Hydraulic fracturing monitoring method and device

Abstract

The present invention provides a hydraulic fracturing monitoring method and device, the method comprising: before and after hydraulic fracturing, exciting a horizontal long wire excitation source once, synchronously collecting electromagnetic signals at a two-component electromagnetic field acquisition station; performing time domain data parameter calculation and frequency domain data parameter calculation on the electromagnetic signal of each measuring point, obtaining time domain charging rate relative abnormal data and frequency domain amplitude relative abnormal data; performing quantitative inversion processing in the time domain and quantitative inversion processing in the frequency domain on the electromagnetic signal data of each measuring point, obtaining three-dimensional resistivity distribution data around the horizontal well; determining the fracture parameters formed underground by hydraulic fracturing according to the time domain charging rate relative abnormal data, frequency domain amplitude relative abnormal data and three-dimensional resistivity distribution data around the horizontal well. The present invention reduces noise interference, reduces the influence of errors, and provides effective reference information for the evaluation of the reservoir transformation effect of hydraulic fracturing of horizontal wells.

Description

Technical Field

[0001] The invention relates to the technical field of electromagnetic exploration and evaluation of oil and gas reservoirs in petroleum and natural gas, and in particular to a hydraulic fracturing monitoring method and device. Background Art

[0002] Many large high-permeability oil and gas fields around the world have entered the late stage of exploitation. The oil and gas in these tight reservoirs need to be hydraulically fractured to achieve economic exploitation. In-depth understanding of the geometry and extension of hydraulic fractures is crucial to improving the effect of hydraulic fracturing and production enhancement operations in low-permeability oil and gas reservoirs, improving oil and gas well productivity and increasing oil and gas recovery. Currently, microseismic monitoring technology has been widely used in hydraulic fracturing fracture monitoring.

[0003] However, in-well microseismic monitoring is usually limited by conditions such as the availability of monitoring wells, while ground microseismic monitoring is usually interfered by the noise at the fracturing site, making it difficult to collect data with a high signal-to-noise ratio; the location of microseismic events depends on the velocity model, and if the velocity model is inaccurate, the error will be large; these limitations of microseismic monitoring technology have put forward the demand for new fracturing monitoring technology. Summary of the invention

[0004] An embodiment of the present invention provides a hydraulic fracturing monitoring method for reducing noise interference and reducing errors. The method includes:

[0005] Before and after hydraulic fracturing, the horizontal long wire excitation source is excited once, and electromagnetic signals are synchronously collected at a two-component electromagnetic field acquisition station; the horizontal long wire excitation source is arranged on the ground above the end of the horizontal well or on the ground far away from the end of the horizontal well; the two-component electromagnetic field acquisition station is arranged on the ground survey line;

[0006] The electromagnetic signal at each measuring point is respectively calculated in the time domain and the frequency domain to obtain the relative abnormal data of the time domain charging rate and the relative abnormal data of the frequency domain amplitude.

[0007] The electromagnetic signal data of each measuring point is subjected to quantitative inversion processing in the time domain and the frequency domain to obtain the three-dimensional resistivity distribution data around the horizontal well;

[0008] The parameters of the fractures formed underground by hydraulic fracturing are determined based on the time domain charging rate relative abnormal data, the frequency domain amplitude relative abnormal data and the three-dimensional resistivity distribution data around the horizontal well.

[0009] The embodiment of the present invention also provides a controllable source electromagnetic device for hydraulic fracturing monitoring, which is used to reduce noise interference and reduce errors. The device includes:

[0010] The signal acquisition module is used to obtain electromagnetic signals synchronously collected at a two-component electromagnetic field acquisition station; the two-component electromagnetic field acquisition station collects electromagnetic signals by stimulating a horizontal long wire excitation source once before and after hydraulic fracturing; the horizontal long wire excitation source is arranged on the ground above the end of the horizontal well or on the ground far away from the end of the horizontal well; the two-component electromagnetic field acquisition station is arranged on the ground survey line;

[0011] The parameter calculation module is used to perform time domain data parameter calculation and frequency domain data parameter calculation on the electromagnetic signal of each measuring point, and obtain the relative abnormal data of the time domain charging rate and the relative abnormal data of the frequency domain amplitude;

[0012] The inversion module is used to perform quantitative inversion processing in the time domain and the frequency domain on the electromagnetic signal data of each measuring point to obtain the three-dimensional resistivity distribution data around the horizontal well;

[0013] The data analysis module is used to determine the fracture parameters formed underground by hydraulic fracturing based on the relative abnormal data of charging rate in the time domain, the relative abnormal data of amplitude in the frequency domain, and the three-dimensional resistivity distribution data around the horizontal well.

[0014] The embodiment of the present invention avoids being restricted by the availability conditions of the monitoring well by deploying a monitoring device outside the horizontal well; adopts a horizontal long wire excitation source deployed on the ground above the end of the horizontal well or on the ground far away from the end of the horizontal well, so that the excitation source is far away from the horizontal wellhead, avoiding the electromagnetic interference caused by the fracturing site, not only increasing the signal strength, but also improving the quality of the received signal and the accuracy of imaging; adopts 2-component signal acquisition, which acquires one more component than the traditional DC charging method, and the fracture parameters predicted after comprehensive analysis are more accurate; thereby effectively obtaining the size and geometric shape of the fractures formed underground after the horizontal well hydraulic fracturing, providing effective reference information for the evaluation of the reservoir transformation effect of the horizontal well hydraulic fracturing. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0016] Figure 1 Schematic diagram of a hydraulic fracturing monitoring method in an embodiment of the present invention.

[0017] Figure 2 It is a schematic diagram of the placement of the horizontal long wire excitation source and the measuring line in a specific embodiment of the present invention.

[0018] Figure 3 It is a schematic diagram of a zero-crossing square wave waveform with a time domain period of 40s in a specific embodiment of the present invention.

[0019] Figure 4 Schematic diagram of a non-zero-crossing square wave waveform with a frequency domain period of Ts in a specific embodiment of the present invention.

[0020] Figure 5 It is a relative abnormal diagram of frequency domain amplitude before and after hydraulic fracturing in a specific embodiment of the present invention.

[0021] Figure 6 This is a cross-sectional diagram of resistivity anomaly before and after hydraulic fracturing in a specific embodiment of the present invention.

[0022] Figure 7 Schematic diagram of a hydraulic fracturing monitoring device in an embodiment of the present invention. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] In order to solve the problems of existing hydraulic fracturing crack monitoring based on microseismic monitoring technology, such as difficulty in collecting data with high signal-to-noise ratio in ground microseismic monitoring, inaccurate velocity model relied on for position determination and large error, the embodiment of the present invention provides a hydraulic fracturing monitoring method, such as Figure 1 As shown, the method includes:

[0025] Step 101: before and after hydraulic fracturing, the horizontal long wire excitation source is excited once, and electromagnetic signals are synchronously collected at a two-component electromagnetic field acquisition station; the horizontal long wire excitation source is arranged on the ground above the end of the horizontal well or on the ground far away from the end of the horizontal well; the two-component electromagnetic field acquisition station is arranged on the ground survey line;

[0026] Step 102: performing time domain data parameter calculation and frequency domain data parameter calculation on the electromagnetic signal of each measuring point to obtain time domain charging rate relative abnormality data and frequency domain amplitude relative abnormality data;

[0027] Step 103: performing quantitative inversion processing in the time domain and quantitative inversion processing in the frequency domain on the electromagnetic signal data of each measuring point to obtain three-dimensional resistivity distribution data around the horizontal well;

[0028] Step 104: Determine the parameters of the fractures formed underground by hydraulic fracturing based on the time domain charging rate relative abnormal data, the frequency domain amplitude relative abnormal data, and the three-dimensional resistivity distribution data around the horizontal well.

[0029] The embodiment of the present invention avoids being restricted by the availability conditions of the monitoring well by deploying a monitoring device outside the horizontal well; a horizontal long wire excitation source is adopted which is deployed on the ground above the end of the horizontal well or on the ground far away from the end of the horizontal well, so that the excitation source is far away from the horizontal wellhead, avoiding the electromagnetic interference caused by the fracturing site, which not only increases the signal strength, but also improves the quality of the received signal and the accuracy of imaging; thereby effectively obtaining the size and geometric shape of the cracks formed underground after the hydraulic fracturing of the horizontal well, thereby providing effective reference information for the evaluation of the reservoir transformation effect of the hydraulic fracturing of the horizontal well.

[0030] In the specific implementation, firstly, a horizontal long wire excitation source is arranged on the ground above the end of the horizontal well or on the ground far away from the end of the horizontal well. For example, in order to achieve the most effective excitation of low-resistance fractures, the arrangement direction of the horizontal long wire excitation source in the specific embodiment of the present invention can be perpendicular to the projection trajectory of the horizontal well on the ground. The length of the emission source is a preset range, for example, 2000 to 6000 meters. Figure 2 As shown, a horizontal long wire source excitation source A1B1 is arranged on the ground above the end of the horizontal well and away from the wellhead. The direction of the excitation source A1B1 is perpendicular to the projection trajectory of the horizontal well on the ground. The projection trajectory of the horizontal well on the ground passes through the midpoint of the emission source. The length of the emission source A1B1 is 3000m. The ground contacts A1 and B1 of the excitation source A1B1 can be made of thin aluminum plates. Those skilled in the art can understand that the above excitation source length and ground contact material are only examples and will not be repeated here.

[0031] Secondly, multiple survey lines parallel to the excitation source A1B1 are arranged on the ground above each perforation position of the horizontal well, and a two-component electromagnetic field acquisition station is arranged at each measuring point of each survey line. The survey line pole arrangement methods include fixed point spacing and variable point spacing, which are determined according to the number of acquisition stations invested in the specific implementation. If the number of acquisition stations is small, such as less than 200, the variable point spacing method is selected; if the number of acquisition stations is large, such as more than 200, the fixed point spacing method is selected.

[0032] The fixed point spacing in the embodiment of the present invention means that the line point spacing is a constant value, such as a certain value between 20 and 50 meters. The variable point spacing means that the line point spacing is a non-constant value, the point spacing is dense directly above the horizontal well, and the number of measuring points directly above the horizontal well cannot be less than 7, and the point spacing is sparse in the direction away from the horizontal well, and the point spacing value is within a set range, such as 50 to 100 meters.

[0033] For example, in Figure 2In a specific embodiment, the length of the measuring line is 2000m, each measuring line is 100m apart, and the minimum distance between the measuring line and the transmitting source A1B1 is 2000m, and the poles are arranged in a fixed point spacing of 50m.

[0034] The electromagnetic signals synchronously collected by the two-component electromagnetic field collection station in the embodiment of the present invention include: the electric field intensity component E in the X direction of the measured electric field X , measure the electric field strength component E in the Y direction of the electric field Y ; The X direction of the electric field is parallel to the measuring line, and the Y direction of the electric field is perpendicular to the measuring line.

[0035] After laying out the horizontal long wire excitation source and the two-component electromagnetic field acquisition station, determine the emission time domain signal and frequency domain signal. The specific steps include: according to the depth of the horizontal well, select the time domain emission waveform and period, and select the frequency domain emission waveform and frequency range. The specific selection basis is: the time domain emission waveform is a zero-crossing square wave with a period range of 10s to 40s. For example, if the depth of the horizontal well is less than 2000m, the period of the emission signal is 20s; if the depth of the horizontal well is greater than 2000m, the period of the emission signal is 40s. The frequency domain emission waveform is a non-zero-crossing square wave with a frequency range of 2 -8 ~2 +8 Hz, the minimum frequency of the transmitted signal is calculated based on the skin depth formula using the depth of the horizontal well and the formation resistivity at the depth of the horizontal well. Figure 2 In the specific embodiment shown, the horizontal well depth is 3000m, and the time domain transmission waveform is selected as follows Figure 3 As shown, it is a zero-crossing periodic square wave signal with a period of 40s; select the frequency domain transmission waveform as Figure 4 As shown, it is a square wave signal with a period of Ts and a non-zero crossing. The period T varies according to the frequency. The range of the transmitting frequency is 2 -6 ~2 +6 Hz, the number of selected frequencies is 41, and the selection of the transmission frequency values ​​is equally spaced in the logarithmic space.

[0036] After determining the emission time domain signal and frequency domain signal, the horizontal long wire excitation source is then excited once before hydraulic fracturing and after each stage of fracturing. According to the waveform and period of the selected time domain signal, the horizontal long wire excitation source is excited to repeatedly emit the time domain signal; according to the waveform and frequency of the selected frequency domain signal, the horizontal long wire excitation source is excited to repeatedly emit the frequency domain signal. If the frequency of the above frequency domain signal is greater than 1Hz, the number of repeated transmissions is greater than 64 times, and the number of repeated transmissions is greater than 32 times if the frequency is less than 1Hz, and the number of repeated transmissions of the time domain signal is greater than 32 times. For example Figure 2In the specific embodiment shown, when the horizontal long wire excitation source A1B1 is excited, the selected time domain transmission signal is repeatedly transmitted 64 times. When the frequency domain transmission signal is transmitted, the number of repeated transmissions is adjusted according to the different signal frequencies. The high-frequency square wave is repeated more times, and the low-frequency square wave is repeated less times.

[0037] After the horizontal long wire excitation source is excited, the electromagnetic signal is synchronously collected at the above-mentioned two-component electromagnetic field acquisition station. In the embodiment of the present invention, the acquisition station and the excitation source A1B1 are synchronized by GPS to achieve the synchronous start of emission and acquisition. In the specific embodiment of the present invention, the sensor connected to the two-component electromagnetic acquisition station can be a non-polarized electrode. Those skilled in the art can understand that the signal can also be collected by other sensors. This is only an example and will not be repeated here.

[0038] After collecting the electromagnetic signal, the electromagnetic signal data of each measuring point is calculated in the time domain and frequency domain. The specific processing includes:

[0039] The specific steps of calculating the time domain data parameters of the electromagnetic signal data of each measuring point include:

[0040] Perform time domain preprocessing on the electromagnetic signal of each measuring point to obtain the attenuation data of the electric field signal at different times; the time domain preprocessing includes filtering, removing DC drift, superposition, polar distance normalization and current normalization, or any combination thereof;

[0041] The charging rate data before and after fracturing at each measuring point are obtained based on the attenuation data at different times;

[0042] According to the charging rate data before and after fracturing at each measuring point, the relative abnormal data of charging rate in time domain are obtained.

[0043] Among them, according to the charging rate data of each measuring point before and after fracturing, the relative abnormal data of charging rate in time domain are obtained, which specifically includes: using the charging rate calculation formula to obtain the charging rate data of each measuring point before fracturing and after each fracturing according to the attenuation data at different times, using the charging rate data before fracturing as the background, and subtracting the background value from the charging rate data after each fracturing to obtain the relative abnormal data of charging rate after each fracturing at each measuring point.

[0044] The specific steps for calculating the frequency domain data parameters of the electromagnetic signal data of each measuring point include:

[0045] Perform frequency domain preprocessing on the electromagnetic signal of each measuring point to obtain the amplitude data of the electric field signal of each measuring point before fracturing and after each section of fracturing; the frequency domain preprocessing includes filtering, removing DC drift, superposition, pole distance normalization, short-time window Fourier transform and current normalization, or any combination thereof;

[0046] According to the amplitude data of the electric field signal before fracturing at each measuring point and after fracturing at each stage, the relative abnormal amplitude data in the frequency domain are obtained.

[0047] Among them, according to the amplitude data of the electric field signal before fracturing at each measuring point and after each stage of fracturing, the frequency domain amplitude relative abnormal data is obtained, which specifically includes:

[0048] The amplitude data before fracturing is used as the background. The amplitude data after each fracturing is subtracted from the background and divided by the background value to finally obtain the relative abnormal amplitude data of each measuring point.

[0049] After obtaining the relative abnormal data of charging rate in time domain and the relative abnormal data of amplitude in frequency domain, the electromagnetic signal data of each measuring point is quantitatively inverted in time domain and frequency domain respectively to obtain the three-dimensional resistivity distribution data around the horizontal well. The specific process includes: first, the attenuation data preprocessed in time domain is calculated by binary division to obtain the apparent resistivity data of the whole area at different times. The apparent resistivity data of the whole area at different times in the time domain and the above-mentioned data preprocessed in the frequency domain are respectively inverted in the time domain and frequency domain to obtain the resistivity-depth data corresponding to each measuring point in the time domain and frequency domain, and the average value of the two sets of data for each measuring point on the same measuring line is calculated, so as to obtain the resistivity-depth one-dimensional model of each measuring line; then, the above-mentioned model is used as the initial model for two-dimensional inversion, and two-dimensional inversion is performed in the time domain and frequency domain respectively to obtain two resistivity-depth profile data of each measuring line, and the average value of the two sets of resistivity-depth profile data obtained is calculated to obtain the resistivity-depth two-dimensional model of each measuring line; finally, the resistivity-depth model of all measuring lines is used to form a resistivity-depth three-dimensional model, and this resistivity-depth three-dimensional model is used as the initial model for three-dimensional inversion, and high-precision three-dimensional inversion results are obtained by fast three-dimensional inversion. The electromagnetic signal data before fracturing and after each section of fracturing are respectively inverted in three dimensions to obtain the three-dimensional resistivity distribution data before fracturing and after each section of fracturing.

[0050] After obtaining the three-dimensional resistivity distribution data before and after each section of fracturing, the resistivity plane anomaly data before and after fracturing at the depth of the horizontal well and the resistivity cross-sectional anomaly data before and after fracturing at each measuring line position are obtained according to the three-dimensional resistivity distribution data around the horizontal well. The specific process is: using the resistivity plane data before fracturing as the background, subtracting the background from the resistivity plane data after each section of fracturing, and obtaining the resistivity anomaly plane data for each section of fracturing; using the resistivity cross-sectional data at each measuring line position before fracturing as the background, subtracting the background from the resistivity cross-sectional data at each measuring line position after fracturing, and obtaining the resistivity anomaly cross-sectional data before and after fracturing at each measuring line position.

[0051] Finally, according to the preset ranges of high charging rate anomaly, low amplitude anomaly and low resistivity anomaly, the length of the crack is determined from the relative anomaly data of charging rate in the time domain, the relative anomaly data of amplitude in the frequency domain and the resistivity plane anomaly data before and after fracturing at the depth of the horizontal well; according to the preset range of low resistivity anomaly, the width and height of the cracks formed underground by hydraulic fracturing are determined from the resistivity section anomaly data before and after fracturing at each measuring line position.

[0052] The preset ranges of abnormal high charging rate, abnormal low amplitude, and abnormal low resistivity in the embodiment of the present invention are preset ranges based on actual operations. Once the data is within the above preset ranges, the area corresponding to the data belongs to the hydraulic fracturing crack area. For example, the preset range of abnormal low amplitude in the frequency domain in the specific embodiment of the present invention is: less than -0.05. Those skilled in the art can understand that this range is only an example and does not limit the embodiment of the present invention. The other preset ranges are not described here one by one.

[0053] The invention is further described with reference to a specific embodiment:

[0054] In order to determine the hydraulic fracturing parameters more intuitively and quickly, the specific embodiment of the present invention plots the time domain charging rate relative abnormal data, the frequency domain amplitude relative abnormal data, and the three-dimensional resistivity distribution data around the horizontal well into a curve form. Figure 5 and Figure 6 As shown, Figure 5 This is a relative abnormal frequency domain amplitude diagram before and after hydraulic fracturing in a specific embodiment. The horizontal axis represents the east direction, the vertical axis represents the north direction, and there are multiple black uniform small dots in the figure, representing multiple measuring points. Multiple measuring points can be connected into multiple parallel lines, representing multiple measuring lines. The area with low amplitude abnormality in the figure is darker in color, representing the preliminary plane outline of the crack formed by hydraulic fracturing, and the length of the crack can be determined. Figure 6 This is a cross-sectional diagram of resistivity anomaly before and after hydraulic fracturing at the depth of a horizontal well in a specific embodiment. The ordinate represents depth and the abscissa represents distance. The area with low resistivity abnormality in the figure has a darker color, which represents the cross-sectional profile of the crack formed by hydraulic fracturing, and the width and height of the crack can be determined.

[0055] Those skilled in the art will appreciate that presenting the time domain charging rate relative abnormal data, the frequency domain amplitude relative abnormal data, and the three-dimensional resistivity distribution data around the horizontal well in the form of a curve is only an example, and may also be presented in the form of a data list, etc., which will not be elaborated here.

[0056] The fracture volume can be obtained based on the length, height and width of the fracture, providing reference information for the evaluation of the hydraulic fracturing reservoir reconstruction effect. Figure 5 as well as Figure 6In the specific embodiment of the present invention, the fracture dimensions formed by hydraulic fracturing are: 1000m in length in the strike direction, 80m in width, 80m in height, and 6.4×10 6 m 3 .

[0057] The embodiment of the present invention avoids being restricted by the availability conditions of the monitoring well by deploying a monitoring device outside the horizontal well; adopts a horizontal long wire excitation source deployed on the ground above the end of the horizontal well or on the ground far away from the end of the horizontal well, so that the excitation source is far away from the horizontal wellhead, avoiding the electromagnetic interference caused by the fracturing site, which not only increases the signal strength, but also improves the quality of the received signal and the accuracy of imaging; adopts 2-component signal acquisition, which collects one more component than the traditional DC charging method, and the fracture parameters predicted after comprehensive analysis are more accurate; thereby effectively obtaining the size and geometric shape of the fractures formed underground after the horizontal well hydraulic fracturing, providing effective reference information for the evaluation of the reservoir transformation effect of the horizontal well hydraulic fracturing.

[0058] The embodiment of the present invention also provides a hydraulic fracturing monitoring device to reduce noise interference and reduce errors. Since the implementation of the hydraulic fracturing monitoring device can refer to the implementation of the hydraulic fracturing monitoring method, the repeated parts will not be repeated. The term "module" used below refers to a combination of software and / or hardware that can achieve a predetermined function. The specific structure is as follows: Figure 7 As shown:

[0059] The signal acquisition module 701 is used to obtain electromagnetic signals synchronously collected at a two-component electromagnetic field acquisition station; the two-component electromagnetic field acquisition station collects electromagnetic signals by stimulating a horizontal long wire excitation source once before and after hydraulic fracturing; the horizontal long wire excitation source is arranged on the ground above the end of the horizontal well or on the ground far away from the end of the horizontal well; the two-component electromagnetic field acquisition station is arranged on the ground survey line;

[0060] The parameter calculation module 702 is used to perform time domain data parameter calculation and frequency domain data parameter calculation on the electromagnetic signal of each measuring point, and obtain the relative abnormal data of the time domain charging rate and the relative abnormal data of the frequency domain amplitude;

[0061] The inversion module 703 is used to perform quantitative inversion processing in the time domain and the frequency domain on the electromagnetic signal data of each measuring point to obtain three-dimensional resistivity distribution data around the horizontal well;

[0062] The data analysis module 704 is used to determine the fracture parameters formed underground by hydraulic fracturing based on the time domain charging rate relative abnormal data, the frequency domain amplitude relative abnormal data and the three-dimensional resistivity distribution data around the horizontal well.

[0063] In the embodiment, the two-component electromagnetic field acquisition station is arranged on the ground survey line specifically including: a horizontal long wire excitation source is arranged on the ground above the end of the horizontal well or on the ground far away from the end of the horizontal well; a plurality of survey lines parallel to the horizontal excitation source are arranged on the ground above each perforation position of the horizontal well, and a two-component electromagnetic field acquisition station is arranged at each measuring point position of the plurality of survey lines.

[0064] In the embodiment of the present invention, the electromagnetic signals synchronously collected by the two-component electromagnetic field collection station include: the electric field intensity component E in the X direction of the measured electric field X , measure the electric field strength component E in the Y direction of the electric field Y ; The X direction of the electric field is parallel to the measuring line, and the Y direction of the electric field is perpendicular to the measuring line.

[0065] In the embodiment, the signal acquisition module 701 is also specifically used to excite the horizontal long wire excitation source to repeatedly emit time domain and frequency domain signals. Specifically, it includes: according to the depth of the horizontal well, selecting the waveform and period of the time domain signal, selecting the waveform and frequency of the frequency domain signal; according to the selected waveform and period of the time domain signal, exciting the horizontal long wire excitation source to repeatedly emit the time domain signal; according to the selected waveform and frequency of the frequency domain signal, exciting the horizontal long wire excitation source to repeatedly emit the frequency domain signal.

[0066] In the embodiment, the parameter calculation module 702 is specifically used for:

[0067] Performing time domain preprocessing on the electromagnetic signal of each measuring point to obtain attenuation data of the electric field signal at different times; the time domain preprocessing includes filtering, removing DC drift, superposition, polarity normalization and current normalization or any combination thereof; obtaining charging rate data of each measuring point before and after fracturing according to the attenuation data at different times; obtaining time domain charging rate relative abnormality data according to the charging rate data of each measuring point before and after fracturing; and

[0068] The electromagnetic signal of each measuring point is preprocessed in the frequency domain to obtain the amplitude data of the electric field signal of each measuring point before fracturing and after each stage of fracturing; the frequency domain preprocessing includes one or any combination of filtering, removing DC drift, superposition, pole distance normalization, short-time window Fourier transform and current normalization; according to the amplitude data of the electric field signal of each measuring point before fracturing and after each stage of fracturing, the frequency domain amplitude relative abnormality data is obtained.

[0069] In the embodiment, the data analysis module 704 is specifically used for:

[0070] According to the three-dimensional resistivity distribution data around the horizontal well, the resistivity plane abnormal data before and after fracturing at the depth of the horizontal well and the resistivity section abnormal data before and after fracturing at the position of each measuring line are obtained;

[0071] Determine the length of the fracture from the relative abnormal data of the charging rate in the time domain, the relative abnormal data of the amplitude in the frequency domain, and the abnormal data of the resistivity plane before and after fracturing at the depth of the horizontal well according to the preset ranges of the high abnormal charging rate, the low abnormal amplitude, and the low abnormal resistivity;

[0072] The width and height of the cracks formed underground by hydraulic fracturing are determined from the resistivity section anomaly data at each measuring line position before and after fracturing according to the preset range of the low resistivity anomaly.

[0073] In summary, the hydraulic fracturing monitoring method and device proposed in the present invention have the following beneficial effects when performing hydraulic fracturing monitoring:

[0074] The present invention firstly arranges a horizontal long wire excitation source perpendicular to the projection trajectory of the horizontal well on the ground at the end of the horizontal well, so that the excitation current flows the longest distance in the low-resistance cracks, thereby realizing the most effective excitation of the low-resistance cracks; secondly, a survey line and an electromagnetic acquisition station are arranged at the perforation position of the horizontal well to obtain the electric field signal of the underground cracks in the survey line direction and the vertical survey line direction when the horizontal long wire source is excited, thereby forming the best detection for the direction and vertical direction of the hydraulic fracturing cracks. In addition, a horizontal long wire excitation source is arranged on the ground above the end of the horizontal well or on the ground far away from the end of the horizontal well, so that the excitation source is far away from the horizontal wellhead, avoiding the electromagnetic interference caused by the fracturing site, which not only increases the signal strength, but also improves the quality of the received signal and the accuracy of the imaging. Using E X 、E Y The 2-component signal acquisition station collects one more component than the traditional DC charging method, and comprehensively analyzes E X and E Y After the qualitative relative amplitude anomaly and charging rate anomaly, the predicted crack width is more accurate; the electric field E X and E Y The imaging accuracy is further improved after the joint inversion of the components. After using two waveforms in the time domain and frequency domain for excitation, the relative abnormal data of the time domain charging rate and the relative abnormal data of the frequency domain amplitude are obtained at the same time. The relative abnormal data of the charging rate can more easily identify the location and geometric size of the low-resistance cracks. After the joint inversion of the electromagnetic response in the time domain and frequency domain, the vertical and horizontal resolution of the inversion results are improved.

[0075] It will be appreciated by those skilled in the art that embodiments of the present invention may be provided as methods, devices, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0076] The present invention is described with reference to flowcharts and / or block diagrams of methods, apparatuses, and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as a combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0077] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0078] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0079] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the embodiments of the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A hydraulic fracturing monitoring method, characterized in that: include: Before and after hydraulic fracturing, the horizontal long wire excitation source is excited once, and electromagnetic signals are synchronously collected at the 2-component electromagnetic field acquisition station; The horizontal long wire excitation source is arranged on the ground above the end of the horizontal well or on the ground far away from the end of the horizontal well; the two-component electromagnetic field acquisition station is arranged on the ground survey line; The electromagnetic signal of each measuring point is respectively calculated in time domain data parameters and frequency domain data parameters to obtain the relative abnormal data of time domain charging rate and the relative abnormal data of frequency domain amplitude; The electromagnetic signal data of each measuring point is subjected to quantitative inversion processing in the time domain and the frequency domain to obtain the three-dimensional resistivity distribution data around the horizontal well; Determine the parameters of the fractures formed underground by hydraulic fracturing according to the relative abnormal data of the time domain charging rate, the relative abnormal data of the frequency domain amplitude, and the three-dimensional resistivity distribution data around the horizontal well; After the horizontal long wire excitation source and the two-component electromagnetic field acquisition station are arranged, the emission time domain signal and the frequency domain signal are determined. The specific steps include: according to the depth of the horizontal well, the time domain emission waveform and period are selected, and the frequency domain emission waveform and frequency range are selected; The time domain data parameter calculation of the electromagnetic signal at each measuring point includes: Performing time domain preprocessing on the electromagnetic signal of each measuring point to obtain attenuation data of the electric field signal at different times; the time domain preprocessing includes one or any combination of filtering, removing DC drift, superposition, polar distance normalization and current normalization; Obtain charging rate data of each measuring point before and after fracturing according to the attenuation data at different times; According to the charging rate data before and after fracturing at each measuring point, the relative abnormal data of charging rate in time domain are obtained; The frequency domain data parameter calculation of the electromagnetic signal at each measuring point includes: Performing frequency domain preprocessing on the electromagnetic signal of each measuring point to obtain amplitude data of the electric field signal of each measuring point before fracturing and after each stage of fracturing; the frequency domain preprocessing includes one or any combination of filtering, removing DC drift, superposition, pole distance normalization, short-time window Fourier transform and current normalization; According to the amplitude data of the electric field signal before fracturing at each measuring point and after fracturing at each stage, the relative abnormal amplitude data in the frequency domain are obtained.

2. The method according to claim 1, characterized in that The two-component electromagnetic field acquisition station is arranged on the ground survey line, including: a plurality of survey lines parallel to the horizontal long wire excitation source are arranged on the ground above each perforation position of the horizontal well, and a two-component electromagnetic field acquisition station is arranged at each measuring point position of the plurality of survey lines.

3. The method according to claim 1, characterized in that The electromagnetic signals collected synchronously at the 2-component electromagnetic field acquisition station include: the electric field intensity component E in the X direction of the measured electric field X , measure the electric field strength component E in the Y direction of the electric field Y ; wherein the electric field X direction is parallel to the measuring line, and the electric field Y direction is perpendicular to the measuring line.

4. The method according to claim 1, characterized in that The exciting horizontal long wire excitation source comprises: the exciting horizontal long wire excitation source repeatedly emits a time domain signal and a frequency domain signal.

5. The method according to claim 4, characterized in that The excitation horizontal long wire excitation source repeatedly emits time domain signals and frequency domain signals, including: According to the depth of the horizontal well, the waveform and period of the time domain signal are selected, and the waveform and frequency of the frequency domain signal are selected; According to the waveform and period of the selected time domain signal, the horizontal long wire excitation source is excited to repeatedly emit the time domain signal; According to the waveform and frequency of the selected frequency domain signal, the horizontal long wire excitation source is excited to repeatedly emit the frequency domain signal.

6. The method according to claim 1, characterized in that The parameters of the cracks formed underground by hydraulic fracturing include: the length of the cracks, the width of the cracks and the height of the cracks.

7. The method according to claim 1, characterized in that Determining the parameters of the fractures formed underground by hydraulic fracturing based on the relative abnormal data of the time domain charging rate, the relative abnormal data of the frequency domain amplitude, and the three-dimensional resistivity distribution data around the horizontal well includes: Obtaining resistivity plane abnormal data before and after fracturing at the depth of the horizontal well and resistivity section abnormal data before and after fracturing at each measuring line position according to the three-dimensional resistivity distribution data around the horizontal well; According to the preset ranges of high charging rate anomaly, low amplitude anomaly and low resistivity anomaly, the length of the fracture is determined from the time domain charging rate relative anomaly data, the frequency domain amplitude relative anomaly data and the resistivity plane anomaly data before and after fracturing at the depth of the horizontal well; According to the preset range of the low resistivity anomaly, the width and height of the cracks formed underground by hydraulic fracturing are determined from the resistivity section anomaly data at each measuring line position before and after the fracturing.

8. A hydraulic fracturing monitoring device, characterized in that: include: A signal acquisition module, used to obtain electromagnetic signals synchronously collected at a two-component electromagnetic field acquisition station; The two-component electromagnetic field acquisition station acquires electromagnetic signals by synchronously acquiring signals when the horizontal long wire excitation source is excited once before and after hydraulic fracturing; the horizontal long wire excitation source is arranged on the ground above the end of the horizontal well or on the ground far away from the end of the horizontal well; the two-component electromagnetic field acquisition station is arranged on the ground survey line; The parameter calculation module is used to perform time domain data parameter calculation and frequency domain data parameter calculation on the electromagnetic signal of each measuring point, and obtain the relative abnormal data of the time domain charging rate and the relative abnormal data of the frequency domain amplitude; The inversion module is used to perform quantitative inversion processing in the time domain and the frequency domain on the electromagnetic signal data of each measuring point to obtain the three-dimensional resistivity distribution data around the horizontal well; A data analysis module, for determining the parameters of fractures formed underground by hydraulic fracturing based on the relative abnormal data of charging rate in the time domain, the relative abnormal data of amplitude in the frequency domain, and the three-dimensional resistivity distribution data around the horizontal well; After the horizontal long wire excitation source and the two-component electromagnetic field acquisition station are arranged, the emission time domain signal and the frequency domain signal are determined. The specific steps include: according to the depth of the horizontal well, the time domain emission waveform and period are selected, and the frequency domain emission waveform and frequency range are selected; Parameter calculation module, specifically used for: Performing time domain preprocessing on the electromagnetic signal of each measuring point to obtain attenuation data of the electric field signal at different times; the time domain preprocessing includes one or any combination of filtering, removing DC drift, superposition, polar distance normalization and current normalization; Obtain charging rate data of each measuring point before and after fracturing according to the attenuation data at different times; According to the charging rate data before and after fracturing at each measuring point, the relative abnormal data of charging rate in time domain are obtained; Parameter calculation module, specifically used for: Performing frequency domain preprocessing on the electromagnetic signal of each measuring point to obtain amplitude data of the electric field signal of each measuring point before fracturing and after each stage of fracturing; the frequency domain preprocessing includes one or any combination of filtering, removing DC drift, superposition, pole distance normalization, short-time window Fourier transform and current normalization; According to the amplitude data of the electric field signal before fracturing at each measuring point and after fracturing at each stage, the relative abnormal amplitude data in the frequency domain are obtained.

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