CN114791633B - Method, system and medium for monitoring shale gas fracturing - Google Patents
Method, system and medium for monitoring shale gas fracturing Download PDFInfo
- Publication number
- CN114791633B CN114791633B CN202210706620.1A CN202210706620A CN114791633B CN 114791633 B CN114791633 B CN 114791633B CN 202210706620 A CN202210706620 A CN 202210706620A CN 114791633 B CN114791633 B CN 114791633B
- Authority
- CN
- China
- Prior art keywords
- frequency
- response
- amplitude
- downhole
- receiving array
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
- G01V3/00—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation
- G01V3/18—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation specially adapted for well-logging
- G01V3/26—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation specially adapted for well-logging operating with magnetic or electric fields produced or modified either by the surrounding earth formation or by the detecting device
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B47/00—Survey of boreholes or wells
- E21B47/10—Locating fluid leaks, intrusions or movements
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B49/00—Testing the nature of borehole walls; Formation testing; Methods or apparatus for obtaining samples of soil or well fluids, specially adapted to earth drilling or wells
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
- G01V3/00—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation
- G01V3/38—Processing data, e.g. for analysis, for interpretation, for correction
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F17/00—Digital computing or data processing equipment or methods, specially adapted for specific functions
- G06F17/10—Complex mathematical operations
- G06F17/11—Complex mathematical operations for solving equations, e.g. nonlinear equations, general mathematical optimization problems
Abstract
The embodiment of the invention discloses a method, a system and a medium for monitoring shale gas fracturing; the method can comprise the following steps: transmitting a multi-frequency transmission signal by using a downhole galvanic couple source; receiving multi-frequency electromagnetic response and induced electrical response in a monitoring area through a ground receiving array and a downhole receiving array; extracting potential difference and electric field response of each frequency from the multi-frequency electromagnetic response and the induced electric response by a digital coherent detection method; acquiring amplitude frequency parameters of the monitoring area based on the potential difference of each frequency; wherein the amplitude-frequency parameter is used for reflecting the change characteristic of the amplitude of the potential difference along with the frequency; obtaining the resistivity and the polarizability of the monitoring area through inversion by a preprocessing conjugate gradient method based on the electric field response of each frequency; and obtaining the evaluation of the shale gas fracturing effect according to the interpretation of the amplitude frequency parameter, the resistivity and the polarizability of the monitoring area.
Description
Technical Field
The embodiment of the invention relates to the technical field of oil and gas development in the field of exploration of geophysical, in particular to a method, a system and a medium for monitoring shale gas fracturing.
Background
The exploitation of shale gas changes the global energy pattern, and China also becomes a world large country for exploiting and utilizing shale gas. In the process of exploitation, fracturing measures are generally adopted, namely, the stratum is artificially fractured, so that the flowing environment of shale gas in the underground is improved, and the yield is improved; therefore, the quality of the fracturing effect has a decisive influence on the recovery efficiency. After the fracturing improvement measures are implemented, an effective monitoring method is needed to determine the fracturing operation effect and acquire a plurality of information such as the flow conductivity, the geometric shape, the complexity and the orientation of the fracturing induced fracture so as to improve the fracturing production increase operation effect of the shale gas reservoir and the gas well productivity and improve the shale gas recovery rate. Therefore, the development of dynamic monitoring about the fracturing effect is an indispensable technology in shale gas exploitation engineering.
Conventional approaches employ monitoring methods including downhole microseismic methods and surface electromagnetic methods. The underground micro seismic method is based on the principle that micro seismic events can be induced by fluid injection, and utilizes the response characteristics of a returned wave field to gas storage layer cracks to carry out wave field response analysis so as to obtain the monitoring reaction result of corresponding fracturing; however, the microseismic monitoring has high cost and unstable effect due to large burial depth, thin reservoir and large vibration interference of well sites in a part of marine shale areas, and the growth process, the geometric shape and the spatial distribution of cracks of the reservoir manufactured by fracturing hydraulic fracturing cannot be effectively and intuitively described due to continuous attenuation of signals, high noise of the shaft environment, high pump pressure, high pump speed and the like when seismic waves are propagated in the stratum. For the ground electromagnetic method, although the reaction to parameters such as porosity, permeability and saturation of an oil and gas reservoir is sensitive, the method has the advantages of high efficiency, low cost, strong capability of adapting to complex earth surface and the like, the detection depth of the ground electromagnetic method is limited to a certain extent along with the increasing complexity of shale gas exploitation and occurrence of geological environment and the continuous deepening of buried depth. In addition, the conventional electromagnetic detection method also has the problems of low resolving power, large electromagnetic interference, difficult improvement of data quality and the like.
Disclosure of Invention
In view of the above, embodiments of the present invention are intended to provide a method, system, and medium for monitoring shale gas fracturing; the method can adapt to complex surface conditions and is simple to construct; the detection depth is improved, the working efficiency and the monitoring accuracy are improved, the anti-interference capability is enhanced, and the calculation complexity is reduced.
The technical scheme of the embodiment of the invention is realized as follows:
in a first aspect, an embodiment of the present invention provides a method for monitoring shale gas fracturing, where the method includes:
transmitting a multi-frequency transmission signal by using a downhole galvanic couple source;
receiving multi-frequency electromagnetic response and excitation response in a monitoring area through a ground receiving array and a downhole receiving array;
extracting potential difference and electric field response of each frequency from the multi-frequency electromagnetic response and the excitation response by a digital coherent detection method;
acquiring amplitude frequency parameters of the monitoring area based on the potential difference of each frequency; wherein the amplitude-frequency parameter is used for reflecting the change characteristic of the amplitude of the potential difference along with the frequency;
obtaining the resistivity and the polarizability of the monitoring area through inversion by a preprocessing conjugate gradient method based on the electric field response of each frequency;
and obtaining the evaluation of the shale gas fracturing effect according to the interpretation of the amplitude-frequency parameter, the resistivity and the polarizability of the monitoring area.
In a second aspect, an embodiment of the present invention provides a system for monitoring shale gas fracturing, the system including:
a downhole galvanic source configured to transmit a multi-frequency transmission signal;
the system comprises a surface receiving array and a downhole receiving array, wherein the surface receiving array and the downhole receiving array are configured to receive multi-frequency electromagnetic response and induced electrical response in a monitoring area;
a signal processor configured to:
extracting potential difference and electric field response of each frequency from the multi-frequency electromagnetic response and the excitation response by a digital coherent detection method; and the number of the first and second groups,
acquiring amplitude frequency parameters of the monitoring area based on the potential difference of each frequency; wherein the amplitude-frequency parameter is used for reflecting the change characteristic of the amplitude of the potential difference along with the frequency; and (c) a second step of,
obtaining the resistivity and the polarizability of the monitoring area through inversion by a preprocessing conjugate gradient method based on the electric field response of each frequency; and the number of the first and second groups,
and obtaining the evaluation of the shale gas fracturing effect according to the interpretation of the amplitude-frequency parameter, the resistivity and the polarizability of the monitoring area.
In a third aspect, an embodiment of the present invention provides a computer storage medium, where the computer storage medium stores a program for monitoring shale gas fracturing, and the program for monitoring shale gas fracturing when executed by at least one processor implements the steps of the method for monitoring shale gas fracturing of the first aspect.
The embodiment of the invention provides a method, a system and a medium for monitoring shale gas fracturing; based on the fact that the shale gas storage area has obvious electrical property difference including resistivity difference and polarizability difference, the shale gas fracturing monitoring method is carried out by combining an electromagnetic method and an induced polarization method, can adapt to complex surface conditions, and is relatively simple in construction; the multi-frequency signal is transmitted once, the multi-frequency response is synchronously received, the working efficiency and the observation speed are improved, equal-precision measurement is facilitated, and the total field potential difference is measured by adopting a frequency domain induced polarization method, so that various interferences are mutually counteracted to a great extent, and the signal-to-noise ratio is high and the anti-interference capability is strong; based on the electric field response of different receiving and transmitting distances, the resistivity parameter and the polarizability parameter are inverted by adopting a preprocessing conjugate gradient method, so that the storage space of a computer is saved, and the calculation efficiency is improved; and giving three-dimensional spread of different parameters of the monitoring area through amplitude frequency, resistivity and polarizability parameters. Therefore, the electric abnormity caused by the injection of the fracturing fluid can be analyzed through the comparison of the electromagnetic information and the induced voltage information before, during and after the fracturing, and the swept range and the fracture complexity of the fracturing fluid can be further judged.
Drawings
Fig. 1 is a block diagram of a system for monitoring shale gas fracturing, which can implement the technical scheme of the embodiment of the present invention.
Fig. 2 is a schematic layout diagram of a system for monitoring shale gas fracturing provided by an embodiment of the present invention.
Fig. 3 is a schematic flow chart of a method for monitoring shale gas fracturing according to an embodiment of the present invention.
Detailed Description
The technical solution in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.
Referring to fig. 1, there is shown a composition of a system 10 for monitoring shale gas fracturing, which is capable of implementing the technical solution of the embodiment of the present invention, wherein the system 10 may include: a downhole galvanic couple source 101, a surface receiving array 102, a downhole receiving array 103, and a signal processor 104; with respect to the system 10, upon deployment, as shown in fig. 2, a first powered electrode a of the downhole galvanic couple source 101 is placed within the bore of the launch well, while the other powered electrode, i.e., a second powered electrode B, is deployed at a substantial distance from the bore of the launch well, thereby acting as an "infinite" pole. For the ground receiving array 102, the number of the first electrodes M is plural, and the first electrodes M are arranged on a circle center measuring line coaxial with the electrode a, and taking fig. 2 as an example, the electrodes M may form a circular array of three concentric circles; the number of the second electrodes N can be 1, and the second electrodes N are arranged at the wellhead of the launching well. For the downhole receiving array 103, the number of the first electrodes M 'may be multiple, and the first electrodes M' are arranged in the wells of adjacent wells of the transmitting well in a linear array manner, and the second electrodes of the downhole receiving array are overlapped with the second electrodes of the ground receiving array, that is, the electrodes can be placed at the well mouth of the transmitting well; taking the example shown in fig. 2, the number of linear arrays of the downhole receiving array may be 2. Furthermore, in fig. 2, the receiver can be connected to the electrodes of the surface receiving array 102 and the downhole receiving array 103 so as to receive the receiving response captured by each electrode, and the receiver can be connected to the signal processor 104 at the back end to transmit the response signal to the signal processor 104, so as to realize the relevant signal processing operation.
In practical operation, with reference to fig. 1 and fig. 2, the downhole galvanic couple source 101 can simultaneously transmit a signal including multiple frequency components at a time, and the surface receiving array 102 and the downhole receiving array 103 receive the multi-frequency response synchronously and record the transmission signal at the same time to maintain synchronization. Since the electrodes a of the downhole galvanic couple source 101 are linearly arranged in the borehole, when a transmitting current is applied, a cylindrical wave with the borehole as an axis can be generated. Because the electric property change of the monitoring area can be caused by the change of the trend and the volume of the fracturing fluid in the fracturing process, concentric circular measuring lines coaxial with the emission source are arranged on the ground, and the method is very favorable for acquiring the excitation anomaly and electromagnetic anomaly information in different directions. The downhole receiving array 103 is closer to the monitoring area, enhancing the response signal strength while giving depth information of the response signal.
In combination with the system 10 shown in fig. 1 and fig. 2, referring to fig. 3, a method for monitoring shale gas fracturing provided by an embodiment of the present invention is shown, where the method includes:
s301: transmitting a multi-frequency transmission signal by using a downhole galvanic couple source;
s302: receiving multi-frequency electromagnetic response and excitation response in a monitoring area through a ground receiving array and a downhole receiving array;
s303: extracting potential difference and electric field response of each frequency from the multi-frequency electromagnetic response and the induced electric response by a digital coherent detection method;
s304: acquiring amplitude frequency parameters of the monitoring area based on the potential difference of each frequency; wherein the amplitude-frequency parameter is used for reflecting the change characteristic of the amplitude of the potential difference along with the frequency;
s305: obtaining the resistivity and the polarizability of the monitoring area through inversion by a preprocessing conjugate gradient method based on the electric field response of each frequency;
s306: and obtaining the evaluation of the shale gas fracturing effect according to the interpretation of the amplitude frequency parameter, the resistivity and the polarizability of the monitoring area.
For the technical scheme shown in fig. 3, based on the fact that the shale gas storage area has obvious electrical property differences including resistivity differences and polarizability differences, the shale gas fracturing monitoring is carried out by combining an electromagnetic method and an induced polarization method, so that the shale gas fracturing monitoring device can adapt to complex surface conditions, and is relatively simple in construction; the multi-frequency signal is transmitted once, the multi-frequency response is synchronously received, the working efficiency and the observation speed are improved, equal-precision measurement is facilitated, and the total field potential difference is measured by adopting a frequency domain induced polarization method, so that various interferences are mutually counteracted to a great extent, and the signal-to-noise ratio is high and the anti-interference capability is strong; based on the electric field responses of different receiving and transmitting distances, the resistivity parameter and the polarizability parameter are inverted by adopting a preprocessing conjugate gradient method, so that the storage space of a computer is saved, and the calculation efficiency is improved; and giving three-dimensional spread of different parameters of the monitoring area through amplitude frequency, resistivity and polarizability parameters. Therefore, the electric abnormity caused by the injection of the fracturing fluid can be analyzed through the comparison of the electromagnetic information and the induced voltage information before, during and after the fracturing, and the swept range and the fracture complexity of the fracturing fluid can be further judged.
For the technical solution shown in fig. 3, in some possible implementations, the first power supply electrode of the downhole galvanic couple source is disposed in a borehole of the launching well, and the second power supply electrode is disposed on the ground and has a distance from a wellhead of the launching well greater than a set distance threshold; accordingly, the transmitting a multi-frequency transmission signal using a downhole galvanic source comprises:
simultaneously transmitting a transmit signal comprising a multi-frequency component signal through a first powered electrode downhole; wherein, the difference between the amplitudes of the frequency component signals is within a set amplitude threshold value.
For the above implementation manner, it should be noted that, by simultaneously transmitting a plurality of frequency component signals at a time, the working efficiency can be greatly improved, and the amplitudes of the frequency component signals are substantially kept consistent, so that the amplitudes of the response signals are equivalent to each other. In the specific implementation process, the main frequency range of the frequency domain induced polarization method is
Then, in some examples, the transmit signal may then employ 2 comprising 7 frequency components n Sequence pseudo-random signal, each frequency component corresponding to frequency according to 2 n In this way, the signals can be distributed uniformly on a logarithmic scale, and the ratio of the frequencies of the adjacent frequency component signals is 2. In detail, the frequency components of the transmission signal are 1/64Hz, 1/32Hz, 1/16Hz, 1/8Hz, 1/4Hz, 1/2Hz, and 1Hz, respectively, as shown in table 1.
TABLE 1
For the above-mentioned multi-frequency transmission signals, in some examples, the receiving, by the surface receiving array and the downhole receiving array, the multi-frequency electromagnetic response and the excitation response in the monitoring area includes: and carrying out multi-frequency synchronous observation by utilizing the ground receiving array and the underground receiving array to obtain multi-frequency electromagnetic response and multi-frequency induced polarization response in the monitoring area. After the multi-frequency electromagnetic response and the multi-frequency induced polarization response are obtained, the electromagnetic response and the frequency components in the induced polarization response can be obtained by extracting and separating from the responses by adopting a digital correlation detection method.
For the technical solution shown in fig. 3, in some possible implementations, the acquiring the amplitude-frequency parameter of the monitored area based on the potential difference of each frequency includes:
based on the difference of the excitation characteristics of different measuring point positions, calculating and acquiring an amplitude-frequency parameter for reflecting the change characteristics of potential difference amplitude of each measuring point position along with frequency according to formula 1:
wherein the content of the first and second substances,
the response amplitude of the potential difference for the high frequency components,
the magnitude of the response of the potential difference for low frequency components.
For the above implementation, it should be noted that, after obtaining the electromagnetic response and each frequency component in the induced voltage response, in order to analyze the induced voltage characteristic difference of different measuring point positions, the embodiment of the present invention introduces the concept of amplitude frequency parameter, which can reflect the variation characteristic of the potential difference amplitude of each measuring point position along with the frequency, and is defined as that
(ii) a Wherein the content of the first and second substances,
is the amplitude of the emission current of the high frequency component,
the amplitude of the emission current is a low frequency component. However, since the emission current amplitudes of the frequency components in the multi-frequency emission signal are substantially consistent, the current amplitudes responded by the measuring point positions can also be substantially consistent, and therefore, the above definition can be further expressed as shown in formula 1. It can be seen that, because the difference of the potential difference responses of different frequencies is adopted when the amplitude frequency parameters are calculated, the method has strong suppression capability on industrial interference, random interference and the like, and improves the measurement accuracy.
In addition, for the technical solution shown in fig. 3, it should be noted that the inversion of shale gas fracture monitoring can be regarded as a process of solving the resistivity and polarizability parameters of the monitoring area by using the observation data and the forward differential operator, and then, the inversion problem of shale gas fracture monitoring can be defined as
(ii) a Wherein the content of the first and second substances,min order to be the parameters of the model,din the form of a set of data,Ais a forward operator. In the usual case, the inverse operatorA -1 Is discontinuous. The embodiment of the invention adopts a regularization method and utilizes a family of proper problems, namely
To approximate the original ill-posed problem; wherein the content of the first and second substances,
referred to as a regularization factor. That is, embodiments of the present invention employ a series of successive inverse operators that depend on a regularization factor
To approximate the original discontinuous inverse operatorA -1 . According to the Gihonov Tikhonov regularization principle, determining an objective function of an inverse problem as follows:
wherein, in the process,
，
，
for given model parametersmThen, data obtained by forward calculation;
for actual measurement data, in the present embodiment, the electric field responses at different frequencies obtained by the downhole receiving array and the surface receiving array are used.
，
Is an error of the ith data,
for a reference model given according to a priori knowledge,Wthe model data is weighted.
The minimum value is calculated for the above-mentioned objective function, so that
The following linear equation can be obtained:
wherein, Jacobian matrixJIs a forward calculation knotThe response to the model data is expressed as:
then, the above linear equation can be further expressed as
(ii) a Wherein, the first and the second end of the pipe are connected with each other,
，
. To pair
Solving is carried out, and the model correction quantity can be obtained
. In embodiments of the present invention, the Jacobian matrix is not explicitly stored and calculated, but rather the solution of the equations is accomplished by taking the product of the Jacobian matrix and the vector.
As described in conjunction with the above description, in some possible implementations, the obtaining the resistivity of the monitored area through a preprocessed conjugate gradient method inversion based on the electric field response of each frequency includes:
setting initial model parameters of resistivity forward modelm 0 Reference model parameters obtained from a priori knowledgem apr Taking logarithm of the model parameter and the data parameter; namely, it is
；
Is the apparent resistivity of the medium and,
as the conductivity of the medium
Reading in regularization factorsλMaximum iteration times and an iteration stop criterion;
performing an iterative process, in the second placekAnd in the second iteration:
solving equation 2 by a pretreatment conjugate gradient method to obtain the secondkThe model correction of the secondary iteration;
wherein the content of the first and second substances,
，
jacobian matrixJRepresenting the response of the forward calculation result to the model data, in the embodiment of the invention, g can be calculated to the preset precision by adopting a Jacobian matrix vector product method;
，
is as followsiError of each data;
actual measurement data;Wweighting the model data;dfor given model parametersmThen, data obtained by forward calculation; parameter(s)mIs a forward modelkModel parameters for a sub-iterationm k ；
Calculating the search step according to equation 3
And when formula 3 is not satisfied, according to
，
Step length updating:
wherein the operator
Operator of
Operator of
，
Is a constant;
based on
Updating the model parameters;
determining whether a maximum number of iterations and an iteration stop criterion are met: if not, returning to the step of solving the formula 2 by adopting a pretreatment conjugate gradient method to obtain the second stepkModel correction for sub-iteration
(ii) a If yes, judging
Whether it is true, if not, reducing the regularization factorλReading in again and executing an iterative process; if yes, solving to obtain model parameters to output a resistivity result; wherein the content of the first and second substances,Ais a positive operator, namely a positive operator,δindicating a set minimum number.
It is to be understood that the above implementation is a specific implementation of the solution to the inverse problem regarding shale gas fracture monitoring described above. On the basis of the implementation process for resistivity parameter inversion, similar methods can be continuously adopted for the inversion of the polarizability parameters. In some examples, the obtaining the polarizability of the monitored region by preprocessing conjugate gradient inversion based on the electric field response of each frequency includes:
setting initial model parameters of forward model of polarizability
Reference model parameters obtained from a priori knowledge
Taking logarithm of the model parameter and the data parameter;
reading in regularization factorsλSolving equation 4 by adopting a pretreatment conjugate gradient method to obtain model parameters
；
Wherein, the Jacobian matrixJRepresenting the response of the forward calculation result to the model data;
，
is as followsiError of each data;
the parameters of the data are represented by,Wweighting the model data;
and inverting the polarizability parameters of the monitoring area according to the model parameters obtained by solving.
For the above example, it should be noted that the data parameters and the model parameters are respectively taken
And
wherein, in the step (A),
which represents the apparent polarization rate of the medium,
represents the polarizability of the medium; for the polarizability parameter, an objective function is established as
If the minimum value is calculated for the objective function, the minimum value can be converted into a linear equation shown in a solution formula 4; regularization factor determined for the solution process for resistivity by the foregoing implementationλAnd solving the formula 4 by adopting a preprocessing conjugate gradient method, so that the polarizability parameters of the monitoring area can be inverted.
It can be understood that the foregoing implementation and example adopt a preprocessing conjugate gradient method to invert the resistivity parameter and the polarizability parameter, and store and calculate the Jacobian matrix without displaying, but solve the equation by directly solving the product of the Jacobian matrix and the vector; the computer storage space can be saved, and the computing efficiency is improved.
For the above technical solution, in some possible implementation manners, the obtaining of the evaluation of the shale gas fracturing effect according to the interpretation of the amplitude-frequency parameter, the resistivity and the polarization rate of the monitored area includes:
the amplitude frequency parameters, the resistivity and the polarization rate interpretations before and during the implementation of the fracturing measures and after the implementation of the fracturing measures are compared to obtain the change of the electromagnetic field and the potential difference caused by the injection of the fracturing fluid;
and judging the complexity of the fracture of the wave coverage map of the fracturing fluid according to the changes of the electromagnetic field and the potential difference.
Specifically, according to the calculation result, by observing the XY section abnormity of different parameters of the monitoring area, the azimuth information and the fluid trend of the fracture fluid wave can be accurately judged. And according to the XZ slice abnormity and the YZ slice abnormity of different parameters, the depth information can be favorably identified. By utilizing the three-dimensional distribution of different parameters, the sweep range and the volume change of the fracturing fluid and the complexity of the fracture can be monitored.
It should be noted that the above evaluation has the advantages of convenience, rapidness, low cost and the like for the shale gas storage area, especially for the complicated underground surface conditions and limestone development in the district of Qian Xiang Huo of China.
Through the technical scheme and the implementation mode and the example thereof, the three-dimensional receiving array is constructed by utilizing the ground receiving array and the underground receiving array, and the excited electric response and the electromagnetic response of different receiving and transmitting distances are received at each measuring point at the same time. By calculating and extracting amplitude frequency, resistivity and polarizability parameters of the monitoring region and giving out three-dimensional layout patterns of different parameters of the monitoring region, the shale gas fracturing dynamic monitoring is completed, and theoretical bases can be provided for well arrangement of subsequent production wells, adjustment of fracturing schemes and the like.
Based on the same inventive concept as the previous solution, for the system 10 shown in fig. 1, in some examples, the downhole galvanic couple source 101 is configured to transmit a multi-frequency transmission signal;
a surface receiving array 102 and a downhole receiving array 103 configured to receive multi-frequency electromagnetic responses and induced electrical responses within a monitored area;
a signal processor 104 configured to:
extracting potential difference and electric field response of each frequency from the multi-frequency electromagnetic response and the excitation response by a digital coherent detection method; and the number of the first and second groups,
acquiring amplitude frequency parameters of the monitoring area based on the potential difference of each frequency; wherein the amplitude-frequency parameter is used for reflecting the change characteristic of the amplitude of the potential difference along with the frequency; and the number of the first and second groups,
obtaining the resistivity and the polarizability of the monitoring area through inversion by a preprocessing conjugate gradient method based on the electric field response of each frequency; and the number of the first and second groups,
and obtaining the evaluation of the shale gas fracturing effect according to the interpretation of the amplitude-frequency parameter, the resistivity and the polarizability of the monitoring area.
It should be noted that, for specific implementation or implementation contents of configuration functions of each component, reference may be made to corresponding steps, implementation manners, and examples in the foregoing technical solutions, and details of embodiments of the present invention are not described herein.
It can be understood that, in this embodiment, the foregoing technical solutions may be implemented in the form of hardware, or in the form of software functional modules. If the software module is implemented as a software functional module and is not sold or used as a standalone product, the software module may be stored in a computer readable storage medium, and based on the understanding, a part of the technical solution of the present embodiment or all or part of the technical solution may be embodied in a software product stored in a storage medium, and include several instructions to enable a computer device (which may be a personal computer, a server, or a network device) or a processor to execute all or part of the steps of the method of the present embodiment. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk, or an optical disk.
Accordingly, the present embodiment provides a computer storage medium, which stores a program for monitoring shale gas fracturing, and when the program is executed by at least one processor, the method for monitoring shale gas fracturing in the above technical solution is implemented.
It should be noted that: the technical schemes described in the embodiments of the present invention can be combined arbitrarily without conflict.
The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention, and all the changes or substitutions should be covered within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the appended claims.
Claims (9)
1. A method of monitoring shale gas fracturing, the method comprising:
transmitting a multi-frequency transmission signal by using a downhole galvanic couple source; the first power supply electrode of the downhole galvanic couple source is arranged in a well hole of the launching well, the second power supply electrode is arranged on the ground, and the distance between the second power supply electrode and the well mouth of the launching well is greater than a set distance threshold value; each frequency component signal of the multi-frequency transmitting signal is 2 n Pseudo-random signal is sequenced, and the frequency corresponding to each frequency component is according to 2 n Carrying out progressive operation;
receiving multi-frequency electromagnetic response and induced electrical response in a monitoring area through a ground receiving array and a downhole receiving array; wherein a first electrode of the downhole receiving array is positioned within an adjacent well bore of the transmitting well and a second electrode of the downhole receiving array is positioned at a well mouth of the transmitting well; the first electrode of the ground receiving array is arranged on a circular measuring line coaxial with the first power supply electrode of the underground galvanic couple source, and the second electrode of the ground receiving array is arranged at the wellhead of the transmitting well;
extracting potential difference and electric field response of each frequency from the multi-frequency electromagnetic response and the excitation response by a digital coherent detection method;
acquiring amplitude frequency parameters of the monitoring area based on the potential difference of each frequency; wherein the amplitude-frequency parameter is used for reflecting the change characteristic of the amplitude of the potential difference along with the frequency;
obtaining the resistivity and the polarizability of the monitoring area through inversion by a preprocessing conjugate gradient method based on the electric field response of each frequency;
and obtaining the evaluation of the shale gas fracturing effect according to the interpretation of the amplitude-frequency parameter, the resistivity and the polarizability of the monitoring area.
2. The method of claim 1, wherein said transmitting a multi-frequency transmission signal using a downhole galvanic source comprises:
simultaneously transmitting a transmit signal comprising a multi-frequency component signal through a first powered electrode downhole; wherein, the difference between the amplitudes of the frequency component signals is within a set amplitude threshold value.
3. The method of claim 1, wherein receiving the multi-frequency electromagnetic and excitatory responses within the monitored area via a surface receive array and a downhole receive array comprises:
and carrying out multi-frequency synchronous observation by utilizing the ground receiving array and the underground receiving array to obtain multi-frequency electromagnetic response and multi-frequency induced polarization response in the monitoring area.
4. The method of claim 1, wherein the obtaining amplitude frequency parameters for the monitored region based on the potential difference at each frequency comprises:
based on the difference of the excitation characteristics of different measuring point positions, calculating and acquiring an amplitude-frequency parameter for reflecting the change characteristics of potential difference amplitude of each measuring point position along with frequency according to formula 1:
wherein the content of the first and second substances,
the magnitude of the response of the potential difference for high frequency components,
the magnitude of the response of the potential difference for low frequency components.
5. The method of claim 1, wherein obtaining the resistivity of the monitored region by pre-processing conjugate gradient inversion based on the electric field response at each frequency comprises:
setting initial model parameters of resistivity forward modelm 0 Reference model parameters obtained from a priori knowledgem apr Taking logarithm of the model parameter and the data parameter;
reading in regularization factorsλMaximum iteration times and an iteration stop criterion;
performing an iterative process, in the second placekAnd in the second iteration:
solving equation 2 by a pretreatment conjugate gradient method to obtain the secondkModel correction for sub-iteration
；
Wherein, the first and the second end of the pipe are connected with each other,
，
jacobian matrixJRepresenting the response of the forward calculation result to the model data;
，
is a firstiError of each data;
actual measurement data;Wweighting the model data;dfor given model parametersmThen, data obtained by forward calculation; parameter(s)mIs a forward modelkModel parameters of sub-iterationsm k ；
Calculating the search step according to equation 3
And when formula 3 is not satisfied, according to
，
Step length updating:
wherein the operators
Operator of
Operator of
，cIs a constant;
based on
Updating the model parameters;
determining whether a maximum number of iterations and an iteration stop criterion are met: if not, returning to the step of solving the formula 2 by adopting a pretreatment conjugate gradient method to obtain the second stepkModel correction for sub-iteration
(ii) a If yes, judging
If it is not true, the regularization factor is reducedSeed of Japanese apricotλReading in again and executing an iterative process; if yes, solving to obtain model parameters to output a resistivity result; wherein, the first and the second end of the pipe are connected with each other,Ais a positive operator, and is a positive operator,δindicating a set minimum number.
6. The method of claim 1, wherein obtaining the polarizability of the monitored region by preprocessing conjugate gradient inversion based on the electric field response at each frequency comprises:
setting initial model parameters of forward model of polarizability
Reference model parameters obtained from a priori knowledge
Taking logarithm of the model parameter and the data parameter;
reading in regularization factorsλSolving equation 4 by adopting a pretreatment conjugate gradient method to obtain model parameters
；
Wherein the Jacobian matrixJRepresenting the response of the forward calculation result to the model data;
，
is as followsiError of each data;
the parameters of the data are represented by,Wweighting the model data;
model parameters obtained from the solution
And inverting the polarizability parameters of the monitoring area.
7. A system for monitoring shale gas fracturing, the system comprising:
a downhole galvanic source configured to transmit a multi-frequency transmission signal; the first power supply electrode of the downhole galvanic couple source is arranged in a well hole of the launching well, the second power supply electrode is arranged on the ground, and the distance between the second power supply electrode and the well mouth of the launching well is greater than a set distance threshold value; each frequency component signal of the multi-frequency transmitting signal is 2 n Pseudo-random signal is sequenced, and the frequency corresponding to each frequency component is according to 2 n Carrying out progressive operation;
the system comprises a surface receiving array and a downhole receiving array, wherein the surface receiving array and the downhole receiving array are configured to receive multi-frequency electromagnetic response and induced electrical response in a monitoring area; wherein a first electrode of the downhole receiving array is positioned within an adjacent well bore of the transmitting well and a second electrode of the downhole receiving array is positioned at a well mouth of the transmitting well; the first electrode of the ground receiving array is arranged on a circular measuring line coaxial with the first power supply electrode of the underground galvanic couple source, and the second electrode of the ground receiving array is arranged at the wellhead of the transmitting well;
a signal processor configured to:
extracting potential difference and electric field response of each frequency from the multi-frequency electromagnetic response and the excitation response by a digital coherent detection method; and the number of the first and second groups,
acquiring amplitude frequency parameters of the monitoring area based on the potential difference of each frequency; wherein the amplitude-frequency parameter is used for reflecting the change characteristics of the potential difference amplitude along with the frequency; and the number of the first and second groups,
obtaining the resistivity and the polarizability of the monitoring area through inversion by a preprocessing conjugate gradient method based on the electric field response of each frequency; and the number of the first and second groups,
and obtaining the evaluation of the shale gas fracturing effect according to the interpretation of the amplitude-frequency parameter, the resistivity and the polarizability of the monitoring area.
8. The system of claim 7, wherein the downhole galvanic couple source is configured to simultaneously transmit a transmission signal comprising multiple frequency component signals through a first powered electrode downhole; wherein, the difference between the amplitudes of the frequency component signals is within a set amplitude threshold value.
9. A computer storage medium storing a program for monitoring shale gas fracturing, the program when executed by at least one processor implementing the steps of the method of any of claims 1 to 6.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210706620.1A CN114791633B (en) | 2022-06-21 | 2022-06-21 | Method, system and medium for monitoring shale gas fracturing |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210706620.1A CN114791633B (en) | 2022-06-21 | 2022-06-21 | Method, system and medium for monitoring shale gas fracturing |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN114791633A CN114791633A (en) | 2022-07-26 |
| CN114791633B true CN114791633B (en) | 2022-09-30 |
Family
ID=82463411
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210706620.1A Active CN114791633B (en) | 2022-06-21 | 2022-06-21 | Method, system and medium for monitoring shale gas fracturing |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114791633B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116448823A (en) * | 2023-06-15 | 2023-07-18 | 中南大学 | Device and method for measuring resistivity of rock in hydraulic fracturing process under high-temperature and high-pressure conditions |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AU2020102911A4 (en) * | 2020-10-21 | 2020-12-17 | Institute Of Geology And Geophysics, Chinese Academy Of Sciences | Ground-borehole electrical source short offset transient electromagnetic detection method |
| CN113031079A (en) * | 2021-04-21 | 2021-06-25 | 中南大学 | New power exciting method based on frequency division power method |
| CN114428359A (en) * | 2020-10-12 | 2022-05-03 | 中国石油化工股份有限公司 | Frequency domain induced polarization forward modeling method, device, electronic equipment and medium |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| RU2399931C2 (en) * | 2008-10-23 | 2010-09-20 | Общество с ограниченной ответственностью "Сибирская геофизическая научно-производственная компания" | Method for quantitative dividing effects of electromagnetic induction and induced polarisation |
| CA2834518A1 (en) * | 2012-11-28 | 2014-05-28 | Eldad Haber | Method and system for surveying a distribution of chargeability in a volume of earth |
| CN113982561B (en) * | 2021-11-17 | 2023-07-07 | 中油奥博(成都)科技有限公司 | Natural gas hydrate exploitation monitoring system and method based on time-frequency electromagnetic of ground well |
-
2022
- 2022-06-21 CN CN202210706620.1A patent/CN114791633B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114428359A (en) * | 2020-10-12 | 2022-05-03 | 中国石油化工股份有限公司 | Frequency domain induced polarization forward modeling method, device, electronic equipment and medium |
| AU2020102911A4 (en) * | 2020-10-21 | 2020-12-17 | Institute Of Geology And Geophysics, Chinese Academy Of Sciences | Ground-borehole electrical source short offset transient electromagnetic detection method |
| CN113031079A (en) * | 2021-04-21 | 2021-06-25 | 中南大学 | New power exciting method based on frequency division power method |
Non-Patent Citations (5)
| Title |
|---|
| Analysis of Pseudo-Random Sequence Correlation Identification Parameters and Anti-Noise Performance;Xijin Song等;《Energies》;20181231;第1-18页 * |
| 三维井-地多参数电法数值模拟及对比研究;幸娟;《中国优秀博硕士学位论文全文数据库（硕士）》;20100915;第3-7，28-51页 * |
| 井-地伪随机电磁探测响应分析;肖钧仁等;《工业控制计算机》;20220331;第62-63页 * |
| 坑（井）-地多参数电磁接收系统;陈凯等;《地球物理学报》;20191031;第3804、3811页 * |
| 基于改进Krylov子空间算法的井中激电反演;李长伟等;《地球物理学报》;20121115(第11期);第3804、3811页 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN114791633A (en) | 2022-07-26 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Anderson et al. | An integrated approach to marine electromagnetic surveying using a towed streamer and source | |
| Luo et al. | Joint inversion of high-frequency surface waves with fundamental and higher modes | |
| US9678236B2 (en) | Fracture characterization by interferometric drillbit imaging, time reversal imaging of fractures using drill bit seismics, and monitoring of fracture generation via time reversed acoustics and electroseismics | |
| CN110187394B (en) | Method and device for acquiring formation resistivity anisotropy by double-field source electromagnetic sounding method | |
| CN102590874B (en) | Method for detecting ground surface crack of upland coal-mining subsidence paddy field | |
| CN113176609B (en) | Underground shallow target positioning method based on earth sound field | |
| US20090108845A1 (en) | System for seismic detection and analysis | |
| Zhou et al. | Migration velocity analysis and prestack migration of common-transmitter GPR data | |
| CN114791633B (en) | Method, system and medium for monitoring shale gas fracturing | |
| CN111290027B (en) | Deep resource electromagnetic detection method combining mobile source and fixed source | |
| WO2021207006A1 (en) | Sparse excitation for 3-dimensional underground cable localization using fiber optic sensing | |
| CN109655918A (en) | Ground shallow well micro-seismic monitoring measuring platform station location determines method and system | |
| CN110579799B (en) | Seismic acquisition observation method and system with equal travel time intervals | |
| RU2685577C1 (en) | Method of hydrocarbons search | |
| Ulugergerli et al. | Detection of cavities in gypsum | |
| JP2862171B2 (en) | Nondestructive method for measuring physical properties of formation using acoustic waves | |
| US11740374B2 (en) | System and method for randomness measurement in sesimic image data using vectorized disorder algorithm | |
| CN110579798B (en) | Seismic acquisition observation method and system with equal reflection angle intervals | |
| US9551803B2 (en) | Geological medium exploration | |
| RU2736810C1 (en) | Formation well evaluation system and method | |
| Liu et al. | An inverted heterogeneous velocity model for microseismic source location in deep buried tunnels | |
| Ezersky et al. | Integrated study of the sinkhole development site on the Western shores of the Dead Sea using geophysical methods | |
| GB2536576A (en) | Buried object detection system | |
| CN112162323A (en) | Underground unfavorable geological survey method and system based on artificial field source frequency domain electrical method | |
| CN111691876A (en) | Method and device for imaging adjacent well by using acoustic logging and storage medium |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |