MWD continuous wave measurement signal processing method and device

Abstract

The invention relates to the technical field of measurement while drilling, in particular to an MWD continuous wave measurement signal processing method and device, and the method comprises the steps: carrying out the modulation processing of an underground MWD continuous wave measurement signal, and obtaining an MWD continuous wave transmission signal; denoising the MWD continuous wave transmission signal twice; and extracting an MWD continuous wave measurement signal from the MWD continuous wave transmission signal after the two times of denoising. According to the invention, the MWD frequency-modulated continuous wave signal is modulated by using the FSK frequency-shift keying, the underground MWD continuous wave measurement signal is enhanced, the external interference resistance of the MWD continuous wave transmission signal in the transmission process is improved, and after the MWD continuous wave transmission signal is received at a wellhead, the MWD continuous wave transmission signal is transmitted to the wellhead. Interference of noise on extraction of the underground MWD continuous wave measurement signal is eliminated to the maximum extent through two times of denoising, so that the accurate underground MWD continuous wave measurement signal can be obtained, and a basis is provided for analyzing the MWD measurement while drilling signal.

Description

Technical Field

[0001] The invention relates to the technical field of measurement while drilling, in particular to a method and a device for processing MWD continuous wave measurement signals. Background Art

[0002] During the drilling process, especially during the drilling of wells with complex structures such as horizontal wells, extended reach wells and branch wells, the various downhole parameters that the well site personnel need to know in real time are completed by the measurement while drilling and logging while drilling systems. The measurement while drilling and logging while drilling systems are composed of downhole controllers, various downhole measurement while drilling instruments MWD, measurement while drilling information transmission systems and ground information receiving, processing and display systems, among which the information transmission system is one of the key technologies. In the measurement while drilling system, the drilling fluid positive / negative mud pulse coding technology is relatively mature and widely used, but the data transmission rate is low, which seriously affects the production efficiency. The measurement while drilling continuous wave pulse transmission technology has the advantages of high information transmission rate, relatively simple mechanical structure, and convenient signal generator implementation, so it has received widespread attention and application in the industry.

[0003] The measurement while drilling data is uploaded to the surface through the downhole drilling fluid pulse signal. The signal is often interfered during the channel transmission process, causing real-time data oscillation and "burr" phenomenon. Therefore, the noise interference generated by the downhole MWD continuous wave measurement signal during the mud channel transmission is affected by multiple noise sources such as the drilling pump, the interaction between the drill bit and the bottom of the hole, the interaction between the drill string and the well wall, and the downhole turbine generator. It has extremely complex noise components, which makes it difficult to accurately process and identify. Therefore, after obtaining the downhole continuous wave signal at the wellhead, effective signal extraction is required. The existing measurement while drilling continuous wave signal method does not consider the influence of factors such as signal reflection, superposition, and echo, and cannot extract accurate and effective signals.

[0004] The first existing public patent document, with the publication number CN116955941B, discloses a method for denoising continuous wave signals during drilling measurement, including determining the frequency band range of the continuous wave signal, determining the frequency interval where the energy of the continuous wave signal is concentrated by a spectrum analysis method, removing the noise outside the frequency band of the continuous wave signal, and removing the pump noise and other noise outside the frequency band of the continuous wave signal by a bandpass filter. The pump noise within the frequency band of the continuous wave signal is reconstructed using an unscented Kalman filter, and the pump noise is removed. The method for denoising the continuous wave signal of the drilling fluid of the present invention can realize the real-time reconstruction of the mud pump noise under the working conditions of extremely low signal-to-noise ratio, thereby realizing the accurate identification and extraction of the continuous wave signal; the denoising method can also effectively remove the pump noise when the carrier frequency of the continuous wave signal and the harmonic frequency of the pump noise are "co-frequency" interfered; the denoising algorithm can still maintain a good denoising ability when the order is high, and realize the effective processing of the continuous wave signal. The public patent document only considers the denoising process, and the denoising process is not the same as the denoising process of the present invention.

[0005] The second existing open patent document, with publication number CN102200009B, discloses a method for processing downhole continuous wave signals for MWD. ​​The method first establishes a simulation diagram of the structure of the downhole MWD system, and then processes the two situations of the drill bit being an open-circuit end reflector and the drill collar-drill string wave impedance mismatch and the drill bit being a closed-circuit end and a solid reflection surface and the drill collar-drill string cross-sectional area mismatch respectively according to the proportional relationship between the drill bit water hole area and the drill bit cross-sectional area; based on the specific signal processing algorithm of the present invention, the interference of reflection, superposition and reverberation contained in the ground receiving signal can be removed to restore the original ΔP signal, and further, the MWD measurement while drilling information is obtained by analyzing the ΔP signal. The open patent document only considers the extraction process, and does not combine denoising with extraction to realize the extraction of MWD measurement while drilling information. Summary of the invention

[0006] The present invention provides a method and device for processing MWD continuous wave measurement signals, which overcome the above-mentioned deficiencies of the prior art and can effectively solve the problem of inaccurate extraction of downhole MWD continuous wave measurement signals in the prior art.

[0007] One of the technical solutions of the present invention is achieved by the following measures: A method for processing MWD continuous wave measurement signals, comprising: Modulate the downhole MWD continuous wave measurement signal to obtain the MWD continuous wave transmission signal; The MWD continuous wave transmission signal is denoised twice, wherein the two denoising processes include: using the frequency domain analysis method to denoise the MWD continuous wave transmission signal once to separate the mud pump noise in the MWD continuous wave transmission signal; using the wavelet transform to denoise the MWD continuous wave transmission signal after the first denoising twice to separate the Gaussian white noise in the MWD continuous wave transmission signal; The MWD continuous wave measurement signal is extracted from the MWD continuous wave transmission signal after two denoising.

[0008] The following are further optimizations and / or improvements to the above technical solutions: The above-mentioned frequency domain analysis method is used to perform a denoising operation on the MWD continuous wave transmission signal, and separate the mud pump noise in the MWD continuous wave transmission signal, including: The sampling signal is obtained from the MWD continuous wave transmission signal, and the periodic function analysis of the sampling signal is performed based on the autocorrelation method to obtain the corresponding mud pump noise period , where the sampling signal is obtained by sampling m binary bits in the MWD continuous wave transmission signal; Utilizing the Mud Pump Noise Cycle , press The MWD continuous wave transmission signal is intercepted in the order of The intercepted signals are sequentially set at the end of the sampled signals to form a set of signals to be processed; The signal set to be processed is averaged, and the result after processing is the mud pump noise signal; Based on the spectrum characteristics of mud pump noise signal, the mud pump noise is removed from the MWD continuous wave transmission signal.

[0009] The above-mentioned method of performing secondary denoising on the MWD continuous wave transmission signal after the primary denoising by using wavelet transform to separate the Gaussian white noise in the MWD continuous wave transmission signal includes: Determine the db9 wavelet basis function and the number of decomposition levels K; The db9 wavelet basis function is used to perform K-layer orthogonal wavelet decomposition on the MWD continuous wave transmission signal after the first denoising; The detail coefficients of each layer from the 1st to the Kth layer are processed by the threshold function; The signal is reconstructed according to the detail coefficient of the Kth layer and the processed detail coefficients of the 1st to Kth layers.

[0010] The above-mentioned method of extracting the MWD continuous wave measurement signal from the MWD continuous wave transmission signal after two denoising steps includes: Get the continuous wave measurement signal extraction model, the model is as follows: in, is the pressure difference on both sides of the continuous wave signal generator, is the cross-sectional area of ​​the drill collar, is the cross-sectional area of ​​the drill string, is the drill collar length, is the distance between the signal generator and the drill bit, is the signal propagation speed, It is the MWD continuous wave transmission signal; The MWD continuous wave transmission signal after two denoising is introduced into , using the difference iteration method to solve , extract the MWD continuous wave measurement signal.

[0011] The above-mentioned modulation processing of the downhole MWD continuous wave measurement signal to obtain the MWD continuous wave transmission signal includes: The downhole MWD continuous wave measurement signal is processed using the continuous wave transmission model to obtain the MWD frequency modulated continuous wave signal. The MWD frequency modulated continuous wave signal is modulated by FSK frequency shift keying to obtain the MWD continuous wave transmission signal, and the transmission mode is selected to transmit it to the wellhead.

[0012] The second technical solution of the present invention is achieved by the following measures: a MWD continuous wave measurement signal processing device, comprising: The transmission unit modulates the downhole MWD continuous wave measurement signal to obtain the MWD continuous wave transmission signal; The denoising unit performs two denoising operations on the MWD continuous wave transmission signal, wherein the two denoising operations include: performing a first denoising operation on the MWD continuous wave transmission signal by using the frequency domain analysis method to separate the mud pump noise in the MWD continuous wave transmission signal; performing a second denoising operation on the MWD continuous wave transmission signal after the first denoising operation by using the wavelet transform to separate the Gaussian white noise in the MWD continuous wave transmission signal; The extraction unit extracts the MWD continuous wave measurement signal from the MWD continuous wave transmission signal after two denoising.

[0013] The following are further optimizations and / or improvements to the above technical solutions: The denoising unit comprises: The first denoising module uses the frequency domain analysis method to denoise the MWD continuous wave transmission signal and separate the mud pump noise in the MWD continuous wave transmission signal, including: The sampling signal is obtained from the MWD continuous wave transmission signal, and the periodic function analysis of the sampling signal is performed based on the autocorrelation method to obtain the corresponding mud pump noise period , where the sampling signal is obtained by sampling m binary bits in the MWD continuous wave transmission signal; Utilizing the Mud Pump Noise Cycle , press The MWD continuous wave transmission signal is intercepted in the order of The intercepted signals are sequentially set at the end of the sampled signals to form a set of signals to be processed; The signal set to be processed is averaged, and the result after processing is the mud pump noise signal; Based on the spectrum characteristics of mud pump noise signal, the mud pump noise is removed from the MWD continuous wave transmission signal. The second denoising module uses wavelet transform to perform secondary denoising on the MWD continuous wave transmission signal after the primary denoising, and separates the Gaussian white noise in the MWD continuous wave transmission signal, including: Determine the db9 wavelet basis function and the number of decomposition levels K; The db9 wavelet basis function is used to perform K-layer orthogonal wavelet decomposition on the MWD continuous wave transmission signal after the first denoising; The detail coefficients of each layer from the 1st to the Kth layer are processed by the threshold function; The signal is reconstructed according to the detail coefficient of the Kth layer and the processed detail coefficients of the 1st to Kth layers.

[0014] The above transmission unit comprises: The signal processing module processes the downhole MWD continuous wave measurement signal using the continuous wave transmission model to obtain the MWD frequency modulated continuous wave signal; The modulation module uses FSK frequency shift keying to modulate the MWD frequency modulated continuous wave signal to obtain the MWD continuous wave transmission signal, and selects the transmission mode to transmit it to the wellhead.

[0015] The present invention processes and modulates the downhole MWD continuous wave measurement signal by using a continuous wave transmission model and FSK frequency shift keying, thereby enhancing the downhole MWD continuous wave measurement signal, so that the obtained MWD continuous wave transmission signal can have a strong ability to resist external interference during the transmission process, and after receiving the MWD continuous wave transmission signal at the wellhead, the interference of noise on the extraction of the downhole MWD continuous wave measurement signal is eliminated to the greatest extent through two denoising, and the downhole MWD continuous wave measurement signal is extracted based on the continuous wave measurement signal extraction model, so that the distortion of the downhole MWD continuous wave measurement signal during the transmission process is effectively eliminated, so that an accurate downhole MWD continuous wave measurement signal can be obtained, and a basis is provided for parsing the MWD while drilling measurement signal. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Attached Figure 1 A schematic flow chart of a method for processing MWD continuous wave measurement signals provided by an embodiment of the present invention.

[0017] Attached Figure 2 A schematic diagram of a primary denoising method flow chart provided by an embodiment of the present invention.

[0018] Attached Figure 3 A schematic flow chart of a secondary denoising method provided by an embodiment of the present invention.

[0019] Attached Figure 4 A schematic diagram of the structure of a device provided in one embodiment of the present invention. DETAILED DESCRIPTION

[0020] The present invention is not limited by the following embodiments, and specific implementation methods can be determined based on the technical solution of the present invention and actual conditions.

[0021] In the embodiments of the present invention, the term "module" or "unit" refers to a computer program or a part of a computer program that has a predetermined function and works together with other related parts to achieve a predetermined goal, and can be implemented in whole or in part by using software, hardware (such as processing circuits or memories) or a combination thereof. Similarly, a processor (or multiple processors or memories) can be used to implement one or more modules or units. In addition, each module or unit can be part of an overall module or unit that includes the function of the module or unit.

[0022] In addition, the term "plurality" in the embodiments of the present invention refers to two or more than two. The terms "first" and "second" in the embodiments of the present invention are used for distinguishing descriptions and should not be understood as implying relative importance.

[0023] Glossary: ‌MWD (Measurement While Drilling) refers to the process in which the drilling rig continuously detects information about the borehole or drill bit during the drilling process and transmits this information to the surface in real time. ‌‌ Based on this, the technical solution of the present invention will be introduced and explained in combination with several examples below.

[0024] Embodiment 1: As attached Figure 1 As shown, an embodiment of the present invention discloses a method for processing MWD continuous wave measurement signals, comprising: Step S110, modulating the downhole MWD continuous wave measurement signal to obtain an MWD continuous wave transmission signal.

[0025] In this embodiment, the downhole MWD continuous wave measurement signal is modulated so that the downhole MWD continuous wave measurement signal can be effectively enhanced, thereby having strong anti-noise and anti-attenuation capabilities, and being able to resist external interference during the transmission process from the downhole to the wellhead, thereby ensuring the stability of signal transmission. The specific modulation processing method can be selected from the existing digital carrier signal modulation methods. Step S120, performing two denoising on the MWD continuous wave transmission signal, wherein the two denoising include: performing a first denoising on the MWD continuous wave transmission signal using a frequency domain analysis method to separate the mud pump noise in the MWD continuous wave transmission signal; performing a second denoising on the MWD continuous wave transmission signal after the first denoising using a wavelet transform to separate the Gaussian white noise in the MWD continuous wave transmission signal.

[0026] In this embodiment, the two denoising operations are as follows: Among them, as attached Figure 2 As shown in the figure, the MWD continuous wave transmission signal is denoised once using the frequency domain analysis method to separate the mud pump noise in the MWD continuous wave transmission signal, including: Step S1211, obtain a sampling signal from the MWD continuous wave transmission signal, and perform periodic function analysis on the sampling signal based on the autocorrelation method to obtain the corresponding mud pump noise period , where the sampling signal is obtained by sampling m binary bits in the MWD continuous wave transmission signal.

[0027] The above-mentioned sampling signal is a sequence. The autocorrelation method uses the autocorrelation function to measure the correlation between the values ​​at different time points in the sequence, that is, to compare a time series with its own copies at different time delays to obtain the autocorrelation function. If there is periodicity in the sequence, then an obvious peak will appear in the autocorrelation function.

[0028] Step S1212, using the mud pump noise cycle , press The MWD continuous wave transmission signal is intercepted in sequence.

[0029] Step S1213, the intercepted signals are sequentially set at the end of the sampled signals to form a set of signals to be processed.

[0030] Step S1214, performing average processing on the signal set to be processed, and the processed result is the mud pump noise signal.

[0031] Step S1215: based on the frequency spectrum characteristics of the mud pump noise signal, remove the mud pump noise from the MWD continuous wave transmission signal.

[0032] The above-mentioned method of removing the mud pump noise from the MWD continuous wave transmission signal based on the spectral characteristics of the mud pump noise signal can specifically include constructing a filter based on the spectral characteristics of the mud pump noise signal, and then removing the mud pump noise from the MWD continuous wave transmission signal based on the filter.

[0033] Based on steps S1211 to S1215, the mud pump noise in the MWD continuous wave transmission signal is separated, for example: The sampling signal is obtained by sampling 60 binary bits in the MWD continuous wave transmission signal, and the pump noise period is obtained according to the autocorrelation analysis. , press The MWD continuous wave transmission signal is intercepted in the order of , and placed at the end of the sampling signal to form a set of signals to be processed. Then, the set number of signals to be processed is averaged by the following formula to obtain the processed signal , that is, the mud pump noise signal. Based on the spectrum characteristics of the mud pump noise signal, a low-pass filter is constructed to remove the mud pump noise in the MWD continuous wave transmission signal.

[0034] Among them, as attached Figure 3 As shown, the wavelet transform is used to perform secondary denoising on the MWD continuous wave transmission signal after the primary denoising, and the Gaussian white noise in the MWD continuous wave transmission signal is separated, including: Step S1221, determine the db9 wavelet basis function and the decomposition level number K.

[0035] Step S1222: Use the db9 wavelet basis function to perform K-layer orthogonal wavelet decomposition on the MWD continuous wave transmission signal after the primary denoising.

[0036] Step S1223, processing each layer detail coefficient from the 1st to the Kth layer by means of a threshold function.

[0037] Step S1224, reconstructing the signal according to the processed detail coefficients of the 1st layer to the Kth layer.

[0038] This embodiment uses wavelet transform threshold denoising to achieve secondary denoising for MWD continuous wave transmission signals, and separates Gaussian white noise in MWD continuous wave transmission signals, that is, using the time-frequency local decomposition capability of orthogonal wavelet decomposition, that is, when performing signal processing, the amplitude of the wavelet component is relatively large, which forms a sharp contrast with the uniform manifestation of noise in the high-frequency part. Therefore, after the MWD continuous wave transmission signal is decomposed by wavelet, most of the detail coefficients with relatively large amplitudes are useful signals, while the detail coefficients with relatively small amplitudes are generally noise, and the detail coefficients of useful signals are greater than the detail coefficients of noise. Therefore, this embodiment finds a suitable threshold, retains the detail coefficients greater than the threshold, and performs corresponding processing on the detail coefficients less than the threshold, and then restores the useful signal based on the processed detail coefficients.

[0039] It should be noted that the larger the number of decomposition layers K is, the more obvious the different characteristics of noise and signal are, and the more conducive to the separation of the two. However, the larger the number of decomposition layers K is, the greater the distortion of the reconstructed signal will be, which will affect the final denoising effect to a certain extent. Therefore, the number of decomposition layers K is determined based on needs, and can be but not limited to 3.

[0040] It should be noted that the threshold evaluates the detail coefficient or the MWD continuous wave transmission signal to determine the threshold that can eliminate the noise in the detail coefficient. After determining the threshold limit of the noise in the detail coefficient, a threshold function is needed to filter the detail coefficient to remove the noise. The threshold function is used to correct the rule of the detail coefficient. Commonly used threshold functions include hard threshold function and soft threshold function. The hard threshold method changes the detail coefficient whose absolute value is less than the threshold to zero, and retains the detail coefficient whose absolute value is greater than the threshold without any processing. It can retain local features such as the edge of the original signal, but because its shrinkage function is discontinuous, the reconstructed signal may produce some oscillations. The soft threshold method does not completely retain the detail coefficient whose absolute value is greater than the threshold, but shrinks it. This method has good overall continuity and will affect the degree of closeness between the reconstructed signal and the real signal. Therefore, it is selected according to needs.

[0041] Step S130: extracting the MWD continuous wave measurement signal from the MWD continuous wave transmission signal after the two denoising steps.

[0042] The embodiment of the present invention discloses a MWD continuous wave measurement signal processing method, which enhances the downhole MWD continuous wave measurement signal by modulating the downhole MWD continuous wave measurement signal, so that the obtained MWD continuous wave transmission signal can have a strong anti-external interference ability during the transmission process, and after the MWD continuous wave transmission signal is received at the wellhead, the interference of noise on the extraction of the downhole MWD continuous wave measurement signal is eliminated to the greatest extent through two denoising, so that an accurate downhole MWD continuous wave measurement signal can be obtained, providing a basis for parsing the MWD while drilling measurement signal.

[0043] Embodiment 2: The embodiment of the present invention discloses a method for processing MWD continuous wave measurement signals, comprising: Step S210, modulating the downhole MWD continuous wave measurement signal to obtain an MWD continuous wave transmission signal.

[0044] In this embodiment, the step specifically includes: (1) The downhole MWD continuous wave measurement signal is processed using the continuous wave transmission model to obtain the MWD frequency modulated continuous wave signal; in, is the pressure difference on both sides of the continuous wave signal generator, is the pulse function, is the propagation speed of sound waves in mud, is the mud volume model, is the rotation angular frequency, is the displacement parameter, for About Time The partial derivative of for About Space The partial derivative of .

[0045] (2) The MWD frequency-modulated continuous wave signal is modulated using FSK frequency shift keying to obtain the MWD continuous wave transmission signal, and the transmission mode is selected to transmit it to the wellhead.

[0046] When FSK frequency shift keying is used to modulate the MWD frequency modulated continuous wave signal, binary, quaternary and octal frequency modulation methods are used respectively, and the transmission time of each code element is set to 0.2s and 0.3s respectively; the transmission mode can be selected from 6 basic transmission modes.

[0047] FSK frequency shift keying has strong anti-noise and anti-attenuation capabilities. Therefore, the MWD continuous wave transmission signal obtained after FSK frequency shift keying modulation will have strong anti-noise and anti-attenuation capabilities.

[0048] Step S220, performing two denoising on the MWD continuous wave transmission signal, wherein the two denoising include: performing a first denoising on the MWD continuous wave transmission signal using a frequency domain analysis method to separate the mud pump noise in the MWD continuous wave transmission signal; performing a second denoising on the MWD continuous wave transmission signal after the first denoising using a wavelet transform to separate the Gaussian white noise in the MWD continuous wave transmission signal.

[0049] Step S230: extracting the MWD continuous wave measurement signal from the MWD continuous wave transmission signal after the two denoising steps.

[0050] In this embodiment, the step specifically includes: (1) Obtain a continuous wave measurement signal extraction model. The model is as follows: in, is the pressure difference on both sides of the continuous wave signal generator, is the cross-sectional area of ​​the drill collar, is the cross-sectional area of ​​the drill string, is the drill collar length, is the distance between the signal generator and the drill bit, is the signal propagation speed, It is the MWD continuous wave transmission signal.

[0051] The construction process of the above-mentioned continuous wave measurement signal extraction model is to establish an impedance model of continuous wave signal transmission in the downhole drilling tool assembly channel, and then analyze the reflection and superposition characteristics of the continuous wave measurement signal during the transmission process of different drilling tool assembly short sections. The continuous wave measurement signal extraction model is formed after reflection and superposition based on the impedance model. This model can effectively eliminate the distortion in the signal transmission process.

[0052] (2) The MWD continuous wave transmission signal after two denoising is introduced into , using the difference iteration method to solve , extract the downhole MWD continuous wave measurement signal, and analyze the MWD while drilling measurement signal in the MWD continuous wave measurement signal.

[0053] In this embodiment, taking into account that the downhole MWD continuous wave measurement signal is affected by factors such as reflection, superposition, and echo, a continuous wave transmission model is used for processing before transmission, and a continuous wave measurement signal extraction model is used for extraction after transmission. This can effectively eliminate the distortion in the transmission process and extract accurate downhole MWD continuous wave measurement signals.

[0054] Embodiment 3: As attached Figure 4 As shown, the embodiment of the present invention discloses a MWD continuous wave measurement signal processing device, comprising: The transmission unit modulates the downhole MWD continuous wave measurement signal to obtain the MWD continuous wave transmission signal; The denoising unit performs two denoising operations on the MWD continuous wave transmission signal, wherein the two denoising operations include: performing a first denoising operation on the MWD continuous wave transmission signal by using the frequency domain analysis method to separate the mud pump noise in the MWD continuous wave transmission signal; performing a second denoising operation on the MWD continuous wave transmission signal after the first denoising operation by using the wavelet transform to separate the Gaussian white noise in the MWD continuous wave transmission signal; The extraction unit extracts the MWD continuous wave measurement signal from the MWD continuous wave transmission signal after two denoising.

[0055] The denoising unit includes: The first denoising module uses the frequency domain analysis method to denoise the MWD continuous wave transmission signal and separate the mud pump noise in the MWD continuous wave transmission signal, including: The sampling signal is obtained from the MWD continuous wave transmission signal, and the periodic function analysis of the sampling signal is performed based on the autocorrelation method to obtain the corresponding mud pump noise period , where the sampling signal is obtained by sampling m binary bits in the MWD continuous wave transmission signal; Utilizing the Mud Pump Noise Cycle , press The MWD continuous wave transmission signal is intercepted in the order of The intercepted signals are sequentially set at the end of the sampled signals to form a set of signals to be processed; The signal set to be processed is averaged, and the result after processing is the mud pump noise signal; Based on the spectrum characteristics of mud pump noise signal, the mud pump noise is removed from the MWD continuous wave transmission signal. The second denoising module uses wavelet transform to perform secondary denoising on the MWD continuous wave transmission signal after the primary denoising, and separates the Gaussian white noise in the MWD continuous wave transmission signal, including: Determine the db9 wavelet basis function and the number of decomposition levels K; The db9 wavelet basis function is used to perform K-layer orthogonal wavelet decomposition on the MWD continuous wave transmission signal after the first denoising; The detail coefficients of each layer from the 1st to the Kth layer are processed by the threshold function; The signal is reconstructed according to the detail coefficient of the Kth layer and the processed detail coefficients of the 1st to Kth layers.

[0056] The transmission unit includes: The signal processing module processes the downhole MWD continuous wave measurement signal using the continuous wave transmission model to obtain the MWD frequency modulated continuous wave signal; The modulation module uses FSK frequency shift keying to modulate the MWD frequency modulated continuous wave signal to obtain the MWD continuous wave transmission signal, and selects the transmission mode to transmit it to the wellhead.

[0057] The implementation steps of each unit / module in this embodiment are the same as those in Embodiment 1 to Embodiment 2, and will not be repeated here.

[0058] The above content is only a specific implementation mode of the present invention, which has strong adaptability and implementation effect, but the protection scope of the present invention is not limited to this. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be covered within the protection scope of the present invention. Therefore, equivalent changes made according to the claims of the present invention are still within the scope covered by the present invention.

Claims

1. A method for processing MWD continuous wave measurement signals, characterized in that: include: Modulate the downhole MWD continuous wave measurement signal to obtain the MWD continuous wave transmission signal; The MWD continuous wave transmission signal is denoised twice, wherein the two denoising processes include: using the frequency domain analysis method to denoise the MWD continuous wave transmission signal once to separate the mud pump noise in the MWD continuous wave transmission signal; using the wavelet transform to denoise the MWD continuous wave transmission signal after the first denoising twice to separate the Gaussian white noise in the MWD continuous wave transmission signal; The MWD continuous wave measurement signal is extracted from the MWD continuous wave transmission signal after two denoising.

2. The MWD continuous wave measurement signal processing method according to claim 1, characterized in that: The method of performing a primary denoising on the MWD continuous wave transmission signal by using the frequency domain analysis method to separate the mud pump noise in the MWD continuous wave transmission signal includes: The sampling signal is obtained from the MWD continuous wave transmission signal, and the periodic function analysis of the sampling signal is performed based on the autocorrelation method to obtain the corresponding mud pump noise period , where the sampling signal is obtained by sampling m binary bits in the MWD continuous wave transmission signal; Utilizing the Mud Pump Noise Cycle , press The MWD continuous wave transmission signal is intercepted in the order of The intercepted signals are sequentially set at the end of the sampled signals to form a set of signals to be processed; The signal set to be processed is averaged, and the result after processing is the mud pump noise signal; Based on the spectrum characteristics of mud pump noise signal, the mud pump noise is removed from the MWD continuous wave transmission signal.

3. The MWD continuous wave measurement signal processing method according to claim 1 or 2, characterized in that: The method of performing secondary denoising on the MWD continuous wave transmission signal after primary denoising by using wavelet transform to separate Gaussian white noise in the MWD continuous wave transmission signal comprises: Determine the db9 wavelet basis function and the number of decomposition levels K; The db9 wavelet basis function is used to perform K-layer orthogonal wavelet decomposition on the MWD continuous wave transmission signal after the first denoising; The detail coefficients of each layer from the 1st to the Kth layer are processed by the threshold function; The signal is reconstructed according to the detail coefficient of the Kth layer and the processed detail coefficients of the 1st to Kth layers.

4. The MWD continuous wave measurement signal processing method according to claim 1 or 2, characterized in that: The extracting of the MWD continuous wave measurement signal from the MWD continuous wave transmission signal after two denoising steps comprises: Get the continuous wave measurement signal extraction model, the model is as follows: in, is the pressure difference on both sides of the continuous wave signal generator, is the cross-sectional area of ​​the drill collar, is the cross-sectional area of ​​the drill string, is the drill collar length, is the distance between the signal generator and the drill bit, is the signal propagation speed, It is the MWD continuous wave transmission signal; The MWD continuous wave transmission signal after two denoising is introduced into , using the difference iteration method to solve , extract the MWD continuous wave measurement signal.

5. The MWD continuous wave measurement signal processing method according to claim 3, characterized in that: The extracting of the MWD continuous wave measurement signal from the MWD continuous wave transmission signal after two denoising steps comprises: Get the continuous wave measurement signal extraction model, the model is as follows: in, is the pressure difference on both sides of the continuous wave signal generator, is the cross-sectional area of ​​the drill collar, is the cross-sectional area of ​​the drill string, is the drill collar length, is the distance between the signal generator and the drill bit, is the signal propagation speed, It is the MWD continuous wave transmission signal; The MWD continuous wave transmission signal after two denoising is introduced into , using the difference iteration method to solve , extract the downhole MWD continuous wave measurement signal.

6. The MWD continuous wave measurement signal processing method according to claim 1, 2 or 5, characterized in that: The method of modulating the downhole MWD continuous wave measurement signal to obtain the MWD continuous wave transmission signal includes: The downhole MWD continuous wave measurement signal is processed using the continuous wave transmission model to obtain the MWD frequency modulated continuous wave signal. The MWD frequency modulated continuous wave signal is modulated by FSK frequency shift keying to obtain the MWD continuous wave transmission signal, and the transmission mode is selected to transmit it to the wellhead.

7. A MWD continuous wave measurement signal processing device using the method according to any one of claims 1 to 6, characterized in that: include: The transmission unit modulates the downhole MWD continuous wave measurement signal to obtain the MWD continuous wave transmission signal; The denoising unit performs two denoising operations on the MWD continuous wave transmission signal, wherein the two denoising operations include: performing a first denoising operation on the MWD continuous wave transmission signal by using the frequency domain analysis method to separate the mud pump noise in the MWD continuous wave transmission signal; performing a second denoising operation on the MWD continuous wave transmission signal after the first denoising operation by using the wavelet transform to separate the Gaussian white noise in the MWD continuous wave transmission signal; The extraction unit extracts the MWD continuous wave measurement signal from the MWD continuous wave transmission signal after two denoising.

8. The MWD continuous wave measurement signal processing device according to claim 7, characterized in that: The denoising unit comprises: The first denoising module uses the frequency domain analysis method to denoise the MWD continuous wave transmission signal and separate the mud pump noise in the MWD continuous wave transmission signal, including: The sampling signal is obtained from the MWD continuous wave transmission signal, and the periodic function analysis of the sampling signal is performed based on the autocorrelation method to obtain the corresponding mud pump noise period , where the sampling signal is obtained by sampling m binary bits in the MWD continuous wave transmission signal; Utilizing the Mud Pump Noise Cycle , press The MWD continuous wave transmission signal is intercepted in the order of The intercepted signals are sequentially set at the end of the sampled signals to form a set of signals to be processed; The signal set to be processed is averaged, and the result after processing is the mud pump noise signal; Based on the spectrum characteristics of mud pump noise signal, the mud pump noise is removed from the MWD continuous wave transmission signal. The second denoising module uses wavelet transform to perform secondary denoising on the MWD continuous wave transmission signal after the primary denoising, and separates the Gaussian white noise in the MWD continuous wave transmission signal, including: Determine the db9 wavelet basis function and the number of decomposition levels K; The db9 wavelet basis function is used to perform K-layer orthogonal wavelet decomposition on the MWD continuous wave transmission signal after the first denoising; The detail coefficients of each layer from the 1st to the Kth layer are processed by the threshold function; The signal is reconstructed according to the detail coefficient of the Kth layer and the processed detail coefficients of the 1st to Kth layers.

9. The MWD continuous wave measurement signal processing device according to claim 7 or 8, characterized in that: The transmission unit comprises: The signal processing module processes the downhole MWD continuous wave measurement signal using the continuous wave transmission model to obtain the MWD frequency modulated continuous wave signal; The modulation module uses FSK frequency shift keying to modulate the MWD frequency modulated continuous wave signal to obtain the MWD continuous wave transmission signal, and selects the transmission mode to transmit it to the wellhead.

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