Method, system and storage medium for extracting abnormal potential of cracks in oil and gas fracturing monitoring

Abstract

A method, system and storage medium for extracting abnormal potential of cracks in monitoring oil and gas fracturing, the method comprising: obtaining potential difference data between a signal detection unit and the wellbore of a fracturing well; performing signal conditioning on the potential difference data, and converting the potential difference data after signal conditioning into a digital signal; removing spike pulses of the digital signal, and performing digital filtering on the digital signal after the spike pulses are removed; performing a deconvolution algorithm on the AC excitation signal and the digital signal after digital filtering to obtain a change data set; calculating characteristic parameters based on the change data set, the characteristic parameters are used to characterize the crack morphology of the fracturing fluid affected body formed in the fracturing well. The present invention can effectively eliminate the interference of various factors in the environment, extract the data changes brought about by the change of crack morphology, i.e., characteristic parameters, from the potential difference data, and then facilitate the subsequent effective use of the characteristic parameters to complete the analysis of the crack morphology.

Description

Technical Field

[0001] The invention belongs to the field of rock stratum fracturing monitoring, and in particular relates to a method, a system and a storage medium for extracting abnormal potential of cracks in oil and gas fracturing monitoring. Background Art

[0002] In the field of petroleum, fracturing refers to a method of using hydraulic force to form cracks in oil and gas layers during oil or gas production, also known as hydraulic fracturing. The principle of hydraulic fracturing is to use a high-pressure pump on the ground to squeeze a fracturing fluid with a high viscosity into the oil layer through the wellbore. When the injection speed of the fracturing fluid exceeds the absorption capacity of the oil layer, a very high pressure is formed on the oil layer at the bottom of the well. When this pressure exceeds the fracture stress of the oil layer rock near the bottom of the well, the oil layer will be squeezed open and cracks will be generated. At this time, the fracturing fluid is continuously squeezed into the oil layer, and the cracks will continue to expand into the oil layer. In order to keep the cracks opened in an open state, a sand-carrying fluid with a proppant (usually quartz sand) is then squeezed into the oil layer. After the sand-carrying fluid enters the crack, on the one hand, it can make the crack continue to extend forward, and on the other hand, it can support the cracks that have been opened so that they will not close. Then, a displacement fluid is injected to displace all the sand-carrying fluid in the wellbore into the cracks, and the cracks are propped up with quartz sand. Finally, the injected high-viscosity fracturing fluid will automatically degrade and be discharged from the wellbore, leaving one or more cracks of varying lengths, widths, and heights in the oil layer, establishing a new fluid channel between the oil layer and the wellbore. After fracturing, the production of oil and gas wells generally increases significantly.

[0003] After fracturing measures are implemented in oil and gas wells, effective monitoring methods are needed to determine the effect of fracturing operations and obtain information such as the conductivity, geometry, complexity and orientation of fracturing-induced fractures, so as to improve the effect of fracturing and production increase operations in shale gas reservoirs and the production capacity of gas wells, and increase shale gas recovery. To obtain information such as the conductivity, geometry, complexity and orientation of fracturing-induced fractures, not only a professional monitoring system is needed to complete the detection work (for example, detection can be completed by monitoring surface vibration signals, or by detecting surface electric field signals), but also a corresponding method is needed to obtain useful parameters from the collected data after obtaining accurate data, so as to conduct subsequent fracture morphology analysis. For electrical monitoring, after collecting electric field data on the ground, it is particularly important to quickly and effectively determine the signal changes caused by changes in fracture morphology. Summary of the invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention proposes a method for extracting abnormal potential of cracks in oil and gas fracturing monitoring, which can quickly determine the potential change caused by the change of crack morphology from the potential difference data. The present invention also proposes an abnormal potential extraction system for oil and gas fracturing monitoring cracks and a storage medium for storing computer executable instructions of the above-mentioned abnormal potential extraction method for oil and gas fracturing monitoring cracks.

[0005] According to the first embodiment of the present invention, a method for extracting abnormal potential of cracks in oil and gas fracturing monitoring comprises the following steps:

[0006] Acquiring potential difference data between a signal detection unit and a wellbore of a fracturing well, wherein the signal detection unit is disposed on the ground above the fracturing well, and the potential difference data is acquired by the signal acquisition unit when a transmitting device sends an AC excitation signal to the wellbore of the fracturing well;

[0007] Performing signal conditioning on the potential difference data, and converting the potential difference data after signal conditioning into a digital signal;

[0008] Removing spike pulses from the digital signal, and performing digital filtering on the digital signal after the spike pulses are removed;

[0009] Performing a deconvolution algorithm on the AC excitation signal and the digital signal after digital filtering to obtain a change data set;

[0010] Characteristic parameters are calculated according to the change data set, and the characteristic parameters are used to characterize the fracture morphology of the fracturing fluid affected body formed in the fracturing well.

[0011] The abnormal potential extraction method for monitoring cracks in oil and gas fracturing according to the embodiment of the present invention has at least the following technical effects: by performing signal conditioning on the collected electrical signal, the interference to subsequent operations can be effectively eliminated; by removing spike pulses from the digital signal, the influence of earth coupling can be eliminated, and then after digital filtering, digital signal data suitable for extracting characteristic parameters can be obtained; and through deconvolution operations and absolute value integral operations, the characteristic parameters can be effectively and quickly extracted, so as to facilitate the subsequent use of characteristic parameters to complete the analysis of crack morphology parameters. The abnormal potential extraction method for monitoring cracks in oil and gas fracturing according to the embodiment of the present invention is aimed at the electrical detection method, which can effectively eliminate the interference of various factors in the environment, extract the data changes caused by the changes in crack morphology from the potential difference data, that is, the characteristic parameters, and then facilitate the subsequent effective use of characteristic parameters to complete the analysis of crack morphology.

[0012] According to some embodiments of the present invention, the signal conditioning includes at least impedance transformation, bandpass filtering, and program-controlled amplification.

[0013] According to some embodiments of the present invention, the conversion of the potential difference data after signal conditioning into a digital signal is accomplished by an analog-to-digital conversion module.

[0014] According to some embodiments of the present invention, removing the spike pulses of the digital signal includes the following steps: filtering the spike pulses at the rising edge and the spike pulses after the falling edge of the step signal in the digital signal through exponential function fitting or directly classifying them as 0 to remove the spike pulses.

[0015] According to some embodiments of the present invention, the digital filtering process uses at least one of FIR filtering, IIR filtering, and sliding average filtering.

[0016] According to some embodiments of the present invention, calculating the characteristic parameter based on the change data set includes the following steps: performing absolute value integration on the change data set, and averaging the values ​​after the absolute value integration to obtain the characteristic parameter.

[0017] According to some embodiments of the present invention, the above method for extracting abnormal potential of cracks in oil and gas fracturing monitoring further includes the following steps:

[0018] A plurality of the characteristic parameters are obtained, and median filtering is performed on the plurality of the characteristic parameters.

[0019] The oil and gas fracturing monitoring crack abnormal potential extraction system according to the second embodiment of the present invention comprises:

[0020] A data acquisition unit, used to acquire potential difference data between the signal detection unit and the wellbore of the fracturing well, wherein the signal detection unit is arranged on the ground above the fracturing well, and the potential difference data is acquired by the signal acquisition unit when the transmitting device sends an AC excitation signal to the wellbore of the fracturing well;

[0021] A conditioning and conversion module, used for performing signal conditioning on the potential difference data and converting the potential difference data after signal conditioning into a digital signal;

[0022] A digital signal preprocessing module, used to remove spike pulses from the digital signal and perform digital filtering on the digital signal after the spike pulses are removed;

[0023] A deconvolution operation module, used for performing a deconvolution algorithm on the AC excitation signal and the digital signal after digital filtering to obtain a change data set;

[0024] The characteristic parameter extraction module is used to calculate characteristic parameters according to the change data set, and the characteristic parameters are used to characterize the fracture morphology of the fracturing fluid affected body formed in the fracturing well.

[0025] The abnormal potential extraction system for monitoring cracks in oil and gas fracturing according to the embodiment of the present invention has at least the following technical effects: by conditioning the collected electrical signal, the interference to subsequent operations can be effectively eliminated; by removing the spike pulses of the digital signal, the influence of earth coupling can be eliminated, and then after digital filtering, digital signal data suitable for extracting characteristic parameters can be obtained; and by deconvolution operation and absolute value integral operation, the characteristic parameters can be effectively and quickly extracted, so as to facilitate the subsequent analysis of the crack morphology parameters using the characteristic parameters. The abnormal potential extraction method for monitoring cracks in oil and gas fracturing according to the embodiment of the present invention is aimed at the electrical detection method, which can effectively eliminate the interference of various factors in the environment, extract the data changes caused by the changes in the crack morphology from the potential difference data, that is, the characteristic parameters, and then facilitate the subsequent effective use of the characteristic parameters to complete the analysis of the crack morphology.

[0026] According to the computer-readable storage medium of the embodiment of the third aspect of the invention, the computer-readable storage medium stores computer-executable instructions, and the computer-executable instructions are used to enable a computer to execute the above-mentioned method for extracting abnormal potential of cracks in oil and gas fracturing monitoring.

[0027] The computer-readable storage medium according to the embodiment of the present invention has at least the following beneficial effects: the storage medium can facilitate the storage and transfer of computer-executable instructions.

[0028] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The above or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0030] Figure 1 is a schematic diagram of the layout of a fracturing detection system according to an embodiment of the present invention;

[0031] Figure 2 is a waveform diagram of an AC excitation signal emitted by a transmitting device according to an embodiment of the present invention;

[0032] Figure 3 is a waveform diagram of potential difference data collected by a signal detection unit in an embodiment of the present invention;

[0033] Figure 4 is a schematic diagram of overlapping signal waveforms of an AC excitation signal and potential difference data collected by a signal detection unit according to an embodiment of the present invention;

[0034] Figure 5It is a waveform diagram extracted by the abnormal potential extraction method for oil and gas fracturing monitoring cracks according to an embodiment of the present invention;

[0035] Figure 6 is a schematic diagram of a deconvolution algorithm according to an embodiment of the present invention;

[0036] Figure 7 It is a flowchart of a method for extracting abnormal potential of cracks in oil and gas fracturing monitoring according to an embodiment of the present invention;

[0037] Figure 8 It is a system block diagram of the abnormal potential extraction system for oil and gas fracturing monitoring cracks according to an embodiment of the present invention. DETAILED DESCRIPTION

[0038] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0039] In the description of the present invention, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, etc., are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0040] In the description of the present invention, "several" means one or more, "more" means more than two, "greater than", "less than", "exceed" etc. are understood as not including the number itself, and "above", "below", "within" etc. are understood as including the number itself. If there is a description of "first" or "second", it is only used for the purpose of distinguishing the technical features, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0041] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0042] In order to better describe the abnormal potential extraction method for oil and gas fracturing monitoring cracks according to the embodiment of the present invention, a monitoring system for executing the abnormal potential extraction method for oil and gas fracturing monitoring cracks according to the embodiment of the present invention is briefly described herein.

[0043] like Figure 1 As shown, Figure 1The schematic diagram of the monitoring system layout is shown below. The transmitting device includes two emitters A and B. Emitter A is connected to the wellhead of the fracturing wellbore, and emitter B is connected to infinity (which can be understood as grounding). After emitter A transmits the test AC signal to the wellhead, emitter A can form a loop with emitter B through the ground, thereby completing the transmission of the test AC signal to the wellbore. The acquisition device includes a common electrode N, multiple signal detection units (for example, copper rods and other metal rods with good conductivity can be used), and a data acquisition unit, a storage unit, and a processor unit for receiving signals from the signal detection units. The multiple signal detection units are Figure 1 As shown in the M1, M2, ..., M2n and other measuring points, the common electrode N of the acquisition device is connected to the wellhead of the wellbore, so that a loop can be formed with multiple signal detection units and the potential difference data detected by each signal detection unit can be guaranteed to have the same reference. After the transmitting device transmits the test alternating current to the wellbore, each signal detection unit can detect the potential difference data, and then the potential difference data can be used to complete the analysis of the crack morphology. The problem solved by the abnormal potential extraction method for oil and gas fracturing monitoring cracks in the embodiment of the present invention is how to extract the characteristic parameters that can reflect the changes in the cracks from the potential difference data, so as to determine the crack morphology using this characteristic parameter later.

[0044] Reference below Figures 1 to 7 The method for extracting abnormal potential of cracks in monitoring oil and gas fracturing according to the first embodiment of the present invention is described. The method for extracting abnormal potential of cracks in monitoring oil and gas fracturing comprises the following steps:

[0045] Acquiring potential difference data between a signal detection unit and the wellbore of the fracturing well, the signal detection unit being arranged on the ground above the fracturing well, and the potential difference data being acquired by a signal acquisition unit when a transmitting device sends an AC excitation signal to the wellbore of the fracturing well;

[0046] Performing signal conditioning on the potential difference data, and converting the potential difference data after signal conditioning into a digital signal;

[0047] Removing spike pulses from the digital signal, and performing digital filtering on the digital signal after the spike pulses are removed;

[0048] Performing a deconvolution algorithm on the AC excitation signal and the digital signal after digital filtering to obtain a change data set;

[0049] Characteristic parameters are calculated based on the variation data set, and the characteristic parameters are used to characterize the fracture morphology of the fracturing fluid swept body formed in the fracturing well.

[0050] First, here is an explanation of the feature parameters that need to be proposed so that the subsequent steps can be understood. Figures 2 to 4 , Figure 2 , Figure 4 The square wave signal is the AC excitation signal sent by the transmitter to the wellbore. Figure 3 , Figure 4 The signal with curvature in the image is the potential difference signal received by the signal detection unit, and as the crack morphology changes, Figure 3 , Figure 4 The curvature of the signal will also change, so the reference Figure 4 It is only necessary to determine the area between the AC excitation signal and the potential difference signal received by the signal detection unit, and the signal changes (i.e., abnormal potential data) caused by different crack forms can be determined based on this area. Therefore, this area is determined as a characteristic parameter here, and the abnormal potential extraction method for oil and gas fracturing monitoring cracks in an embodiment of the present invention is also used to extract characteristic parameters.

[0051] After the potential difference signal read by the signal detection unit is obtained, the signal has a lot of interference and the signal itself is weak. Therefore, signal conditioning is required. After the conditioning is completed, the analog signal is converted into a digital signal so that it can be read and stored by the analog-to-digital conversion module, which makes it easier to process the data. Considering that there is inductive coupling between the signal detection unit and the common electrode and the ground, that is, there is "spike pulse" interference on both the rising and falling edges of the step signal (such as Figure 3 This interference will affect the stability of the measurement to a certain extent, so it is necessary to filter or "chop decouple" the interference of the spike pulse. After filtering the data to eliminate the spike pulse, the influence of the interference factor is basically eliminated. At this time, the characteristic parameters can be formally extracted.

[0052] refer to Figure 6 , the AC excitation signal is regarded as the input quantity X, the potential difference signal collected by the signal detection unit is regarded as the response output quantity Y after passing through the linear time-invariant system C, and the entire fracturing characteristic parameter system that causes this change can be regarded as the linear time-invariant system C. Then according to the deconvolution theory, the digital signal converted by the analog-to-digital conversion module is regarded as y(t), and the waveform data set of the AC excitation signal emitted by the transmitter is regarded as x(t). The change data set c(t) generated by the AC excitation signal after passing through the fracturing target layer system can be solved by the deconvolution algorithm, and the characteristic parameters can be obtained by performing absolute value integration on the data set and taking the mean.

[0053] According to the method for extracting abnormal potential of cracks in monitoring oil and gas fracturing according to the embodiment of the present invention, by performing signal conditioning on the collected electrical signal, the interference to subsequent operations can be effectively eliminated; by removing spike pulses from the digital signal, the influence of earth coupling can be eliminated, and then after digital filtering, digital signal data suitable for extracting characteristic parameters can be obtained; and through deconvolution operation and absolute value integral operation, the characteristic parameters can be effectively and quickly extracted, so as to facilitate the subsequent analysis of the crack morphology parameters using the characteristic parameters. The method for extracting abnormal potential of cracks in monitoring oil and gas fracturing according to the embodiment of the present invention is aimed at the electrical detection method, which can effectively eliminate the interference of various factors in the environment, extract the data changes caused by the changes in the crack morphology from the potential difference data, that is, the characteristic parameters, and then facilitate the subsequent effective use of the characteristic parameters to complete the analysis of the crack morphology.

[0054] In some embodiments of the present invention, signal conditioning includes at least impedance transformation, bandpass filtering, and program-controlled amplification, which can reduce clutter interference and allow data to be better converted to digital by the analog-to-digital conversion module.

[0055] In some embodiments of the present invention, the potential difference data after signal conditioning is converted into a digital signal by an analog-to-digital conversion module. The analog-to-digital conversion module can use the ADC channel of the processor unit of the acquisition device itself, or use an external analog-to-digital conversion module to complete the conversion.

[0056] In some embodiments of the present invention, the spike pulse of the digital signal is removed, including the following steps: filtering the spike pulse at the rising edge and the spike pulse after the falling edge of the step signal in the digital signal through exponential function fitting or directly returning them to 0 value to remove the spike pulse. The spike pulse can be eliminated by filtering through exponential function fitting. In some cases, the spike pulse position can be directly returned to 0 to eliminate it.

[0057] In some embodiments of the present invention, the digital filtering process uses at least one of FIR filtering, IIR filtering, and sliding average filtering. FIR filtering, IIR filtering, and sliding average filtering can achieve better filtering effects and filter out clutter effects.

[0058] In some embodiments of the present invention, the characteristic parameters are calculated based on the change data set, including the following steps: absolute value integration of the change data set, and averaging the absolute value integrated values ​​to obtain the characteristic parameters. Based on the absolute value integration method, the characteristic parameters (i.e. Figure 4 The area between the square wave and the curved wave).

[0059] In some embodiments of the present invention, the above-mentioned method for extracting abnormal potential of cracks for oil and gas fracturing monitoring further includes the following steps:

[0060] A plurality of characteristic parameters are obtained, and median filtering is performed on the plurality of characteristic parameters.

[0061] Regarding the determination of characteristic parameters, in actual engineering, in order to further ensure the stability of the output characteristic parameters, multiple characteristic parameters are stored continuously and the multiple characteristic parameters are filtered at the mid-position to obtain characteristic parameters with higher stability.

[0062] In addition, here is a brief description of how to use this characteristic parameter to determine the fracture height. After the wellbore is fracturing, as the fracturing fluid enters the fracture, a fracturing fluid wave body is formed. At this time, the upper and lower surfaces of the fracturing fluid wave body can be regarded as the two plates of a flat capacitor. If the fracturing fluid wave body is equivalent to an RC series circuit, then this characteristic parameter U c The constraint formula can be determined as U c =τ=RC. The physical formula of the flat plate capacitor is:

[0063]

[0064] therefore,

[0065]

[0066] Where R is the resistance of the first equivalent resistor. Define β as the engineering correction coefficient, then:

[0067]

[0068] β can be obtained by model determination, that is, for different characteristic parameters U c It can correspond to a set of β values, and then β can be treated as a constant in a certain state, while S can be directly treated as a unit area by the dissection method, so that the characteristic parameter U can be established. c and the crack height h, and the characteristic parameter U c is the potential difference signal collected by the signal detection unit (i.e. Figure 3 Therefore, when determining U c After that, the crack height can be quickly determined. It should also be noted that after being equivalent to the RC model, the RC model is essentially a charge and discharge circuit. Figure 3 The bends in the waveform can also be seen as the result of charging and discharging of the RC circuit.

[0069] The oil and gas fracturing monitoring crack abnormal potential extraction system according to the second embodiment of the present invention includes: a data acquisition unit, a conditioning conversion module, a digital signal preprocessing module, a deconvolution operation module, and a characteristic parameter extraction module.

[0070] A data acquisition unit, used to acquire potential difference data between the signal detection unit and the wellbore of the fracturing well, the signal detection unit is arranged on the ground above the fracturing well, and the potential difference data is acquired by the signal acquisition unit when the transmitting device sends an AC excitation signal to the wellbore of the fracturing well;

[0071] A conditioning and conversion module, used for performing signal conditioning on the potential difference data and converting the potential difference data after signal conditioning into a digital signal;

[0072] A digital signal preprocessing module is used to remove spike pulses from digital signals and perform digital filtering on the digital signals after the spike pulses are removed;

[0073] A deconvolution operation module, used for performing a deconvolution algorithm on the AC excitation signal and the digital signal after digital filtering to obtain a change data set;

[0074] The characteristic parameter extraction module is used to calculate characteristic parameters according to the change data set, and the characteristic parameters are used to characterize the fracture morphology of the fracturing fluid swept body formed in the fracturing well.

[0075] refer to Figures 1 to 8 After the data acquisition unit obtains the potential difference signal read by the signal detection unit, the signal has more interference and the signal itself is weak. Therefore, the signal needs to be conditioned by the conditioning conversion module, and the analog signal is converted into a digital signal after the conditioning is completed. Considering that there will be inductive coupling between the signal detection unit and the common electrode and the earth, that is, there will be "spike pulse" interference at both the rising and falling edges of the step signal (as shown in the figure), this interference will affect the stability of the measurement to a certain extent, so it is necessary to filter or "chop decouple" the interference of this spike pulse through the digital signal preprocessing module. After the data filtering is performed on the data that eliminates the spike pulse, the influence of the interference factor is basically eliminated. At this time, the characteristic parameters can be formally extracted. It should be noted that the conditioning conversion module includes a conditioning circuit module and an analog-to-digital conversion module. The conditioning circuit module completes the signal conditioning, and the digital-to-analog conversion module completes the digital-to-analog conversion.

[0076] refer to Figure 6, the AC excitation signal is regarded as the input quantity X, the potential difference signal collected by the signal detection unit is regarded as the response output quantity Y after passing through the linear time-invariant system C, and the entire fracturing characteristic parameter system that causes this change can be regarded as the linear time-invariant system C. Then according to the deconvolution theory, the digital signal converted by the analog-to-digital conversion module is regarded as y(t), and the waveform data set of the AC excitation signal emitted by the transmitter is regarded as x(t). The deconvolution algorithm can be used to solve the change data set c(t) generated by the AC excitation signal after passing through the fracturing target layer system. The characteristic parameter extraction module performs absolute value integration on the data set and obtains the mean to obtain the characteristic parameters.

[0077] According to the oil and gas fracturing monitoring crack abnormal potential extraction system of the embodiment of the present invention, by performing signal conditioning on the collected electrical signal, the interference to the subsequent operation can be effectively eliminated; by removing the spike pulse of the digital signal, the influence of the earth coupling can be eliminated, and then after digital filtering, the digital signal data suitable for extracting the characteristic parameters can be obtained; and the characteristic parameters can be effectively and quickly extracted through the deconvolution operation and the absolute value integral operation, so as to facilitate the subsequent use of the characteristic parameters to complete the analysis of the crack morphology parameters. The oil and gas fracturing monitoring crack abnormal potential extraction method of the embodiment of the present invention is aimed at the electrical detection method, which can effectively eliminate the interference of various factors in the environment, extract the data changes caused by the crack morphology changes from the potential difference data, that is, the characteristic parameters, and then facilitate the subsequent effective use of the characteristic parameters to complete the analysis of the crack morphology.

[0078] According to the computer-readable storage medium of the embodiment of the third aspect of the invention, the computer-readable storage medium stores computer-executable instructions, and the computer-executable instructions are used to enable a computer to execute the above-mentioned method for extracting abnormal potential of cracks in oil and gas fracturing monitoring.

[0079] According to the computer-readable storage medium of the embodiment of the present invention, the storage and transfer of computer-executable instructions can be facilitated through the storage medium.

[0080] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0081] Although the embodiments of the present invention are described in detail above in conjunction with the accompanying drawings, the present invention is not limited to the above embodiments. Those skilled in the art will understand that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and purpose of the present invention. The scope of the present invention is defined by the claims and their equivalents.

Claims

1. A method for extracting abnormal potential of cracks in oil and gas fracturing monitoring, It is characterized in that The following steps are involved: Acquiring potential difference data between a signal detection unit and a wellbore of a fracturing well, wherein the signal detection unit is disposed on the ground above the fracturing well, and the potential difference data is acquired by the signal acquisition unit when a transmitting device sends an AC excitation signal to the wellbore of the fracturing well; Performing signal conditioning on the potential difference data, and converting the potential difference data after signal conditioning into a digital signal; Removing spike pulses from the digital signal, and performing digital filtering on the digital signal after the spike pulses are removed; Performing a deconvolution algorithm on the AC excitation signal and the digital signal after digital filtering to obtain a change data set; Characteristic parameters are calculated according to the change data set, and the characteristic parameters are used to characterize the fracture morphology of the fracturing fluid affected body formed in the fracturing well.

2. The method for extracting abnormal potential of cracks in oil and gas fracturing monitoring according to claim 1, It is characterized in that The signal conditioning at least includes impedance transformation, bandpass filtering, and program-controlled amplification.

3. The method for extracting abnormal potential of cracks in oil and gas fracturing monitoring according to claim 1, It is characterized in that The conversion of the potential difference data after signal conditioning into a digital signal is completed by an analog-to-digital conversion module.

4. The method for extracting abnormal potential of cracks in oil and gas fracturing monitoring according to claim 1 or 3, It is characterized in that The method for removing the spike pulse of the digital signal comprises the following steps: filtering the spike pulse at the rising edge and the spike pulse after the falling edge of the step signal in the digital signal through exponential function fitting or directly returning them to 0 value to remove the spike pulse.

5. The method for extracting abnormal potential of cracks in oil and gas fracturing monitoring according to claim 1 or 3, It is characterized in that The digital filtering process uses at least one of FIR filtering, IIR filtering, and sliding average filtering.

6. The method for extracting abnormal potential of cracks in oil and gas fracturing monitoring according to claim 1 or 3, It is characterized in that The step of calculating the characteristic parameter according to the change data set comprises the following steps: performing absolute value integration on the change data set, and averaging the values ​​after the absolute value integration to obtain the characteristic parameter.

7. The method for extracting abnormal potential of cracks in oil and gas fracturing monitoring according to claim 6, It is characterized in that The following steps are also included: A plurality of the characteristic parameters are obtained, and median filtering is performed on the plurality of the characteristic parameters.

8. An abnormal potential extraction system for oil and gas fracturing monitoring cracks, It is characterized in that include: A data acquisition unit, used to acquire potential difference data between the signal detection unit and the wellbore of the fracturing well, wherein the signal detection unit is arranged on the ground above the fracturing well, and the potential difference data is acquired by the signal acquisition unit when the transmitting device sends an AC excitation signal to the wellbore of the fracturing well; A conditioning and conversion module, used for performing signal conditioning on the potential difference data and converting the potential difference data after signal conditioning into a digital signal; A digital signal preprocessing module, used to remove spike pulses from the digital signal and perform digital filtering on the digital signal after the spike pulses are removed; A deconvolution operation module, used for performing a deconvolution algorithm on the AC excitation signal and the digital signal after digital filtering to obtain a change data set; The characteristic parameter extraction module is used to calculate characteristic parameters according to the change data set, and the characteristic parameters are used to characterize the fracture morphology of the fracturing fluid affected body formed in the fracturing well.

9. A computer-readable storage medium, Features: The computer-readable storage medium stores computer-executable instructions, and the computer-executable instructions are used to enable a computer to execute a method for extracting abnormal potential of cracks in oil and gas fracturing monitoring according to any one of claims 1 to 7.

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