Downhole pole launched near field magnetic coupling two-way communication receive compensation method and apparatus

Abstract

The application discloses a downhole rod-throw type near-field magnetic coupling bidirectional communication receiving compensation method and device, which comprises the following steps: using a discrete high-temperature-resistant double-frequency receiving front end, sequentially receiving data of a baseline reference acquisition process, a training preamble section, a main data section and a check data section within a limited communication time window, combining phase auxiliary observation and training preamble statistics, combining a sweep response parameter, training preamble statistics and phase / period auxiliary observation, and compensating for double-branch response imbalance, baseline drift and residual detuning after coarse adjustment caused by downhole metal, liquid and high-temperature environment. The technical scheme of the application improves the anti-interference ability, decision stability and reliable communication ability in downhole near-field magnetic coupling bidirectional communication.

Description

Technical Field

[0001] This invention belongs to the field of information processing technology, specifically relating to a method and device for receiving and compensating for near-field magnetic coupling bidirectional communication using a downhole boom-type device. Background Technology

[0002] With the continuous development of technologies such as downhole stratified water injection and intelligent water distributors, downhole devices no longer only need to perform simple triggering or single identification, but also need to perform functions such as opening adjustment, stratified control, status monitoring, and parameter feedback. Correspondingly, the amount of data that can be collected downhole is also increasing, such as pressure, temperature, flow rate, valve position, and execution status. If this data is to be truly used for surface decision-making and control, it must be stably transmitted back to the surface from downhole. In existing downhole near-field magnetic coupling systems, the lever-type communicator is usually not stationary in the read / write area, but rather rapidly traverses the corresponding well section along the downhole path, completing information exchange within a limited coupling zone and a limited time window. At the same time, the downhole environment is constantly exposed to high temperature, high pressure, metal enclosure, and the coexistence of conductive liquids, which can easily cause problems such as weakened coupling, resonance shift, amplitude fluctuation, and unstable decision-making, leading to a decrease in the reliability of two-way communication. Summary of the Invention

[0003] To address the problems existing in the prior art, this invention provides a method and device for compensation of downhole rod-type near-field magnetic coupling bidirectional communication receiver.

[0004] To achieve the above objectives, the present invention provides the following solution: A method for compensating for near-field magnetic coupling bidirectional communication receivers in downhole boom-type applications includes: Step S1: Using a discrete high-temperature resistant dual-frequency receiver front end, during the ground calibration stage or the pre-communication calibration stage, perform multi-frequency sweep frequency tests on the low-frequency branch and the high-frequency branch to obtain the dual-path energy response curves, and establish a static compensation table by fitting, table lookup or interpolation. Step S2: Within a limited communication time window, the baseline reference acquisition process, training prelude, main data segment, and verification segment are received sequentially. Step S3: Based on the low-frequency known training units and high-frequency known training units in the training preamble, extract the training preamble statistics in the current communication window, and combine them with phase, period, frequency jump or capacitor array position auxiliary observations to construct a comprehensive compensation state quantity. Step S4: Based on the static compensation coefficients obtained from the frequency sweep fitting calibration table, the training compensation coefficients obtained from the training pre-training statistics, and the residual detuning auxiliary correction amount, perform digital domain compensation decision on the main data segment.

[0005] Preferably, in step S2, the baseline reference acquisition process is used to acquire baseline reference values ​​for the low-frequency branch and the high-frequency branch; the baseline reference acquisition process includes at least one of pre-frame empty window sampling, integrator reset sampling, moving average sampling, or training preamble pre-reference sampling. The training preamble segment is used to extract the receive status value within the current communication window under known bit conditions; the main data segment is used to transmit control commands or downhole backhaul data; and the verification segment is used for validity verification.

[0006] Preferably, the static compensation coefficients are obtained through a frequency sweep fitting calibration table. The training compensation coefficient is obtained through the training pre-training statistics. The residual detuning correction amount is obtained by using phase, period, frequency jump, or capacitor array range-assisted observations. Then, the three are combined to obtain the comprehensive compensation state quantity: in, The amount of compensation actually used when making a decision on the main data segment. This represents the fusion weights between static compensation and training compensation.

[0007] As a preferred option, the digital domain collaborative compensation decision for the main data segment is as follows: For any unknown data bit k in the main data segment, the dual-path energy response of the low-frequency branch and the high-frequency branch is obtained using the method described above. and And construct the normalized difference criterion: in, It is a small positive constant used to avoid the denominator approaching zero when the total energy is too low.

[0008] Using comprehensive compensation state quantities The master data criterion has been revised: like If it is, then it is judged as a high-frequency bit; if Then it is judged as a low-frequency bit; if or It is then classified as a low-confidence bit or an erased bit. Where T is the decision threshold. This is the minimum energy threshold.

[0009] This invention also provides a downhole rod-type near-field magnetic coupling bidirectional communication receiving compensation device, comprising a discrete high-temperature resistant dual-frequency receiving front-end, a switched capacitor array, an auxiliary observation branch, an analog-to-digital conversion sampling module, and a microcontroller main control module; wherein, The discrete high-temperature resistant dual-frequency receiver front end includes a low-frequency branch and a high-frequency branch, which are used to obtain the energy response near two target frequency points respectively; the switched capacitor array is used to coarsely tune the resonant network; the auxiliary observation branch is used to obtain residual detuning auxiliary observations related to phase, period, frequency jump or capacitor array level; the analog-to-digital conversion sampling module is used to collect the integral and hold sampling values ​​of the low-frequency branch and the high-frequency branch.

[0010] The microcontroller main control module includes a baseline reference acquisition module, a sweep frequency response calibration module, a static compensation lookup table interpolation module, a training preamble statistics module, a comprehensive compensation state quantity generation module, a digital domain compensation decision module, and a frame-level evaluation module. The frequency sweep response calibration module is used to establish a static compensation table, and the static compensation lookup interpolation module is used to obtain... The training pre-training statistics module is used to obtain... The integrated compensation state quantity generation module is used to obtain The digital domain compensation decision module is used to determine the appropriate decision based on the following criteria: Make a compensation decision for the main data segment.

[0011] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. In this invention, the baseline reference acquisition process, training preamble, and main data segment are received sequentially under the same receiving link. The training preamble statistics are not only used for receiving state extraction, but also for generating training compensation coefficients, and together with Ks obtained from the frequency sweep fitting calibration table, they form Kcomp. This makes the training preamble no longer only used for synchronization, but also for receiving state extraction within the current communication window, thereby improving the stability of receiving decisions within a limited communication time window.

[0012] 2. Using a training preamble, the main branch response, overall reference response, main branch response miscalculation, and noise-related statistics are extracted. Combined with a swept-frequency fitting calibration table and auxiliary observations such as phase, period, frequency jumps, or capacitor array settings, a comprehensive compensation state quantity is constructed. Further, a comprehensive compensation state quantity or dual-branch compensation weight is constructed to reduce the decision error in incoherent demodulation of dual-path energy in downhole environments. A digital domain collaborative compensation approach suitable for limited communication windows in downhole environments is proposed, improving the reliability of through-path near-field magnetic coupling communication without relying on complex analog online tuning networks.

[0013] 3. A digital domain collaborative compensation method for main data segment decision is proposed. Through baseline correction, normalized differential criteria, static compensation table lookup interpolation, training leader dynamic correction and adaptive threshold control, the adaptability of downhole dual-frequency receiver chain to residual detuning, baseline drift and noise fluctuation is improved.

[0014] 4. A method for evaluating the output of low-reliability bits and the amount of reliable data suitable for limited communication time windows in downhole is proposed. It can output not only the decision result, but also low-reliability bits or erased bits. When the compensated criterion is near the decision threshold, or the total energy of the two channels is lower than the minimum energy threshold, low-reliability bits or erased bits can be output. The proportion of low-reliability bits, the proportion of erased bits, and the frame check result can be used to evaluate the amount of reliable data within the limited communication window. Attached Figure Description

[0015] To more clearly illustrate the technical solution of the present invention, the drawings used in the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a flowchart of the downhole rod-type near-field magnetic coupling bidirectional communication receiving compensation method according to an embodiment of the present invention; Figure 2 This is a system structure block diagram of the single main coil, dual-path energy main demodulation chain, phase auxiliary branch, and reader / writer main control and transmission module of the present invention. Figure 3 This is a schematic diagram of the tag transmission frame structure; it includes a training preamble, a main data segment, and a verification segment. Figure 4 This is a flowchart of the training pre-training statistics extraction and state estimation process; Figure 5 This is a flowchart of the collaborative compensation judgment process. Detailed Implementation

[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0019] Example 1 like Figure 1As shown, this invention provides a method for receiving compensation in downhole near-field magnetic coupling bidirectional communication. This method can be deployed in the receiving chain of a permanently installed intelligent device or in the receiving chain of a pole-mounted communicator. Based on a discrete high-temperature resistant dual-frequency receiving front-end, this invention extracts the overall reference response, dual-branch response misalignment, and noise indicators during the receiving process of a permanently installed intelligent device or a pole-mounted communicator through a training preamble. It then combines phase auxiliary quantities to characterize the residual detuning state and performs baseline correction, branch rebalancing, overall amplitude normalization, and adaptive threshold decision on the main data segment. This improves the anti-interference capability, decision stability, and reliable communication capability within a limited communication time window in downhole near-field magnetic coupling bidirectional communication. The method includes: Step 1: Construct a discrete dual-frequency receiver structure like Figure 2 As shown, the downhole permanently installed intelligent device includes: a main reader / writer coil, a low-frequency branch bandpass filter, a high-frequency branch bandpass filter, two shaping and integrating units, an analog-to-digital conversion sampling module, a microcontroller main control module, and a phase auxiliary branch; wherein, the phase auxiliary branch is used to obtain the phase relationship between the main coil current reference and the resonant node. The stick-type communicator includes a stick-shaped housing, a main coil, a resonant network, a main control circuit, and a battery module; the main reader / writer coil is used to complete near-field magnetic coupling transmission and reception, the low-frequency branch and the high-frequency branch respectively establish frequency selection and energy decision links around two target frequencies, and the phase auxiliary branch is used to characterize the residual detuning state of the main circuit in the downhole environment.

[0020] The downhole permanent intelligent device also includes: a switched capacitor array and a swept frequency response calibration module; wherein, the switched capacitor array is used to coarsely tune the resonant network so that the target operating frequency is as close as possible to the peak value of the received response; the swept frequency response calibration module is used to obtain the response curves of the low-frequency branch and the high-frequency branch during the ground calibration stage or the pre-communication calibration stage, and to establish a static compensation table.

[0021] Step 2: Define the bidirectional communication frame structure The data frames transmitted by the pole-mounted communicator are constructed in the following order: "baseline reference acquisition process + at least low-frequency known training units and high-frequency known training units + main data segment + check segment", such as... Figure 3 As shown.

[0022] The baseline reference can be obtained by integrator reset sampling, moving average sampling, or training leader reference sampling; the main data segment is used to transmit control commands or downhole data; and the verification segment is used for subsequent validity verification.

[0023] Step 3: Obtain the static baseline of the two branches Using the baseline reference acquisition process, the low-frequency branch and the high-frequency branch are sampled to obtain the baseline of the low-frequency branch. and high frequency branch baseline The baseline reference can be obtained from the pre-frame window, the integrator reset state, the moving average, or the pre-training reference sampling.

[0024] If the i-th sample collected by the low-frequency branch and the high-frequency branch during the silent period are respectively and The number of sampling points is Then it is acceptable: This step is used to eliminate the effects of static bias and differential zero-point drift caused by the discrete receiver chain under long-term high-temperature downhole operation conditions.

[0025] Step 4: Frequency sweep fitting calibration and establishment of static compensation table During the ground calibration phase or the pre-communication calibration phase, multi-frequency sweep tests are performed on the low-frequency branch and the high-frequency branch to obtain the dual-path energy response curves at different frequency points and under different tuning states.

[0026] The low-frequency branch baseline and high-frequency branch baseline obtained in step three are used respectively and denoted as follows: and Set at the sweep frequency point Below, the sampled values ​​after integration and holding of the low-frequency branch and the high-frequency branch are respectively and The energy response of the two sweep frequencies can then be expressed as: Based on frequency sweep and The response curves of the low-frequency branch and the high-frequency branch were fitted separately to extract the center frequency. Quality factor Q, amplitude coefficient K, or equivalent compensation coefficient.

[0027] In one implementation, the dual-path response curve can be fitted using a bandpass response model: Where i represents a low-frequency branch or a high-frequency branch, Let i be the equivalent center frequency of the i-th branch. In response to the width parameter, For amplitude coefficient, For background items.

[0028] Furthermore, based on the response differences between the two branches near the operating frequency, a static compensation coefficient is established. In one implementation, the normalized differential response under the frequency sweep state is defined as: in, It is a small positive constant used to avoid the denominator being too small.

[0029] When the low-frequency operating frequency is The high-frequency operating frequency is In this case, the offset of the criterion center at the two operating frequency points can be used as the basis for static compensation: During the calibration process, different capacitor array settings can be applied. Repeat the frequency sweep fitting process at different operating frequencies or under different temperature conditions to establish a static compensation table: in, Indicates temperature.

[0030] In actual communication, it is not necessary to perform a complete frequency sweep fitting again. Instead, based on the current operating frequency, the current capacitor array level, and the current observable state variables, the adjacent calibration points are found from the static compensation table, and the current static compensation coefficients are obtained by linear interpolation.

[0031] If the current frequency Located at two calibration frequency points and Between these points, linear interpolation can be performed using the following formula: in: , If capacitor array positions are considered simultaneously, linear interpolation can be performed first within the same capacitor position according to frequency, and then linear interpolation can be performed between adjacent capacitor positions to obtain the current communication status. .

[0032] This step is used to convert the dual-path response characteristics obtained from ground frequency sweep fitting into static compensation quantities that can be quickly invoked during actual communication, providing a foundation for subsequent training preamble dynamic correction and main data segment decision compensation.

[0033] Step 5: Define dual-path energy and extract training pre-training statistics For any k-th training bit or data bit, the sampled values ​​after integration and preservation of the low-frequency branch and the high-frequency branch are denoted as follows: and Subtract the low-frequency branch baseline obtained in step three. and high frequency branch baseline Then, the dual-path energy response was obtained: in, and These represent the baseline energy response of the k-th bit in the low-frequency branch and the high-frequency branch, respectively.

[0034] Let the set of low-frequency known training units be . The set of high-frequency known training units is ,in and These represent the number of known training units at low and high frequencies, respectively. Four training means are then defined: in, This represents the main response of the low-frequency branch under low-frequency training conditions. This represents the main response of the high-frequency branch under high-frequency training conditions; and These represent the non-target branch responses under low-frequency and high-frequency training states, respectively, and are used to characterize branch crosstalk or frequency selection isolation.

[0035] Step Six: Estimate the overall reference response magnitude Define the overall reference response amplitude The average of the average responses of the two main branches after removing the baseline: in, It is used to characterize the overall receiving intensity under the combined effects of the current downhole location, propagation distance, metallic environment, and liquid environment.

[0036] when A larger value indicates stronger coupling within the current communication window; when... When the value is small, it indicates that the current window may be in a weakly coupled region or at the edge of the effective read region.

[0037] Step 7: Estimate the response loss of the main branch Define the main branch loss measurement The logarithmic ratio of the means of the two main branches: when When it is greater than zero, it indicates that the high-frequency main branch is relatively strong; when When it is less than zero, it indicates that the low-frequency main branch is relatively strong; when When the value approaches zero, it indicates that the two main branches are basically balanced. Using a logarithmic form naturally maps the equilibrium point to zero and matches it with the subsequent exponential compensation weights. In the formula... This is to introduce a small positive constant when the average response of a certain main branch is too small or close to zero. This is to avoid logarithmic singularities and suppress instability in ratio calculations under extremely low signal conditions.

[0038] Step 8: Estimate the residual detuning phase error Let the zero-crossing time difference between the main coil current reference and the resonant node be... The residual detuning phase error It can be represented as: in, This is the center frequency or the reference frequency selected during the training phase. This quantity mainly characterizes the direction and extent of the reader's residual detuning caused by factors such as proximity to downhole metal.

[0039] Step 9: Construct the comprehensive compensation state variables The process for generating comprehensive compensation state variables is as follows: Figure 4 As shown, based on the frequency sweep fitting calibration results, training preamble statistics, and residual detuning auxiliary observations, a comprehensive compensation state quantity for the main data segment decision is constructed.

[0040] First, training compensation coefficients are constructed based on the known low-frequency and high-frequency training responses. The normalized difference response under high-frequency training conditions is defined as: Define the normalized difference response under low-frequency training conditions as: in, It is a small positive constant used to avoid the denominator being too small.

[0041] Therefore, the training compensation coefficient is obtained: in, It is used to characterize the dynamic criterion center offset caused by coupling state, branch response imbalance and baseline drift within the current communication window.

[0042] The residual mistuning correction is constructed based on the residual mistuning auxiliary observations: in, , , The coefficients are obtained from surface calibration or downhole calibration. This indicates the current capacitor array setting. If the capacitor array setting is not used for correction, then it can be set... If residual detuning auxiliary observations are not used, then it can be made .

[0043] By integrating the static compensation coefficient, the training compensation coefficient, and the residual detuning correction, the comprehensive compensation state quantity is obtained: in, The actual amount of compensation used when making a decision on the main data segment; For the fusion weights between static compensation and training compensation. When When the frequency is large, the system relies more on the sweep frequency fitting calibration table; when When the values ​​are smaller, the system relies more on the training pre-training statistics of the current frame.

[0044] When frequency sweep static compensation is not used, it can be set to When training pre-training dynamic compensation is not used, it can be set to... ; In this way, the system can first use the frequency sweep fitting calibration table to provide a long-term stable static compensation basis, and then use the training preamble statistics to correct the dynamic offset within the current communication window, thereby reducing the impact of residual detuning after coarse adjustment of the capacitor array, dual-branch response imbalance and baseline drift on the decision of the main data segment.

[0045] Step 10: Generate dual-branch compensation weights In one implementation, the comprehensive compensation state quantity obtained in step eight can be used directly. The normalized differential criterion for the main data segment is modified, and the dual-branch compensation weights are no longer generated separately.

[0046] In another implementation, to achieve rebalancing of the two branches, it can also be based on Generate compensation weights for low-frequency and high-frequency branches: in, For high-frequency branch compensation weights, For low-frequency branch compensation weights, This is the weighting adjustment coefficient. Using an exponentially symmetric form ensures that the compensation directions of the two branches are opposite and prevents excessive amplification of the overall gain by one side. When not using a dual-branch weighted compensation method, we can set: At this time, the main data segment decision is only made by... The normalized difference criterion is corrected for center offset.

[0047] Step 11: Estimate the noise index and generate an adaptive threshold Estimate the variance of the two branches based on the training leader segment or the pre-leader window segment. and Define noise metrics for: Further define the adaptive threshold T as: in, Based on the basic threshold, This is an adjustment coefficient related to the noise index.

[0048] Step 12: Implement digital domain collaborative compensation decision on the master data segment. The digital domain collaborative compensation decision process of the main data segment is as follows: Figure 5 As shown. For any unknown data bit k in the main data segment, the dual-path energy response is obtained according to the method described in step five. and And using the normalized difference form from step eight, construct the master data criterion: in, It is a small positive constant used to avoid the denominator approaching zero when the total energy is too low.

[0049] Using the comprehensive compensation state variables obtained in step eight The master data criterion has been revised: like If it is, then it is judged as a high-frequency bit; if Then it is judged as a low-frequency bit; if or It is then classified as a low-confidence bit or an erased bit. Where T is the decision threshold obtained in step ten. This is the minimum energy threshold.

[0050] Step 13: Perform frame-level evaluation and window-level evaluation After completing the main data segment decision, the validity of the current frame is checked based on the check segment, and the number of low-reliability bits, erased bits, and valid decision bits are counted to obtain the reliable transmission ratio of the current frame.

[0051] If the communication window for the lever-type communicator crosses the valid read area is... The communication rate is The reliable transmission ratio is The amount of reliable data within a finite communication window can be expressed as: in, It can be determined by a combination of the low-confidence bit ratio, the erased bit ratio, and the frame check results.

[0052] The evaluation results can be used to adjust the training preamble length, decision threshold, compensation coefficient, or capacitor array level.

[0053] (1) The purpose of the training preamble is different in this invention compared with the prior art.

[0054] Existing burst frequency shift keying schemes typically only utilize a training preamble to complete frame synchronization, symbol timing recovery, or coarse frequency offset estimation; this invention, however, utilizes the training preamble to further extract the overall reference response amplitude. Main branch response loss measurement and noise index This allows the training preamble to simultaneously perform the functions of "state estimation," rather than just "synchronization." Furthermore, the training preamble statistics are also used to generate training compensation coefficients. And the static compensation coefficients obtained from the frequency sweep fitting calibration table. The data is integrated to form a comprehensive compensation state quantity used in the main data segment decision. .

[0055] (2) The compensation entry point of the present invention is different from that of the prior art.

[0056] Existing phase difference tuning schemes typically follow a closed-loop analog path of "phase difference measurement - controllable capacitor adjustment - resonant point callback"; this invention uses a switched capacitor array as a coarse tuning method, and uses phase, period or frequency jump auxiliary quantities as state observations of residual detuning after coarse tuning, and combines the sweep frequency fitting calibration table and training preamble statistics to construct a comprehensive compensation state quantity Kcomp.

[0057] (3) Compared with the prior art, the present invention has split the source of disturbance.

[0058] For disturbances in the downhole environment, this invention no longer uniformly regards them as "signal weakening" or "requiring re-resonance," but rather divides them into three categories: The first category is the static criterion offset caused by differences in dual-channel frequency response, capacitor array settings, and long-term environmental conditions, mainly obtained from the frequency sweep fitting calibration table. Characterization; the second category is the dynamic criterion offset within the current communication window caused by coupling position, baseline drift, and branch response imbalance, mainly obtained from the training preamble. Characterization; the third type is residual detuning after coarse adjustment, mainly composed of phase, period, frequency jumps, or capacitor array range-assisted observations. Characterization; weak coupling and noise fluctuations are handled through adaptive thresholds, minimum energy thresholds, and low-confidence bit outputs. The aforementioned static offset, dynamic offset, and residual detuning corrections are ultimately fused into... And used as the normalized difference criterion for the main data segment. Corrections.

[0059] (4) Compared with the prior art, the output format and evaluation index of the present invention are more suitable for the limited communication time window in the well.

[0060] Existing solutions typically only provide hard decision results or evaluate recognition success rates in static scenarios. This invention further introduces low-reliability bit or erase bit output formats. When the compensated criterion dc(k) is near the decision threshold, or the total energy of the two channels is lower than the minimum energy threshold, the corresponding bit can be marked as a low-reliability bit or erase ratio. The number of reliable bits, the reliable transmission ratio, and the maximum amount of reliable data within a limited communication time window are used as evaluation indicators. The reliable transmission ratio can be determined by a combination of the low-reliability bit ratio, the erase bit ratio, and the frame verification results. Therefore, it is more in line with the actual needs of the downhole rod-type near-field magnetic coupling bidirectional communication scenario.

[0061] (5) Compared with the prior art, the present invention is more suitable for discrete high temperature resistance implementation route.

[0062] This invention establishes a method chain around a discrete dual-frequency receiver front-end, making it more suitable for device selection, parameter adjustment, and engineering implementation in high-temperature downhole environments. It also leaves room for future expansion to higher temperature levels. Furthermore, this invention achieves coarse tuning through a switched capacitor array and transforms the ground-based frequency sweep fitting results into a static compensation table. In actual communication, only table lookup and linear interpolation are needed to obtain the necessary information. Then, combined with training pre-generation This avoids performing complex online frequency sweep fitting or continuous analog closed-loop tuning within a limited communication window.

[0063] Example 2 This invention also provides a downhole rod-type near-field magnetic coupling bidirectional communication receiving compensation device, comprising a discrete high-temperature resistant dual-frequency receiving front-end, a switched capacitor array, an auxiliary observation branch, an analog-to-digital conversion sampling module, and a microcontroller main control module; wherein, The discrete high-temperature resistant dual-frequency receiver front end includes a low-frequency branch and a high-frequency branch, used to obtain the energy response near two target frequency points respectively; the switched capacitor array is used for coarse tuning of the resonant network; the auxiliary observation branch is used to acquire residual detuning auxiliary observations related to phase, period, frequency jump, or capacitor array position; the analog-to-digital conversion sampling module is used to acquire the integral-hold sampled values ​​of the low-frequency branch and the high-frequency branch; the microcontroller main control module includes a baseline reference acquisition module, a sweep frequency response calibration module, a static compensation lookup table interpolation module, a training preamble statistics module, a comprehensive compensation state quantity generation module, a digital domain compensation decision module, and a frame-level evaluation module; The frequency sweep response calibration module is used to establish a static compensation table, and the static compensation lookup interpolation module is used to obtain... The training pre-training statistics module is used to obtain... The integrated compensation state quantity generation module is used to obtain The digital domain compensation decision module is used to determine the appropriate decision based on the following criteria: Make a compensation decision for the main data segment.

[0064] During implementation, a static rig or semi-physical simulation platform is first erected on the ground, along with sweep frequency response parameters and static compensation tables for different capacitor array settings and frequency points; simultaneously, the training preamble length and basic threshold are also determined. Noise weight The method is calibrated using phase / period auxiliary correction coefficients, dual-channel sweep frequency response parameters under different capacitor array settings, and static compensation tables. Once the surface calibration is complete, the method can be deployed into the downhole reader software. Since the core of this invention lies in the device structure, state variable definitions, and formula processing flow, it does not rely on complex large-scale downhole tests to be valid. Those skilled in the art can implement this method based on the circuit structure, parameter relationships, and processing flow given in the specification; surface bench verification, limited cross-country tests, or subsequent downhole verification are all preferred implementation methods.

[0065] In the embodiments, the training preamble preferably includes continuous Low-frequency training bits and continuous High-frequency training bits; baseline sampling is preferably completed during the silent period before the training preamble; when making decisions on master data, if the magnitude of the decision variable is small or the confidence level is insufficient, the corresponding bit can be recorded as a low-confidence bit so that it can be processed in conjunction with check bits or frame-level strategies in the future.

[0066] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for compensating for near-field magnetic coupling bidirectional communication reception in downhole rod-type applications, characterized in that, include: Step S1: Using a discrete high-temperature resistant dual-frequency receiver front end, during the ground calibration stage or the pre-communication calibration stage, perform multi-frequency sweep frequency tests on the low-frequency branch and the high-frequency branch to obtain the dual-path energy response curves, and establish a static compensation table by fitting, table lookup or interpolation. Step S2: Within a limited communication time window, the baseline reference acquisition process, training prelude, main data segment, and verification segment are received sequentially. Step S3: Based on the low-frequency known training units and high-frequency known training units in the training preamble, extract the training preamble statistics in the current communication window, and combine them with phase, period, frequency jump or capacitor array position auxiliary observations to construct a comprehensive compensation state quantity. Step S4: Based on the static compensation coefficients obtained from the static compensation table, the training compensation coefficients obtained from the training pre-training statistics, and the residual detuning auxiliary correction amount, perform digital domain compensation decision on the main data segment.

2. The downhole rod-type near-field magnetic coupling bidirectional communication receiving compensation method as described in claim 1, characterized in that, In step S2, the baseline reference acquisition process is used to acquire the baseline reference values ​​for the low-frequency branch and the high-frequency branch; The baseline reference acquisition process includes at least one of the following: pre-frame empty window sampling, integrator reset sampling, moving average sampling, or training preamble pre-reference sampling. The training preamble is used to extract the receive status quantity within the current communication window under known bit states; the main data segment is used to transmit control commands or downhole backhaul data; and the verification segment is used for validity verification.

3. The downhole rod-type near-field magnetic coupling bidirectional communication receiving compensation method as described in claim 2, characterized in that, The static compensation coefficients were obtained using a frequency sweep fitting calibration table. The training compensation coefficient is obtained through the training pre-training statistics. The residual detuning correction amount is obtained by using phase, period, frequency jump, or capacitor array range-assisted observations. Then, the three are combined to obtain the comprehensive compensation state quantity: in, The amount of compensation actually used when making a decision on the main data segment. This represents the fusion weights between static compensation and training compensation.

4. The downhole rod-type near-field magnetic coupling bidirectional communication receiving compensation method as described in claim 3, characterized in that, The following decision is made regarding the digital domain collaborative compensation for the main data segment: For any unknown data bit k in the main data segment, the dual-path energy response of the low-frequency branch and the high-frequency branch is obtained using the method described above. and And construct the normalized difference criterion: in, It is a small positive constant used to avoid the denominator approaching zero when the total energy is too low. Using comprehensive compensation state quantities The master data criterion has been revised: like If it is, then it is judged as a high-frequency bit; if Then it is judged as a low-frequency bit; if or It is then classified as a low-confidence bit or an erased bit. Where T is the decision threshold. This is the minimum energy threshold.

5. A downhole rod-type near-field magnetic coupling bidirectional communication receiving and compensation device, characterized in that, It includes a discrete high-temperature resistant dual-frequency receiver front-end, a switched capacitor array, an auxiliary observation branch, an analog-to-digital conversion sampling module, and a microcontroller main control module; among which, The discrete high-temperature resistant dual-frequency receiver front end includes a low-frequency branch and a high-frequency branch, used to obtain the energy response near two target frequency points respectively; the switched capacitor array is used for coarse tuning of the resonant network; the auxiliary observation branch is used to acquire residual detuning auxiliary observations related to phase, period, frequency jump, or capacitor array position; the analog-to-digital conversion sampling module is used to acquire the integral-hold sampled values ​​of the low-frequency branch and the high-frequency branch; the microcontroller main control module includes a baseline reference acquisition module, a sweep frequency response calibration module, a static compensation lookup table interpolation module, a training preamble statistics module, a comprehensive compensation state quantity generation module, a digital domain compensation decision module, and a frame-level evaluation module.

6. The downhole rod-type near-field magnetic coupling bidirectional communication receiving and compensation device as described in claim 5, characterized in that, The frequency sweep response calibration module is used to establish a static compensation table, and the static compensation lookup and interpolation module is used to obtain... The training pre-training statistics module is used to obtain... The integrated compensation state quantity generation module is used to obtain The digital domain compensation decision module is used to determine the appropriate decision based on the following criteria: Make a compensation decision for the main data segment.

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