Hydraulic fracturing crack real-time prediction method and system based on charging conductor

Abstract

The invention provides a hydraulic fracturing crack real-time prediction method and system based on a charging conductor, and the method comprises the steps: taking the continuous stability of a field source and a monitoring point before and after fracturing as a target, laying a charging conductor electromagnetic monitoring device, and collecting a fracturing electromagnetic observation signal; potential abnormity is determined through time difference based on the observation signals, and corresponding single-slit crack parameters are calculated through inversion by means of a charging conductor single-slit operation model; setting constraint conditions by considering priori information factors, and obtaining a crack prediction model containing multi-moment single-crack parameters; and on the basis, envelope identification is carried out on a multi-seam boundary to delineate a fracturing fluid wave and range. By adopting the method, the defect of insufficient authenticity of fracturing parameter prediction in the prior art can be overcome, the fracture prediction model is constructed to obtain the fracturing fracture parameters in real time, and technical support is provided for electromagnetic monitoring and hydraulic fracturing effect evaluation.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of hydraulic fracturing electromagnetic monitoring, and particularly relates to a hydraulic fracturing fracture real-time prediction method and system based on a charged conductor. BACKGROUND

[0002] Unconventional oil and gas increases the recovery ratio by increasing the length of horizontal wells and continuous fracturing of multiple segments and multiple stages. Dry hot rock type geothermal resource development forms a connected fracture network system through hydraulic fracturing to realize dry hot rock heat utilization. Hydraulic fracturing is one of the key technologies for oil and gas production and energy conversion, and real-time monitoring is a key means to ensure that fracturing construction achieves an ideal effect.

[0003] The hydraulic fracturing electromagnetic monitoring technology based on a charged conductor has the characteristics of small power consumption, strong signal, high signal-to-noise ratio, simple operation, safety, etc., and can obtain reservoir reconstruction fracture expansion and delineate fracturing fluid swept range. However, to monitor the fracture growth in real time, the existing technology needs to solve the following key problems: 1) potential anomaly calculation; 2) fracture parameter inversion; 3) construction of a real-time fracture prediction model. For example, the patent document CN202210846583.4 provides a method for calculating electromagnetic anomalies of a charged conductor fracture, establishes a fracture model by monitoring well position, burial depth, fracture size, power supply current and frequency setting; the formation equivalent resistivity is calculated by converting the multi-layer profile parameters; the charged conductor is divided into Nd electric dipoles, and the vector potential and scalar potential of each electric dipole at the ground surface are obtained; the E and H values of the electric dipole at the ground surface are obtained according to the electric field and magnetic field calculation formula, the reference point N is determined, and the MN direction electric field and magnetic field are obtained; based on the vector superposition principle, the electromagnetic fields of all the divided electric dipoles are superimposed, the electromagnetic fields before and after fracturing are obtained, and the electric field anomaly and magnetic field anomaly caused by the fracturing fracture are obtained by difference calculation. It is only used to obtain the electromagnetic anomalies caused by the fracturing fracture, and cannot provide technical support for the evaluation of the hydraulic fracturing effect.

[0004] The patent scheme CN112302636A provides a hydraulic fracturing monitoring method and device, which synchronously collects electromagnetic signals by exciting a horizontal long wire source and using a 2-component electromagnetic acquisition station; time domain and frequency domain data parameter calculations are performed on the electromagnetic signals of each measuring point to obtain three-dimensional resistivity distribution data around the horizontal well; and the fracture parameters formed by hydraulic fracturing underground are determined according to the relative anomalies before and after fracturing. The existing scheme uses a traditional electromagnetic induction method, the transmission source is a ground long wire source, the electric field and magnetic field signals need to be measured, the noise interference is large, and the signal is small; in addition, the resistivity distribution data need to be obtained by inversion through the electric field, magnetic field signals and frequency data to reflect the underground fracture parameter operation, which is complex and has insufficient reliability.

[0005] Therefore, there is an urgent need to design a real-time fracture prediction method to overcome or at least partially solve the above problems, so as to obtain fracturing fracture parameters in real time, delineate the fracturing fluid sweep range, and guide the adjustment of fracturing operations.

[0006] The information disclosed in the background section of this invention is intended only to enhance the understanding of the general background of this invention, and should not be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art. Summary of the Invention

[0007] To address the aforementioned problems, this invention provides a real-time prediction method for hydraulic fracturing fractures based on a charged conductor. This method overcomes the shortcomings of existing technologies in predicting fracturing parameters due to insufficient accuracy. It constructs a fracture prediction model to acquire fracturing fracture parameters in real time, providing technical support for electromagnetic monitoring and evaluation of hydraulic fracturing effects. The method deploys a charged conductor electromagnetic monitoring device with the goal of maintaining the stability of the field source and monitoring points before and after fracturing, collecting fracturing electromagnetic observation signals. Based on the observation signals, potential anomalies are determined through time difference analysis, and the corresponding single-fracture parameters are calculated using a charged conductor single-fracture computational model. Furthermore, constraints are set considering prior information factors to obtain a fracture prediction model containing single-fracture parameters at multiple time points. Based on this, the fracturing fluid sweep range is delineated and marked by envelope identification of the multi-fracture boundaries. Preferably, in one embodiment, the method includes:

[0008] Step S100: Deploy a charging conductor electromagnetic monitoring device with the goal of ensuring that the stability of the field source and monitoring point before and after fracturing meets the set conditions, and collect electromagnetic observation signals during the fracturing operation.

[0009] Step S200: Determine the potential anomaly based on the electromagnetic observation signal through time difference, and calculate the corresponding single-slit crack parameters based on the potential anomaly using the set charging conductor single-slit operation model.

[0010] Step S300: Set constraints based on perforation and fracturing section factors to obtain a fracture prediction model containing single fracture parameters at multiple time points, characterizing the distribution characteristics of fracturing fractures;

[0011] Step S400: Based on the distribution characteristics of the fracturing fractures, the fracturing fluid sweep range is delineated by enveloping the boundaries of the multiple fractures.

[0012] In one embodiment, in step S100, the deployed electromagnetic monitoring device for the charging conductor includes a first power supply electrode and a second power supply electrode for transmitting current, and a first receiving electrode and a second receiving electrode for receiving current observation signals.

[0013] Furthermore, in one embodiment, the first power supply electrode is connected to the wellhead of the fracturing well, the second power supply electrode is located away from the wellhead, the first receiving electrode is placed at the monitoring point, and the second receiving electrode is placed at the wellhead as a reference point.

[0014] Optionally, in one embodiment, the electromagnetic observation signal includes the real-time transmission current and the observation potential difference between the first receiving electrode and the second receiving electrode.

[0015] In a preferred embodiment, the potential anomaly in step S200 is calculated using the time-difference algorithm of the following formula:

[0016]

[0017] in,

[0018]

[0019] We can obtain,

[0020]

[0021] In the formula, T represents the current time T, T-1 represents the previous time, and I T For the current being transmitted, U represents the potential difference at time T. T It normalizes the current in the potential difference at the current moment. This indicates that the potential is abnormal at the current moment.

[0022] In one embodiment, a single-slit charging conductor model as described below is used:

[0023]

[0024] In the formula, Let be the wavenumber in the frequency domain, where ω = 2πf is the angular frequency, f is the electromagnetic wave frequency, and μ and σ are the magnetic permeability and electrical conductivity of the medium, respectively. It is an electric dipole moment. I is the current intensity, and dl is the length of the electric dipole; for and The included angle, Represents the radius vector, r j Let be the distance between the j-th electric dipole source and the observation point M.

[0025] Furthermore, in one embodiment, in step S200, the least squares method or an improved marine predator optimization algorithm is used in combination with the set fracturing prior information to achieve the inversion calculation; the fracturing prior information includes perforation and fracturing segment information to constrain the optimization range during the inversion calculation of the fracture endpoint coordinates; the single fracture parameters of the inversion calculation include fracture depth, fracture length and fracture orientation, and the fracture length and fracture orientation are determined according to the fracture endpoint coordinates.

[0026] Preferably, in one embodiment, step S300, the process of obtaining a crack prediction model containing single-crack parameters at multiple time points, includes the following operations:

[0027] According to the set time period, the operation is repeatedly executed to obtain multi-fracturing parameters containing single-fracturing parameters at multiple times until the fracturing operation is completed.

[0028] The multi-fracture parameters are combined with a geological model for visualization, forming a fracture prediction model with characteristics of hydraulic fracturing fracture distribution.

[0029] Based on other aspects of the methods described in any one or more of the foregoing embodiments, the present invention also provides a storage medium storing program code that can implement the methods described in any one or more of the foregoing embodiments.

[0030] Based on the application aspects of the methods described in any one or more of the above embodiments, the present invention also provides a real-time prediction system for hydraulic fracturing fractures based on a charging conductor, which performs the methods described in any one or more of the above embodiments.

[0031] Compared with the closest prior art, the present invention also has the following beneficial effects:

[0032] This invention provides a real-time prediction method and system for hydraulic fracturing fractures based on a charged conductor. The method deploys a charged conductor electromagnetic monitoring device with the goal of maintaining the stability of the field source and monitoring points before and after fracturing to collect fracturing electromagnetic observation signals. Based on the charged conductor electromagnetic monitoring, the changes in electromagnetic signals caused by fracturing are effectively obtained. The charged conductor electromagnetic monitoring device is specially deployed to ensure the stability of the field source and monitoring points before and after hydraulic fracturing, and to ensure the authenticity of the observation signals collected and transmitted in real time during the fracturing process.

[0033] Based on the observed signals, potential anomalies are determined by time difference, and the corresponding single-slit crack parameters are calculated by inversion using a charging conductor single-slit operation model. The obtained potential anomalies are calculated based on time difference, providing feasibility for real-time and convenient calculation of crack parameters.

[0034] Furthermore, considering prior information factors, constraints are set to obtain a fracture prediction model containing single fracture parameters at multiple time points. The constructed real-time fracture prediction model uses reservoir fracturing prior information as the constraint for fracture parameter inversion, which is more consistent with actual fracturing. Based on this, the fracturing fluid sweep range is delineated and marked by envelope identification of multi-fracture boundaries, making it easier for users to intuitively view the effective fracture information related to the model, thus improving its practicality.

[0035] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the description, claims, and drawings. Attached Figure Description

[0036] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with the embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0037] Figure 1 This is a flowchart illustrating a real-time prediction method for hydraulic fracturing fractures based on a charging conductor provided in an embodiment of the present invention.

[0038] Figure 2 This is a schematic diagram of electromagnetic monitoring for hydraulic fracturing in vertical wells, based on the real-time prediction method for hydraulic fracturing fractures using a charging conductor, as provided in this embodiment of the invention.

[0039] Figure 3 This is a schematic diagram of electromagnetic monitoring for horizontal well hydraulic fracturing based on a real-time prediction method for hydraulic fracturing fractures using a charging conductor, provided in another embodiment of the present invention.

[0040] Figure 4 This is a schematic diagram of different orientation crack models of the real-time prediction method for hydraulic fracturing cracks based on charging conductors provided in the embodiments of the present invention;

[0041] Figure 5 This is a schematic diagram illustrating the inversion error of fracture parameters in different orientations in the real-time prediction method for hydraulic fracturing fractures based on charging conductors provided in this embodiment of the invention.

[0042] Figure 6 This is a schematic diagram of the crack prediction model construction algorithm implementation process of the real-time prediction method for hydraulic fracturing cracks based on charging conductors provided in the embodiments of the present invention;

[0043] Figure 7 This is a schematic diagram of the vertical well fracturing fracture prediction model and fracturing fluid sweep range effect of the real-time prediction method for hydraulic fracturing fractures based on charging conductors provided in an embodiment of the present invention.

[0044] Figure 8This is a schematic diagram of the horizontal well fracturing fracture prediction model and fracturing fluid sweep range effect of the real-time prediction method for hydraulic fracturing fractures based on charging conductors provided in the embodiments of the present invention.

[0045] Figure 9 This is a schematic diagram of the structure of a real-time prediction system for hydraulic fracturing fractures based on a charging conductor provided in another embodiment of the present invention. Detailed Implementation

[0046] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings and examples. Those skilled in the art will then fully understand how the present invention uses technical means to solve technical problems and achieve technical effects, and will be able to implement the present invention specifically based on the above-described implementation process. It should be noted that, as long as there is no conflict, the various embodiments and features of the present invention can be combined with each other, and the resulting technical solutions are all within the protection scope of the present invention.

[0047] Although the flowchart describes the operations as sequential processes, many of these operations can be performed in parallel, concurrently, or simultaneously. The order of the operations can be rearranged. A process can terminate when its operation is complete, but it may also have additional steps not included in the diagram. A process can correspond to a method, function, procedure, subroutine, subroutine, etc.

[0048] Computer equipment includes user equipment and network equipment. User equipment or clients include, but are not limited to, computers, smartphones, and PDAs (Personal Digital Assistants); network equipment includes, but is not limited to, a single network server, a server group consisting of multiple network servers, or a cloud based on cloud computing consisting of a large number of computers or network servers. Computer equipment can operate independently to implement this invention, or it can connect to a network and implement this invention through interaction with other computer devices within the network. The network in which the computer equipment resides includes, but is not limited to, the Internet, wide area networks (WANs), metropolitan area networks (MANs), local area networks (LANs), and VPN networks.

[0049] The terms “first,” “second,” etc., may be used herein to describe various units, but these units should not be limited by these terms; they are used merely to distinguish one unit from another. The term “and / or” as used herein includes any and all combinations of one or more of the associated listed items. When a unit is referred to as “connected” or “coupled” to another unit, it may be directly connected or coupled to said other unit, or there may be intermediate units present.

[0050] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments. Unless the context clearly indicates otherwise, the singular forms “a” and “an” as used herein are also intended to include the plural. It should also be understood that the terms “comprising” and / or “including” as used herein specify the presence of the stated features, integers, steps, operations, units, and / or components, without excluding the presence or addition of one or more other features, integers, steps, operations, units, components, and / or combinations thereof.

[0051] Unconventional oil and gas recovery rates are improved by increasing horizontal well length and employing multi-stage, multi-level continuous fracturing. In the development of hot dry rock geothermal resources, hydraulic fracturing creates an interconnected network of fractures to utilize the thermal energy of the hot dry rock. Hydraulic fracturing is a key technology for enhancing oil and gas production and energy conversion, and real-time monitoring is crucial for ensuring the desired results from fracturing operations.

[0052] Electromagnetic monitoring technology for hydraulic fracturing based on charging conductors has the advantages of low power consumption, strong signal, high signal-to-noise ratio, simple operation, and safety. It can obtain information on the propagation of reservoir stimulation fractures and delineate the range of fracturing fluid. However, compared with existing technologies, the following key issues still need to be addressed to monitor fracture growth in real time: 1) calculation of potential anomalies; 2) fracture parameter inversion; 3) construction of real-time fracture prediction models.

[0053] To address the aforementioned problems, this invention provides a real-time fracture prediction method based on a charging conductor. This method aims to construct a fracture prediction model and acquire fracturing fracture parameters in real time, thereby providing technical support for electromagnetic monitoring and evaluation of hydraulic fracturing effectiveness.

[0054] This invention can effectively acquire electromagnetic signal changes caused by fracturing, obtain fracture parameters in real time, and delineate the range of fracturing fluid. It has important application value in electromagnetic monitoring and effect evaluation of hydraulic fracturing in shale gas, coalbed methane, and hot dry rock.

[0055] The following describes the detailed flow of the method according to an embodiment of the present invention with reference to the accompanying drawings, the steps of which can be executed in a computer system containing, for example, a set of computer-executable instructions. Although the logical order of the steps is shown in the flowchart, in some cases, the steps shown or described may be performed in a different order than that shown here.

[0056] Example 1

[0057] Figure 1 This diagram illustrates a flow chart of the real-time prediction method for hydraulic fracturing fractures based on a charging conductor provided in Embodiment 1 of the present invention. (Refer to...) Figure 1As can be seen, the method includes the following steps.

[0058] Step S100: Deploy a charging conductor electromagnetic monitoring device with the goal of ensuring that the stability of the field source and monitoring point before and after fracturing meets the set conditions, so as to collect electromagnetic observation signals during the fracturing operation.

[0059] Step S200: Determine the potential anomaly based on the electromagnetic observation signal through time difference, and calculate the corresponding single-slit crack parameters based on the potential anomaly using the set charging conductor single-slit operation model.

[0060] Step S300: Set constraints based on perforation and fracturing section factors to obtain a fracture prediction model containing single fracture parameters at multiple time points;

[0061] Step S400: Delineate and mark the fracturing fluid sweep range by enveloping the multi-fracturing boundaries.

[0062] This invention aims to obtain fracturing fracture parameters in real time through the basic theory of charging conductors and electromagnetic monitoring data, construct a fracture prediction model, delineate the fracturing fluid sweep range, and provide technical support for evaluating the effectiveness of hydraulic fracturing.

[0063] In an optional embodiment, in step S100, the deployed electromagnetic monitoring device for the charging conductor includes a first power supply electrode and a second power supply electrode for transmitting current, and a first receiving electrode and a second receiving electrode for receiving current observation signals.

[0064] The first power supply electrode is connected to the wellhead of the fractured well and the second power supply electrode is located away from the wellhead. The first receiving electrode is placed at the monitoring point and the second receiving electrode is placed at the wellhead as a reference point.

[0065] In this step, a pre-deployed electromagnetic monitoring device for charging conductors ensures the stability of the field source and monitoring points before and after hydraulic fracturing, and the observation signals are collected and transmitted in real time during the fracturing process. Preferably, the electromagnetic monitoring device in step S100 mainly includes power supply electrodes A and B and receiving electrodes M and N. Power supply electrode A is connected to the wellhead of the fracturing well, power supply electrode B is located away from the wellhead, receiving electrode M is placed at the monitoring point, and receiving electrode N is placed at the wellhead as a reference point. The power supply electrodes are used to transmit current, and the receiving electrodes are used to receive signals. The transmitted current is transmitted through a power supply cable.

[0066] The monitoring points are arranged in different ways depending on the type of well. Generally, in fracturing sites, vertical wells are arranged in a "ring" pattern, while horizontal wells are arranged in a "mesh" pattern.

[0067] The electromagnetic observation signal includes the real-time transmission current and the observation potential difference between the first receiving electrode and the second receiving electrode.

[0068] The electromagnetic observation signal includes a transmitting current and an observation potential difference, which is actually the potential difference ΔU between the receiving electrodes M and N. MN .

[0069] The method of the present invention uses the wellbore as the emission source and only needs to measure the potential difference between the measuring electrodes, resulting in a strong signal and a high signal-to-noise ratio. Figure 2 , Figure 3 The diagrams show electromagnetic monitoring of hydraulic fracturing based on charging conductors for both vertical and horizontal wells. The basic principle is to use a direct excitation-ground reception method, supplying a current signal through the fracturing wellbore. During hydraulic fracturing, fractures are generated, and a dynamic charging conductor is formed at the target layer. The electromagnetic response changes are observed on the ground to analyze the development of the fractures.

[0070] Further, step S200 is executed, the potential anomaly is determined by time difference based on the electromagnetic observation signal, and the corresponding single-slit crack parameters are calculated by inversion using the set charging conductor single-slit operation model according to the potential anomaly.

[0071] To ensure the electromagnetic monitoring device operates normally, the observed signal is used to obtain the potential anomaly through time difference analysis. Based on the single-slit model of the charging conductor, the potential anomaly is used to obtain the crack parameters through inversion calculation.

[0072] In an optional embodiment, the least squares method or an improved marine predator optimization algorithm is used in combination with pre-defined fracturing prior information to achieve inversion calculation; the fracturing prior information includes perforation and fracturing segment information to constrain the optimization range during the inversion calculation of fracture endpoint coordinates; the single fracture parameters in the inversion calculation include fracture depth, fracture length and fracture orientation, wherein the fracture length and fracture orientation are determined based on the fracture endpoint coordinates.

[0073] Preferably, in step S200, the potential anomaly can be calculated using the time difference formula (1), i.e.

[0074]

[0075] in,

[0076]

[0077] Similarly, we can conclude that

[0078]

[0079] In the formula, T represents the current time, T-1 represents the previous time, and I T For the current being transmitted, U T It normalizes the current in the potential difference at the current moment. This indicates that the potential is abnormal at the current moment.

[0080] According to equation (1), the potential anomaly of the observed potential difference at the current moment relative to the previous moment can be obtained in real time.

[0081] The single-slit model of the charging conductor associated with the theoretical value of the potential anomaly is as follows (4):

[0082]

[0083] In the formula, Let ω be the wave number in the frequency domain, where ω = 2πf is the angular frequency, f is the electromagnetic wave frequency, and μ and σ are the magnetic permeability and electrical conductivity of the medium, respectively. It is an electric dipole moment. I represents the current intensity, and dl represents the length of the electric dipole, with arbitrary direction, expressed as a vector. This indicates that i is an imaginary number; for and The included angle; r is the radius vector. j Let d be the distance between the j-th electric dipole source and the observation point M, where j = 1, 2, 3...Nd, and Nd = L / dl.

[0084] The computational principle of the single-slit model of a charging conductor is actually to divide a charging conductor of length L into Nd electric dipoles and then superimpose their potentials. Since the potential is a scalar Φ, the potential anomaly U before and after the crack formation is... S =Φ. The potential anomaly includes the potential difference changes of all monitoring points that meet the data quality requirements, and is used in the inversion calculation to solve for the crack parameters.

[0085] The inversion calculation can employ methods such as least squares and the improved marine predator optimization algorithm (IMPA) to achieve efficient and high-precision identification of fracture parameters. The improved marine predator optimization algorithm features fast optimization speed, strong stability, and high accuracy.

[0086] The crack parameters include crack depth, crack length, and crack orientation. The crack length and crack orientation can be obtained by the coordinates of the crack endpoints.

[0087] Existing technologies require inversion of resistivity distribution data through electric field, magnetic field signals, and frequency data to reflect underground fracture parameters. This process is complex and lacks reliability. In contrast, the method of this invention is based on the charging conductor theory and can quickly calculate fracture parameters using observation data, achieving efficient and accurate calculations.

[0088] Settings such as Figure 4 The crack models shown have different orientations, with a crack depth of 4000m, a length of 200m, and an orientation ranging from 0° to 30°. The IMPA optimization algorithm was used for inversion calculations, and the calculation results are as follows: Figure 5As shown;

[0089] In practical applications, the crack length obtained by inversion using the optimization algorithm of this invention can be compared and analyzed with the crack length of the theoretical model to calculate the relative error value of the crack length and verify the calculation effect; the relative error of the crack length is less than 0.003%, and the absolute error of the crack orientation is less than 0.004°.

[0090] Calculate the relative error value of the seam length using the following formula:

[0091] (L pre -L) / L*100%

[0092] In the formula, L pre The crack length is represented by denoted by L, which is obtained by inversion using the IMPA optimization algorithm.

[0093] Further, step S300 is executed to set constraints based on perforation and fracturing section factors to construct an initial physical fracture model, and then combine the fracture parameters calculated by inversion to determine a fracture prediction model containing single fracture parameters at multiple times.

[0094] This invention uses prior information about reservoir fracturing as a constraint to obtain a fracture prediction model that includes single-fracture parameters at multiple time points; wherein the multi-fracture parameters are visualized through a geological model to characterize the distribution features of fracturing fractures.

[0095] In a preferred embodiment, it can be understood that after determining the initial model of the physical fracture prediction model by considering the constraints of fracturing prior information, the fracture models at multiple times obtained through real-time inversion calculation are combined with the initial model to determine the final fracture prediction model.

[0096] In an optional embodiment, step S300, in determining the crack prediction model containing single-crack parameters at multiple time points, includes the following operations:

[0097] According to the set time period, step S200 is executed repeatedly to obtain multi-fracturing parameters containing single-fracturing parameters at multiple times until the fracturing operation is completed.

[0098] The multi-fracture parameters are combined with a geological model for visualization, forming a fracture prediction model with characteristics of hydraulic fracturing fracture distribution.

[0099] Preferably, the fracturing prior information mentioned in step S300 mainly includes information such as perforation and fracturing sections, which is used to constrain the optimization range during the inversion calculation of fracture endpoint coordinates, enabling faster and more accurate acquisition of the optimal solution. The fracture prediction model can be constructed and applied based on software program algorithms.

[0100] The real-time prediction method for hydraulic fracturing fractures based on charging conductors in this embodiment of the invention further includes: step S400, delineating and marking the fracturing fluid sweep range by enveloping and identifying the boundaries of multiple fractures.

[0101] The crack prediction model can be constructed and visualized through a program algorithm. The implementation process of the crack prediction model construction algorithm includes the following steps:

[0102] S301, Fracturing begins, real-time acquisition of emission current and monitoring point potential difference data;

[0103] S302. Calculation of time difference anomaly: Calculate the potential anomaly at the current time according to formula (1).

[0104] S303. Fracture parameter inversion: Based on the least squares method or the aforementioned IMPA optimization algorithm and fracturing prior information, the potential anomaly is... Convert to single-slit parameters;

[0105] S304. Loop to the next moment, repeat steps S302 to S303, obtain multi-fracturing parameters, and exit the loop when fracturing ends.

[0106] S305. Construction of fracture prediction model: Visualize the multi-fracture parameters through a geological model to obtain the distribution characteristics of hydraulic fracturing fractures;

[0107] S306. Based on the distribution characteristics of fracturing fractures, the fracturing fluid sweep range is delineated by identifying the fracture endpoints using envelope recognition; for example... Figure 6 As shown.

[0108] The fracture prediction model determines the fracturing fluid sweep range based on the identification of multi-fracture boundary envelopes. Figure 7 , Figure 8 The diagrams show the fracturing fracture prediction models and fracturing fluid sweep range effects for vertical and horizontal wells, respectively.

[0109] For the foregoing method embodiments, in order to simplify the description, they are all described as a series of actions. However, those skilled in the art should understand that the present invention is not limited to the described order of actions, because according to the present invention, some steps can be performed in other orders or simultaneously. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions and modules involved are not necessarily essential to the present invention.

[0110] It should be noted that, in other embodiments of the present invention, the method can also combine one or more of the above embodiments to obtain a new real-time prediction method for hydraulic fracturing fractures based on charging conductors, so as to realize dynamic prediction and distribution characteristic analysis of hydraulic fracturing fracture parameters in water.

[0111] Example 2

[0112] It should be noted that, based on the methods in any one or more embodiments of the present invention described above, the present invention also provides a storage medium storing program code that can implement the methods described in any one or more embodiments. When the program code is executed by the operating system, it can implement the real-time prediction method for hydraulic fracturing fractures based on charging conductors as described above.

[0113] Example 3

[0114] The methods described in detail in the above-disclosed embodiments of the present invention can be implemented using various forms of devices or systems. Therefore, based on other aspects of the methods described in any one or more of the above embodiments, the present invention also provides a real-time prediction system for hydraulic fracturing fractures based on a charging conductor. This system is used to execute the real-time prediction method for hydraulic fracturing fractures based on a charging conductor described in any one or more of the above embodiments. Specific embodiments are given below for detailed description.

[0115] Specifically, Figure 9 The diagram shows a schematic representation of the real-time prediction system for hydraulic fracturing fractures based on a charging conductor provided in an embodiment of the present invention. Figure 9 As shown, the system includes:

[0116] The electromagnetic signal acquisition system is configured to deploy charged conductor electromagnetic monitoring devices with the goal of ensuring that the stability of the field source and monitoring point before and after fracturing meets the set conditions, and to collect electromagnetic observation signals during fracturing operations.

[0117] The crack parameter calculation module is configured to determine potential anomalies based on electromagnetic observation signals through time difference, and to invert and calculate the corresponding single-crack parameters based on the potential anomalies using a set charging conductor single-crack operation model.

[0118] The fracture model construction module is configured to set constraints based on perforation and fracturing section factors to obtain a fracture prediction model containing single fracture parameters at multiple time points, which characterizes the distribution characteristics of fracturing fractures.

[0119] The boundary and sweep range identification module is configured to: delineate the sweep range of fracturing fluid by enveloping the boundaries of multiple fractures based on the distribution characteristics of the fracturing fractures.

[0120] In one embodiment, the electromagnetic monitoring device for the charging conductor deployed in the electromagnetic signal acquisition system includes a first power supply electrode and a second power supply electrode for transmitting current, and a first receiving electrode and a second receiving electrode for receiving current observation signals.

[0121] Furthermore, in one embodiment, the first power supply electrode is connected to the wellhead of the fracturing well, the second power supply electrode is located away from the wellhead, the first receiving electrode is placed at the monitoring point, and the second receiving electrode is placed at the wellhead as a reference point.

[0122] Optionally, in one embodiment, the electromagnetic observation signal includes the real-time transmission current and the observation potential difference between the first receiving electrode and the second receiving electrode.

[0123] In a preferred embodiment, the crack parameter calculation module is configured to calculate the potential anomaly using a time-difference algorithm based on the following formula:

[0124]

[0125] in,

[0126]

[0127] We can obtain,

[0128]

[0129] In the formula, T represents the current time, T-1 represents the previous time, and I T For the current being transmitted, U T It normalizes the current in the potential difference at the current moment. This indicates that the potential is abnormal at the current moment.

[0130] In one embodiment, the crack parameter calculation module uses the single-crack model of the charging conductor as described below:

[0131]

[0132] In the formula, Let ω be the wave number in the frequency domain, where ω = 2πf is the angular frequency, f is the electromagnetic wave frequency, and μ and σ are the magnetic permeability and electrical conductivity of the medium, respectively. It is an electric dipole moment. I represents the current intensity, and dl represents the length of the electric dipole, with arbitrary direction, expressed as a vector. express; for and The included angle; r j Let d be the distance between the j-th electric dipole source and the observation point M, where j = 1, 2, 3...Nd, and Nd = L / dl.

[0133] Furthermore, in one embodiment, the fracture parameter calculation module uses the least squares method or an improved marine predator optimization algorithm combined with pre-defined fracturing prior information to perform inversion calculation; the fracturing prior information includes perforation and fracturing segment information to constrain the optimization range during the fracture endpoint coordinate inversion calculation; the single fracture parameters calculated by inversion include fracture depth, fracture length, and fracture orientation, wherein the fracture length and fracture orientation are determined based on the fracture endpoint coordinates.

[0134] Preferably, in one embodiment, the process by which the crack model building module obtains a crack prediction model containing single-crack parameters at multiple time points includes the following operations:

[0135] According to the set time period, the operation is repeatedly executed to obtain multi-fracturing parameters containing single-fracturing parameters at multiple times until the fracturing operation is completed.

[0136] The multi-fracture parameters are combined with a geological model for visualization, forming a fracture prediction model with characteristics of hydraulic fracturing fracture distribution.

[0137] In the real-time prediction system for hydraulic fracturing fractures based on charging conductors provided in this embodiment of the invention, each module or unit structure can operate independently or in combination according to the actual parameter inversion requirements and fracture model construction requirements to achieve the corresponding technical effects.

[0138] It should be understood that the embodiments disclosed herein are not limited to the specific structures, processing steps, or materials disclosed herein, but should be extended to equivalent substitutions of these features as understood by those skilled in the art. It should also be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting.

[0139] The phrase "an embodiment" in the specification means that a specific feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. Therefore, the phrase "an embodiment" appearing in various places throughout the specification does not necessarily refer to the same embodiment.

[0140] While the embodiments disclosed in this invention are as described above, the content is merely for the purpose of facilitating understanding of the invention and is not intended to limit the invention. Any person skilled in the art to which this invention pertains may make any modifications and variations in form and detail of the implementation without departing from the spirit and scope disclosed herein; however, the scope of patent protection for this invention shall still be determined by the scope defined in the appended claims.

Claims

1. A real-time prediction method for hydraulic fracturing fractures based on a charging conductor, characterized in that, The method includes: Step S100: Deploy a charging conductor electromagnetic monitoring device with the goal of ensuring that the stability of the field source and monitoring point before and after fracturing meets the set conditions, and collect electromagnetic observation signals during the fracturing operation. Step S200: Determine the potential anomaly based on the electromagnetic observation signal through time difference, and calculate the corresponding single-slit crack parameters based on the potential anomaly using the set charging conductor single-slit operation model. Step S300: Set constraints based on perforation and fracturing section factors to obtain a fracture prediction model containing single fracture parameters at multiple time points, characterizing the distribution characteristics of fracturing fractures; Step S400: Based on the distribution characteristics of the fracturing fractures, the fracturing fluid sweep range is delineated by enveloping the boundaries of the multiple fractures.

2. The method according to claim 1, characterized in that, In step S100, the deployed electromagnetic monitoring device for the charging conductor includes a first power supply electrode and a second power supply electrode for transmitting current, and a first receiving electrode and a second receiving electrode for receiving current observation signals.

3. The method according to claim 2, characterized in that, The first power supply electrode is connected to the wellhead of the fractured well and the second power supply electrode is located away from the wellhead. The first receiving electrode is placed at the monitoring point and the second receiving electrode is placed at the wellhead as a reference point.

4. The method according to claim 1, characterized in that, The electromagnetic observation signal includes the real-time transmission current and the observation potential difference between the first receiving electrode and the second receiving electrode.

5. The method according to claim 1, characterized in that, The potential anomaly mentioned in step S200 is calculated using the time difference algorithm shown below: in, We can obtain, In the formula, T represents the current time T, T-1 represents the previous time, and I T For the current being transmitted, The potential difference at time T, U T This represents the current potential difference after current normalization. This indicates that the potential is abnormal at the current moment.

6. The method according to claim 1, characterized in that, The single-slit model of the charging conductor is adopted as described below: In the formula, ω=2πf, k is the wave number in the frequency domain, ω is the angular frequency, f is the electromagnetic wave frequency, and μ and σ are the magnetic permeability and electrical conductivity of the medium, respectively. Let d be the electric dipole moment, I be the current intensity, and dl be the electric dipole length. for and The included angle, Represents the radius vector, r j Let be the distance between the j-th electric dipole source and the observation point M.

7. The method according to claim 1, characterized in that, In step S200, the least squares method or the improved marine predator optimization algorithm is used in combination with the set fracturing prior information to realize the inversion calculation; the fracturing prior information includes perforation and fracturing segment information to constrain the optimization range in the inversion calculation of the fracture endpoint coordinates; the single fracture parameters of the inversion calculation include fracture depth, fracture length and fracture orientation, and the fracture length and fracture orientation are determined according to the fracture endpoint coordinates.

8. The method according to claim 1, characterized in that, In step S300, the process of obtaining a crack prediction model containing single-crack parameters at multiple time points includes the following operations: According to the set time period, the operation is repeatedly executed to obtain multi-fracturing parameters containing single-fracturing parameters at multiple times until the fracturing operation is completed. The multi-fracture parameters are combined with a geological model for visualization, forming a fracture prediction model with characteristics of hydraulic fracturing fracture distribution.

9. A storage medium, characterized in that, The storage medium stores program code that can implement the method as described in any one of claims 1 to 8.

10. A real-time prediction system for hydraulic fracturing fractures based on a charging conductor, characterized in that, The system performs the method as described in any one of claims 1 to 8.

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