Fracturing parameter optimization method and system based on refracturing fracture form

Abstract

The invention discloses a fracturing parameter optimization method and a fracturing parameter optimization system based on a refracturing fracture form, and belongs to the technical field of integral repeated reconstruction of old oil field blocks. Obtaining a seismic source crack length, a crack width, a crack height, a crack branch index, a crack network length, an apparent stress, a stress index, a diffusion index and a plasticity index by combining seismic source positioning information; and obtaining a fracturing result of the remaining oil enrichment area based on the parameters, and adjusting construction parameters according to the fracturing result of the remaining oil enrichment area to realize fracturing parameter optimization of the refracturing fracture form. Therefore, the optimization method provided by the invention solves the problems existing in the prior art, the fracturing effect can be evaluated and the hydraulic fracturing design can be optimized by applying the interpretation result of the microseism monitoring data, and finally, on the basis of the re-fracturing fracture form and fracture parameters, the optimization of the hydraulic fracturing design can be realized. And optimizing an old oil field refracturing effect evaluation method and forming a set of parameter system.

Description

Technical Field

[0001] The present invention belongs to the technical field of overall repeated transformation of old oilfield blocks, and relates to a method and system for optimizing fracturing parameters based on the morphology of repeated fracturing fractures. Background Art

[0002] After long-term injection and production in old oilfields, the in-situ stress field undergoes dynamic changes, which will affect the azimuth and morphology of repeated fracturing fractures.

[0003] At present, downhole microseismic is the main means for monitoring fracturing fractures, and microseismic monitoring has been carried out many times on old oilfield wells. However, the existing technology only interprets and analyzes the microseismic monitoring data, does not conduct fracturing evaluation on the data, nor combines with the fracturing results for optimization, resulting in the inability to effectively evaluate the fracturing effect of repeated fracturing fractures during the construction process. Summary of the Invention

[0004] The purpose of the present invention is to solve the problems in the existing technology that during microseismic monitoring, data cannot be subjected to fracturing evaluation and optimization is not combined with the fracturing results, and to provide a method and system for optimizing fracturing parameters based on the morphology of repeated fracturing fractures.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] A method for optimizing fracturing parameters based on the morphology of repeated fracturing fractures proposed by the present invention includes the following steps:

[0007] Establish an initial velocity model, correct the initial velocity model, and obtain a corrected velocity model; based on the corrected velocity model, obtain P-waves and S-waves, and process the P-waves and S-waves to obtain source location information;

[0008] Based on the source location information, obtain the source fracture length, fracture width, fracture height, fracture branch index, fracture network length, apparent stress, stress index, diffusion index, and plastic index;

[0009] Based on the above parameters, obtain the fracturing results in the remaining oil enrichment area, and adjust the construction parameters according to the fracturing results in the remaining oil enrichment area to realize the optimization of fracturing parameters for the morphology of repeated fracturing fractures.

[0010] Preferably, the arrival time difference method based on the initial arrival information of P-waves and S-waves is used for microseismic event location, the source vector is calculated by combining P-wave polarization analysis, and microseismic source inversion location is carried out based on the picked first arrivals of P-waves and S-waves, Geiger location method, and grid search method. During the location process, ray tracing forward modeling is combined, and the time residuals of theoretical and actual P-waves and S-waves and the angular residuals of the source vector are used for constraint to obtain the source location information.

[0011] Preferably, the method for obtaining the stress index SI is as follows:

[0012]

[0013] where η c is the cumulative seismic efficiency of the clustering event; c is the coefficient for different lithologies, times, and volumes; DI is the diffusion index.

[0014] Preferably, the method for obtaining the plastic index PI is as follows:

[0015]

[0016] where μ is the dynamic shear modulus, and η c is the cumulative seismic efficiency of the clustering event.

[0017] Preferably, the method for obtaining the diffusion index DI is as follows:

[0018]

[0019] where X 2 is the square of the average distance of the clustering event, and t is the average time interval of the clustering event. Preferably, the method for obtaining the apparent stress σ a is as follows:

[0020] σ a = μ 0 E / M O

[0021] where μ 0 is the shear modulus of the reservoir rock; M O is the seismic moment of the microseismic event; Energy

[0022]

[0023] Preferably, the fracturing results of the remaining oil enrichment area obtained are as follows:

[0024] The length of the source fracture is less than half of the well spacing, the fracture width is less than 5 mm, and the fracture height is less than 10 m, and fracture reconstruction is carried out; the fracture branching index is less than 4, and the main fracture is formed; the fracture branching index is greater than 4, and a complex fracture network is generated; the fracture network length is less than 500, and fracture reconstruction is carried out; the apparent stress value is greater than 5, indicating that a large number of new hydraulic fractures are opened during refracturing; the apparent stress value is less than 5, indicating that the old fractures are opened during refracturing; the stress index value is greater than 0.2, and the stress field is more stable; the diffusion index is greater than 0.4, the time interval between events is small, the distance interval is large, and in the case of refracturing, the hydraulic fracture can extend a long distance in a short time, and fracture reconstruction is carried out; the plastic index is greater than 0.2, and the reservoir is extremely easy to deform; the plastic index is less than 0.2, and the reservoir is not easy to deform.

[0025] Preferably, the method for adjusting construction parameters according to the fracturing results in the remaining oil enrichment area is as follows:

[0026] When the length of the source fracture is less than half of the well spacing, the fracture width is less than 5 mm, the fracture height is less than 10 m, and the stress index is less than 0.2, the sand volume and liquid volume are increased to 130% of those of the fractured well.

[0027] When the fracture branching index is less than 4 and the fracture network length is less than 500, during the fracturing construction in the same research area, the sand volume and liquid volume are increased to 140% of the parameters of the fractured well.

[0028] When the logarithm of the apparent stress is less than 5, during the fracturing construction in the same research area, multi-stage temporary plugging is added, and the dosage of the temporary plugging agent is adjusted according to the construction pressure.

[0029] When the diffusion index is greater than 0.4, the sand volume and liquid volume are reduced to 80% of those of the fractured well.

[0030] When the plasticity index is greater than 0.2, the sand volume and liquid volume are increased to 130% of those of the fractured well.

[0031] A fracturing parameter optimization system based on the fracture morphology of refracturing proposed by the present invention includes:

[0032] A model establishment module, which is used to establish an initial velocity model, correct the initial velocity model, and obtain a corrected velocity model; based on the corrected velocity model, obtain P-wave and S-wave, and process the P-wave and S-wave to obtain source location information.

[0033] A parameter acquisition module, which is used to obtain the source fracture length, fracture width, fracture height, fracture branching index, fracture network length, apparent stress, stress index, diffusion index, and plasticity index based on the source location information.

[0034] A parameter processing module, which is used to obtain the fracturing results in the remaining oil enrichment area based on the above parameters, adjust the construction parameters according to the fracturing results in the remaining oil enrichment area, and realize the optimization of the fracturing parameters of the refracturing fracture morphology.

[0035] A computer device includes a memory and a processor. The memory stores a computer program, and when the processor executes the computer program, the steps of the fracturing parameter optimization method based on the fracture morphology of refracturing are realized.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] An optimization method for fracturing parameters based on the fracture morphology of refracturing proposed by the present invention first obtains the seismic source location information, and then combines the seismic source location information to obtain the fracture length, fracture width, fracture height, fracture branching index, fracture network length, apparent stress, stress index, diffusion index, and plastic index of the seismic source fracture; based on the above parameters, the fracturing results in the remaining oil enrichment area are obtained; the construction parameters are adjusted according to the fracturing results in the remaining oil enrichment area to realize the optimization of the fracturing parameters of the refracturing fracture morphology. Among them, the higher the fracture branching index, the more complex the hydraulic fracture network. The longer the fracture network length, the more complex the fracture network. A lower apparent stress value indicates that the old fractures are opened during refracturing; a higher apparent stress value indicates that a large number of new fractures are generated in the reservoir during refracturing. A lower stress index value indicates that the stress conduction is unstable and limited to a very small range of the reservoir, usually a microseismic event driven by the increase of pore pressure, and the released energy is small; a larger stress index value indicates that the microseismic event releases a large amount of energy, the stress field is more stable, and the final fracturing influence range is larger, usually a fracture or fault with the maximum principal stress direction as the strike triggered by stress microseismic events. A lower diffusion index value indicates that the time interval between events is large, but the distance interval is small; a larger diffusion index value indicates that the time interval between events is small, but the distance interval is large. A lower plastic index value indicates that the reservoir is not easily deformed; a larger plastic index value indicates that the reservoir is extremely easy to deform. Therefore, the optimization method proposed by the present invention can realize the evaluation of fracturing effects and the optimization of hydraulic fracturing design by applying the interpretation results of microseismic monitoring data, and finally, on the basis of the refracturing fracture morphology and fracture parameters, optimize the evaluation method of refracturing effects in old oilfields and form a set of parameter systems.

[0038] An optimization system for fracturing parameters based on the fracture morphology of refracturing proposed by the present invention realizes the optimization of the fracturing parameters of the refracturing fracture morphology by dividing the system into a model establishment module, a parameter acquisition module, and a parameter processing module. The modular idea is adopted to make each module independent of each other, which is convenient for unified management of each module. Description of the Drawings

[0039] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required to be used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can be obtained based on these drawings without creative efforts.

[0040] Figure 1 It is a flow chart of the optimization method for fracturing parameters based on the fracture morphology of refracturing of the present invention.

[0041] Figure 2 It is a displacement spectrogram of the microseismic event of the present invention.

[0042] Figure 3 This is a diagram of the fracturing parameter optimization system based on the fracture morphology of repeated fracturing for the present invention. Specific embodiments

[0043] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions 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. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Components of the embodiments of the present invention usually described and illustrated in the drawings here can be arranged and designed in various different configurations.

[0044] Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed present invention, but merely represents selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0045] It should be noted that similar reference numerals and letters denote similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0046] In the description of the embodiments of the present invention, it should be noted that if terms such as "upper", "lower", "horizontal", "inner", etc. are used to indicate the orientation or positional relationship, it is based on the orientation or positional relationship shown in the drawings or the orientation or positional relationship in which the product of the invention is usually placed during use. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention. In addition, terms such as "first", "second", etc. are only used for distinguishing descriptions and cannot be understood as indicating or implying relative importance.

[0047] In addition, if the term "horizontal" appears, it does not mean that the component is required to be absolutely horizontal, but it can be slightly inclined. For example, "horizontal" only means that its direction is more horizontal relative to "vertical", and it does not mean that the structure must be completely horizontal, but it can be slightly inclined.

[0048] In the description of the embodiments of the present invention, it should also be noted that unless otherwise clearly specified and limited, if terms such as "set", "installed", "connected", "connected" are used, they should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0049] The present invention will be further described in detail below with reference to the accompanying drawings:

[0050] A method for optimizing fracturing parameters based on the fracture morphology of refracturing proposed by the present invention, as Figure 1 shown, includes the following steps:

[0051] S1. Establish an initial velocity model, correct the initial velocity model, and obtain a corrected velocity model; obtain P-wave and S-wave based on the corrected velocity model, and process the P-wave and S-wave to obtain seismic source location information;

[0052] Adopt the arrival time difference method based on the initial arrival information of P-wave and S-wave to locate microseismic events, calculate the seismic source vector by combining P-wave polarization analysis, and perform microseismic source inversion location based on the picked first arrivals of P-wave and S-wave, Geiger location method and grid search method. During the location process, combine ray tracing forward modeling, and use the time residual value of theoretical and actual P-wave and S-wave and the angular residual value of the seismic source vector for constraint to obtain seismic source location information.

[0053] S2. Obtain the fracture length, fracture width, fracture height, fracture branch index, fracture network length, apparent stress, stress index, diffusion index, and plastic index based on the seismic source location information;

[0054] The method for obtaining the stress index SI is as follows:

[0055]

[0056] where η c is the cumulative seismic efficiency of clustering events; c is the coefficient for different lithologies, times, and volumes; DI is the diffusion index.

[0057] The method for obtaining the plastic index PI is as follows:

[0058]

[0059] where μ is the dynamic shear modulus, and η c is the cumulative seismic efficiency of clustering events.

[0060] The method for obtaining the diffusion index DI is as follows:

[0061]

[0062] where X 2 is the square of the average distance of clustering events, and t is the average time interval of clustering events.

[0063] The method for obtaining the apparent stress σ a is as follows:

[0064] σa = μ 0 E / M O

[0065] where μ 0 is the shear modulus of the reservoir rock; M O is the seismic moment of the microseismic event; Energy

[0066]

[0067] S3. Obtain the fracturing results of the remaining oil enrichment area based on the above parameters, and adjust the construction parameters according to the fracturing results of the remaining oil enrichment area to achieve the optimization of fracturing parameters for the fracture morphology of refracturing.

[0068] The obtained fracturing results of the remaining oil enrichment area are as follows:

[0069] The length of the source fracture is less than half of the well spacing, the fracture width is less than 5 mm, and the fracture height is less than 10 m, then carry out fracture transformation; the fracture branching index is less than 4, and a main fracture is formed; the fracture branching index is greater than 4, and a complex fracture network is generated; the fracture network length is less than 500, then carry out fracture transformation; the apparent stress value is greater than 5, indicating that a large number of new hydraulic fractures are opened during refracturing; the apparent stress value is less than 5, indicating that the old fractures are opened during refracturing; the stress index value is greater than 0.2, and the stress field is more stable; the diffusion index is greater than 0.4, the time interval between events is small, and the distance interval is large. In the case of refracturing, the hydraulic fractures can extend a long distance in a short time, then carry out fracture transformation; the plasticity index is greater than 0.2, and the reservoir is extremely easy to deform; the plasticity index is less than 0.2, and the reservoir is not easy to deform.

[0070] The method for adjusting the construction parameters according to the fracturing results of the remaining oil enrichment area is as follows:

[0071] When the length of the source fracture is less than half of the well spacing, the fracture width is less than 5 mm, the fracture height is less than 10 m, and the stress index is less than 0.2, the sand volume and liquid volume are increased to 130% of the fractured well;

[0072] When the fracture branching index is less than 4 and the fracture network length is less than 500, during the fracturing construction in the same study area, the sand volume and liquid volume are increased to 140% of the parameters of the fractured well;

[0073] When the logarithm of the apparent stress is less than 5, add multi-stage temporary plugging during the fracturing construction in the same study area, and the dosage of the temporary plugging agent is adjusted according to the construction pressure;

[0074] When the diffusion index is greater than 0.4, the sand volume and liquid volume are reduced to 80% of the fractured well;

[0075] When the plasticity index is greater than 0.2, the sand volume and liquid volume are increased to 130% of the fractured well.

[0076] The optimization method will be described in detail below:

[0077] First: Obtain the location where the microseismic event occurs, which is used to evaluate whether it occurs in the remaining oil enrichment area. Fractures are generated in the remaining oil enrichment area, and the remaining oil is mobilized. The specific steps to obtain the location where the microseismic event occurs are as follows:

[0078] Step 1) Use the acoustic logging data of some fracturing wells and monitoring wells in the study area (obtained from the actual acoustic logging before fracturing) to establish an initial velocity model. The model assumes isotropy, and the reservoir is horizontally stratified. The velocity model is stratified according to the change of acoustic logging velocity, and the average value of the acoustic logging velocity in the stratified section is used as the velocity value of this layer.

[0079] Step 2) When the initial fracturing perforation positions are known, use the picked P-wave first arrivals to match the perforation positions according to the velocity model obtained in Step 1). During the velocity model correction process, a small perturbation velocity is applied in each layer, and the residual and the change value at each perturbation position are determined. In this way, a perturbation matrix is established. This analysis process evaluates the perturbation matrix and selects a position change value that maximally satisfies the conditions of minimizing the residual and minimizing the position error (the error between the known perforation position and the calculated perforation position) at the same time. Based on this new velocity structure, iterative operations are performed with the improved velocity structure until an optimal position is found. Continuously adjust the velocity model until the calculated position is sufficiently close to the actual position, and the corresponding velocity model is relatively accurate, that is, relatively accurate P-waves and S-waves are obtained.

[0080] Step 3) Use the arrival time difference method based on the first arrival information of P-waves and S-waves for microseismic event location. Combine P-wave polarization analysis to calculate the source vector, and perform microseismic source inversion location using the Geiger location method and the grid search method based on the picked P-wave and S-wave first arrivals. During the location process, combine ray tracing forward modeling, and use the time residuals of theoretical and actual P-waves and S-waves and the angular residuals of the source vector for constraint to finally obtain an accurate source location result.

[0081] Step 4) Return the waveform data of the located microseismic events one by one for inspection. For microseismic events with large residuals, fine adjustment of the first arrivals should be performed and the first arrivals should be updated and then re-located.

[0082] Second: Obtain the parameters related to the microseismic events, which are used to evaluate the fracturing effect, whether complex fractures are generated in the remaining oil enrichment area, and provide channels for the remaining oil. The obtained parameters are as follows:

[0083] Fracture length, width, and height: Inversion of the composite source mechanism is performed for event clusters with close spatial distribution and similar waveforms to obtain the fracture length, width, and height.

[0084] Fracture branch index: The branch index of a single fracture. For the main fracture that extends from the perforation point, its branch index is 1; for the fractures branching out from the main fracture, their branch indices increase by 1 in sequence. The higher the branch index, the more complex the hydraulic fracture network.

[0085] Fracture network length: The cumulative length of all hydraulic fractures in the entire fracture network, that is, the sum of the lengths of all single fractures. The longer the fracture network length, the more complex the fracture network.

[0086] Apparent stress: It can describe the ease or difficulty of the fracture process. Apparent stress is related to the energy released by the fracture of reservoir rocks. When the fracturing fluid enters the reservoir matrix and fractures, it will change the amount of energy released by the reservoir fracture. The fracturing fluid can play a role similar to "lubrication" to reduce the stress on the fracture surface of the reservoir rock, making the reservoir easier to fracture. To calculate the apparent stress, it is first necessary to accurately calculate the energy released by microseismic events. The energy can be calculated by the integral of the displacement spectrum of each microseismic event Figure 2 The lower the apparent stress value, it represents the reopening of old fractures during refracturing; the higher the apparent stress value, it represents that a large number of new fractures are generated in the reservoir during refracturing.

[0087] Stress index: The stress index describes the stress change during the fracturing process. A lower stress index value represents unstable stress conduction and is limited to a very small range of the reservoir, usually microseismic events driven by increased pore pressure, releasing less energy; a larger stress index value represents that the microseismic events release a large amount of energy, the stress field is more stable, and the final fracturing influence range is larger, usually fractures or faults with the maximum principal stress direction as the strike are triggered by stress microseismic events.

[0088] Diffusion index: A lower diffusion index value represents a large time interval between events but a small distance interval; a larger diffusion index value represents a small time interval between events but a large distance interval.

[0089] Plasticity index: A lower plasticity index value represents that the reservoir is not easily deformed; a larger diffusion index value represents that the reservoir is extremely easily deformed.

[0090] Then: According to the information and parameters obtained above, evaluate the fracturing effect.

[0091] The location of the microseismic event is within the range of the remaining oil enrichment area, and the evaluation result is effective transformation;

[0092] The distance between the location of the microseismic event and the remaining oil enrichment area is greater than 3 meters, and the evaluation result is low-degree transformation.

[0093] The following are all based on the calculation results of the fractured wells in the study area:

[0094] When the length of the source fracture is less than half of the well spacing, the width is less than 5 mm, and the height is less than 10 m, the evaluation result is low-level stimulation. When the fracture branching index is less than 4, the evaluation result is that only the main fracture is mainly formed. Considering the refracturing operation, it is highly likely that the pre-existing fracture is opened; when the fracture branching index is greater than 4, the evaluation result is that a complex fracture network is generated. When the fracture network length is less than 500, the evaluation result is low-level stimulation; when the fracture network length is greater than 500, the evaluation result is high-level stimulation. Apparent stress is generally expressed by the logarithm of the apparent stress value. When the apparent stress value is greater than 5, the evaluation result is that a large number of new hydraulic fractures are opened during refracturing; when the apparent stress value is less than 5, the evaluation result is that the old fracture is opened during refracturing. When the stress index is greater than 0.2, the evaluation result is that the microseismic event releases a large amount of energy, the stress field is more stable, and the final fracturing influence range is larger; when the stress index is less than 0.2, the evaluation result is that the stress conduction is unstable and limited to a very small range of the reservoir, usually a microseismic event driven by the increase in pore pressure, and the released energy is small. When the diffusion index is greater than 0.4, the evaluation result is that the time interval between events is small, but the distance interval is large. In the case of refracturing, the hydraulic fracture can extend a long distance in a short time, and there is a risk of fracture connection; when the diffusion index is less than 0.4, the evaluation result is that the time interval between events is large, but the distance interval is small. When the plasticity index is greater than 0.2, the evaluation result is that the reservoir is extremely easy to deform; when the plasticity index is less than 0.2, the evaluation result is that the reservoir is not easy to deform, and more hydraulic fractures are likely to be generated during refracturing.

[0095] Finally: Combine the fracturing fracture design, adjust the construction parameters, and guide the optimization design of the subsequent single-well refracturing process and parameter system.

[0096] When the microseismic event location of the fractured well in the study area shows a failed fracture, during the fracturing construction design in the same study area, the fracturing construction parameters should be increased: the sand volume and liquid volume are increased to 130% of the fractured well.

[0097] The following are all based on the calculation results of the fractured wells in the study area:

[0098] When the length of the source fracture is less than half of the well spacing, the width is less than 5 mm, the height is less than 10 m, and the stress index is less than 0.2, the fracturing construction parameters should be increased: the sand volume and liquid volume are increased to 130% of the fractured well. When the fracture branching index is less than 4 and the fracture network length is less than 500, during the fracturing construction design in the same study area, the fracturing construction parameters should be increased: the sand volume and liquid volume are increased to 140% of the parameters of the fractured well. When the logarithm of the apparent stress is less than 5, multi-stage temporary plugging should be added in the design, and the amount of the temporary plugging agent is generally greater than 200 kg. If the construction fracturing is relatively high, the amount of the temporary plugging agent needs to be adjusted according to the construction pressure. When the diffusion index is greater than 0.4, the fracturing construction parameters should be increased: the sand volume and liquid volume are reduced to 80% of the fractured well. When the plasticity index is greater than 0.2, the fracturing construction parameters should be increased: the sand volume and liquid volume are increased to 130% of the fractured well.

[0099] A fracturing parameter optimization system based on the fracture morphology of refracturing proposed by the present invention, as Figure 3 shown, includes a model establishment module, a parameter acquisition module, and a parameter processing module;

[0100] The model establishment module is used to establish an initial velocity model, correct the initial velocity model, and obtain a corrected velocity model; obtain P-wave and S-wave based on the corrected velocity model, and process the P-wave and S-wave to obtain the seismic source location information;

[0101] The parameter acquisition module is used to obtain the fracture length, fracture width, fracture height, fracture branch index, fracture network length, apparent stress, stress index, diffusion index, and plastic index of the seismic source based on the seismic source location information;

[0102] The parameter processing module is used to obtain the fracturing result of the remaining oil enrichment area based on the above parameters, adjust the construction parameters according to the fracturing result of the remaining oil enrichment area, and realize the construction of the refracturing fracture morphology and parameter system.

[0103] The terminal device provided by the embodiment of the present invention includes: a processor, a memory, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps in the above-mentioned method embodiments are implemented. Alternatively, when the processor executes the computer program, the functions of each module / unit in the above-mentioned device embodiments are implemented.

[0104] The computer program can be divided into one or more modules / units, and the one or more modules / units are stored in the memory and executed by the processor to complete the present invention.

[0105] The terminal device can be a computing device such as a desktop computer, a notebook, a palm computer, and a cloud server. The terminal device may include, but is not limited to, a processor and a memory.

[0106] The processor may be a central processing unit (CPU), or may also be other general-purpose processors, digital signal processors (DSPs), application specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc.

[0107] The memory can be used to store the computer program and / or module. By running or executing the computer program and / or module stored in the memory, and invoking the data stored in the memory, the processor implements various functions of the terminal device.

[0108] If the module / unit integrated in the terminal device is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on such understanding, to implement all or part of the processes in the above-described embodiment methods of the present invention, it can also be completed by a computer program instructing relevant hardware. The computer program can be stored in a computer-readable storage medium. When the computer program is executed by a processor, the steps of the above various method embodiments can be implemented. Among them, the computer program includes computer program code, and the computer program code can be in the form of source code, object code, executable file, or some intermediate form, etc. The computer-readable medium can include: any entity or device capable of carrying the computer program code, recording medium, USB flash drive, mobile hard disk, magnetic disk, optical disc, computer memory, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), electrical carrier signal, telecommunication signal, and software distribution medium, etc. It should be noted that the content included in the computer-readable medium can be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, the computer-readable medium does not include electrical carrier signals and telecommunication signals.

[0109] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for optimizing fracturing parameters based on repeated fracturing crack morphology, characterized in that: The steps include: Establishing an initial velocity model, correcting the initial velocity model, and obtaining a corrected velocity model; obtaining P waves and S waves based on the corrected velocity model, and processing the P waves and S waves to obtain earthquake source location information; Based on the earthquake source location information, the earthquake source crack length, crack width, crack height, crack branching index, crack network length, apparent stress, stress index, diffusion index and plasticity index are obtained; Based on the above parameters, the fracturing results of the remaining oil-rich area are obtained, and the construction parameters are adjusted according to the fracturing results of the remaining oil-rich area to achieve the optimization of fracturing parameters for repeated fracturing crack morphology.

2. The method for optimizing fracturing parameters based on repeated fracturing crack morphology according to claim 1, characterized in that: The microseismic event location is carried out by using the arrival time difference method based on the first arrival information of P-wave and S-wave, and the source vector is calculated by combining the P-wave polarization analysis. The microseismic source is inverted and located based on the picked first arrival of P- and S-waves, the Geiger positioning method and the grid search method. In the positioning process, ray tracing forward modeling is combined, and the time residual values ​​of theoretical and actual P- and S-waves and the angle residual values ​​of the source vector are used for constraints to obtain the source location information.

3. The method for optimizing fracturing parameters based on repeated fracturing crack morphology according to claim 1, characterized in that: The method for obtaining the stress index SI is as follows: Among them, η c is the cumulative seismic efficiency of clustered events; c is the coefficient of different lithology, time and volume; DI is the diffusion index.

4. The method for optimizing fracturing parameters based on repeated fracturing crack morphology according to claim 1, characterized in that: The method for obtaining the plasticity index PI is as follows: Where, μ is the dynamic shear modulus, η c is the cumulative earthquake efficiency of clustered events.

5. The method for optimizing fracturing parameters based on repeated fracturing crack morphology according to claim 1, characterized in that: The method for obtaining the diffusion index DI is as follows: Among them, X 2 is the square of the average distance between cluster events, and t is the average time interval between cluster events.

6. The method for optimizing fracturing parameters based on repeated fracturing crack morphology according to claim 1, characterized in that: Obtain apparent stress σ a The method is as follows: s a =μ0E / M O Where, μ0 is the shear modulus of the reservoir rock; M O is the seismic moment of the microseismic event; 7. The method for optimizing fracturing parameters based on repeated fracturing crack morphology according to claim 1, characterized in that: The fracturing results of the remaining oil-rich area are as follows: When the length of the earthquake source crack is less than half of the well spacing, the crack width is less than 5mm, and the crack height is less than 10 meters, crack reconstruction is carried out; when the crack branching index is less than 4, a main crack is formed; when the crack branching index is greater than 4, a complex crack network is generated; when the crack network length is less than 500, crack reconstruction is carried out; when the apparent stress value is greater than 5, a large number of new hydraulic cracks are opened during repeated fracturing; when the apparent stress value is less than 5, old cracks are opened during repeated fracturing; when the stress index value is greater than 0.2, the stress field is more stable; when the diffusion index is greater than 0.4, the time interval between events is small and the distance interval is large, in the case of repeated fracturing, hydraulic cracks can expand over a long distance in a short time, and crack reconstruction is carried out; when the plasticity index is greater than 0.2, the reservoir is extremely easy to deform; when the plasticity index is less than 0.2, the reservoir is not easy to deform.

8. The method for optimizing fracturing parameters based on repeated fracturing crack morphology according to claim 7, characterized in that: The method for adjusting the construction parameters according to the fracturing results of the remaining oil-rich area is as follows: When the length of the earthquake source fracture is less than half of the well spacing, the fracture width is less than 5 mm, the fracture height is less than 10 meters, and the stress index is less than 0.2, the sand and liquid volumes are increased to 130% of the fractured well; When the fracture branching index is less than 4 and the fracture network length is less than 500, the sand and liquid volumes are increased to 140% of the parameters of the fractured wells during fracturing in the same study area; When the logarithmic value of apparent stress is less than 5, multi-stage temporary plugging is added during fracturing construction in the same study area, and the amount of temporary plugging agent is adjusted according to the construction pressure; When the diffusion index is greater than 0.4, the sand and fluid volumes are reduced to 80% of those in the fractured well; The plasticity index is greater than 0.2, and the amount of sand and fluid increases to 130% of the fractured well.

9. A fracturing parameter optimization system based on repeated fracturing crack morphology, characterized in that: include: A model building module, wherein the model building module is used to build an initial velocity model, correct the initial velocity model, and obtain a corrected velocity model; obtain P waves and S waves based on the corrected velocity model, and process the P waves and S waves to obtain earthquake source location information; A parameter acquisition module, wherein the parameter acquisition module is used to acquire the earthquake source crack length, crack width, crack height, crack branching index, crack network length, apparent stress, stress index, diffusion index and plasticity index based on the earthquake source location information; The parameter processing module is used to obtain the fracturing results of the remaining oil-rich area based on the above parameters, adjust the construction parameters according to the fracturing results of the remaining oil-rich area, and realize the optimization of the fracturing parameters of the repeated fracturing crack morphology.

10. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that: When the processor executes the computer program, the steps of the method for optimizing fracturing parameters based on repeated fracturing crack morphology as described in any one of claims 1 to 8 are implemented.

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