A micro-earthquake positioning method, device, equipment and medium

Abstract

The present invention discloses a method, device, equipment and medium for positioning microseismic, and relates to the field of seismic exploration technology, including: using geological modeling software to construct a geological model based on underground structure data obtained from geological exploration data; and using numerical simulation software to simulate underground stress fields in combination with hydraulic fracturing parameters obtained from underground fracturing operations; and using simulated underground stress field changes as boundary conditions to position the underground spatial position of microseismic according to microseismic data obtained from a deployed microseismic monitoring network. The present invention can accurately locate the depth position of microseismic underground.

Description

Technical Field

[0001] The present invention relates to the field of seismic exploration technology, and in particular to a micro-earthquake positioning method, device, equipment and medium. Background Art

[0002] Ground microseismic monitoring technology utilizes seismological principles and acoustic emission methods to observe, analyze, and locate microseismic events generated during production activities. This technology has been widely used in petroleum engineering, and is particularly crucial in hydraulic fracturing. Hydraulic fracturing involves injecting high-pressure water into a wellbore, fracturing the rock and forming fractures, thereby increasing the permeability of the reservoir and improving oil and gas recovery. The fracturing process generates a series of microseismic waves that propagate and diffuse into the surrounding area. Ground microseismic monitoring technology can receive and record these microseismic waves, and then process them to characterize the morphology of the fracture network. This allows for the timely detection of changes in formation conditions, such as fractures and stress distribution, enabling timely adjustments to construction parameters and avoiding potential risks and accidents.

[0003] In the prior art, the ground microseismic monitoring method uses a seismometer to record seismic waves, and then performs data analysis and structural inference on the earthquake source.

[0004] However, the above method has a large error in depth positioning due to the lack of vertical observation points, and is therefore limited in its application in fracturing projects. Summary of the Invention

[0005] The embodiments of the present invention provide a microseismic positioning method, device, equipment and medium, which can solve the problem in the prior art that a lack of longitudinal observation points leads to large errors in depth positioning.

[0006] An embodiment of the present invention provides a microseismic location method, comprising the following steps: constructing a geological model based on underground structural data obtained through geological exploration, and simulating an underground stress field using numerical simulation software in combination with hydraulic fracturing parameters obtained from underground fracturing operations; locating the location of the microseism in the geological model based on microseismic data obtained through a deployed microseismic monitoring network, using the simulated stress distribution of the underground stress field and the boundary range generated by the stress distribution; the stress distribution of the underground stress field includes regions of high and low stress and strong and weak deformation; locating the location of the microseism in the geological model includes: dividing the simulated underground stress field into grids, assuming that a microseismic event exists at a location in each grid; obtaining the time difference between the receipt of microseismic signals by the geophones based on multiple geophone locations in the microseismic data and the assumed location of the microseismic event; designating a grid and obtaining the time difference between the arrival of the grid center at each geophone; and superimposing the geophone amplitude values ​​based on the time difference between the arrival of the microseismic signals at each geophone to obtain superimposed energy. When the superimposed energy exceeds a set threshold, the location is determined to be the precise location of the microseismic event.

[0007] Furthermore, the construction of the geological model specifically includes: constructing a geological model based on the underground structure data obtained from geological exploration and using geological modeling software; the underground structure data includes: comprehensive logging data, seismic data, geological stratification information, fault data, surface and underground structure data, drilling data, geological interpretation, geomechanical parameters, fluid property data, production data, geological statistical data and various types of geological and engineering data of three-dimensional grid data.

[0008] Furthermore, the simulation of the underground stress field specifically includes the following steps: using numerical simulation software to divide the geological model into finite element or finite difference grids; inputting the numerical simulation software and setting boundary conditions and initial conditions according to the hydraulic fracturing parameters of the underground fracturing operation, and running the numerical simulation software to simulate the distribution of the underground stress field, wherein the distribution reflects the changes in the stress field in the rock formation due to the expansion of the cracks as the fracturing fluid is injected.

[0009] An embodiment of the present invention provides a microseismic locating device, comprising: a model construction module for constructing a geological model based on underground structural data obtained through geological exploration, and simulating an underground stress field using numerical simulation software in combination with hydraulic fracturing parameters obtained from underground fracturing operations; a microseismic locating module for locating the position of a microseism in the geological model based on microseismic data obtained through a deployed microseismic monitoring network, in combination with the simulated stress distribution of the underground stress field and the boundary range generated by the stress distribution. The stress distribution of the underground stress field includes regions of high and low stress and strong and weak deformation. Locating the position of the microseism in the geological model comprises: dividing the simulated underground stress field into grids, assuming that a microseismic event exists at a location in each grid; obtaining the time difference between the receipt of microseismic signals by the geophones based on multiple geophone locations in the microseismic data and the assumed microseismic event location; designating a grid and obtaining the time difference between the arrival of the grid center at each geophone; and superimposing the amplitude values ​​of the geophones based on the time difference between the arrival of the microseismic signals at each geophone to obtain superimposed energy. When the superimposed energy exceeds a set threshold, the location is determined to be the precise location of the microseismic event.

[0010] An embodiment of the present invention provides a computer device, comprising: a memory and a processor; the memory stores a computer program, and the processor implements the above-mentioned micro-earthquake locating method when executing the computer program.

[0011] An embodiment of the present invention provides a computer-readable storage medium storing a computer program. When the computer program is executed by a processor, the computer program implements the above-mentioned microseismic locating method.

[0012] The embodiments of the present invention provide a microseismic positioning method, device, equipment, and medium. Compared with the prior art, the advantages thereof are as follows:

[0013] A geological model is constructed based on underground structural data obtained from geological exploration, and numerical simulation software is used to simulate the underground stress field in combination with hydraulic fracturing parameters obtained from underground fracturing operations. The position of microseismic events in the geological model is located based on microseismic data obtained from the deployed microseismic monitoring network, combined with the stress distribution of the simulated underground stress field and the boundary range generated by the stress distribution. The positioning method includes: dividing the simulated underground stress field into grids, assuming that a microseismic event exists at one location in each grid; obtaining the time difference between the geophone receiving the microseismic signal and the assumed microseismic event location based on the locations of multiple geophones in the microseismic data; specifying a grid and obtaining the time difference between the grid center and each geophone; and superimposing the geophone amplitude values ​​based on the time difference between the microseismic signal reaching each geophone to obtain the superimposed energy. When the superimposed energy exceeds a set threshold, the location is determined to be the precise location of the microseismic event.

[0014] Among them, the simulated underground stress field can obtain the stress distribution, which includes the lateral and vertical distribution of the stress field; using the simulated underground stress field as a constraint condition and combining it with microseismic data to locate the spatial position of microseisms can more accurately reflect the depth position of microseisms underground. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 A schematic flow chart of a microseismic location method provided by an embodiment of the present invention;

[0016] Figure 2 A schematic diagram of a geological model provided in an embodiment of the present invention;

[0017] Figure 3 A schematic diagram of stress simulation results after inputting hydraulic fracturing data provided by an embodiment of the present invention;

[0018] Figure 4 A comparison diagram of the positioning effect of microseismic monitoring signals before and after stress constraint in a microseismic positioning method provided by an embodiment of the present invention, wherein (a) is before stress constraint and (b) is after stress constraint;

[0019] Figure 5 This is a fracture network morphological feature analysis diagram of the positioning results of a microseismic positioning method provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0020] To make the above-mentioned objects, features, and advantages of the present invention more readily apparent, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings. The following description sets forth numerous specific details to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways than those described herein, and those skilled in the art may make similar modifications without departing from the scope of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0021] See also Figures 1 to 5 The embodiment of the present invention provides a micro-earthquake positioning method, comprising the following steps:

[0022] Step 1: Use geological exploration data to construct a high-precision geological model and initial stress field.

[0023] Specifically, a high-precision three-dimensional geological model is constructed by integrating various types of geological and engineering data such as well logging data, seismic data, geological stratification information, fault data, surface and underground structure data, drilling data, geological interpretation, geomechanical parameters, fluid property data, production data, geological statistical data and three-dimensional grid data.

[0024] Furthermore, constructing a high-precision geological model requires the integrated application of key technologies such as geostatistics, 3D geological modeling, multi-source data fusion, geomechanics, rock physics modeling, and numerical simulation. Geostatistics simulates the uncertainty of geological parameters, while 3D gridding ensures the spatial resolution of the model. Multi-source data, such as well logging, seismic data, and geological stratification, are integrated to enhance the geological constraints of the model. Geomechanical modeling predicts the subsurface stress field, while rock physics and seismic inversion techniques improve the accuracy of reservoir parameter predictions. Numerical simulation verifies the rationality of the model's production dynamics, 3D visualization aids model interpretation, and local grid refinement improves resolution in key areas. Parallel computing improves computational efficiency, while model calibration ensures prediction reliability, achieving integrated geology and engineering, and providing decision support for oil and gas reservoir development.

[0025] Step 2: Combine hydraulic fracturing data and simulate the stress field using advanced numerical simulation technology.

[0026] Specifically, the application of numerical simulation technology in hydraulic fracturing primarily integrates key hydraulic fracturing parameters, including fracture parameters, fracturing fluid parameters, fracturing operation parameters, and geological parameters. Fracturing fluid parameters include type, injection volume, and injection pressure, while fracturing operation parameters include fracturing method, number of fracturing stages, and fracturing spacing. The established numerical model is then used to simulate changes in the stress field. During the simulation process, the software calculates the stress distribution and changes in the rock formation, specifically how the stress field in the rock formation changes due to fracture expansion as the fracturing fluid is injected. Ultimately, the simulation results demonstrate the distribution and changes in the stress field.

[0027] Step 3: Use the ground microseismic monitoring signal and the stress simulation results obtained in the second step as constraints to perform high-precision signal positioning.

[0028] Specifically, based on the microseismic data obtained from the deployed microseismic monitoring network, the simulated underground stress field changes are used as boundary conditions to accurately locate the underground spatial position of the microseism.

[0029] Step 4: Output the positioning results and provide a visual analysis of the crack network morphological characteristics.

[0030] Use geological modeling software to build geological models, including:

[0031] 1. First, it is necessary to collect and organize the data obtained from geological exploration, including seismic profiles, velocity analysis, core and well data, etc.

[0032] 2. Loading the collected data into geological modeling software usually involves data format conversion and coordinate system unification.

[0033] 3. Based on seismic profiles and velocity analysis, interpret the underground strata and determine the interface position and lithology of each stratum.

[0034] 4. Create a three-dimensional grid model in the geological modeling software, and the nodes of the grid will be used to represent the interface position of the stratum.

[0035] 5. Based on the results of stratigraphic interpretation, construct the interfaces of each stratum in the grid model to form a three-dimensional geological model.

[0036] 6. Verify and modify the established geological model through well data and other geological information to ensure the accuracy of the model.

[0037] 7. Apply the established geological model to further geological analysis and simulation, such as oil and gas reservoir simulation and fracturing numerical simulation.

[0038] Stress field simulation is performed using advanced numerical simulation technology, including:

[0039] 1. Collect formation parameters for the target area, including rock type, porosity, permeability, elastic modulus, and Poisson's ratio. Furthermore, relevant parameters for the fracturing operation, such as injection rate, injection pressure, and fracturing fluid properties, need to be obtained.

[0040] 2. Based on the collected data, a geological model of the target area is established, including geological structures such as strata, faults, and fractures. This can be done using 3D geological modeling software such as Petrel or Geomodeller.

[0041] 3. Based on the geological model, divide the finite element or finite difference grid.

[0042] 4. Input the collected formation parameters and fracturing operation parameters into numerical simulation software. These parameters will be used to calculate the mechanical properties of the formation and the fluid flow characteristics.

[0043] 5. Select an appropriate computational model based on the research objectives and geological conditions. Common computational models include elastic models, elastoplastic models, and damage models. For hydraulic fracturing problems, nonlinear rock mechanical properties often need to be considered.

[0044] 6. Set boundary conditions and initial conditions based on the geological model and actual project conditions. Boundary conditions include fixed boundaries, free boundaries, and displacement boundaries; initial conditions include initial stress field and initial pore pressure.

[0045] 7. Run numerical simulation software to solve the governing equations of the geostress field, which usually include equilibrium equations, constitutive equations, and fluid flow equations.

[0046] 8. After the solution is completed, analyze the calculation results, mainly including stress distribution, displacement distribution and crack expansion.

[0047] 9. Adjust the geological model, calculation model and boundary conditions based on the analysis results to improve the calculation accuracy and reliability.

[0048] 10. Compare the calculated results with the actual observed data to verify the accuracy of the numerical simulation. If necessary, repeat steps 8 to 10 until the calculated results are consistent with the actual observed data.

[0049] Accurately locate the location of microseismic events in the geological model, including:

[0050] 1. First, deploy a microseismic monitoring network. This involves installing a series of geophones on the surface or in wells. These geophones can detect seismic waves. When a microseismic event occurs underground, the geophones record the arrival time and waveform of the first wave.

[0051] 2. Determine the arrival time of the first wave (P wave or S wave) by analyzing the seismic waveform and pick up the arrival time of the first wave on each detector.

[0052] 3. Establish an initial velocity model based on geological structure and known geological parameters for calculation of seismic wave propagation time.

[0053] 4. Select an appropriate positioning algorithm, such as geometric positioning, grid search, linear inversion, or nonlinear inversion, and use the algorithm in combination with the first wave arrival time and velocity model to estimate the three-dimensional coordinates of the microseismic event.

[0054] 5. Use geomechanical models and simulation software to simulate the stress distribution of the underground stress field. Combined with the location of the microseismic event, the precise location of the microseismic event can be analyzed. Velocity model and positioning algorithm parameters are adjusted, and iterative positioning is performed to reduce positioning errors.

[0055] 6. Use precisely located microseismic events in areas such as geological risk assessment, resource development, and earthquake early warning.

[0056] The present invention aims to provide a high-precision positioning method and device for ground microseismic monitoring signals that combines geological and fracturing information to improve the accuracy and reliability of positioning, thereby optimizing fracturing construction parameters, improving reservoir fracturing transformation effects, and reducing fracturing operation risks.

[0057] The present invention also has the following beneficial effects:

[0058] This method significantly improves the positioning accuracy and reliability of surface microseismic monitoring signals by integrating fracturing data and geological information. This method effectively reduces positioning errors and improves spatial focus, thereby more accurately determining the location of microseismic events. Furthermore, this method offers advantages such as ease of operation, significant effectiveness, and high production value, making it of great significance for real-time guidance of fracturing operations and improving the effectiveness of reservoir fracturing.

[0059] An embodiment of the present invention provides a microseismic positioning device, comprising:

[0060] The model building module is used to construct a geological model based on underground structural data obtained from geological exploration and, in combination with hydraulic fracturing parameters obtained from underground fracturing operations, simulate the underground stress field using numerical simulation software. The microseismic positioning module is used to locate microseismic events in the geological model based on microseismic data obtained from the deployed microseismic monitoring network, combined with the simulated stress distribution of the underground stress field and the boundary range of the stress distribution. The stress distribution of the underground stress field includes areas of high and low stress and strong and weak deformation. Locating the location of microseismic events in the geological model involves: dividing the simulated underground stress field into grids, assuming that a microseismic event exists at a location in each grid; obtaining the time difference between the time when the geophones receive the microseismic signal based on the locations of multiple geophones in the microseismic data and the assumed location of the microseismic event; specifying a grid and obtaining the time difference between the grid center and each geophone; and superimposing the geophone amplitude values ​​based on the time difference between the microseismic signal reaching each geophone to obtain the superimposed energy. When the superimposed energy exceeds a set threshold, the location is determined to be the precise location of the microseismic event.

[0061] An embodiment of the present invention provides a computer device, comprising: a memory and a processor; the memory stores a computer program, and the processor implements the steps of a micro-earthquake positioning method when executing the computer program.

[0062] An embodiment of the present invention provides a computer-readable storage medium storing a computer program. When the computer program is executed by a processor, the computer program implements the steps of a micro-earthquake positioning method.

[0063] A specific embodiment is as follows:

[0064] The present invention carries out ground microseismic monitoring signal positioning based on stress constraints, which greatly improves the positioning accuracy and reliability of ground microseismic monitoring signals. The method is efficient and has strong production practicality. With the development of unconventional oil and gas hydraulic fracturing, it has broad application prospects. The method steps are as follows: Figure 1 As shown, taking Example 1 as an example, the steps include:

[0065] 1. Geological model construction: Using the latest geological exploration data, a high-precision geological model reflecting the underground structure is constructed.

[0066] 2. Stress field simulation: Use numerical simulation technology and hydraulic fracturing parameters to simulate the stress field changes in the formation.

[0067] 3. Signal positioning: Based on the stress simulation results, ground microseismic data processing is carried out to accurately locate the microseismic signals.

[0068] 4. Result output and analysis: Output positioning results and provide morphological feature analysis of the fracture network to provide a scientific basis for fracturing operations.

[0069] The specific steps for precise positioning are as follows:

[0070] (1) Input: geophone location, time when the geophone receives the microseismic signal, and three-dimensional spatial boundary model of stress field changes.

[0071] (2) Boundary modeling: Use professional software to build an irregular three-dimensional space boundary model.

[0072] (3) Grid division: Divide the grid inside the boundary model and assume that there are microseismic events in each grid.

[0073] (4) Time difference calculation: Based on the position of the detector and the assumed microseismic event position, the time difference of the microseismic signal received by the detector is calculated.

[0074] (5) Since it is difficult to accurately pick the first arrival of microseismic data, time difference is used instead. Specify a grid and calculate the time difference between the grid center and each detector, that is:

[0075]

[0076] Where x k ,y k ,z k To specify the coordinate information of the grid center, x i ,y i ,z i and x l ,y l ,z l are the coordinate information of two different detectors, and Vp is the wave velocity.

[0077] The arrival time of the signal at the reference geophone is set to T0. The arrival time of the microseismic signal at each geophone is calculated based on the calculated time difference. The corresponding amplitude values ​​of each geophone are superimposed according to their arrival times to obtain the superimposed energy E. When the superimposed energy E value (or the signal-to-noise ratio) exceeds a certain threshold, the location is considered a candidate for a microseismic event.

[0078] (6) Output: microseismic event location (x, y, z).

[0079] The above-described embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

Claims

1. A method for locating micro-earthquakes, characterized in that: The following steps are involved: A geological model is constructed based on underground structural data obtained from geological exploration, and combined with hydraulic fracturing parameters obtained from underground fracturing operations, numerical simulation software is used to simulate underground stress fields; Based on the microseismic data obtained by the deployed microseismic monitoring network, the location of the microseism in the geological model is located in combination with the stress distribution of the simulated underground stress field and the boundary range of the stress distribution; the stress distribution of the underground stress field includes areas of high and low stress and strong and weak deformation; The positioning of the microseismic event in the geological model includes: dividing the grids according to the simulated underground stress field, assuming that a microseismic event exists at a location in each grid; Based on the positions of multiple detectors in the microseismic data and the assumed positions of microseismic events, the time difference of the detector receiving the microseismic signal is obtained; a grid is specified and the time difference from the center of the grid to each detector is obtained; based on the time difference of the microseismic signal reaching each detector, the amplitude values ​​of the detectors are superimposed to obtain the superposition energy. When the superposition energy exceeds the set threshold, the position is determined to be the precise position of the microseismic event.

2. A micro-earthquake positioning method as claimed in claim 1, characterized in that: The simulation of underground stress field specifically comprises the following steps: Use numerical simulation software to divide the geological model into finite element or finite difference grids; According to the hydraulic fracturing parameters of the underground fracturing operation, the numerical simulation software is input and the boundary conditions and initial conditions are set. The numerical simulation software is run to simulate the distribution of the underground stress field. The distribution reflects the changes in the stress field in the rock formation due to the expansion of the cracks as the fracturing fluid is injected.

3. A micro-earthquake positioning device, characterized in that: include: A model building module is used to build a geological model based on underground structural data obtained from geological exploration, and to simulate underground stress fields using numerical simulation software in combination with hydraulic fracturing parameters obtained from underground fracturing operations; A microseismic positioning module is used to locate the position of microseisms in the geological model based on the microseismic data obtained by the deployed microseismic monitoring network, combined with the simulated stress distribution of the underground stress field and the boundary range generated by the stress distribution; The positioning of the microseismic event in the geological model includes: dividing the grids according to the simulated underground stress field, assuming that a microseismic event exists at a location in each grid; Based on the positions of multiple detectors in the microseismic data and the assumed positions of microseismic events, the time difference of the detector receiving the microseismic signal is obtained; a grid is specified and the time difference from the center of the grid to each detector is obtained; based on the time difference of the microseismic signal reaching each detector, the amplitude values ​​of the detectors are superimposed to obtain the superposition energy. When the superposition energy exceeds the set threshold, the position is determined to be the precise position of the microseismic event.

4. A computer device comprising: Memory and processor; The memory stores a computer program, wherein the processor implements a micro-earthquake locating method according to any one of claims 1 to 2 when executing the computer program.

5. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, a micro-earthquake locating method as described in any one of claims 1 to 2 is implemented.

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