure sensor 3 and pressure sensor 5 will start acquiring pressure wave signals at the wellbore inlet and annulus outlet.

[0123] On the signal acquisition page, observe whether the pressure wave fluctuations collected by the pressure sensor are stable and within a controllable range. If the pressure wave fluctuations are large or abnormally distorted, check in time whether the drilling fluid circulation device and the signal acquisition device are abnormal and troubleshoot the problem promptly.

[0124] Step 6: Observe the status of each instrument. If the drilling fluid circulation is normal, check whether the operation of each instrument is within the normal and controllable range.

[0125] Step 7: After the excitation conditions are met, pressurize the hydraulic gun 12, observe the changes in the hydraulic dial, and increase the pressure to the pressure value required for the experiment.

[0126] Step 8: Turn on the air compressor, close the first air inlet valve 13; the second air inlet valve 14; the third air inlet valve 15; and open the intake valve 17.

[0127] Step 9: After completing step 8, open the second gas inlet valve 14, keep the inlet valve 17 open, and record the reading of the gas flow meter.

[0128] Step 10: Open the one-way valve 10, reset the signal acquisition channel button, and start acquiring pressure wave signals from this moment. When the pressure wave signal is acquired, quickly trigger the hydraulic gun trigger device 3 to 5 seconds after the acquisition begins to generate the flow variable Δq.

[0129] Step 11: After the hydraulic gun is energized, the inlet pressure sensor 3 and the outlet sensor 5 collect the pressure wave signal through dual channels until the energized pressure wave waveform disappears 3 to 5 seconds after recording. Then click the stop button.

[0130] Step 12: After completing step 11, store the collected pressure wave signal in the corresponding folder on the computer.

[0131] Step 13: Extract the collected pressure wave signal data from the corresponding folder and perform data processing. Due to experimental environmental factors, the pressure wave contains a large amount of noise signal, which makes spectrum analysis difficult. Therefore, signal denoising processing is performed.

[0132] Step 14: After completing step 13, the denoised signal is transformed by FFT to convert the pressure wave time domain signal to the spectrum for analysis.

[0133] Step 15: Establish the pressure variable response function Δh of the simulated wellbore annulus system. D (ω), deriving the theoretical response curve for air intrusion occurring at 2 / 3. Analysis of the function's frequency domain curve shows that the pressure wave is a low-frequency signal, exhibiting the following pattern on the spectrum: the first peak of amplitude decays, the second peak increases again, and subsequent amplitudes decay rapidly with increasing frequency.

[0134] Step 16: After completing steps 14 and 15, compare the measured pressure wave frequency domain curve with the function frequency domain curve, and combine them... Figure 3B By comparison, the measured peak amplitude of the pressure wave frequency domain curve and the peak amplitude of the function frequency domain curve are basically consistent with each other as the frequency increases, and the operating characteristics are consistent. By comparing the spectrum curves, it can be determined that the location of gas invasion in the wellbore annulus is at 2 / 3 of the wellbore.

[0135] Since the pressure wave propagates within the annulus, the effective information at the location of the air intrusion is contained in the characteristics of the pressure wave signal, which is more obvious and intuitive from the spectrum analysis, and can effectively locate the location of the air intrusion.

[0136] (III) Explanation of the principles of the above-mentioned simulated gas invasion device and gas invasion simulation experiment:

[0137] The simulated gas intrusion device and method for gas intrusion simulation experiments provided in the above embodiments are based on the principle of a real pressure and flow transmission model within an annulus. The principle of this simulated gas intrusion device and method is explained below:

[0138] The simulated gas intrusion device simulates the wellbore annulus system and obtains the simulated frequency response curve by exciting the pressure wave pulse response.

[0139] The acquired waveform is the time-domain waveform of the pressure wave, which needs to be obtained by fast Fourier transform to obtain the frequency domain response spectrum of the excitation pressure wave.

[0140] Reference Figure 4 As shown, due to gas intrusion at a certain location in the wellbore, the wellbore annulus system is divided into two parts: wellbore annulus system 1 and annulus system 2. To study the transient flow problem within the annulus caused by a determined excitation signal, the transfer matrix method can be used. According to distributed parameter theory, for a wellbore of fixed length, its terminal pressure and flow rate can be represented by its initial pressure and flow rate.

[0141] The function of pressure and flow rate at any point within the annulus is:

[0142] When x = l, the field matrix equation of the one-dimensional pipe can be expressed as:

[0143]

[0144] Due to air intrusion in the annulus, at the point of air intrusion H U2 =H D1 Q U2 =Q D1 -Q l =Q U1 -H D1 / Z L The relation holds, therefore the transfer matrix equation at the gas intrusion point is: Therefore, the overall transfer matrix equation of the wellbore annulus system can be obtained as follows:

[0145]

[0146] Transfer function of an atoll system:

[0147] The impedance at any point within the wellbore annulus is defined as: Z(x) = H(x) / Q(x), which is the transfer function of the wellbore annulus system.

[0148] When no gas intrusion occurs in the annulus, since the annulus originates from a constant pressure source, the fluctuating pressure at the inlet is H. U =0, the impedance at the entrance of the annulus is ZU =H U / Q U =0; the output impedance of the annular system is:

[0149]

[0150] As can be seen from the system output impedance formula when no gas intrusion occurs in the annulus, when there is no fluctuation at the inlet, the transfer function of the wellbore annulus system is only related to the characteristic impedance of the system, the propagation constant in the annulus, and the fixed length of the annulus. Therefore, when no gas intrusion occurs in the annulus, the system transfer function will not change.

[0151] When gas intrusion occurs in the annulus, because the annulus inlet is a constant pressure source, the fluctuating pressure at the annulus inlet is H. U1 =0, the impedance at the entrance of the annulus is Z U1 =H U1 / Q U1 =0; the cross-sectional area of ​​the annulus remains unchanged, therefore γ = γ1 = γ2 and Z C =Z C1 =Z C2 Established.

[0152] The output impedance of the annular system is:

[0153]

[0154] (H D2 Q D2 (The pressure and flow transfer matrix of the wellbore annulus system has been obtained above)

[0155] From the output impedance formula of the system when gas intrusion occurs in the annulus, it can be seen that when there is no fluctuation at the inlet, the wellbore annulus system is divided into two parts, wellbore annulus system 1 and annulus system 2, due to gas intrusion at a certain location in the wellbore. Therefore, the transfer function of the entire annulus system is obtained from the pressure and flow transfer matrix of annulus system 1, the transfer matrix at the leak point, and the pressure and flow transfer matrix of annulus system 2.

[0156] Based on the overall transfer function analysis of simulated wellbore 1, the characteristics of the simulated wellbore system are analyzed, ignoring pipe friction. and If true, then the annular output impedance between simulated wellbore 1 and simulated drill string 2 is:

[0157]

[0158] The transfer matrix of the wellbore annulus system shows that the system's transfer function is only related to the system's own characteristics. Once the system characteristics change, the system transfer function will also change. Therefore, gas intrusion in the wellbore will significantly affect the system characteristics.

[0159] Explanation of the impulse response method:

[0160] The annulus starts at a constant pressure source, and instantaneous hydraulic excitation is applied at the annulus outlet by a pulse flow rate Δq. D (t), the relative flow rate causes a step-like signal change: Fourier transform of the pulse flow function: Frequency domain amplitude modulus function Δq(ω) r ): In the formula, Δq′ represents the steady-state flow rate of the annulus minus the average flow rate after the valve is closed; This indicates a half-cycle of the annular space.

[0161] The hydraulic excitation momentarily closes, generating an excitation pulse flow. Using the Fourier transform convolution theorem, the pressure head function Δh relative to the response function and the pulse flow can be calculated. D (t): When the pressure at the top of the annulus is constant, the annulus outlet is momentarily partially closed due to hydraulic excitation and forced with a pulse flow. A Fourier transform of the unit pulse function yields: By applying the superposition principle, when a pulse pressure is applied to the annulus outlet, the pulse pressure response and flow response at any point in the annulus can be calculated:

[0162]

[0163] Based on the time-domain impulse pressure and flow responses, the Fourier transform can be used to convert the time-domain response into the frequency-domain response of the impulse pressure. Applying the Fourier convolution theorem, the Fourier transform of the pressure variable is the product of the Fourier transform of the response function and the Fourier transform of the flow variable: Δh D (ω)=H D (ω)Δq D (ω)=Z D (ω)Δq D (ω). This equation shows that for a valve that is momentarily partially closed, the pressure head spectrum consists of two parts: the Fourier transform of the system transfer function and the Fourier transform of the flow variable. The former depends only on the characteristics of the system, while the latter depends only on the valve's operating characteristics, and the pressure head spectrum has a linear relationship with the Fourier transform of the flow variable.

[0164] Generating a pressure wave at the drilling fluid outlet is a prerequisite for implementing pressure wave detection of lost circulation. This pressure wave is generated by connecting a pressure wave excitation device to the pressure gauge interface at the drilling site. The characteristics of the pressure wave generated by the excitation device are analyzed, and a reasonable pressure pulse intensity and control program are designed. By using casing, open hole walls, drill bits, and other components with different geometric dimensions, pressure waves with different shapes and flow channel characteristics are collected to study their propagation laws. The location and amount of lost or overflow layers will change the inherent characteristics of the wellbore flow channel, and the waveform and spectral characteristics of the pressure wave reflected and refracted at the lost or overflow layers will also change accordingly. The reflected and refracted waves of the excitation pressure wave at the lost or overflow layers are recorded, their propagation characteristics are studied, and a time-domain and frequency-domain mathematical model suitable for pressure wave detection of lost or overflow layers is established.

[0165] The pressure measurement system consists of a high-precision pressure sensor, which mainly tests and records the process pressure signal during the experiment. The high-frequency sensor acquires the pulse waveform at a sampling rate of 14KHz, uses dual channels, and the sampling rate can be adjusted according to the experimental needs.

[0166] The measured pressure wave signal is analyzed, and the Fourier convolution theorem is applied. The Fourier transform of the pressure variable is the product of the Fourier transform of the response function and the Fourier transform of the flow rate variable. The system response function is determined through spectral analysis and compared with the measured results to determine the location of gas intrusion.

[0167] In the above formula:

[0168] l: Length of the loop; l1: Length of loop 1; l2: Length of loop 2; H U Initial pressure; Q U : Initial flow; H D Terminal pressure; Q D Terminal traffic; Q l Leakage flow; H U1 Pressure at the inlet of annulus 1; H U2 Pressure at the inlet of annulus 2; H D1 Pressure at the outlet of annulus 1; H D2 : Pressure at the outlet of annulus 2; g: acceleration due to gravity;

[0169] A: Cross-sectional area of ​​the annulus pipe; a: Pressure wave velocity; D: Inner diameter of the annulus pipe; f: Darcy-Weibach coefficient of friction; Propagation constants; γ1: Propagation constant of annular space 1; γ2: Propagation constant of annular space 2; Z C =γ / Cs: Characteristic impedance of the annulus; Z C1 Characteristic impedance of the annular loop 1; Z C2 Characteristic impedance of the annular loop; L = 1 / gA: inductive reactance per unit length;

[0170] s = iω: Laplace variable; i: complex unit; ω: frequency; C = gA / a 2 : Capacitive reactance per unit length; q: Flow rate

[0171] R = fq 2 / (2gDA 2 ): Impedance per unit length; Z D : Output impedance of the annular system; Z U1 Impedance at the entrance of annular space 1;

[0172] Z D2 Impedance at the annular outlet; Z L Δq: Dynamic impedance at the leakage point. D : Flow rate variable at the annular outlet;

[0173] Δq(ω r ): Frequency domain amplitude modulus function of flow variable; Δq′: Annular steady-state flow rate minus the average flow rate after valve closure;

[0174] Circular half-cycle; H D (t): Pressure response function; Δh D (t): Pressure head function.

[0175] Using the above-mentioned experimental simulation method, pressure wave response spectrum curves at different wellbore depths can be simulated. With these pressure wave response spectrum curves at different locations, the actual pressure wave response spectrum curve can be obtained during actual gas intrusion monitoring using a similar principle. This can be compared with the pressure wave response spectrum curve obtained during simulation to determine the actual location of gas intrusion.

[0176] (iv) Examples of methods for determining the location of gas intrusion:

[0177] Based on the above explanation of the principles, embodiments of the present invention also provide a method for determining the location of gas intrusion, referring to... Figure 5 As shown, it includes:

[0178] S51. If gas intrusion is detected, an excitation pressure wave signal is emitted at the wellbore outlet through an excitation device, and the original pressure wave signal is collected through pressure sensors at the surface throttling manifold and riser.

[0179] S52. The acquired original pressure wave signal is subjected to noise reduction processing;

[0180] S53. The denoised signal is subjected to a fast Fourier transform to obtain the pressure wave response spectrum curve, which retains low-frequency characteristics.

[0181] S54. By comparing the pressure wave response spectrum curve with the simulated pressure wave response spectrum curves at various locations in the wellbore during gas intrusion, the actual location of gas intrusion is determined.

[0182] The pressure wave response spectrum curves at various locations in the wellbore obtained by the above simulation were obtained through the gas intrusion simulation experiment method described above.

[0183] Furthermore, step S52 above can be used to denoise the original pressure wave signal using variational mode decomposition (VMD) or wavelet transform algorithms.

[0184] Furthermore, in step S54 above, the measured pressure wave response spectrum curve can be compared with the pressure wave response spectrum curves when gas intrusion occurs at multiple different locations in the simulated wellbore.

[0185] Based on the peak position and trend of the curve, the actual location of the measured pressure wave response spectrum curve is determined using the bisection method.

[0186] The dichotomy method uses a recursive approach to continuously narrow down the comparison space through dichotomy, in order to quickly determine the actual location of gas intrusion.

[0187] For example, after collecting the measured data, compare it with the simulated spectrum curve to compare the peak position and the sudden drop position to determine the interval where the gas invasion occurs. Then, use the bisection method to divide the interval into two parts to narrow the interval range and continue to simulate the frequency response curve of this interval. For example, simulate the pressure wave spectrum curve when gas invasion occurs at 1 / 3, 1 / 2, and 2 / 3. If the trend of the measured curve is the same as the trend of the simulated curve when gas invasion occurs between 1 / 3 and 1 / 2, then compare it with the simulated curve at 5 / 12 between 1 / 3 and 1 / 2. If the fit with the curve at 5 / 12 is very high, the gas invasion location is near the well depth × 5 / 12.

[0188] This invention employs the principle of pressure wave technology: a pressure excitation device generates an appropriate intensity pressure wave into the wellbore. As the excitation wave propagates downhole, it encounters an overflow point, resulting in pressure wave reflection and refraction. The reflected wave propagates from the overflow point towards the wellhead, while the original excitation wave, affected by refraction, changes its waveform and continues propagating downhole. Upon reaching the bottom of the well, it enters the drill string through the drill bit and then propagates towards the wellhead. During propagation, the pressure wave carries effective information about the leakage point. Due to the influence of drilling fluid flow and wellbore trajectory during propagation, pressure waves at the surface choke manifold and riser are detected, and characteristic information is extracted to determine the overflow layer. Using this method, gas intrusion at different depths in the wellbore is simulated, and the corresponding theoretical pressure wave response spectrum curves are obtained. By comparing these theoretical and theoretical pressure wave response spectrum curves with those of actual gas intrusion, the actual location of the gas intrusion can be accurately determined.

[0189] Compared with the prior art, the simulated gas invasion device, the gas invasion simulation experiment method, and the method for determining the location of gas invasion provided in the embodiments of the present invention have the following technical effects:

[0190] 1. Accurate detection: Although conventional gas intrusion detection devices can determine whether gas intrusion has occurred, they cannot accurately detect the location of the gas intrusion. This invention, based on the pressure excitation wave detection method, not only realizes the function of conventional gas intrusion detection, but also accurately determines the location of the gas intrusion, making up for the defect of existing devices that cannot accurately determine the location of the gas intrusion, and effectively improving work efficiency.

[0191] 2. High immediacy: This invention uses pressure sensors and gas-liquid flow meters to detect changes in pressure and flow rate at the inlet and outlet positions in real time, which not only improves the accuracy of gas intrusion detection, but also realizes real-time monitoring of the drilling process, effectively improving the sensitivity of detection.

[0192] 3. Low equipment cost: This invention does not require large-scale modifications to the well site. It generates pressure waves through a hydraulic gun, uses a pressure sensor to detect the wellhead pressure, and transmits the detection data to an industrial control computer via a data transmission line. The industrial control computer calculates the parameters, thereby enabling the detection of gas intrusion location.

[0193] 4. Simple operation: Simply turn on the industrial control computer, connect the data transmission lines, input the relevant parameters, and observe the output results on the industrial control computer screen to complete the gas intrusion detection and gas intrusion location determination.

[0194] 5. Wide range of applications: This invention can be widely used to detect the location of gas intrusion during drilling processes such as underbalanced drilling, controlled pressure drilling, and micro-flow drilling.

[0195] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A method for determining the location of gas intrusion, characterized in that, include: If gas intrusion is detected, an excitation pressure wave signal is emitted at the wellbore outlet through an excitation device, and the original pressure wave signal is collected by pressure sensors at the surface throttling manifold and riser. The acquired raw pressure wave signal is then denoised. The denoised signal is subjected to a fast Fourier transform to obtain the measured pressure wave response spectrum curve, which retains low-frequency characteristics. By comparing the measured pressure wave response spectrum curve with the simulated theoretical pressure wave response spectrum curve at various locations in the wellbore during gas intrusion, the actual location of gas intrusion can be determined. The theoretical pressure wave response spectrum curves at various locations in the wellbore obtained by simulation were obtained by conducting gas intrusion simulation experiments using a simulated gas intrusion device. The simulated gas intrusion device includes: a simulated wellbore, a simulated drill string, an inlet pipe, an inlet pressure sensor, an outlet pipe, an outlet pressure sensor, a drilling pump, and a storage tank; an excitation device, multiple gas intrusion valves, an inlet valve, and an air compressor; a hydraulic throttle valve, a gas-liquid flow meter, and an industrial control computer; among which: The simulated drill string is set inside the simulated wellbore; the drilling pump is connected to the storage tank, the inlet pipe is connected to the top of the simulated drill string in the simulated wellbore, and the other end is connected to the drilling pump; One end of the outlet pipeline is connected to the outlet of the annulus between the simulated wellbore and the simulated drill string, and the other end is connected to the storage tank. The outlet pressure sensor is located near the outlet of the outlet pipeline; the inlet pressure sensor is located near the inlet of the inlet pipeline. The inlet pressure sensor, the outlet pressure sensor, the hydraulic throttle valve, and the gas-liquid flow meter are sequentially installed on the outlet pipeline and connected to the industrial control computer via a transmission line. The excitation device is connected to the outlet pipeline and is positioned between the outlet pressure sensor and the gas-liquid flow meter. Multiple air intrusion valves are respectively installed on multiple air intrusion simulation pipelines at different heights. One end of each of the multiple air intrusion simulation pipelines is connected to a different depth in the simulated well, and the other end is connected to an air compressor through an air inlet valve. The multiple air intrusion valves are used to open to simulate the occurrence of air intrusion. The industrial control computer is used to monitor the gas and / or drilling fluid flow signal data collected by the gas-liquid flow meter in real time, control the liquid flow in the pipeline through the hydraulic throttle valve, and obtain the outlet pressure wave signal data collected by the outlet pressure sensor and the inlet pressure wave signal data collected by the inlet pressure sensor when different gas intrusion valves are opened to simulate gas intrusion at different locations, and process them to obtain the theoretical pressure wave response spectrum curves at different gas intrusion locations. The method for the gas intrusion simulation experiment includes: Start the drilling pump to pump the drilling fluid from the storage tank and circulate it in the inlet pipeline, the simulated drill string, the simulated wellbore annulus, and the outlet pipeline until the simulated wellbore and the simulated drill string are filled with the drilling fluid. After the preset excitation conditions are met, the excitation device is pressurized until the preset pressure value is reached; Turn on the air compressor, close all air inlet valves, and open the air intake valve; Open the air inlet valve at the preset position and close the air inlet valves at other positions, keep the air inlet valve open, and record the flow meter reading; The excitation device is triggered to emit an excitation pressure wave signal, and the pressure wave signals at the inlet pressure sensor and the outlet pressure sensor are collected until the excitation pressure wave disappears and then a preset time is delayed. The collected pressure wave signal data is denoised. The denoised pressure wave signal is subjected to a fast Fourier transform to convert the pressure wave time domain signal to a frequency domain signal. The theoretical pressure wave response spectrum curve at the location of gas intrusion is derived by using a pre-established simulated wellbore annulus system pressure variable response function.

2. The method for determining the location of gas intrusion as described in claim 1, characterized in that, The acquired raw pressure wave signal is subjected to noise reduction processing, including: The original pressure wave signal is denoised using variational mode decomposition (VMD) or wavelet transform algorithms.

3. The method for determining the location of gas intrusion as described in claim 1 or 2, characterized in that, By comparing the measured pressure wave response spectrum curves with the simulated theoretical pressure wave response spectrum curves at various locations during air intrusion, the locations where air intrusion occurs are determined, including: The measured pressure wave response spectrum curves were compared with the theoretical pressure wave response spectrum curves when gas intrusion occurred at multiple different locations in the simulated wellbore. Based on the peak position and trend of the curve, the actual location of the measured pressure wave response spectrum curve is determined using the bisection method.

4. The method for determining the location of gas intrusion as described in claim 1, characterized in that, If the experimental method requires continuous simulation of gas intrusion at different locations in the simulated wellbore, after the gas intrusion simulation at the previous location is completed, all gas intrusion valves are closed, and the drilling fluid is circulated for a preset time until there is no gas in the simulated wellbore and the simulated drill string; then the gas intrusion valve at the current location is opened, and the gas intrusion at the current location is simulated again.

5. The method for determining the location of gas intrusion as described in claim 1, characterized in that, The excitation device in the simulated gas invasion device includes: a hydraulic gun, a hydraulic pipeline, and a one-way valve; One end of the hydraulic line is connected to the outlet line, and the other end of the hydraulic line is connected to the hydraulic gun; the one-way valve is located at the junction of the hydraulic line and the outlet line; the hydraulic gun is equipped with an excitation wrench to reset after excitation.

6. The method for determining the location of gas intrusion as described in claim 5, characterized in that, After the hydraulic gun completes the excitation, the industrial control computer continuously collects the pressure wave signal from the inlet pressure sensor and the pressure wave signal from the outlet pressure sensor until the excitation pressure wave disappears and then delays for a preset time. The collected pressure wave signal data is denoised; the denoised pressure wave signal data is then subjected to a fast Fourier transform to obtain the corresponding frequency domain signal. The theoretical pressure wave response spectrum curve at the location of gas intrusion is derived by using a pre-established simulated wellbore annulus system pressure variable response function.

7. The method for determining the location of gas intrusion as described in any one of claims 1, 4-6, characterized in that, The storage tank of the simulated gas intrusion device is used to hold drilling fluid; before the simulated gas intrusion, the drilling pump pumps the drilling fluid out of the storage tank and circulates it until the simulated wellbore and simulated drill string are filled with the drilling fluid.

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