Downhole measuring devices and methods

Abstract

This application belongs to the technical field of oil drilling measurement, specifically relating to a downhole measurement device and method. The downhole measurement device includes a drill pipe sub and multiple NFC target devices. The drill pipe sub is connected to the drill pipe and has a built-in NFC initiator that can be radially separated from it. The NFC initiator can move axially within the well and measure well parameters. Multiple NFC target devices are arranged axially at intervals on the outer peripheral wall of the drill pipe, and are used to send NFC signals to the NFC initiator. In this application, well parameters at multiple axial positions are measured by the movement of the NFC initiator within the well, and NFC signals are sent to the NFC initiator by the multiple NFC target devices on the outer peripheral wall of the drill pipe. The axial positions of the NFC target devices downhole are known, thus establishing a one-to-one correspondence between the measured well parameters and the axial positions, thereby obtaining the distribution of well parameters throughout the entire well.

Description

Technical Field

[0001] This application belongs to the technical field of oil drilling measurement, specifically relating to a downhole measurement device and a downhole measurement method. Background Technology

[0002] As oil and gas drilling advances towards deep and ultra-deep wells, the drilling process faces challenges such as high temperature and pressure, complex formation pressure, and difficulty in pressure control. Accurate measurement of wellbore temperature and pressure is crucial for overcoming these challenges, improving drilling efficiency, and ensuring drilling safety. Because temperature and pressure affect the physical properties of drilling fluids (such as density and rheology), inaccurate temperature and pressure measurements can easily lead to complex accidents.

[0003] Currently, domestic and international oil companies primarily use measurement-while-drilling (MWD) tools to measure downhole temperature and pressure information in real time. These MWD tools are typically mounted on the drill pipe near the drill bit and transmit bottom-hole temperature and pressure data to the surface via mud pulses, allowing technicians to accurately grasp bottom-hole information. However, because the MWD tools are installed in a fixed position, they can only acquire downhole temperature and pressure information at a specific location within the well, thus failing to meet the information measurement needs during the drilling process. Summary of the Invention

[0004] The purpose of this application is to provide a downhole measurement device and a downhole measurement method to achieve information measurement at multiple locations downhole.

[0005] To achieve the above objectives, this application provides a downhole measuring device, comprising:

[0006] A drill pipe sub, connected to the drill pipe, has a built-in NFC initiator that can be radially separated from the drill pipe sub. This NFC initiator is axially movable within the wellbore and can measure in-well parameters.

[0007] Multiple NFC target devices are arranged at intervals along the axial direction on the outer peripheral wall of the drill pipe, and the NFC target devices are used to send NFC signals to the NFC initiating device.

[0008] In some embodiments, the drill pipe sub includes:

[0009] A storage cavity is provided for storing the NFC initiating device;

[0010] Release channel, connecting the storage cavity and the well; and

[0011] The control unit is used to control the opening and closing of the release channel.

[0012] In some embodiments, a drill pipe cavity is formed within the drill pipe, and the drill pipe subsection further includes an intake channel connecting the drill pipe cavity and the storage cavity.

[0013] In some implementations, the NFC initiating device includes:

[0014] Spherical carrier;

[0015] An NFC processor, built into the spherical carrier, is used to receive the NFC signals; and

[0016] A timer, built into the spherical carrier, is used to record the signal time when the NFC signal is received.

[0017] In some embodiments, the well parameters include pressure and temperature, and the NFC initiating device includes a temperature sensor and a pressure sensor built into the spherical carrier, the temperature sensor being used to measure the temperature inside the well and the pressure sensor being used to measure the pressure inside the well.

[0018] In some embodiments, the drill string includes multiple sub-drill strings connected along the axial direction, and the NFC target device includes an NFC tag disposed at the connection point of adjacent sub-drill strings, the NFC tag being used to store location information and transmit the NFC signal.

[0019] A second aspect of this application provides a downhole measurement method applied to a downhole measurement device, the downhole measurement method comprising:

[0020] S1: Calculate the movement speed of the NFC-initiated device within the drilling rig;

[0021] S2: Measure the drilling fluid flow rate in the well, and calculate the actual speed of the NFC initiating device in the well based on the transport speed and the drilling fluid flow rate;

[0022] S3: Based on the actual speed, the relationship between time and depth is obtained using the finite element method;

[0023] S4: Based on the relationship between time and depth and the signal time recorded by the NFC initiating device, obtain the downhole position corresponding to the signal time.

[0024] S5: By correlating the downhole location and in-well parameters at the same signal time, the distribution of in-well parameters within the well is obtained.

[0025] In some embodiments, the formula for calculating the transport speed is:

[0026]

[0027] Among them, vs The transport velocity is m / s; ρ is the drilling fluid density, kg / m³. 3 ;ρ s The density of the NFC initiating device, kg / m 3 ;d s The diameter of the NFC initiating device is m; φ is the sphericity coefficient, dimensionless; μ a The viscosity of the drilling fluid is expressed in Pa·s.

[0028] In some embodiments, the drilling is divided into multiple well sections with different flow areas, and step S2 includes:

[0029] Measure the drilling fluid flow rate and the flow area of ​​each section of the well;

[0030] The drilling fluid velocity for each well section is calculated based on the drilling fluid flow rate and the plurality of flow areas.

[0031] In some implementations, step S2 includes:

[0032] The actual transport speed is obtained by correcting the transport speed.

[0033] The actual velocity is obtained by subtracting the true migration velocity from the drilling fluid flow velocity.

[0034] Through the above technical solutions, the downhole measurement device and downhole measurement method provided in this application have the following beneficial effects:

[0035] To ensure drilling efficiency and safety during drilling operations, it is necessary to measure multiple sets of wellbore parameters in real time by moving an NFC-initiating device axially within the well. However, these parameters cannot be directly correlated with the locations downhole. In this application, multiple NFC target devices mounted on the outer perimeter of the drill pipe send NFC signals to the NFC initiating device. Since the locations of these target devices downhole are known, the multiple sets of wellbore parameters measured by the NFC initiating device are mapped one-to-one with their downhole locations, thus completing the information measurement of each location downhole.

[0036] Other features and advantages of the embodiments of this application will be described in detail in the following detailed description section. Attached Figure Description

[0037] The accompanying drawings are provided to further illustrate the embodiments of this application and form part of the specification. They are used together with the following detailed description to explain the embodiments of this application, but do not constitute a limitation on the embodiments of this application. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without any inventive effort. In the drawings:

[0038] Figure 1 This is a schematic diagram of signal transmission between an NFC initiating device and an NFC target device according to a specific embodiment of this application;

[0039] Figure 2 This is a schematic diagram of the arrangement of drill pipe sub sections according to a specific embodiment of this application;

[0040] Figure 3 This is a schematic diagram of the drill pipe sub according to a specific embodiment of this application;

[0041] Figure 4 This is a schematic diagram of the arrangement of the NFC target device according to a specific embodiment of this application;

[0042] Figure 5 This is a schematic diagram of the structure of an NFC initiating device according to a specific embodiment of this application;

[0043] Figure 6 This is a schematic diagram of the forces acting on an NFC initiating device in drilling fluid according to a specific embodiment of this application;

[0044] Figure 7 This is a flowchart illustrating the steps of a downhole measurement method according to a specific embodiment of this application;

[0045] Figure 8 This is a flowchart illustrating the calculation of the correction factor according to a specific embodiment of this application;

[0046] Figure 9 This is a flowchart illustrating the steps of obtaining the relationship between time and depth using the finite element method according to a specific embodiment of this application.

[0047] Explanation of reference numerals in the attached figures

[0048] 1. Drill pipe sub 2. NFC target device

[0049] 3 NFC initiating device 4 Storage cavity

[0050] 5. Release channel 6. Spherical carrier

[0051] 7 NFC processor 8 timers

[0052] 9 Temperature sensor 10 Pressure sensor

[0053] 11 Battery 12 Data transmission interface

[0054] 13 Drill pipe 14 Drill bit

[0055] 15 Drilling 16 Drill pipe cavity Detailed Implementation

[0056] The specific embodiments of this application will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit this application.

[0057] The terminology of the downhole measuring apparatus and downhole measuring method according to this application is described below with reference to the accompanying drawings.

[0058] As shown in the figure, a downhole measurement device provided in a specific embodiment of this application includes a drill pipe section 1 and a plurality of NFC target devices 2. The drill pipe section 1 is connected to the drill pipe 13. The drill pipe section 1 has an NFC initiating device 3 that can be radially separated from the drill pipe section 1. The NFC initiating device 3 can move axially within the drilling rig 15 and measure well parameters. The plurality of NFC target devices 2 are arranged axially at intervals on the outer peripheral wall of the drill pipe 13. The NFC target devices 2 are used to send NFC signals to the NFC initiating device 3.

[0059] During drilling operations, it is necessary to measure the downhole parameters in the drilling rig 15 in real time. These parameters include temperature and pressure, which affect the physical properties of the drilling fluid in the drilling rig 15. Based on these temperature and pressure readings, the drilling fluid physical properties are obtained, allowing for timely adjustments to the drilling tool rotation speed and drill pipe pressure to improve drilling efficiency and ensure drilling safety. In this application, an NFC initiating device 3 moves within the drilling rig 15 to measure temperature and pressure at multiple locations along the downhole axis. Multiple NFC target devices 2, positioned on the outer periphery of the drill pipe 13, send NFC signals to the NFC initiating device 3. The axial positions of the NFC target devices 2 downhole are known, thus mapping the multiple sets of temperature and pressure measurements taken by the NFC initiating device 3 to the axial positions downhole, thereby completing the information measurement at each downhole location.

[0060] Specifically, the drilling tools include a drill bit 14 and a drill pipe 13. The drill pipe 13 includes multiple sub-drill pipes connected end-to-end along the axial direction. The number of sub-drill pipes and the length of each sub-drill pipe are known. The sub-drill pipe located at the wellhead is the first sub-drill pipe section. In this application, the axial distance between the horizontal plane where the wellhead is located and the horizontal plane where the end of the first sub-drill pipe section is located is measured, and the measured axial distance is added to the length of the sub-drill pipe section, thus obtaining the axial distance from the horizontal plane where the connection of each sub-drill pipe section is located to the wellhead, thereby confirming the downhole location of the connection of each sub-drill pipe section.

[0061] Furthermore, multiple NFC target devices 2 are installed at the connection points of each section of the drill pipe to determine the downhole location of each NFC target device 2. When the NFC initiating device 3 passes by the NFC target device 2, the NFC target device 2 sends an NFC signal to the NFC initiating device 3, thereby corresponding the pressure and temperature measured by the NFC initiating device 3 with the downhole location.

[0062] Those skilled in the art will understand that NFC stands for Near Field Communication (NFC) technology. Devices using NFC technology can exchange data when they are close to each other, which will not be elaborated here.

[0063] In some embodiments, the drill pipe section 1 includes a storage cavity 4, a release channel 5, and a control unit, wherein the storage cavity 4 is used to store the NFC initiator 3; the release channel 5 connects the storage cavity 4 and the drill 15; and the control unit is used to control the opening and closing of the release channel 5.

[0064] Specifically, the sub-drill pipe connected to the drill bit 14 is the tail section sub-drill pipe. The drill pipe short section 1 connects the tail section sub-drill pipe and the drill bit 14. After the NFC initiator 3 is released from the storage cavity 4 into the well 15, it flows with the drilling fluid. The drilling fluid circulates in the well 15 from bottom to top to bottom, thereby driving the NFC initiator 3 to pass through each NFC target device 2 along the axial direction.

[0065] Furthermore, the drill pipe section 1 also includes a release sensor electrically connected to the control unit. The release sensor can detect one or more of pressure fluctuations, speed changes, and displacement changes. These fluctuations are generated by the action of a mud pump connected to the drill pipe 13 on the drilling fluid. Specifically, when operators need to start detecting pressure and temperature information, they change the speed and drive pressure of the mud pump to induce pressure fluctuations and / or speed and / or displacement changes in the drilling fluid. A solenoid valve electrically connected to the control unit is installed in the release channel 5. After the release sensor detects pressure fluctuations and / or speed and / or displacement changes, it sends pressure fluctuation signals and / or speed and / or displacement change signals to the control unit. This causes the control unit to control the solenoid valve to open the release channel 5, thereby activating the NFC initiator 3 stored in the cavity 4 and allowing it to enter the drilling rig 15 through the release channel 5.

[0066] It should be noted that the structure and operation of the mud pump, as well as the method of operating the mud pump, are well known to those skilled in the art. Furthermore, the working principles of the release sensor, control unit, and solenoid valve are also well known to those skilled in the art and are not part of the core improvement of this application, so they will not be described in detail here.

[0067] In some embodiments, the drill pipe 13 is hollow to form a drill pipe cavity 16. Drilling fluid enters the drill pipe cavity 16 from the wellhead and flows to the drill bit 14, then flows from the drill bit 14 to the bottom of the well, and finally flows from the bottom of the well back to the wellhead to achieve the circulation of drilling fluid.

[0068] Preferably, the drill pipe section 1 further includes an intake channel connecting the drill pipe cavity 16 and the storage cavity 4, and an intake sensor electrically connected to the control unit. The intake channel is equipped with a solenoid valve electrically connected to the control unit. When the NFC initiator 3 flows from the wellhead to the bottom of the well with the drilling fluid, the intake sensor detects the pressure fluctuation caused by the NFC initiator 3 reaching the vicinity of the intake channel and sends a pressure fluctuation signal to the control unit, thereby causing the control unit to control the solenoid valve to open the intake channel. Then, the water pressure is used to suck the NFC initiator 3 into the storage cavity through the intake channel for the next detection.

[0069] It should be noted that the NFC initiator 3 can be received into the storage cavity not only by the water pressure suction method described above, but also by an interception mechanism that expands and contracts radially with the receiving channel. Specifically, when the NFC initiator 3 flows from the wellhead to the bottom of the well with the drilling fluid, the interception mechanism extends into the drill pipe cavity 16 to intercept the NFC initiator 3. After the interception mechanism successfully intercepts the NFC initiator 3, it is received into the receiving channel and enters the storage cavity 4. Other methods of recovering the NFC initiator 3 are also within the scope of protection of this application.

[0070] In some embodiments, the NFC initiating device 3 includes a spherical carrier 6, an NFC processor 7, a timer 8, a temperature sensor 9, a pressure sensor 10, a battery 11, and a flexible circuit board. The NFC processor 7 is built into the spherical carrier 6 and is used to receive NFC signals. The timer 8 is built into the spherical carrier 6 and is used to record the signal time of receiving NFC signals, i.e., the time of each measurement. The temperature sensor 9 and the pressure sensor 10 are built into the spherical carrier 6; the temperature sensor 9 is used to measure the temperature inside the well 15, and the pressure sensor 10 is used to measure the pressure inside the well 15. The battery 11 is used to power the electronic devices inside the spherical carrier 6. The flexible circuit board is used to electrically connect the NFC processor 7, the timer 8, the temperature sensor 9, and the pressure sensor 10.

[0071] Specifically, the NFC processor 7 includes a microcontroller, a chip, an antenna, and radio frequency field components. The radio frequency field components are used to adjust the NFC radio frequency frequency, the antenna is used to enhance the reception strength of the NFC signal, and the chip is used to process, store, read, and transmit data information. The data information includes NFC signals, signal time, temperature and pressure inside the well 15, etc. At the same time, the chip can also control the power supply and power off of the battery 11.

[0072] Furthermore, the spherical carrier 6 is equipped with a data transmission interface 12 to realize the transmission of data information, specifically communication with a host computer, which can be a terminal device such as a computer.

[0073] In fact, when designing the spherical carrier 6, it is necessary to consider the size matching with the storage cavity 4, release channel 5 and intake channel of the drill pipe sub 1, so as to ensure that the micro measuring device can be smoothly released and retrieved from the drill pipe sub 1; at the same time, it is necessary to ensure that the diameter of the spherical carrier 6 is smaller than the diameter of the drill pipe cavity 16 and smaller than the gap between the outer wall of the drill pipe 13 and the well wall, so as to ensure that the micro measuring device can move smoothly with the flow of drilling fluid, thereby ensuring the practicality of the downhole measuring device.

[0074] It should be noted that the NFC initiator 3 can also be inserted into the drill pipe cavity 16 from the wellhead. Then, the NFC initiator 3 flows with the drilling fluid to the bottom of the well and passes through the water hole on the drill bit 14 to enter the well 15. Finally, the NFC initiator 3 flows with the drilling fluid to the wellhead to complete the detection. Compared with the method of releasing the NFC initiator 3 using the drill pipe section 1, the method of directly inserting the NFC initiator 3 into the wellhead and entering the well 15 through the water hole requires the NFC initiator 3 to be designed to be smaller than the water hole. The smaller size of the NFC initiator 3 results in a smaller battery capacity in the battery 11, leading to poor battery life. Furthermore, after passing through the water hole, the NFC initiator 3 is easily ground or collided with by the drill bit 14, which may damage the NFC initiator 3 or affect the measurement results. However, the direct insertion method eliminates the need for the drill pipe section 1, thereby effectively reducing the cost of the device.

[0075] Preferably, the other spaces within the spherical carrier 6 are filled with a polymer crosslinking agent, thereby giving the spherical carrier 6 good temperature and pressure resistance.

[0076] In some implementations, the NFC target device 2 includes an NFC tag disposed at the connection of adjacent sub-drill pipes, the NFC tag being used to store location information and send NFC signals.

[0077] Specifically, the location information is the sequence number marked on each sub-drill pipe in sequence. For example, the connection between the first and second sub-drill pipe sections is marked as "1", the connection between the second and third sub-drill pipe sections is marked as "2", and so on, marking the sequence number of all sub-drill pipe connection points. The NFC initiating device 3 obtains the downhole location by receiving the location information and the length of each sub-drill pipe section.

[0078] Those skilled in the art will understand that the serial number is not limited to the above-mentioned "1" and "2" and can also be other numbers or symbols that can record the sequence; the NFC tag can also be set at the center of each section of the drill rod, 1 / 3 of the way, etc., and the above-mentioned setting position is also within the protection scope of this application.

[0079] Furthermore, the NFC tag is also used to store specification information such as drill pipe type and drill pipe size. The NFC initiating device 3 calculates the downhole position by receiving specification information and location information, thus eliminating the need to measure drill pipe specifications in advance and improving the convenience of downhole measurement devices.

[0080] In detail, the NFC initiating device 3 and the NFC tag communicate using a specific radio frequency. NFC communication can be achieved as long as the NFC initiating device 3 and the NFC tag are within the transmission distance range. To ensure the security and stability of the communication process, a commonly used international high-frequency signal (13.56MHz) is preferred. The NFC tag does not require a battery 11; it obtains radio wave energy through inductive coupling with the NFC initiating device 3. After receiving the initialization request from the NFC initiating device 3, the NFC tag responds at the same transmission rate and using load modulation data. The NFC initiating device 3 can then obtain the location and specification information stored in the NFC tag. Since the length of each sub-drill pipe section is known, the NFC initiating device 3 can obtain the downhole position by sensing the NFC tag information and recording the data. Combining this with the time of receiving the NFC signal detected by the NFC initiating device 3, the time-depth relationship of the NFC initiating device 3's movement in the drilling rig 15 can be obtained. Finally, after data acquisition, the data is transmitted to the host computer through the data transmission interface 12.

[0081] Preferably, the transmission distance between the NFC initiating device 3 and the NFC target device 2 is set according to the distance between the well wall of the drilling 15 and the outer wall of the drill pipe 13. Generally, the distance between the well wall of the drilling 15 and the outer wall of the drill pipe 13 is less than 20cm, so the transmission distance is set to 20cm.

[0082] Optionally, the temperature sensor 9, pressure sensor 10, sensing circuit, storage chip, antenna, and other devices built into the NFC initiating device 3 can be integrated into the NFC tag, thereby directly collecting parameters such as temperature and pressure through the NFC tag. When the NFC initiating device 3 passes by the NFC tag, it obtains radio wave energy through inductive coupling. After receiving the initialization request from the NFC initiating device 3, the NFC tag responds at the same transmission rate and using load modulation data. The NFC initiating device 3 can then obtain the location information and specification information stored in the NFC tag, as well as the collected temperature and pressure parameters.

[0083] As shown in the figure, a specific embodiment of this application also provides a downhole measurement method, applied to a downhole measurement device, the downhole measurement method including:

[0084] S1: Calculate the movement speed of NFC initiating device 3 within drill 15;

[0085] S2: Measure the drilling fluid flow rate within the drilling well 15, and calculate the actual speed of the NFC initiator 3 within the drilling well 15 based on the transport speed and the drilling fluid flow rate;

[0086] S3: The relationship between time and depth is obtained using the finite element method based on the actual speed;

[0087] S4: Based on the relationship between time and depth and the signal time recorded by NFC initiating device 3, the downhole position corresponding to the signal time is obtained;

[0088] S5: By correlating the downhole location and in-well parameters at the same signal time, the distribution of in-well parameters within drilling 15 is obtained.

[0089] Due to the complexity of drilling operations, various types of drill pipes 13 are often used. Therefore, the NFC target device 2 cannot be installed on every section of drill pipe, resulting in insufficient data and affecting the accuracy of temperature and pressure measurements within the well 15. In this application, a downhole measurement method is used to calculate the position-time relationship within the well 15. Based on the signal time recorded by the NFC initiating device 3, the downhole position of the NFC initiating device 3 is deduced. Then, the temperature and pressure data corresponding to the signal time are mapped one-to-one with the downhole position of the NFC initiating device 3, ultimately obtaining the temperature and pressure distribution throughout the entire well 15. This is of great significance for analyzing downhole operation risks, optimizing drilling processes, improving drilling efficiency, and ensuring drilling safety.

[0090] In some implementations, the formula for calculating the transport velocity is:

[0091]

[0092] Among them, v s ρ is the migration velocity, m / s; ρ is the drilling fluid density, kg / m³. 3 ;ρ s Density of NFC initiating device 3, kg / m 3 ;d s The diameter of the NFC initiating device 3 is in meters (m); φ is the sphericity coefficient, dimensionless; μ a The viscosity of the drilling fluid is expressed in Pa·s.

[0093] Specifically, the derivation process of the transport velocity is as follows:

[0094] First, force analysis of the NFC initiating device 3 moving with the drilling fluid within the drilling well 15:

[0095] The external forces acting on the device include buoyancy and resistance. The NFC initiating device 3 also experiences gravity. The specific calculation formula and related parameters are as follows:

[0096] Gravity calculation formula for NFC-initiated device 3:

[0097] Buoyancy calculation formula for NFC initiating device 3:

[0098] The resistance calculation formula for NFC initiating device 3:

[0099] Where G is gravity, N; F b d is buoyancy, N; R is drag, N; s ρ is the diameter of the NFC initiating device 3, in meters; ρ is the density of the drilling fluid, in kilograms per cubic meter of water. 3 ;γ s The volumetric force of NFC-initiating device 3, N / m 3 γ represents the bulk force of the drilling fluid, in N / m³. 3 v is the drop speed of the NFC initiating device 3, in m / s; f is the drag coefficient, dimensionless.

[0100] Second, the relationship between the force applied to the NFC initiating device 3 and the sliding speed:

[0101] The resultant force of the buoyancy force on NFC initiating device 3 and the gravity of NFC initiating device 3 is the buoyant weight. The buoyant weight gives NFC initiating device 3 acceleration but also causes resistance. The specific calculation formula and related parameters are as follows:

[0102] NFC initiator device 3's buoyancy calculation formula:

[0103]

[0104] The relationship between the acceleration and the force applied by the NFC initiating device 3 is as follows:

[0105] Substituting the formulas for calculating buoyancy and resistance into the relationship between acceleration and force, we obtain:

[0106]

[0107] Among them, W o For buoyancy, N; d s ρ is the diameter of the NFC initiating device 3, in meters; ρ is the density of the drilling fluid, in kilograms per cubic meter of water. 3 ;ρ s Density of NFC initiating device 3, kg / m 3 g is the acceleration due to gravity, m / s² 2 ;γ s The volumetric force of NFC-initiating device 3, N / m 3 γ represents the bulk force of the drilling fluid, in N / m³. 3m is the mass of NFC initiating device 3, kg; v is the sliding speed of NFC initiating device 3, m / s; Acceleration of NFC-initiated device 3, m / s 2 f is the drag coefficient, which is dimensionless.

[0108] Third, the relationship between the moving speed and the slippage speed of NFC initiating device 3:

[0109] From the relationship between the acceleration of the NFC initiator 3 and the force applied, we know that the acceleration of the NFC initiator 3 is equal to the buoyancy acceleration of the NFC initiator 3 moving in the drilling fluid minus the resistance acceleration. When the NFC initiator 3 is dropped from the wellhead, its sliding velocity is zero, and the resistance it experiences is also zero. At this time, the acceleration of the NFC initiator 3 is at its maximum, and its sliding velocity gradually increases. As the NFC initiator 3 continues to slide, the resistance causes the acceleration to gradually decrease until the resistance acceleration and the buoyancy acceleration are equal in magnitude and opposite in direction. At this point, the acceleration of the NFC initiator 3 is zero, and its sliding velocity no longer changes. That is, the NFC initiator 3 is in a constant-speed sliding state within the drilling fluid 15, and its sliding velocity at this time is its movement velocity.

[0110] Furthermore, once the NFC initiating device 3 reaches force equilibrium, the resistance fluctuations it experiences are relatively small, resulting in a small acceleration. Therefore, the acceleration or deceleration of the NFC initiating device 3 during its constant-speed sliding motion can be ignored.

[0111] Therefore, by We can obtain:

[0112]

[0113] Among them, v s ρ is the velocity of movement, m / s; f is the drag coefficient, dimensionless; g is the acceleration due to gravity, m / s². 2 ;

[0114] Fourth, the calculation of the drag coefficient:

[0115] Since the movement of NFC initiating device 3 in drill 15 is very similar to that of cuttings in drill 15, the influence of drag coefficient and particle Reynolds number in drilling is considered based on relevant research on cuttings slip. Experimental data is used to analyze the relationship between drag coefficient and particle Reynolds number when irregular particles slip, resulting in the following formulas relating drag coefficient, particle Reynolds number, and sphericity coefficient:

[0116]

[0117] Among them, Re p, particle Rell's number, dimensionless; f is the drag coefficient, dimensionless; φ is the sphericity coefficient, dimensionless;

[0118] In fact, the applicable range of the formula relating drag coefficient to particle Reynolds number and sphericity coefficient is Re p = 0.001~10000 and φ=0.2~1.0; the sphericity coefficient is related to the shape of the NFC initiator 3 used. If the NFC initiator 3 is a sphere, the sphericity coefficient is 1. The NFC initiator 3 can also be other shapes. In this case, the sphericity coefficient is the minimum diameter of the NFC initiator divided by the maximum diameter.

[0119] Formula for calculating particle Reynolds number:

[0120]

[0121] Among them, Re p Particle Rell's number, dimensionless; μ a The viscosity of the drilling fluid is expressed in Pa·s and d. s ρ is the diameter of the NFC initiating device 3, in meters; ρ is the density of the drilling fluid, in kilograms per cubic meter of water. 3 ;v s The velocity is the speed of movement, in m / s;

[0122] Formula for calculating drilling fluid viscosity:

[0123]

[0124] Wherein, n is the flow index, which is dimensionless; K is the consistency coefficient, which is dimensionless. Both the flow index and the consistency coefficient are commonly used parameters in fluid mechanics, and their calculation formulas are well known to those skilled in the art, so they will not be elaborated here.

[0125] Fifth, substitute the calculation formulas for the relevant parameters into... The formula for calculating transport velocity is obtained as follows:

[0126]

[0127] The density of the NFC initiating device 3, the diameter of the NFC initiating device 3, and the density of the drilling fluid can all be directly measured. The measurement methods are well known to those skilled in the art and will not be described in detail here. The viscosity of the drilling fluid is calculated using the formula for calculating the viscosity of the drilling fluid. The sphericity coefficient is determined by the shape of the NFC initiating device 3.

[0128] In summary, all relevant parameters in the formula for calculating the migration speed can be obtained, thereby calculating the migration speed of the NFC initiating device 3 in the drilling rig 15.

[0129] In some implementations, since the NFC initiating device 3 moves with the flow of drilling fluid, its movement speed is affected by the drilling fluid flow rate. Therefore, the actual speed of the NFC initiating device 3 is calculated as follows:

[0130] v = v l -v s

[0131] Among them, v l The drilling fluid velocity is given in m / s.

[0132] In fact, the flow area of ​​well 15 changes along the axial direction, resulting in different drilling fluid flow velocities in well sections with different flow areas.

[0133] Preferably, the well is divided into multiple well sections with different flow areas, and step S2 includes:

[0134] Measure the drilling fluid flow rate and the flow area of ​​each well section;

[0135] The drilling fluid velocity for each well section is calculated based on the drilling fluid flow rate and multiple flow areas.

[0136] Specifically, the drilling pump is used to pump drilling fluid and pump back drilling fluid. The drilling fluid flow rate depends on the specifications of the drilling pump, i.e., the pump that drives the flow of drilling fluid within the drill well 15. The specifications of the drilling pump are readily available and well-known to those skilled in the art. The flow area is the cross-sectional area of ​​the annular region between the inner wall of the drill well and the outer wall of the drill pipe, which can be obtained by measuring the inner diameter of the drill well 15 and the outer diameter of the drill pipe 13.

[0137] Furthermore, while measuring the flow area, it is also necessary to measure the axial length of each well section to accurately divide each well section. After knowing the flow area and drilling fluid flow rate of each well section, the drilling fluid flow rate is divided by the flow area to obtain the drilling fluid velocity of each well section. Then, the drilling fluid velocity and transport speed are substituted into the actual velocity calculation formula to finally obtain the actual velocity of the NFC initiator 3 flowing with the drilling fluid in each well section.

[0138] However, the movement of the NFC initiating device 3 in the drilling rig 15 is often three-dimensional, and during the movement process, it will be affected by friction and collision with the well wall, which will cause the movement speed of the NFC initiating device 3 to change. Therefore, it is necessary to correct the movement speed and then calculate the actual speed.

[0139] In some implementations, step S2 includes:

[0140] The true transport velocity is obtained by correcting the transport velocity.

[0141] The actual velocity is obtained by subtracting the actual migration velocity from the drilling fluid flow velocity.

[0142] Specifically, since the drilling fluid flow rate is constant within the same well section, a migration velocity correction algorithm is proposed:

[0143] v = v l -xv s

[0144] Where x is a correction factor, which is dimensionless; each pair of adjacent NFC target devices 2 is a calculation segment. The movement speed of NFC initiating device 3 in the calculation segment can be obtained by using the time of NFC initiating device 3 passing through each calculation segment and combining it with the axial distance of each calculation segment. The correction factor of NFC initiating device 3 in the next calculation segment can be obtained by combining it with the movement speed correction algorithm.

[0145] like Figure 8 As shown, the specific calculation process for the correction factor is as follows:

[0146] Step 1: Calculation Initialization: Adjust the calculation process to optimize the startup speed of the current calculation segment;

[0147] Step 2: Determine the time interval: Check if the time interval of the NFC initiating device 3 in the current calculation segment has reached the minimum interval required for calculation; if not, terminate the speed correction calculation process; if it has, continue to the next step.

[0148] The minimum interval value is determined through experimental data analysis: several candidate interval values ​​are set, and the effect of each candidate interval value is tested through experiments. The candidate interval value that is at the best balance point (the measurement data of NFC initiating device 3 is relatively stable and the response speed of NFC initiating device 3 to NFC target device 2 is relatively fast) is selected as the minimum interval value.

[0149] Step 3, Check Calculation Stage: Determine whether the speed correction calculation of the current calculation segment is the first speed correction calculation; if yes, perform the initialization operation of the correction factor (set the correction factor as the initial value of the first calculation based on calculation experience), and then continue to the next step; if no, input the correction factor of the previous calculation segment as the correction factor of the current calculation segment, and then continue to the next step.

[0150] Step 4: Calculate the movement speed: Based on the time and axial distance of the current calculation segment, calculate the movement speed of the NFC initiating device in the current calculation segment;

[0151] Step 5, Migration speed correction: Multiply the migration speed by the correction factor to obtain the corrected migration speed;

[0152] Step 6: Calculate the relative error between the corrected transport velocity and the velocity threshold;

[0153] Among them, the speed threshold is used to ensure that the corrected migration speed is within a reasonable range, so as to exclude the corrected migration speed under abnormal conditions that do not conform to the actual physical conditions or data anomalies. The speed threshold is generally determined based on the analysis of actual historical data, that is, by analyzing the speed of NFC initiating device 3 under different conditions, a speed upper limit that can reflect abnormal conditions is set.

[0154] Step 7, Error Judgment: Evaluate the corrected transport speed and determine whether the relative error between the corrected transport speed and the speed threshold is within the allowable error threshold; if yes, proceed to the next step; if no, update the correction factor and return to step 5.

[0155] The error threshold is set according to engineering requirements, and is generally 0.01. The new correction factor is usually adjusted based on the previous calculation results and its adaptability to the current data. If the current correction factor causes the correction movement speed to exceed the speed threshold, it indicates that the correction factor needs to be adjusted to achieve more accurate correction. This adjustment can be based on an optimization algorithm (gradient descent algorithm) to gradually adjust the correction factor until the relative error between the correction movement speed and the speed threshold is within the allowable error threshold.

[0156] Step 8: Output correction factor: After completing the calculation, output the correction factor of the current calculation segment for use in the next calculation segment.

[0157] like Figure 9 As shown, in some implementations, the finite element calculation method mentioned in step S3 is well known to those skilled in the art, and the specific calculation process is as follows:

[0158] S31: Grid division;

[0159] Specifically, the drilling is divided into multiple grids along the axial direction and the step size (dz1, dz2, dz3, ...) for each grid is input;

[0160] S32: Input the actual speed at which NFC initiating device 3 passes through each grid;

[0161] S33: Calculate the time it takes for NFC initiating device 3 to pass through each grid;

[0162] Specifically, the time (t1, t2, t3, ...) for the NFC initiating device 3 to pass through each grid is obtained by dividing the step size (axial length) of each grid by the actual speed (v1, v2, v3, ...) of each grid.

[0163] S34: Calculate cumulative time;

[0164] Specifically, the cumulative time is calculated by accumulating the time of each grid cell, and the formula is: t(i) = t (i)+t(i-1), where t(i) is the cumulative time of the i-th calculation, t (i) t is the current grid time, and t(i-1) is the cumulative time of the previous time. For example, t(1) = t (1) +t(0), that is, t(1)=t (1) ; t(2)=t (2) +t(1), that is, t(2)=t (2) +t (1) ;

[0165] S35: Calculate cumulative displacement;

[0166] Specifically, the cumulative displacement is calculated by accumulating the step size of each grid cell. The calculation formula is: dz(i)=dz (i) +dz(i-1), where dz(i) is the cumulative displacement of the i-th time, dz (i) dz(i-1) is the current grid step size, and dz(i-1) is the cumulative displacement of the previous step. For example, dz(1) = dz (1) +dz(0), that is, dz(1)=dz (1) ;dz(2)=dz (2) +dz(1), that is, dz(2)=dz (2) +dz (1) ;

[0167] S36: Obtain the relationship between time and depth;

[0168] Specifically, the relationship between time and depth is obtained by corresponding the cumulative time and cumulative displacement according to the number of times, that is, dz(1) corresponds to t(1), dz(2) corresponds to t(2), and so on.

[0169] Furthermore, the average velocity can be calculated based on the cumulative time and cumulative displacement for further analysis or calculation.

[0170] In the description of this application, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0171] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between components; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0172] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0173] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A downhole measuring device, characterized in that, include: A drill pipe section (1) is connected to the drill pipe (13). The drill pipe section (1) has a built-in NFC initiator (3) that can be radially separated from the drill pipe section (1). The NFC initiator (3) can move axially within the well (15) and measure well parameters. The drill pipe section (1) includes a storage cavity (4), a release channel (5), and a control unit. The storage cavity (4) is used to store the NFC initiator (3). The release channel (5) connects the storage cavity (4) and the well (15). The control unit controls the opening and closing of the release channel (5). A drill pipe cavity (16) is formed within the drill pipe (13). The drill pipe section (1) also includes a receiving channel connecting the drill pipe cavity (16) and the storage cavity (4). The NFC initiator (3) includes a spherical carrier (6), an NFC processor (7), and a timer (8). Multiple NFC target devices (2) are arranged at intervals along the axial direction on the outer peripheral wall of the drill pipe (13), and the NFC target devices (2) are used to send NFC signals to the NFC initiating device (3); The NFC processor (7) is built into the spherical carrier (6) and is used to receive the NFC signal, and the timer (8) is built into the spherical carrier (6) and is used to record the signal time of receiving the NFC signal.

2. The downhole measuring device according to claim 1, characterized in that, The well parameters include pressure and temperature. The NFC initiating device (3) includes a temperature sensor (9) and a pressure sensor (10) built into the spherical carrier (6). The temperature sensor (9) is used to measure the temperature inside the well (15), and the pressure sensor (10) is used to measure the pressure inside the well (15).

3. The downhole measuring device according to claim 1, characterized in that, The drill pipe (13) includes multiple sub-drill pipes connected along the axial direction, and the NFC target device (2) includes an NFC tag disposed at the connection of adjacent sub-drill pipes, the NFC tag being used to store location information and send the NFC signal.

4. A downhole measurement method, characterized in that, The downhole measurement method, applied to the downhole measurement apparatus according to any one of claims 1 to 3, comprises: S1: Calculate the movement speed of the NFC initiating device (3) within the drilling (15); S2: Measure the drilling fluid flow rate in the well (15) and calculate the actual speed of the NFC initiating device (3) in the well (15) based on the transport speed and the drilling fluid flow rate; S3: Based on the actual speed, the relationship between time and depth is obtained using the finite element method; S4: Based on the relationship between time and depth and the signal time recorded by the NFC initiating device (3), obtain the downhole position corresponding to the signal time; S5: By correlating the downhole location and in-well parameters at the same signal time, the distribution of in-well parameters within the well (15) is obtained.

5. The downhole measurement method according to claim 4, characterized in that, The formula for calculating the transport speed is: in, The transport speed is... m / s ; For drilling fluid density, kg / m 3 ; The density of the NFC initiating device (3), kg / m 3 ; The diameter of the NFC initiating device (3) m ; φ sphericity coefficient, dimensionless; The viscosity of the drilling fluid. pa.s .

6. The downhole measurement method according to claim 4, characterized in that, The drilling (15) is divided into multiple well sections with different flow areas, and step S2 includes: Measure the drilling fluid flow rate and the flow area of ​​each section of the well; The drilling fluid velocity for each well section is calculated based on the drilling fluid flow rate and the plurality of flow areas.

7. The downhole measurement method according to claim 4, characterized in that, Step S2 includes: The actual transport speed is obtained by correcting the transport speed. The actual velocity is obtained by subtracting the true migration velocity from the drilling fluid flow velocity.

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