Logging-while-drilling apparatus based on muon imaging

Abstract

The present application belongs to the field of geological exploration, and discloses a device for logging while drilling based on muon imaging technology; the device comprises an outer shell, an inner cylinder and a muon detector, wherein the inner cylinder is coaxially nested in the outer shell, and a relatively sealed detection space is formed between the inner cylinder and the outer shell; the muon detector is arranged in the detection space; the muon detector comprises a scintillator assembly coaxially sleeved and arranged in the detection space and a photodetector arranged on the inner side of the scintillator assembly, wherein the scintillator assembly is made of a scintillator material resistant to high temperature above 140 DEG C, and the inner wall of the detection space is provided with a heat insulation layer. The present application can be widely applied to oil and gas exploration, mineral resources investigation and underground structure detection, and can improve the detection depth and imaging accuracy of logging while drilling.

Description

Technical Field

[0001] This invention belongs to the field of geological exploration and relates to a logging-while-drilling technology, specifically, a logging-while-drilling device based on muon imaging technology. Background Technology

[0002] Logging While Drilling (LWD) technology provides formation information during drilling to assist in geological exploration and development. However, current mainstream LWD technologies mainly rely on resistivity, gamma rays, neutrons, and acoustic waves. These methods suffer from limited penetration range, are greatly affected by formation density, and have insufficient imaging accuracy, making it difficult to identify large-scale structures (such as faults). Muon imaging is a non-destructive testing technique based on cosmic ray muons. Due to their high penetrating power, muons can be used for imaging the interiors of media with large density variations and have been applied in fields such as volcano monitoring and nuclear waste detection. However, traditional muon detectors are bulky, relying on large-area detector arrays; the electronic components of the detectors lack the environmental tolerance to high temperatures and pressures and drilling vibrations; and muon imaging measurement time is long.

[0003] Therefore, muon detectors cannot be adapted to logging-while-drilling (LOD) tools, and muon technology is difficult to apply directly to downhole detection. In view of this, it is essential to propose a muon detection system suitable for LOD, possessing miniaturization, high temperature and pressure resistance, vibration resistance, and real-time imaging capabilities. Summary of the Invention

[0004] The purpose of this invention is to provide a logging-while-drilling device based on muon imaging technology. Through innovative design, it solves the problems of large size, poor temperature and pressure resistance, and susceptibility to vibration interference of muon detectors, and achieves high-precision detection of formation structure during drilling.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0006] A logging-while-drilling device based on muon imaging technology, including

[0007] outer shell;

[0008] The inner cylinder is coaxially nested within the outer shell, forming a relatively sealed detection space between the inner cylinder and the outer shell; and

[0009] Muon detectors are placed within the detection space;

[0010] The muon detector includes a scintillator assembly coaxially mounted in the detection space and a photodetector located inside the scintillator assembly. The scintillator assembly is made of a scintillator material that can withstand temperatures above 140°C, and the inner wall of the detection space is provided with a heat insulation layer.

[0011] Furthermore, the detection space is filled with a high-melting-point phase change material to prevent high-temperature shock, and the melting point of the high-melting-point phase change material is not lower than 140°C.

[0012] Furthermore, the scintillator assembly is provided with a vibration suppression module, which includes a first piezoelectric conversion module and a second piezoelectric conversion module. The first piezoelectric conversion module monitors the vibration signal of the scintillator assembly and generates a reverse drive signal based on the vibration signal to drive the second piezoelectric conversion module to generate reverse vibration, thereby suppressing the vibration.

[0013] Furthermore, the outer shell is a titanium alloy shell, and an inlet is provided on the side wall of the outer shell corresponding to the scintillator assembly. The inlet is sealed with a muon high-transmittance material to form a muon inlet window.

[0014] Furthermore, the scintillator assembly includes several coaxially stacked ring scintillators, and each scintillator assembly has at least one corresponding photodetector.

[0015] Furthermore, the scintillator assembly also includes a second scintillator array disposed circumferentially on the outer side of the scintillator assembly, and a photodetector is provided at the end of the second scintillator array.

[0016] Furthermore, both the scintillator assembly and the second scintillator are coated with a reflective layer.

[0017] Furthermore, the logging-while-drilling device based on muon imaging technology also includes an attitude sensor for monitoring the attitude of the logging-while-drilling device.

[0018] Furthermore, the logging-while-drilling device based on muon imaging technology also includes a data processing system, which includes a downhole real-time processing module and a surface processing platform. The downhole real-time processing module divides the continuous drilling process into multiple time slices for data storage. Each time slice independently calculates the muon flux attenuation rate, and then improves the signal-to-noise ratio through weighted fusion. The surface processing platform includes an industrial control computer for processing and analyzing the acquired data.

[0019] Furthermore, the detection space is filled with inert gas.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0021] This invention creatively designs a detection space composed of an inner cylinder and an outer shell. The drill pipe passes through the hollow axis of the inner cylinder, thereby installing the logging-while-drilling (LWD) device on the drill pipe to achieve LWD measurement. This invention designs a unique structure of a muon detector composed of a scintillator component and a photodetector, and encapsulates it within the detection space to isolate the effects of high temperature and high pressure on the scintillator component, photodetector, and other electronic components. Furthermore, a high-temperature resistant scintillator component is selected to meet the requirements for high temperature and high pressure resistance. Unexpectedly, this design of the present invention enables the first successful installation of a muon detector within a LWD device and the achievement of logging. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the downhole muon imaging system of the present invention;

[0023] Figure 2 This is a partial schematic diagram of the logging-while-drilling device in the downhole muon imaging system of the present invention;

[0024] Figure 3 yes Figure 2 Sectional view of AA;

[0025] Figure 4 This is a schematic diagram of an axially stacked ring scintillator array, which is a specific substantive examination method of the present invention.

[0026] Figure 5 This is a schematic diagram of a logging-while-drilling method based on muon imaging technology in a specific embodiment of the present invention.

[0027] Figure 6 This is a schematic diagram of the control module in one embodiment of the present invention.

[0028] Figure 7 This is a schematic diagram of the control module in another embodiment of the present invention.

[0029] 100-Logging while drilling device; 110-Outer shell; 111-Detection space; 120-Inner cylinder; 130-Müller detector; 131-Annular scintillator; 132-Annular scintillator array; 133-Photodetector; 140-Attitude sensor; 150-Vibration suppression module; 151-First piezoelectric conversion module; 152-Second piezoelectric conversion module;

[0030] 210-Drill pipe, 220-Drill bit; 300-Data processing system, 310-Downhole real-time processing module, 320-Surface processing platform. Detailed Implementation

[0031] To more clearly illustrate the technical solution described in this invention, the invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0032] It should be noted that the drawings provided in the following embodiments are only schematic illustrations of the basic ideas of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art are within the scope of protection of the present invention.

[0033] In existing technologies, logging temperatures are generally around 50-150℃, while ultra-deep well temperatures can reach over 200℃. The pressure range for atmospheric wells is 10-30MPa, for high-pressure gas wells it is 30-70MPa, and for ultra-high-pressure wells it is around 70-140MPa. Therefore, logging is a typical high-temperature and high-pressure environment. In addition, the space for logging while drilling is limited, making design difficult. Thus, although logging while drilling has its own technical advantages, there is no precedent for combining it with logging while drilling in existing technologies. The reason is that it is difficult to meet the high-temperature and high-pressure logging requirements within a limited space.

[0034] To solve the above technical problems, such as Figures 1 to 3 As shown, the present invention provides a logging-while-drilling device 100 based on muon imaging technology, including...

[0035] 110 outer casing;

[0036] The inner cylinder 120 is coaxially nested within the outer shell 110, forming a relatively sealed detection space 111 between the inner cylinder 120 and the outer shell 110; and

[0037] Muon detector 130 is installed in detection space 111;

[0038] The muon detector 130 includes a scintillator assembly coaxially mounted in the detection space 111 and a photodetector 133 disposed inside the scintillator assembly. The scintillator assembly is made of a scintillator material that can withstand temperatures above 140°C, and the inner wall of the detection space 111 is provided with a heat insulation layer.

[0039] This invention creatively designs a detection space 111 composed of an inner cylinder 120 and an outer shell 110. The drill pipe 210 passes through the hollow axis of the inner cylinder 120, thereby installing the logging-while-drilling device 100 on the drill pipe 210 to achieve logging-while-drilling. This invention designs a unique structure of a muon detector 130 composed of a scintillator assembly and a photodetector 133, and encapsulates it within the detection space 111 to isolate the effects of high temperature and high pressure on the scintillator assembly, photodetector 133, and other electronic components. Furthermore, a high-temperature resistant scintillator assembly is selected to meet the requirements of high temperature and high pressure resistance. Unexpectedly, this design of the present invention enables the first time that the muon detector 130 has been installed inside a logging-while-drilling device, and logging has been successfully achieved.

[0040] It should be noted that the installation method of the inner cylinder 120 and the drill rod 210 can use existing technology and is not limited by this invention. For example, a high-temperature bearing can be used to fit the inner cylinder 120 onto the drill rod 210, and a drill bit 220, such as a PDC drill bit, can be installed at the bottom of the drill rod 210. Generally, the drilling diameter of the drill bit 220 should be larger than the maximum diameter of the outer shell 110.

[0041] To meet the requirements of muon logging under high temperature and high pressure environments, this invention uses titanium alloy for the outer casing 110. Compared to other common metal materials, titanium alloy has higher muon transmittance, high strength, and high temperature resistance, effectively meeting protection requirements. To further reduce muon loss due to the outer casing 110, this invention provides a preferred embodiment where an inlet is provided on the side wall of the outer casing 110 corresponding to the scintillator assembly. This inlet is sealed with a high-transmittance muon material to form a muon injection window. The high-transmittance muon material includes materials such as beryllium (Be), aluminum nitride (AlN), and silicon carbide (SiC), which not only have better muon transmittance than titanium alloy (and also better than most other metal materials), but also meet the requirements of high temperature and high pressure environments.

[0042] Generally, the inner cylinder 120 is made of high-strength stainless steel, which has a low cost. Of course, if the muon detector 130 needs to measure the muon scattering angle and azimuth angle, then it is necessary to measure the transmission path of the muon in the muon detector 130. In this case, the inner cylinder 120 should also be made of a material with high muon transmittance, such as titanium alloy.

[0043] To further improve high-temperature resistance, the inner wall of the detection space 111 of this invention is provided with a heat insulation layer. Figures 1 to 3 (Not shown in the image), mainly the inner wall of the outer shell 110 is provided with a heat insulation layer. Of course, the outer wall of the inner cylinder 120 can also be provided with a heat insulation layer. The heat insulation layer is made of materials such as alumina ceramic, zirconium oxide ceramic, silicon carbide ceramic, and mullite fiber to provide excellent heat insulation performance.

[0044] To further improve high-temperature resistance, the present invention fills the detection space 111 with a high-melting-point phase change material to prevent high-temperature shock. The melting point of the high-melting-point phase change material is not lower than 140°C. For example, the high-melting-point phase change material refers to a phase change material with a melting point 3-50°C higher than the normal operating environment temperature. More preferably, it can be a phase change material with a melting point 5-30°C higher than the operating environment temperature, which can meet the requirements of the working environment and also cope well with high-temperature shock. For example, some high-melting-point phase change materials and their characteristics are shown in Table 1.

[0045] Table 1. High-melting-point phase change materials that can be used for well logging

[0046]

[0047] It should be noted that the high-melting-point phase change material is only used to prevent damage to the muon detector 130 and other electrical components during high-temperature shocks, such as sudden increases in wellbore temperature or to extend the operating time in high-temperature environments. When the wellbore operating temperature is significantly higher than the operating temperature of the muon detector 130 (in an abnormal situation), other measures should be taken to cool it down or to remove the logging-while-drilling device 100 from the high-temperature zone by raising the drill pipe 210.

[0048] To improve the compressive strength of the detection space 111, an inert gas, such as argon or nitrogen, can be added to the detection space 111, and the deformation resistance of the outer shell 110 can be improved by filling it with a preset pressure.

[0049] It should be noted that the use of inert gas and phase change material do not conflict with each other. They can be set separately or together. The inert gas itself does not affect the function of the phase change material. On the contrary, it can improve the durability of the phase change material and prevent the phase change material from undergoing chemical reactions due to environmental influences, which would lead to changes in its physical properties.

[0050] The outer shell 110 and the inner cylinder 120 can be connected and assembled in any of the following ways: threaded connection, welding, or snap-fit. A sealing ring or other structure can be provided to improve the sealing performance, thereby improving the pressure resistance of the logging-while-drilling device 100.

[0051] To further improve the high-temperature resistance and reduce the size of the muon detector 130, the scintillator assembly uses barium fluoride (BaF2), thallium-doped cesium iodide (CsI(Tl)), and cerium-doped gadolinium aluminum gallium garnet (GAGG:Ce,Gd3Al2Ga3O) 12 LuAG:Ce, Lu3Al5O 12 :Ce), yttrium lutetium silicate (LYSO:Ce, Lu2( 1-x )Y 2x SiO5:Ce 3+ It can be made of any material such as ceramic scintillator (e.g., Gd2O2S:Pr, Ce, F).

[0052] Furthermore, an aluminum reflective layer (reflectivity ≥ 95%) can be deposited on the surface of the scintillator to improve detection accuracy. Of course, the reflective layer material can also be TiO2 (sol-gel method) ceramic material.

[0053] The scintillator component of this invention can be configured in various forms, selected according to the imaging method; such as... Figure 2 and Figure 3As shown, for example, if only muon flux attenuation calculation is performed and the density difference coefficient is generated using the muon flux attenuation rate, then the scintillator assembly can be set as a ring scintillator 131. The ring scintillator 131 is coaxially installed in the detection space 111 by means of snap-fit, bonding or screw fastening (for example, it can be installed on the inner side wall of the outer shell 110), and the photodetector 133 is set close to the inner wall of the ring scintillator 131.

[0054] If it is necessary to calculate the incident trajectory of the muon, such as Figure 4 As shown, the scintillator assembly can be configured with multiple axially stacked annular scintillator arrays 132, each annular scintillator 131 corresponding to at least one photodetector 133, and the muon incident angle can be calculated through the annular scintillator array 132.

[0055] If the incident azimuth angle of the technical muon is still required, a second scintillator array distributed circumferentially needs to be set on the outer layer of the ring scintillator array 132. Figure 4 (Not shown in the figure, formed by a circumferential array of several types of prism scintillators, for details please refer to the technology described in CN117724178A). The end of the second scintillator array is equipped with a photodetector 133. By numbering the second scintillators, the incident azimuth angle of the muon can be calculated. By combining the incident angle and the azimuth angle, the spatial coordinates of the muon incident point can be determined, thereby determining the muon incident trajectory.

[0056] For example, the photodetector 133 can be selected as a high-temperature resistant (above 140°C) photodetector, such as a high-temperature optimized silicon photomultiplier tube (SiPM), silicon carbide (SiC) based photodiode, gallium nitride (GaN) based photodetector, etc., which can adapt well to high-temperature environments.

[0057] To reduce the impact of drilling vibration on muon monitoring, such as Figure 2 or Figure 4 As shown, the scintillator assembly is provided with a vibration suppression module 150. The vibration suppression module 150 includes a first piezoelectric conversion module 151, a second piezoelectric conversion module 152, and a control module. The control module is connected to the first piezoelectric conversion module 151 and the second piezoelectric conversion module 152 through signal lines. The first piezoelectric conversion module 151 monitors the vibration signal of the scintillator assembly and transmits the vibration signal to the control module. The control module has a built-in control algorithm, generates a reverse drive signal based on the vibration signal, and transmits the reverse drive signal to the second piezoelectric conversion module 152 to drive the second piezoelectric conversion module 152 to generate reverse vibration, thereby suppressing the vibration.

[0058] Specifically, the first piezoelectric conversion module 151 is a sensor-end piezoelectric ceramic used to collect vibration signals (monitoring end); the second piezoelectric conversion module 152 is an actuator-end piezoelectric ceramic used to generate reverse vibration (cancellation end); a high-temperature resistant controller is set in the control module to process the signal in real time and generate reverse excitation, and a high-temperature power supply and signal conditioning module are set to provide stable power supply and signal amplification.

[0059] Both the first piezoelectric conversion module 151 and the second piezoelectric conversion module 152 need to use high-temperature piezoelectric ceramic materials, specifically bismuth layered high-temperature piezoelectric ceramics (such as Bi4Ti3O4). 12 Doped): Curie temperature > 600℃, piezoelectric coefficient d at 200℃ 33 >20 pC / N; or lithium niobate (LiNbO3) single crystal: temperature resistance up to 1200℃; or alumina ceramic substrate + high-temperature silver paste electrode, covered with a stainless steel shell, and filled with high-temperature resistant silicone (temperature resistance 300℃) for metal / ceramic composite encapsulation to meet the requirements of high temperature and high pressure downhole. The first piezoelectric conversion module 151 and the second piezoelectric conversion module 152 are respectively installed at the upper and lower ends of the annular scintillator 131, mainly monitoring axial vibration and eliminating axial vibration; of course, it can also monitor vibration in other directions, and can be modified as needed. Generally, the first piezoelectric conversion module 151 and the second piezoelectric conversion module 152 appear in pairs.

[0060] For example, such as Figure 6 As shown, the control module ( Figure 2 This part of the structure (not shown in the image, but which can be arbitrarily distributed within the detection space without affecting the solution of the technical problem) includes a high-temperature controller, a signal conditioning module, an AD / DA conversion module (including an ADC module and a DAC module), a power amplifier, and a high-temperature power supply. The connection relationships of each module are as follows: Figure 6 As shown, the arrows indicate the signal direction, and the control algorithm is built into the high-temperature controller. For example, the high-temperature controller uses a SiC-based MCU (such as Cree C3M0075120K): operating temperature -55℃~300℃, and supports high-speed signal processing.

[0061] The signal conditioning circuit of the signal conditioning module uses a high-temperature operational amplifier (such as HT-AMP-200, based on GaN technology): bandwidth 10 MHz, temperature resistance 250℃.

[0062] AD / DA conversion modules: using SiC-based AD7980 high-temperature ADC (temperature resistance 225℃, 16-bit resolution) and DAC8775 DAC (temperature resistance 210℃, 16-bit resolution).

[0063] Power amplifier: High-temperature resistant amplifiers with ceramic hermetically sealed packages, such as the CISSOID PAH200T power amplifier (temperature resistant to 225°C).

[0064] High-temperature power supply: The high-temperature power supply uses a high-temperature DC-DC converter (such as VPT DV-285, input 28V, output ±15V, temperature resistance 200°C); Cable: silver-plated copper core + polyimide insulation layer + stainless steel braided shielding layer (temperature resistance 300°C).

[0065] The control algorithm employs an improved FXLMS algorithm. FXLMS (Filtered-X Least Mean Square) is a commonly used adaptive filtering algorithm for active noise (or vibration) control. Its core principle is to continuously adjust the filter coefficients so that the output signal can cancel out interference signals. Even better, a temperature drift compensation module can be introduced to correct changes in piezoelectric ceramic parameters (such as d) in real time. 33 (Variation with temperature).

[0066] The specific execution method of the control algorithm is as follows:

[0067] Step 1, Signal Acquisition:

[0068] The piezoelectric ceramic at the sensor end (first piezoelectric conversion module 151) collects vibration signals in real time and converts them into digital signals via ADC (analog-to-digital converter);

[0069] Step 2, Secondary Path Filtering

[0070] The vibration signal is filtered to generate a secondary path filter. ,in The estimation model for the secondary path (the transfer function from the actuator to the sensor) is a discrete transfer function, where z is a complex frequency domain variable in the Z-transform. For the first n Vibration signals collected by the sensor at each moment;

[0071] Step 3: Generation of cancellation signal

[0072] Calculate the adaptive filter output:

[0073]

[0074] For the adaptive filter at time n, the nth time... k One coefficient, L Let the filter order be . k Index of filter coefficients The input signal is after filtering. This is the output signal of the adaptive filter.

[0075] In another embodiment, error feedback and temperature compensation are introduced, and a temperature sensor (which can be installed in the detection space) and an accelerometer (which can be installed together with the first piezoelectric conversion module 151, or installed in the middle position between the first piezoelectric conversion module 151 and the second piezoelectric conversion module 152) are added, such as Figure 7 As shown, based on the newly added speedometer, a signal conditioning module and an ADC module have been added. The specific execution method of the corresponding control algorithm is as follows:

[0076] Step 1, Signal Acquisition:

[0077] The piezoelectric ceramic at the sensor end (first piezoelectric conversion module 151) collects vibration signals in real time and converts them into digital signals via ADC (analog-to-digital converter);

[0078] Step 2, Secondary Path Filtering

[0079] The vibration signal is filtered to generate a secondary path filter. ,in The estimation model for the secondary path (the transfer function from the actuator to the sensor) is a discrete transfer function, where z is a complex frequency domain variable in the Z-transform. For the first n Vibration signals collected by the sensor at each moment;

[0080] Step 3: Generation of cancellation signal

[0081] Calculate the adaptive filter output:

[0082]

[0083] For the adaptive filter at time n, the nth time... k One coefficient, L Let the filter order be . k Index of filter coefficients The input signal is after filtering. This is the output signal of the adaptive filter.

[0084] Step 4, Error Feedback

[0085] Error signals are obtained using accelerometers or residual vibration sensors. ,in For the first n The original vibration signal at that moment; This is the actual secondary path.

[0086] Original vibration signal and vibration signals The relationship is as follows:

[0087]

[0088] This refers to the sensor transfer function (such as the frequency response characteristics of piezoelectric ceramics). To measure noise (thermal noise, electromagnetic interference, etc.).

[0089] Step 5: Coefficient Update

[0090] The improved LMS update formula (including temperature compensation) is as follows:

[0091]

[0092] The adaptive filter at time n+1 is... k One coefficient;

[0093] The step size factor related to temperature T is obtained by looking up a table or calculating online.

[0094] This is the sensitivity compensation coefficient for piezoelectric ceramics (from calibration data).

[0095] At the next moment, the formula in step 3 is used... Calculate the adaptive filter output at time n+1. The second piezoelectric conversion module 152 is controlled to generate an excitation signal, and this process is repeated to achieve active control and vibration elimination.

[0096] In some embodiments, the present invention further includes a data processing system 300, which includes a downhole real-time processing module 310 and a surface processing platform 320. The downhole real-time processing module 310 divides the continuous drilling process into multiple time slices for data storage, calculates the muon flux decay rate independently for each time slice, and then improves the signal-to-noise ratio through weighted fusion. The surface processing platform 320 includes an industrial control computer for processing and analyzing the acquired data. The downhole real-time processing module 310 calculates the muon flux decay rate in real time and generates a density difference coefficient. Background cosmic ray subtraction (combined with synchronous count correction from ground-based Muon 130 detector); density difference coefficient ( ) and confidence parameters are transmitted to the surface via mud pulses (data volume <1kB / min). Downhole The data is transmitted to the industrial control computer, where the ground processing platform 320 is used to process and analyze the collected data.

[0097] In some embodiments, an attitude sensor 140 is also included for monitoring the attitude of the logging-while-drilling device 100. The attitude of the logging-while-drilling device 100 is monitored to perform attitude correction processing on the muon monitoring. The attitude sensor 140 may be an accelerometer, gyroscope, or north finder, etc., and is installed in the detection space.

[0098] This invention also provides a logging-while-drilling method based on muon imaging technology to detect formation density information at a specific depth. The specific steps are as follows:

[0099] Step S1: Fix the processed muon detector 130 onto the inner surface of the outer shell 110, and then fix the outer shell 110 onto the inner cylinder 120 to complete the assembly of the logging-while-drilling device 100.

[0100] Step S2: Connect the inner cylinder 120 to the drill pipe 210, inject mud, and assemble the downhole muon imaging system;

[0101] Step S3: Use ground power equipment to drill the drill bit 220 into the formation. Stop drilling when the formation depth H0 to be measured is reached, and the muon detector 130 starts to measure the change of muon flux N at that depth.

[0102] Step S4: Due to the influence of density when muons penetrate the formation, their flux will decrease. The downhole real-time processing module 310 preprocesses the raw data, including: calculating the muon flux attenuation rate and generating the density difference coefficient. :

[0103] Muon flux decay rate As in the formula:

[0104]

[0105] In the formula, For the muon count at the downhole depth H0, These are baseline measurements of the ground surface.

[0106] Generation density difference coefficient According to the following formula:

[0107]

[0108] In the formula, μ is the muon attenuation coefficient, μ≈0.1 cm 2 / g.

[0109] Step S5: Count muons every 10 seconds. Use an FPGA (Field-Programmable Gate Array) to perform vibration filtering and background subtraction on the original muon pulse signal to generate the signal for that depth. The sequence was transmitted to the ground data processing platform;

[0110] This invention also provides another logging-while-drilling method based on muon imaging technology, for continuous depth measurement and formation imaging.

[0111] Step M1: Refer to step S1;

[0112] Step M2: Refer to step S2;

[0113] Step M3: Using ground power equipment, drill bit 220 is driven into the formation and drilled a certain distance (e.g., about 1 meter) before stopping. Muon detector 130 measures the muon flux of the current formation and calculates the density decay rate. .

[0114] Step M4: The downhole real-time processing module 310 performs background subtraction and transmits the data to the surface data processing platform. The surface data processing platform calculates the formation density at the current depth and records the data.

[0115] Step M5: Perform continuous depth measurement, add a drill rod of a certain length (e.g., 1 meter) 210, continue drilling, and stop again at the new depth to collect the density decay rate at the new depth.

[0116] Step M6: Repeat steps M3-M5 to form a density profile at a continuous depth by continuously measuring the muon flux at different depths.

[0117] Step M7: The ground data processing platform receives density attenuation rate data at each depth and generates a continuous depth density profile.

[0118] Finally, it should be noted that the above-described embodiments are merely specific implementations of the present invention, used to illustrate the technical solutions of the present invention, and not to limit it. The scope of protection of the present invention is not limited thereto. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can still modify or easily conceive of changes to the technical solutions described in the foregoing embodiments within the scope of the technology disclosed in the present invention, or make equivalent substitutions for some of the technical features; and these modifications, changes, or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention. All should be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

[0119] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and illustrations shown and described herein.

Claims

1. A logging-while-drilling device based on muon imaging technology, characterized in that, include outer shell; The inner cylinder is coaxially nested within the outer shell, forming a relatively sealed detection space between the inner cylinder and the outer shell; as well as Muon detectors are placed within the detection space; The muon detector includes a scintillator assembly coaxially mounted in the detection space and a photodetector located inside the scintillator assembly. The scintillator assembly is made of a scintillator material that can withstand temperatures above 140°C, and the inner wall of the detection space is provided with a heat insulation layer. The scintillator assembly is equipped with a vibration suppression module, which includes a first piezoelectric conversion module, a second piezoelectric conversion module, and a control module. The control module is connected to the first and second piezoelectric conversion modules via signal lines. The first piezoelectric conversion module monitors the vibration signal of the scintillator assembly and transmits the vibration signal to the control module. The control module has a built-in control algorithm that generates a reverse drive signal based on the vibration signal and transmits the reverse drive signal to the second piezoelectric conversion module to drive the second piezoelectric conversion module to generate reverse vibration, thereby suppressing the vibration. The specific execution method of the control algorithm is as follows: Step 1, Signal Acquisition: The first piezoelectric conversion module acquires vibration signals in real time; Step 2, Secondary Path Filtering The vibration signal is filtered to generate a secondary path filter. ,in The estimation model for the secondary path (the transfer function from the actuator to the sensor) is a discrete transfer function, where z is a complex frequency domain variable in the Z-transform. For the first n Vibration signals collected by the sensor at each moment; Step 3: Generation of cancellation signal Calculate the adaptive filter output: For the adaptive filter at time n, the nth time... k One coefficient, L Let the filter order be . k Index of filter coefficients The input signal is after filtering. The output signal of the adaptive filter; Step 4, Error Feedback Error signals are obtained using accelerometers or residual vibration sensors. ,in For the first n The original vibration signal at that moment; This is the actual secondary path; Original vibration signal and vibration signals The relationship is as follows: For sensor transfer function, For measuring noise; Step 5: Coefficient Update The improved LMS update formula is as follows: The adaptive filter at time n+1 is... k One coefficient; The step size factor related to temperature T is obtained by looking up a table or calculating online. This is the sensitivity compensation coefficient for piezoelectric ceramics; At the next moment, the adaptive filter output formula from step 3 is applied. Calculate the adaptive filter output at time n+1. The second piezoelectric conversion module is controlled to generate an excitation signal, thereby achieving active vibration control and elimination.

2. The logging-while-drilling device based on muon imaging technology according to claim 1, characterized in that, The detection space is filled with a high-melting-point phase change material to prevent high-temperature impact, and the melting point of the high-melting-point phase change material is not lower than 140°C.

3. The logging-while-drilling device based on muon imaging technology according to claim 1, characterized in that, The outer shell is a titanium alloy shell, and an inlet is provided on the side wall of the outer shell corresponding to the scintillator assembly. The inlet is sealed with a muon high-transparency material to form a muon inlet window.

4. The logging-while-drilling device based on muon imaging technology according to claim 1, characterized in that, The scintillator assembly includes several coaxially stacked ring scintillators, and each scintillator assembly has at least one corresponding photodetector.

5. The logging-while-drilling device based on muon imaging technology according to claim 4, characterized in that, The scintillator assembly further includes a second scintillator array disposed circumferentially on the outer side of the scintillator assembly, and a photodetector is provided at the end of the second scintillator array.

6. The logging-while-drilling device based on muon imaging technology according to claim 5, characterized in that, Both the scintillator assembly and the second scintillator are coated with a reflective layer.

7. The logging-while-drilling device based on muon imaging technology according to claim 1, characterized in that, It also includes attitude sensors used to monitor the attitude of the logging-while-drilling device.

8. The logging-while-drilling device based on muon imaging technology according to claim 1, characterized in that, It also includes a data processing system, which includes a downhole real-time processing module and a surface processing platform. The downhole real-time processing module divides the continuous drilling process into multiple time slices for data storage. Each time slice independently calculates the muon flux decay rate and then improves the signal-to-noise ratio through weighted fusion. The surface processing platform includes an industrial control computer for processing and analyzing the acquired data.

9. The logging-while-drilling device based on muon imaging technology according to claim 1, characterized in that, The detection space is filled with inert gas.

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