CN112302636B - Hydraulic fracturing monitoring method and device - Google Patents
Hydraulic fracturing monitoring method and device Download PDFInfo
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Abstract
本发明提供了一种水力压裂监测方法及装置，该方法包括：在水力压裂前和压裂后，均激发水平长导线激发源一次，在2分量电磁场采集站同步采集电磁信号；对每个测点的电磁信号分别做时间域数据参数计算和频率域数据参数计算，获得时间域充电率相对异常数据、频率域振幅相对异常数据；对每个测点的电磁信号数据分别做时间域的定量反演处理和频率域的定量反演处理，获得水平井周围三维电阻率分布数据；根据所述时间域充电率相对异常数据、频率域振幅相对异常数据以及水平井周围三维电阻率分布数据，确定水力压裂在地下形成的裂缝参数。本发明减少了噪音干扰，降低了误差影响，为水平井水力压裂储层改造效果的评价提供有效参考信息。
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
The invention relates to the technical field of petroleum and natural gas electromagnetic exploration oil and gas reservoir evaluation, in particular to a hydraulic fracturing monitoring method and device.
Background
Many large fields of high permeability around the world have been put into the late stages of production and the oil and gas in these tight reservoirs need to be hydraulically fractured to achieve economic recovery. Deep knowledge of the geometry and extension of hydraulic fracturing cracks is important to improve the fracturing yield-increasing operation effect of low-permeability reservoirs, improve the productivity of oil and gas wells and improve the oil and gas recovery ratio. At present, microseism monitoring technology is widely applied to hydraulic fracture monitoring.
However, in-well microseism monitoring is usually limited by conditions such as monitoring well availability, ground microseism monitoring is usually interfered by noise of a fracturing site, data with high signal to noise ratio are difficult to collect, the position of a microseism event is determined by a speed model, the speed model is inaccurate, errors are large, and the limitations of the microseism monitoring technology bring demands to new fracturing monitoring technology.
Disclosure of Invention
The embodiment of the invention provides a hydraulic fracturing monitoring method for reducing noise interference and error, which comprises the following steps:
Exciting a horizontal long-wire excitation source for one time before hydraulic fracturing and after hydraulic fracturing, and synchronously acquiring electromagnetic signals at a 2-component electromagnetic field acquisition station, wherein the horizontal long-wire excitation source is arranged on the ground above the tail end of a horizontal well or on the ground far away from the tail end of the horizontal well;
Respectively performing time domain data parameter calculation and frequency domain data parameter calculation on the electromagnetic signals of each measuring point to obtain time domain charging rate relative abnormal data and frequency domain amplitude relative abnormal data;
Respectively carrying out quantitative inversion processing of a time domain and quantitative inversion processing of a frequency domain on electromagnetic signal data of each measuring point to obtain three-dimensional resistivity distribution data around a horizontal well;
And determining fracture parameters formed by hydraulic fracturing underground according to 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.
The embodiment of the invention also provides a controllable source electromagnetic device for hydraulic fracturing monitoring, which is used for reducing noise interference and error, and comprises the following components:
The system comprises a signal acquisition module, a 2-component electromagnetic field acquisition station, a horizontal long wire excitation source, a horizontal well and a signal transmission module, wherein the signal acquisition module is used for acquiring electromagnetic signals synchronously at the 2-component electromagnetic field acquisition station, the 2-component electromagnetic field acquisition station acquires electromagnetic signals synchronously when exciting the horizontal long wire excitation source once before hydraulic fracturing and after hydraulic fracturing;
the parameter calculation module is used for respectively carrying out time domain data parameter calculation and frequency domain data parameter calculation on the electromagnetic signals of each measuring point to obtain time domain charging rate relative abnormal data and frequency domain amplitude relative abnormal data;
The inversion module is used for respectively carrying out quantitative inversion processing of a time domain and quantitative inversion processing of a frequency domain on the electromagnetic signal data of each measuring point to obtain three-dimensional resistivity distribution data around the horizontal well;
And the data analysis module is used for determining fracture parameters formed by hydraulic fracturing underground according to 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.
The embodiment of the invention avoids the limitation of the usability condition of the monitored well by arranging the monitoring device outside the horizontal well, adopts a horizontal long wire excitation source arranged on the ground above the tail end of the horizontal well or on the ground far away from the tail end of the horizontal well to lead the excitation source to be far away from the horizontal well mouth, avoids electromagnetic interference caused by a fracturing site, increases the signal strength, improves the quality of a received signal, improves the imaging precision, adopts 2-component signal acquisition, acquires one component more than the traditional direct current charging method, and comprehensively analyzes the predicted fracture parameter more accurately, thereby effectively obtaining the size and the geometric form of the fracture formed underground after the hydraulic fracturing of the horizontal well and providing effective reference information for evaluating the transformation effect of the hydraulic fracturing reservoir of the horizontal well.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for the description of the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
Fig. 1 is a schematic diagram of a hydraulic fracturing monitoring method according to an embodiment of the invention.
FIG. 2 is a schematic diagram of a horizontal long wire excitation source and a line placement in an embodiment of the invention.
Fig. 3 is a schematic diagram of a square waveform with a zero crossing of 40s in time domain period in an embodiment of the present invention.
Fig. 4 is a schematic diagram of a square waveform with a frequency domain period Ts that is not zero crossing in an embodiment of the present invention.
FIG. 5 is a graph showing the amplitude versus anomaly of the frequency domain before and after hydraulic fracturing in an embodiment of the present invention.
FIG. 6 is a cross-sectional view showing resistivity anomalies before and after hydraulic fracturing in accordance with an embodiment of the present invention.
Fig. 7 is a schematic diagram of a hydraulic fracturing monitoring apparatus according to an embodiment of the present invention.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
In order to solve the problems that the ground microseism monitoring based on the existing microseism monitoring technology is difficult to collect data with high signal to noise ratio, a speed model on which position determination depends is inaccurate and has large error, the embodiment of the invention provides a hydraulic fracturing monitoring method, as shown in figure 1, which comprises the following steps:
step 101, exciting a horizontal long lead excitation source for one time before hydraulic fracturing and after hydraulic fracturing, and synchronously collecting electromagnetic signals at a 2-component electromagnetic field collection station, wherein the horizontal long lead excitation source is arranged on the ground above the tail end of a horizontal well or on the ground far away from the tail end of the horizontal well;
102, respectively performing time domain data parameter calculation and frequency domain data parameter calculation on electromagnetic signals of each measuring point to obtain time domain charging rate relative abnormal data and frequency domain amplitude relative abnormal data;
Step 103, respectively carrying out quantitative inversion processing of a time domain and quantitative inversion processing of a frequency domain on electromagnetic signal data of each measuring point to obtain three-dimensional resistivity distribution data around a horizontal well;
and 104, determining fracture parameters formed by hydraulic fracturing underground according to 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.
The embodiment of the invention avoids the limitation of the availability condition of the monitored well by arranging the monitoring device outside the horizontal well, adopts the horizontal long wire excitation source arranged on the ground above the tail end of the horizontal well or on the ground far away from the tail end of the horizontal well, so that the excitation source is far away from the horizontal well mouth, avoids electromagnetic interference caused by a fracturing site, not only increases the signal strength, but also improves the quality of received signals, and improves the imaging precision, thereby effectively obtaining the size and the geometric form of a crack formed underground after the hydraulic fracturing of the horizontal well, and further providing effective reference information for evaluating the transformation effect of the hydraulic fracturing reservoir of the horizontal well.
In the implementation, first, a horizontal long wire excitation source is arranged on the ground above the tail end of the horizontal well or on the ground far away from the tail end of the horizontal well. For example, to achieve the most effective excitation of the low resistance fracture, in the embodiment of the present invention, the horizontal long-wire excitation source arrangement direction may be perpendicular to the projection track of the horizontal well on the ground. The length of the emission source is a preset range, for example, 2000-6000 m, as shown in fig. 2, a horizontal long-wire source excitation source A1B1 is arranged on the ground above the tail end of the horizontal well and is far away from the wellhead, the direction of the excitation source A1B1 is perpendicular to the projection track of the horizontal well on the ground, the projection track of the horizontal well on the ground passes through the midpoint of the emission source, and the length of the emission source A1B1 is 3000m. The ground contacts A1 and B1 of the excitation source A1B1 may be made of a thin aluminum plate, and those skilled in the art will understand that the length of the excitation source and the ground contact material are only examples, and are not described herein again.
Secondly, a plurality of measuring lines parallel to the excitation source A1B1 are distributed on the ground corresponding to the upper part of each perforation position of the horizontal well, and each measuring point position of each measuring line is provided with a 2-component electromagnetic field acquisition station. The electrode distribution mode of the measuring line comprises fixed point distances and variable point distances, the fixed point distances are determined according to the number of the input collecting stations in the implementation process, the number of the collecting stations is small, for example, less than 200, the variable point distances are selected, and the number of the collecting stations is large, for example, more than 200, and the fixed point distances are selected.
The fixed point distance in the embodiment of the invention is a constant value of the measuring line distance, such as a certain constant value in 20-50 m. The variable point distance is that the measuring point distance is a non-constant value, the point distance right above the horizontal well is dense, the number of measuring points right above the horizontal well cannot be less than 7, the point distance is thin in the direction away from the horizontal well, and the point distance takes a value in a set range, for example, 50-100 m.
For example, in the embodiment shown in fig. 2, the length of the measuring lines is 2000m, each measuring line is 100m apart, the minimum distance between the measuring lines and the emitting source A1B1 is 2000m, and the measuring lines are distributed in a fixed point distance mode with a point distance of 50 m.
The electromagnetic signals synchronously collected by the 2-component electromagnetic field collecting station in the embodiment of the invention comprise an electric field intensity component E X in the X direction of an electric field and an electric field intensity component E Y in the Y direction of the electric field, wherein the X direction of the electric field is a direction parallel to a measuring line, and the Y direction of the electric field is a direction perpendicular to the measuring line.
After the horizontal long lead excitation source and the 2-component electromagnetic field acquisition station are arranged, the time domain signal and the frequency domain signal are determined, and the specific steps include selecting a time domain emission waveform and period and selecting a frequency domain emission waveform and frequency range according to the depth of a horizontal well. The specific selection basis is that the time domain emission waveform is a square wave with zero crossing, the period range is 10 s-40 s, for example, the depth of a horizontal well is smaller than 2000m, the period of an emission signal is 20s, the depth of the horizontal well is larger than 2000m, and the period of the emission signal is 40s. The frequency domain emission waveform is a square wave which is not zero crossing, the frequency range is 2 -8～2+8 Hz, and the minimum frequency of the emission signal is calculated according to a skin depth formula by using the depth of the horizontal well and the stratum resistivity of the depth of the horizontal well. For example, in the specific embodiment shown in fig. 2, the depth of the horizontal well is 3000m, the time domain emission waveform is shown in fig. 3, the period is 40s, the frequency domain emission waveform is shown in fig. 4, the period is a Ts square wave signal, the period is not zero crossing, the period T is changed according to the frequency, the range of the emission frequency is 2 -6～2+6 Hz, the number of the selected frequencies is 41, and the selection of the emission frequency values is distributed at equal intervals in logarithmic space.
After the time domain signal and the frequency domain signal are transmitted, the horizontal long wire excitation source is excited once before hydraulic fracturing and after each stage of fracturing, the horizontal long wire excitation source is excited to repeatedly transmit the time domain signal according to the waveform and the period of the selected time domain signal, and the horizontal long wire excitation source is excited to repeatedly transmit the frequency domain signal according to the waveform and the frequency of the selected frequency domain signal. If the frequency of the frequency domain signal is greater than 1Hz, the repeated transmission times are greater than 64 times, and if the frequency is less than 1Hz, the repeated transmission times are greater than 32 times, and the repeated transmission times of the time domain signal are greater than 32 times. For example, in the specific embodiment shown in fig. 2, when the horizontal long wire excitation source A1B1 is excited, the selected time domain transmitting signal is repeatedly transmitted 64 times, when the frequency domain transmitting signal is transmitted, the number of repeated transmitting times is adjusted according to different signal frequencies, the number of repeated transmitting times of the high-frequency square wave is more, and the number of repeated transmitting times of the low-frequency square wave is less.
After the excitation source of the horizontal long lead is excited, the electromagnetic signals are synchronously collected by the 2-component electromagnetic field collecting station, and in the embodiment of the invention, the collecting station and the excitation source A1B1 synchronously realize the synchronous start of emission and collection through GPS. In the embodiment of the present invention, the sensor connected to the 2-component electromagnetic acquisition station may be a non-polarized electrode, and those skilled in the art can understand that signals may also be acquired by other sensors, which is only an example and will not be described herein.
After the electromagnetic signals are collected, carrying out time domain data parameter calculation and frequency domain data parameter calculation on the electromagnetic signal data of each measuring point, wherein the specific processing comprises the following steps:
The specific steps of calculating the time domain data parameters of the electromagnetic signal data of each measuring point comprise:
performing time domain preprocessing on the electromagnetic signals of each measuring point to obtain attenuation data of the electric field signals at different moments, wherein the time domain preprocessing comprises one or any combination of filtering, DC drift removal, superposition, pole pitch normalization and current normalization;
according to the attenuation data at different moments, charging rate data before and after fracturing of each measuring point are obtained;
And obtaining time domain charging rate relative abnormal data according to the charging rate data before and after fracturing of each measuring point.
The method specifically comprises the steps of calculating the charging rate data before and after each measuring point fracturing according to attenuation data at different moments by using a charging rate calculation formula, and subtracting a background value from the charging rate data after each fracturing by using the charging rate data before fracturing as a background to obtain the charging rate relative abnormal data after each fracturing of each measuring point.
The specific steps of carrying out frequency domain data parameter calculation on the electromagnetic signal data of each measuring point include:
The method comprises the steps of carrying out frequency domain pretreatment on electromagnetic signals of each measuring point to obtain amplitude data of electric field signals before fracturing and after fracturing of each measuring point, wherein the frequency domain pretreatment comprises one or any combination of filtering, DC drift removal, superposition, pole pitch normalization, short-time window Fourier transform and current normalization;
And obtaining frequency domain amplitude relative abnormal data according to the amplitude data of the electric field signals before fracturing of each measuring point and after fracturing of each section.
The method for obtaining the frequency domain amplitude relative abnormal data specifically comprises the following steps of:
And taking the amplitude data before fracturing as a background, subtracting the background from the amplitude data after fracturing each time, dividing the background by a background value, and finally obtaining the amplitude relative abnormal data of each measuring point.
After the time domain charging rate relative abnormal data and the frequency domain amplitude relative abnormal data are obtained, respectively carrying out time domain quantitative inversion processing and frequency domain quantitative inversion processing on electromagnetic signal data of each measuring point to obtain three-dimensional resistivity distribution data around the horizontal well. The specific process includes that firstly, the attenuation data preprocessed in the time domain is calculated by a dichotomy method, and the whole-area apparent resistivity data at different moments is obtained. And respectively carrying out one-dimensional inversion of the time domain and the frequency domain on the all-region apparent resistivity data at different time of the time domain and the data subjected to the frequency domain pretreatment to obtain the time domain and the frequency domain resistivity-depth data corresponding to each measuring point, calculating the average value of two groups of data of each measuring point on the same measuring line to obtain a one-dimensional model of the resistivity-depth of each measuring line, then respectively carrying out two-dimensional inversion of the time domain and the frequency domain by using the model as a two-dimensional inversion initial model to obtain two resistivity-depth profile data of each measuring line, carrying out average value calculation on the two groups of resistivity-depth profile data to obtain the resistivity-depth two-dimensional model of each measuring line, finally forming a resistivity-depth three-dimensional model by using the resistivity-depth model of all the measuring lines, and adopting quick three-dimensional inversion to obtain a high-precision three-dimensional inversion result. And respectively carrying out three-dimensional inversion on the electromagnetic signal data before fracturing and after fracturing to obtain resistivity three-dimensional distribution data before fracturing and after fracturing.
And after three-dimensional distribution data of resistivity before fracturing and after fracturing of each section are obtained, obtaining abnormal data of resistivity planes before and after fracturing on the depth of the horizontal well and abnormal data of resistivity sections before and after fracturing at the position of each measuring line according to the three-dimensional resistivity distribution data around the horizontal well. The method comprises the steps of taking resistivity plane data before fracturing as a background, subtracting the background from the resistivity plane data after fracturing to obtain resistivity abnormal plane data of each segment, taking resistivity section data at each test line position before fracturing as the background, and subtracting the background from the resistivity section data at each test line position after fracturing to obtain resistivity abnormal section data before and after fracturing at each test line position.
Finally, determining the length of the crack from the time domain charging rate relative abnormal data, the frequency domain amplitude relative abnormal data and the resistivity plane abnormal data before and after fracturing on the depth of the horizontal well according to the preset ranges of the charging rate high abnormality, the amplitude low abnormality and the resistivity low abnormality; and determining the width and the height of the hydraulic fracturing crack formed in the underground from the abnormal data of the resistivity section before and after fracturing at each measuring line position according to the preset range of the low resistivity abnormality.
The preset range of the high-charging-rate abnormality, the low-amplitude abnormality and the low-resistivity abnormality in the embodiment of the invention is a range preset according to actual operation, and once the data is positioned in the preset range, the area corresponding to the data belongs to a hydraulic fracture area. For example, in the embodiment of the present invention, the preset range of the low frequency domain amplitude abnormality is less than-0.05, and those skilled in the art will understand that this range is only an example and is not limited to the embodiment of the present invention, and the remaining preset ranges are not described herein.
Further description will be made in connection with one embodiment of the present invention:
In order to more intuitively and rapidly determine the parameters of the hydraulic fracture, the embodiment of the invention draws 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. As shown in fig. 5 and fig. 6, fig. 5 is a graph of amplitude versus anomaly in the frequency domain before and after hydraulic fracturing in the embodiment, the abscissa indicates the east direction, the ordinate indicates the north direction, and the graph has a plurality of black uniform dots, which represent a plurality of measuring points, and the plurality of measuring points may be connected into a plurality of parallel lines, which represent a plurality of measuring lines. The areas of the graph with low amplitude anomalies are darker and represent the preliminary plane profile of the fracture created by the hydraulic fracturing, and the length of the fracture can be determined. FIG. 6 is a cross-sectional view of resistivity anomalies before and after fracturing at a horizontal well depth, with the vertical axis representing depth and the horizontal axis representing distance, and with areas of low resistivity anomalies in the graph, darker in color, representing the fracture profile of the fracture forming fracture, and the width and height of the fracture can be determined.
It will be understood by those skilled in the art that 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 are presented in a curve form only as examples, and may also be presented in a data list manner, etc., and will not be described herein.
And the volume of the crack can be obtained according to the length, the height and the width of the crack, and reference information is provided for evaluating the transformation effect of the hydraulic fracturing reservoir. For example, according to fig. 5 and 6, the size of the crack formed by hydraulic fracturing in the embodiment of the invention is 1000m in the direction of the direction, 80m in the width, 80m in the height and 6.4x10 6m3 in the volume.
The embodiment of the invention avoids the limitation of the availability condition of the monitored well by arranging the monitoring device outside the horizontal well, adopts a horizontal long wire excitation source arranged on the ground above the tail end of the horizontal well or on the ground far away from the tail end of the horizontal well, so that the excitation source is far away from the horizontal well mouth, avoids electromagnetic interference caused by a fracturing site, not only increases the signal intensity, but also improves the quality of a received signal, improves the imaging precision, adopts 2-component signal acquisition, acquires one component more than the traditional direct current charging method, and comprehensively analyzes the predicted fracture parameters more accurately, thereby effectively obtaining the size and the geometric form of the fracture formed underground after the hydraulic fracturing of the horizontal well and providing effective reference information for evaluating the transformation effect of the hydraulic fracturing reservoir of the horizontal well.
The embodiment of the invention also provides a hydraulic fracturing monitoring device which is used for reducing noise interference and reducing errors. Since the implementation of the hydraulic fracture monitoring device can be referred to the implementation of the hydraulic fracture monitoring method, the repetition is not repeated. The term "module" as used below refers to a combination of software and/or hardware that can perform a predetermined function, the specific structure of which is shown in fig. 7:
The signal acquisition module 701 is used for acquiring electromagnetic signals synchronously acquired at a 2-component electromagnetic field acquisition station, wherein the electromagnetic signals are acquired by the 2-component electromagnetic field acquisition station synchronously when a horizontal long wire excitation source is excited once before hydraulic fracturing and after hydraulic fracturing;
the parameter calculation module 702 is configured to perform time domain data parameter calculation and frequency domain data parameter calculation on the electromagnetic signal of each measurement point, so as to obtain time domain charging rate relative abnormal data and frequency domain amplitude relative abnormal data;
The inversion module 703 is used for respectively performing quantitative inversion processing of a time domain and quantitative inversion processing of a frequency domain on the electromagnetic signal data of each measuring point to obtain three-dimensional resistivity distribution data around the horizontal well;
The data analysis module 704 is configured to determine fracture parameters formed by hydraulic fracturing in the underground according to 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 embodiment, the 2-component electromagnetic field acquisition station is arranged on a measuring line on the ground, and specifically comprises the steps of arranging a horizontal long wire excitation source on the ground above the tail end of a horizontal well or on the ground far away from the tail end of the horizontal well, arranging a plurality of measuring lines parallel to the horizontal excitation source on the ground above each perforation position of the horizontal well, and arranging the 2-component electromagnetic field acquisition station at each measuring point position of the plurality of measuring lines.
In the embodiment of the invention, the electromagnetic signals synchronously acquired by the 2-component electromagnetic field acquisition station comprise an electric field intensity component E X in the X direction of an electric field and an electric field intensity component E Y in the Y direction of the electric field, wherein the X direction of the electric field is a direction parallel to a measuring line, and the Y direction of the electric field is a direction perpendicular to the measuring line.
In an embodiment, the signal obtaining module 701 is specifically further configured to repeatedly emit time-domain and frequency-domain signals by using the excitation source with the excitation level and the long wire. The method comprises the steps of selecting waveforms and periods of time domain signals according to the depth of a horizontal well, selecting waveforms and frequencies of frequency domain signals, exciting a horizontal long wire excitation source to repeatedly emit the time domain signals according to the waveforms and periods of the selected time domain signals, and exciting the horizontal long wire excitation source to repeatedly emit the frequency domain signals according to the waveforms and frequencies of the selected frequency domain signals.
In an embodiment, the parameter calculation module 702 is specifically configured to:
Performing time domain pretreatment on electromagnetic signals of each measuring point to obtain attenuation data of the electric field signals at different moments, wherein the time domain pretreatment comprises one or any combination of filtering, DC drift removal, superposition, pole pitch normalization and current normalization, obtaining charging rate data before and after each measuring point is cracked according to the attenuation data at different moments, obtaining time domain charging rate relative abnormal data according to the charging rate data before and after each measuring point, and
The method comprises the steps of carrying out frequency domain pretreatment on electromagnetic signals of each measuring point to obtain amplitude data of electric field signals before fracturing of each measuring point and after fracturing of each section, wherein the frequency domain pretreatment comprises one or any combination of filtering, DC drift removal, superposition, pole pitch normalization, short-time window Fourier transformation and current normalization, and obtaining frequency domain amplitude relative abnormal data according to the amplitude data of the electric field signals before fracturing of each measuring point and after fracturing of each section.
In an embodiment, the data analysis module 704 is specifically configured to:
obtaining resistivity plane abnormal data before and after fracturing on the depth of the horizontal well according to the three-dimensional resistivity distribution data around the horizontal well, and resistivity section abnormal data before and after fracturing at each measuring line position;
determining the length of a crack from time domain charging rate relative abnormal data, frequency domain amplitude relative abnormal data and resistivity plane abnormal data before and after fracturing on the depth of a horizontal well according to a preset range of high charging rate, low amplitude and low resistivity;
And determining the width and the height of the hydraulic fracturing to form a crack in the underground from the abnormal data of the resistivity section at each line position before and after the fracturing according to the preset range of the low resistivity abnormality.
In summary, the hydraulic fracturing monitoring method and device provided by the invention have the following beneficial effects when being used for hydraulic fracturing monitoring:
according to the method, firstly, a horizontal long-wire excitation source perpendicular to the projection track of the horizontal well on the ground is arranged on the ground at the tail end of the horizontal well, so that the flowing distance of excitation current in the low-resistance cracks is longest, the most effective excitation of the low-resistance cracks is realized, secondly, a measuring line and an electromagnetic acquisition station are arranged at the perforation position of the horizontal well, electric field signals of underground cracks in the measuring line direction and the vertical measuring line direction when the horizontal long-wire source is excited are obtained, and the optimal detection for detecting the trend and the vertical trend direction of the hydraulic fracturing cracks is formed. And the excitation source is far away from the horizontal wellhead by adopting the ground above the tail end of the horizontal well or the horizontal long wire excitation source on the ground far away from the tail end of the horizontal well, so that electromagnetic interference caused by fracturing sites is avoided, the signal intensity is increased, the quality of received signals is improved, and the imaging precision is also improved. The 2-component signal acquisition station of E X、EY is adopted to acquire one component more than the traditional direct current charging method, the predicted crack width is more accurate after the qualitative relative amplitude abnormality and the charging rate abnormality of E X and E Y are comprehensively analyzed, and the imaging precision after the joint inversion of the components of the electric fields E X and E Y is further improved. After the two waveforms of the time domain and the frequency domain are adopted for excitation, the relative abnormal data of the charging rate of the time domain and the relative abnormal data of the amplitude of the frequency domain are obtained, the position and the geometric dimension of the low-resistance crack are more easily identified by utilizing the relative abnormal data of the charging rate, and the longitudinal resolution of the inversion result is improved after the electromagnetic response joint inversion of the time domain and the frequency domain.
It will be apparent to those skilled in the art that embodiments of the present invention may be provided as a method, apparatus, or computer program product. Accordingly, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.
The present invention is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus and computer program products according to embodiments of the invention. It will be understood that each flow and/or block of the flowchart illustrations and/or block diagrams, and combinations of flows and/or blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
The above description is only of the preferred embodiments of the present invention and is not intended to limit the present invention, and various modifications and variations can be made to the embodiments of the present invention by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (8)
1. A method of hydraulic fracture monitoring, comprising:
Exciting a horizontal long-wire excitation source for one time before hydraulic fracturing and after hydraulic fracturing, and synchronously acquiring electromagnetic signals at a 2-component electromagnetic field acquisition station, wherein the horizontal long-wire excitation source is arranged on the ground above the tail end of a horizontal well or on the ground far away from the tail end of the horizontal well;
Respectively performing time domain data parameter calculation and frequency domain data parameter calculation on the electromagnetic signals of each measuring point to obtain time domain charging rate relative abnormal data and frequency domain amplitude relative abnormal data;
Respectively carrying out quantitative inversion processing of a time domain and quantitative inversion processing of a frequency domain on electromagnetic signal data of each measuring point to obtain three-dimensional resistivity distribution data around a horizontal well;
determining fracture parameters formed by hydraulic fracturing underground according to 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;
after a horizontal long wire excitation source and a 2-component electromagnetic field acquisition station are arranged, determining a transmitting time domain signal and a frequency domain signal, wherein the specific steps include selecting a time domain transmitting waveform and period according to the depth of a horizontal well, and selecting a frequency domain transmitting waveform and frequency range;
the calculating of the time domain data parameters of the electromagnetic signals of each measuring point comprises the following steps:
Performing time domain preprocessing on the electromagnetic signals of each measuring point to obtain attenuation data of the electric field signals at different moments, wherein the time domain preprocessing comprises one or any combination of filtering, removing direct current drift, superposition, pole pitch normalization and current normalization;
According to the attenuation data at different moments, charging rate data before and after fracturing of each measuring point are obtained;
obtaining time domain charging rate relative abnormal data according to the charging rate data before and after fracturing of each measuring point;
the calculating of the frequency domain data parameters of the electromagnetic signals of each measuring point comprises the following steps:
Performing frequency domain pretreatment on the electromagnetic signals of each measuring point to obtain amplitude data of electric field signals before fracturing and after fracturing of each measuring point, wherein the frequency domain pretreatment comprises one or any combination of filtering, DC drift removal, superposition, pole pitch normalization, short-time window Fourier transform and current normalization;
And obtaining frequency domain amplitude relative abnormal data according to the amplitude data of the electric field signals before fracturing of each measuring point and after fracturing of each section.
2. The method of claim 1, wherein the 2-component electromagnetic field acquisition station is deployed on a survey line of the ground, comprising deploying a plurality of survey lines parallel to the horizontal long conductor excitation source on the ground above each perforation location of a horizontal well, and deploying a 2-component electromagnetic field acquisition station at each survey point location of the plurality of survey lines.
3. The method of claim 1, wherein the electromagnetic signals synchronously acquired at the 2-component electromagnetic field acquisition station include measuring an electric field strength component E X in an X-direction of an electric field and measuring an electric field strength component E Y in a Y-direction of the electric field, wherein the X-direction of the electric field is parallel to the line and the Y-direction of the electric field is perpendicular to the line.
4. The method of claim 1, wherein the excitation source of excitation level long conductor comprises repeatedly transmitting a time domain signal and a frequency domain signal.
5. The method of claim 4, wherein the excitation horizontal long wire excitation source repeatedly emits a time domain signal and a frequency domain signal, comprising:
Selecting the waveform and the period of the time domain signal and the waveform and the frequency of the frequency domain signal according to the depth of the horizontal well;
Exciting the horizontal long wire excitation source to repeatedly emit the time domain signal according to the waveform and period of the selected time domain signal;
The excitation horizontal long wire excitation source repeatedly emits a frequency domain signal according to the waveform and frequency of the selected frequency domain signal.
6. The method of claim 1, wherein the parameters of the fracture formed in the subsurface by the hydraulic fracture include the length of the fracture, the width of the fracture, and the height of the fracture.
7. The method of claim 1, wherein determining fracture parameters for hydraulic fracturing formed in the subsurface based on the time domain charge rate versus anomaly data, frequency domain amplitude versus anomaly data, and three-dimensional resistivity profile data around the horizontal well comprises:
Obtaining resistivity plane abnormal data before and after fracturing on the depth of the horizontal well according to the three-dimensional resistivity distribution data around the horizontal well, and resistivity section abnormal data before and after fracturing at each measuring line position;
Determining the length of a crack from the time domain charging rate relative abnormal data, the frequency domain amplitude relative abnormal data and the resistivity plane abnormal data before and after fracturing on the depth of the horizontal well according to preset ranges of the charging rate high abnormality, the amplitude low abnormality and the resistivity low abnormality;
And determining the width and the height of the hydraulic fracturing to form a crack in the underground from the abnormal data of the resistivity section at each measuring line position before and after the fracturing according to the preset range of the low resistivity abnormality.
8. A hydraulic fracture monitoring device, comprising:
The system comprises a signal acquisition module, a 2-component electromagnetic field acquisition station, a horizontal long wire excitation source, a horizontal well and a signal transmission module, wherein the signal acquisition module is used for acquiring electromagnetic signals synchronously at the 2-component electromagnetic field acquisition station, the 2-component electromagnetic field acquisition station acquires electromagnetic signals synchronously when exciting the horizontal long wire excitation source once before hydraulic fracturing and after hydraulic fracturing;
the parameter calculation module is used for respectively carrying out time domain data parameter calculation and frequency domain data parameter calculation on the electromagnetic signals of each measuring point to obtain time domain charging rate relative abnormal data and frequency domain amplitude relative abnormal data;
The inversion module is used for respectively carrying out quantitative inversion processing of a time domain and quantitative inversion processing of a frequency domain on the electromagnetic signal data of each measuring point to obtain three-dimensional resistivity distribution data around the horizontal well;
The data analysis module is used for determining fracture parameters formed by hydraulic fracturing underground according to 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;
after a horizontal long wire excitation source and a 2-component electromagnetic field acquisition station are arranged, determining a transmitting time domain signal and a frequency domain signal, wherein the specific steps include selecting a time domain transmitting waveform and period according to the depth of a horizontal well, and selecting a frequency domain transmitting waveform and frequency range;
The parameter calculation module is specifically used for:
Performing time domain preprocessing on the electromagnetic signals of each measuring point to obtain attenuation data of the electric field signals at different moments, wherein the time domain preprocessing comprises one or any combination of filtering, removing direct current drift, superposition, pole pitch normalization and current normalization;
According to the attenuation data at different moments, charging rate data before and after fracturing of each measuring point are obtained;
obtaining time domain charging rate relative abnormal data according to the charging rate data before and after fracturing of each measuring point;
The parameter calculation module is specifically used for:
Performing frequency domain pretreatment on the electromagnetic signals of each measuring point to obtain amplitude data of electric field signals before fracturing and after fracturing of each measuring point, wherein the frequency domain pretreatment comprises one or any combination of filtering, DC drift removal, superposition, pole pitch normalization, short-time window Fourier transform and current normalization;
And obtaining frequency domain amplitude relative abnormal data according to the amplitude data of the electric field signals before fracturing of each measuring point and after fracturing of each section.
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| CN114459912B (en) * | 2022-01-24 | 2023-08-08 | 湖南继善高科技有限公司 | Method and system for determining volume of oil and gas fracturing cracks |
| CN114458289B (en) * | 2022-02-23 | 2024-07-26 | 湖南继善高科技有限公司 | Oil-gas fracturing fracture monitoring data processing method, system and storage medium |
| CN114896673B (en) * | 2022-06-14 | 2022-11-15 | 中国地质调查局油气资源调查中心 | Hot dry rock reservoir hydraulic fracturing reconstruction volume prediction method |
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