A fracturing parameter optimization method and system based on repeated fracturing fracture morphology

Abstract

The application discloses a fracturing parameter optimization method and system based on repeated fracturing fracture morphology, belongs to the technical field of overall repeated reconstruction of old oilfield blocks, and comprises the following steps: first, obtaining seismic source positioning information; then, in combination with the seismic source positioning information, obtaining seismic source fracture length, fracture width, fracture height, fracture branch index, fracture network length, apparent stress, stress index, diffusion index and plasticity index; based on the above parameters, obtaining fracturing results of a remaining oil enrichment area; and according to the fracturing results of the remaining oil enrichment area, adjusting construction parameters to realize fracturing parameter optimization of the repeated fracturing fracture morphology. Therefore, the optimization method solves the problems in the prior art, can realize evaluation of fracturing effects by using interpretation results of microseismic monitoring data, optimization of hydraulic fracturing design, and ultimately, on the basis of the repeated fracturing fracture morphology and the fracture parameters, optimization of an old oilfield repeated fracturing effect evaluation method and formation of a parameter system.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of overall repeated reconstruction of old oilfield blocks, and relates to a fracturing parameter optimization method and system based on repeated fracturing fracture morphology. BACKGROUND

[0002] After long-term injection and production, the ground stress field of the old oilfield changes dynamically, thereby affecting the azimuth and morphology of the repeated fracturing fractures.

[0003] At present, downhole microseism is used as a main means for monitoring fracturing fractures, and has been used for microseismic monitoring in old oilfields for many times. However, the prior art only interprets and analyzes the microseismic monitoring data, does not evaluate the data for fracturing, and does not optimize the data in combination with the fracturing results, so that the fracturing effect of the repeated fracturing fractures cannot be effectively evaluated in the construction process. SUMMARY

[0004] The application aims to solve the problem that the data cannot be evaluated for fracturing and the data cannot be optimized in combination with the fracturing results in the prior art, and provides a fracturing parameter optimization method and system based on repeated fracturing fracture morphology.

[0005] To achieve the above-mentioned purpose, the following technical solutions are adopted in the application:

[0006] The fracturing parameter optimization method based on repeated fracturing fracture morphology provided by the application comprises the following steps:

[0007] An initial velocity model is established, the initial velocity model is corrected, and a corrected velocity model is obtained; P waves and S waves are obtained based on the corrected velocity model, and the P waves and S waves are processed to obtain source positioning information;

[0008] The source crack length, crack width, crack height, crack branching index, crack network length, apparent stress, stress index, diffusion index and plastic index are obtained based on the source positioning information;

[0009] The fracturing results of the remaining oil enrichment zone are obtained based on the above parameters, the construction parameters are adjusted according to the fracturing results of the remaining oil enrichment zone, and the fracturing parameter optimization of the repeated fracturing fracture morphology is realized.

[0010] Preferably, the arrival time difference method based on the first information of P waves and S waves is used for microseismic event positioning, the source vector is calculated by combining P wave polarization analysis, the microseismic source inversion positioning is performed according to the picked-up P wave and S wave first arrivals, the Geiger positioning method and the grid search method, and the source positioning information is obtained by combining the ray tracing forward in the positioning process, and using the time residual values of the theoretical and actual P waves and S waves and the angle residual values of the source vectors for constraint.

[0011] Preferably, the stress index SI is obtained by the following method:

[0012]

[0013] wherein η c is the cumulative seismic efficiency of clustered events; c is a coefficient of different lithologies, times and volumes; DI is the diffusion index.

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

[0015]

[0016] wherein μ is the dynamic shear modulus, η c is the cumulative seismic efficiency of clustered events.

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

[0018]

[0019] wherein X 2 is the square of the average distance of clustered events, t is the average time interval of clustered events. Preferably, the method for obtaining the apparent stress σ a is as follows:

[0020] σ a = μ0E / M O

[0021] wherein μ0 is the shear modulus of the reservoir rock; M O is the seismic moment of the microseismic event; E

[0022]

[0023] Preferably, the fracturing result of the remaining oil enrichment zone is as follows:

[0024] The source fracture length is less than one-half of the well spacing, the fracture width is less than 5 mm, the fracture height is less than 10 meters, and the fracture is reformed; the fracture branch index is less than 4, and a main fracture is formed; the fracture branch index is greater than 4, and a complex fracture network is generated; the fracture network length is less than 500, and the fracture is reformed; the apparent stress value is greater than 5, and a large number of new hydraulic fractures are opened in the repeated fracturing; the apparent stress value is less than 5, and the old fracture is opened in the repeated fracturing; 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 of the event is small, the distance interval is large, the hydraulic fracture can be extended for a long distance in a short time under the condition of repeated fracturing, and the fracture is reformed; 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.

[0025] Preferably, the method for adjusting the construction parameters according to the fracturing result of the remaining oil enrichment zone is as follows:

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

[0027] When the crack branch index is less than 4 and the crack network length is less than 500, the sand and liquid volume is increased to 140% of the fractured well parameters during the fracturing operation in the same research area;

[0028] When the stress logarithmic value is less than 5, a multi-stage temporary plugging is added during the fracturing operation in the same research area, and the amount of temporary plugging agent is adjusted according to the construction pressure;

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

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

[0031] The fracturing parameter optimization system based on repeated fracturing crack morphology provided by the application comprises:

[0032] A model establishing module is configured to establish an initial velocity model, correct the initial velocity model, and obtain a corrected velocity model; P waves and S waves are obtained based on the corrected velocity model, and the P waves and S waves are processed to obtain source positioning information;

[0033] A parameter obtaining module is configured to obtain a 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 based on the source positioning information;

[0034] A parameter processing module is configured to obtain a remaining oil enrichment zone fracturing result based on the above parameters, adjust the construction parameters according to the remaining oil enrichment zone fracturing result, and realize fracturing parameter optimization of the repeated fracturing crack morphology.

[0035] A computer device comprises a memory and a processor, the memory stores a computer program, and the processor realizes the steps of the fracturing parameter optimization method based on the repeated fracturing crack morphology when executing the computer program.

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

[0037] The application provides a fracturing parameter optimization method based on repeated fracturing fracture morphology, and first acquires seismic source positioning information, and then acquires a seismic source fracture length, a fracture width, a fracture height, a fracture branch index, a fracture network length, an apparent stress, a stress index, a diffusion index and a plasticity index in combination with the seismic source positioning information; the fracturing results of a remaining oil enrichment zone are acquired based on the above parameters; and the fracturing parameter optimization of the repeated fracturing fracture morphology is realized by adjusting construction parameters according to the fracturing results of the remaining oil enrichment zone. The higher the fracture branch index is, the more complex the hydraulic fracture network is. The longer the fracture network length is, the more complex the fracture network is. The lower the apparent stress value is, the more old fractures are opened during the repeated fracturing. The higher the apparent stress value is, the more new fractures are generated in the reservoir due to the repeated fracturing reconstruction. The lower the stress index value is, the more unstable the stress conduction is and the smaller the range of the reservoir is, and the stress index value is usually a microseismic event driven by the increase of pore pressure and fluid, and the released energy is small. The larger the stress index value is, the more stable the stress field is, and the larger the final fracturing influence range is, and the stress index value is usually a fracture or fault in the maximum principal stress direction triggered by a stress microseismic event. The lower the diffusion index value is, the larger the time interval of the event is and the smaller the distance interval is. The larger the diffusion index value is, the smaller the time interval of the event is and the larger the distance interval is. The lower the plasticity index value is, the less the reservoir is deformed. The larger the plasticity index value is, the more the reservoir is deformed. Therefore, the optimization method can realize the evaluation of the fracturing effect by using the interpretation results of the microseismic monitoring data, the optimization of the hydraulic fracturing design, and finally the optimization of the repeated fracturing effect evaluation method of the old oilfield and the formation of a parameter system based on the repeated fracturing fracture morphology and the fracture parameters.

[0038] The application provides a fracturing parameter optimization system based on repeated fracturing fracture morphology, and the system is divided into a model establishment module, a parameter acquisition module and a parameter processing module to realize the fracturing parameter optimization of the repeated fracturing fracture morphology. The modularization thought is adopted to make the modules independent of each other, and the modules are convenient to manage. BRIEF DESCRIPTION OF DRAWINGS

[0039] In order to more clearly illustrate the technical scheme of the embodiments of the application, the drawings needed in the embodiments will be briefly introduced as follows, and it should be understood that the following drawings only show some embodiments of the application, and therefore should not be regarded as a limitation to the scope, and other related drawings can be obtained by those skilled in the art without any creative effort on the premise of not paying any creative effort.

[0040] Figure 1 The application provides a fracturing parameter optimization method based on repeated fracturing fracture morphology, and first acquires seismic source positioning information, and then acquires a seismic source fracture length, a fracture width, a fracture height, a fracture branch index, a fracture network length, an apparent stress, a stress index, a diffusion index and a plasticity index in combination with the seismic source positioning information; the fracturing results of a remaining oil enrichment zone are acquired based on the above parameters; and the fracturing parameter optimization of the repeated fracturing fracture morphology is realized by adjusting construction parameters according to the fracturing results of the remaining oil enrichment zone. The higher the fracture branch index is, the more complex the hydraulic fracture network is. The longer the fracture network length is, the more complex the fracture network is. The lower the apparent stress value is, the more old fractures are opened during the repeated fracturing. The higher the apparent stress value is, the more new fractures are generated in the reservoir due to the repeated fracturing reconstruction. The lower the stress index value is, the more unstable the stress conduction is and the smaller the range of the reservoir is, and the stress index value is usually a microseismic event driven by the increase of pore pressure and fluid, and the released energy is small. The larger the stress index value is, the more stable the stress field is, and the larger the final fracturing influence range is, and the stress index value is usually a fracture or fault in the maximum principal stress direction triggered by a stress microseismic event. The lower the diffusion index value is, the larger the time interval of the event is and the smaller the distance interval is. The larger the diffusion index value is, the smaller the time interval of the event is and the larger the distance interval is. The lower the plasticity index value is, the less the reservoir is deformed. The larger the plasticity index value is, the more the reservoir is deformed. Therefore, the optimization method can realize the evaluation of the fracturing effect by using the interpretation results of the microseismic monitoring data, the optimization of the hydraulic fracturing design, and finally the optimization of the repeated fracturing effect evaluation method of the old oilfield and the formation of a parameter system based on the repeated fracturing fracture morphology and the fracture parameters based on the repeated fracturing fracture morphology and the fracture parameters.

[0041] Figure 2 The application provides a fracturing parameter optimization method based on repeated fracturing fracture morphology, and first acquires seismic source positioning information, and then acquires a seismic source fracture length, a fracture width, a fracture height, a fracture branch index, a fracture network length, an apparent stress, a stress index, a diffusion index and a plasticity index in combination with the seismic source positioning information; the fracturing results of a remaining oil enrichment zone are acquired based on the above parameters; and the fracturing parameter optimization of the repeated fracturing fracture morphology is realized by adjusting construction parameters according to the fracturing results of the remaining oil enrichment zone. The higher the fracture branch index is, the more complex the hydraulic fracture network is. The longer the fracture network length is, the more complex the fracture network is. The lower the apparent stress value is, the more old fractures are opened during the repeated fracturing. The higher the apparent stress value is, the more new fractures are generated in the reservoir due to the repeated fracturing reconstruction. The lower the stress index value is, the more unstable the stress conduction is and the smaller the range of the reservoir is, and the stress index value is usually a microseismic event driven by the increase of pore pressure and fluid, and the released energy is small. The larger the stress index value is, the more stable the stress field is, and the larger the final fracturing influence range is, and the stress index value is usually a fracture or fault in the maximum principal stress direction triggered by a stress microseismic event. The lower the diffusion index value is, the larger the time interval of the event is and the smaller the distance interval is. The larger the diffusion index value is, the smaller the time interval of the event is and the larger the distance interval is. The lower the plasticity index value is, the less the reservoir is deformed. The larger the plasticity index value is, the more the reservoir is deformed. Therefore, the optimization method can realize the evaluation of the fracturing effect by using the interpretation results of the microseismic monitoring data, the optimization of the hydraulic fracturing design, and finally the optimization of the repeated fracturing effect evaluation method of the old oilfield and the formation of a parameter system based on the repeated fracturing fracture morphology and the fracture parameters based on the repeated fracturing fracture morphology and the fracture parameters.

[0042] Figure 3 FIG. 1 is a diagram of a fracturing parameter optimization system based on a repeated fracturing fracture morphology according to an embodiment of the present application. DETAILED DESCRIPTION

[0043] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the following will be combined with the accompanying drawings for the embodiments of the present application to make a clear and complete description of the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the accompanying drawings can be arranged and designed in various different configurations.

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

[0045] It should be noted that: similar reference numerals and letters represent 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 the subsequent drawings.

[0046] In the description of the embodiments of the present application, it should be noted that, if the orientation or position relationship indicated by the terms "upper", "lower", "horizontal", "inner" and the like is based on the orientation or position relationship shown in the drawings, or is the orientation or position relationship when the product of the present application is used, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second" and the like are only used for differentiation in description, 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 must be absolutely horizontal, but can be slightly inclined. For example, "horizontal" only means that its direction is relatively more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly inclined.

[0048] In the description of the embodiments of the present application, it should also be noted that, unless otherwise explicitly specified and limited, if the terms "arrange", "mount", "connect", "connect" appear, they should be understood in a broad sense, for example, can be fixedly connected, can be detachably connected, or integrally connected; can be mechanically connected, can be electrically connected; can be directly connected, can be indirectly connected through an intermediate medium, or can be the communication inside two elements. For those of ordinary skill in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

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

[0050] A fracturing parameter optimization method based on repeated fracturing fracture morphology is provided, as shown in the figure, comprising the following steps: Figure 1

[0051] S1, an initial velocity model is established, the initial velocity model is corrected, and a corrected velocity model is obtained; P waves and S waves are obtained based on the corrected velocity model, and the P waves and S waves are processed to obtain source positioning information;

[0052] The arrival time difference method based on P wave and S wave first arrival information is used for microseismic event positioning, the source vector is calculated by combining P wave polarization analysis, and the microseismic source inversion positioning is performed according to the picked-up P wave and S wave first arrivals, Geiger positioning method and grid search method. In the positioning process, ray tracing forward is combined, and the time residual value of the theoretical and actual P wave and S wave and the angle residual value of the source vector are used for constraint to obtain the source positioning information.

[0053] S2, the source crack length, crack width, crack height, crack branch index, crack network length, apparent stress, stress index, diffusion index and plasticity index are obtained based on the source positioning information;

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

[0055]

[0056] Wherein, 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.

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

[0058]

[0059] Wherein, μ is the dynamic shear modulus, η c is the cumulative seismic efficiency of clustered events.

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

[0061]

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

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

[0064] σ​a =μ0E / M O

[0065] Where μ0 is the shear modulus of the reservoir rock; M O The seismic moment and energy of this micro-seismic event.

[0066]

[0067] S3. Based on the above parameters, obtain the fracturing results of the remaining oil-rich area, and adjust the construction parameters according to the fracturing results of the remaining oil-rich area to achieve optimization of fracturing parameters for repeated fracturing fracture morphology.

[0068] The fracturing results of the remaining oil-rich zone are as follows:

[0069] Fracture modification is required when the source fracture length is less than half the well spacing, the fracture width is less than 5 mm, and the fracture height is less than 10 meters; a fracture branching index of less than 4 indicates the formation of a main fracture; a fracture branching index of greater than 4 indicates the formation of a complex fracture network; a fracture network length of less than 500 mm indicates fracture modification; an apparent stress value of greater than 5 indicates the opening of numerous new hydraulic fractures during repeated fracturing; an apparent stress value of less than 5 indicates the opening of old fractures during repeated fracturing; a stress index of greater than 0.2 indicates a more stable stress field; a diffusion index of greater than 0.4 indicates a short time interval and large distance interval between events, meaning that hydraulic fractures can expand a long distance in a short time under repeated fracturing conditions, thus requiring fracture modification; a plasticity index of greater than 0.2 indicates that the reservoir is highly deformable; a plasticity index of less than 0.2 indicates that the reservoir is not easily deformable.

[0070] The method for adjusting construction parameters based on the fracturing results of the remaining oil-rich zone is as follows:

[0071] When the fracture length at the epicenter is less than half 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 fluid volume increases to 130% of that of the fractured well.

[0072] When the fracture branching index is less than 4 and the fracture network length is less than 500, the sand and fluid volume increases to 140% of the parameters of the fractured well during fracturing operations in the same study area.

[0073] If the logarithm of apparent stress is less than 5, multiple stages of temporary plugging are added during fracturing operations in the same study area, and the amount of temporary plugging agent is adjusted according to the construction pressure.

[0074] When the diffusion index is greater than 0.4, the sand and fluid volume are reduced to 80% of that of a fractured well.

[0075] The plasticity index is greater than 0.2, and the sand and fluid volume increases to 130% of that of a fractured well.

[0076] The optimization method is described in detail below:

[0077] Firstly: Obtain the location of microseismic event, which is used to evaluate whether it occurs in the remaining oil enrichment area, whether the fracture is produced in the remaining oil enrichment area, and whether the remaining oil is produced. The specific steps are as follows:

[0078] Step 1) Use the acoustic logging data of part of the fracturing well and monitoring well in the study area (obtained from the actual acoustic logging before fracturing) to establish an initial velocity model. The model assumes isotropy and horizontal layering of the reservoir. The velocity model is layered according to the acoustic logging velocity variation, and the average value of the acoustic logging velocity of the layered segment is used as the velocity value of the layer.

[0079] Step 2) In the case where the perforation position of the initial fracturing is known, the velocity model obtained in step 1) is used to match the perforation position according to the picked P-wave first arrival. During the velocity model correction process, a small perturbation velocity is applied in each layer, and the residual error and the change value of 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 maximizes the conditions of minimizing the residual error and minimizing the position error (the error between the known perforation position and the calculated perforation position). Based on the improved velocity structure, the velocity structure is iterated until an optimal position is found. When the calculated position is close to the actual position, the corresponding velocity model is relatively accurate, that is, the relative accurate P-wave and S-wave are obtained.

[0080] Step 3) Use the time difference method based on P-wave and S-wave first arrival information to locate the microseismic event. Combine P-wave polarization analysis to calculate the source vector, and use the Geiger positioning method and grid search method to perform microseismic source inversion positioning based on the picked P-wave and S-wave first arrival. In the positioning process, ray tracing forward is combined to apply theoretical and actual P-wave and S-wave time residuals and source vector angle residuals for constraint, and finally accurate source positioning results are obtained.

[0081] Step 4) Check the waveform data of the located microseismic event one by one, and adjust the first arrival finely and update the first arrival for repositioning for the microseismic event with large residual error.

[0082] Secondly: Obtain the related parameters of microseismic event, which is used to evaluate the fracturing effect, whether complex fractures are produced in the remaining oil enrichment area, and whether channels are provided for the remaining oil. The obtained parameters are as follows:

[0083] Fracture length, width, and height: For the event cluster with close spatial distribution and similar waveform, the composite source mechanism inversion is performed to obtain the fracture length, width, and height.

[0084] Fracture branch index: the branch index of a single fracture, the main fracture, i.e. the fracture extending from the perforation point, has a branch index of 1; the fracture branching out from the main fracture has a branch index of 1 plus 1 in turn. 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, i.e. the sum of the lengths of all single fractures. The longer the fracture network length, the more complex the fracture network.

[0086] Apparent stress: can describe the difficulty of the fracture process. Apparent stress is related to the energy released by the fracture of reservoir rock. The entry of fracturing fluid into the reservoir matrix and fractures changes the size of the energy released by the fracture of the reservoir. The fracturing fluid can play a role similar to "lubrication" to reduce the stress on the fracture surface of the reservoir rock, thereby making the reservoir more prone to fracture. To calculate the apparent stress, the energy released by each microseismic event needs to be accurately calculated. The energy can be calculated by integrating the displacement spectrum of each microseismic event Figure 2 . A lower apparent stress value represents the opening of old fractures during repeated fracturing; a higher apparent stress value represents the generation of a large number of new fractures in the reservoir during repeated fracturing.

[0087] Stress index: the stress index describes the stress change during fracturing. 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 the increase in pore pressure and fluid, releasing less energy; a larger stress index value represents microseismic events releasing large amounts of energy, a more stable stress field, and a larger final fracturing range, usually fractures or faults in the direction of the maximum principal stress 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 a reservoir that is not easily deformed; a larger plasticity index value represents a reservoir that is extremely easily deformed.

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

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

[0092] If the microseismic event location is more than 3 meters away from the remaining oil enrichment area, the evaluation result is low degree of transformation.

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

[0094] When the source fracture length is less than half the well spacing, the width is less than 5 mm, the height is less than 10 meters, and the stress index is less than 0.2, the fracturing construction parameters should be increased: the sand and liquid volume should be increased to 130% of the parameters of the fractured well. When the fracture branch index is less than 4 and the fracture network length is less than 500, the fracturing construction parameters should be increased in the fracturing design of the same research area: the sand and liquid volume should be increased to 140% of the parameters of the fractured well. When the apparent stress logarithm value is less than 5, multi-stage temporary plugging should be added in the design, and the temporary plugging agent is generally greater than 200 kg. If the fracturing is high, the amount of 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 and liquid volume should be reduced to 80% of the parameters of the fractured well. When the plasticity index is greater than 0.2, the fracturing construction parameters should be increased: the sand and liquid volume should be increased to 130% of the parameters of the fractured well.

[0095] Finally: combined with fracturing fracture design, adjust construction parameters, guide subsequent single well repeated fracturing process and parameter system optimization design.

[0096] When the microseismic event position of the fractured well in the study area shows that the fracture is invalid, the fracturing construction parameters should be increased in the fracturing design of the same research area: the sand and liquid volume should be increased to 130% of the parameters of the fractured well.

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

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

[0099] The application provides a fracturing parameter optimization system based on repeated fracturing fracture morphology, as shown in the accompanying drawings. Figure 3 The system comprises a model establishing module, a parameter obtaining module and a parameter processing module.

[0100] The model establishing module is used for establishing an initial velocity model, correcting the initial velocity model, and obtaining a corrected velocity model; P waves and S waves are obtained based on the corrected velocity model, and the P waves and the S waves are processed to obtain seismic source positioning information.

[0101] The parameter obtaining module is used for obtaining a seismic source fracture length, a fracture width, a fracture height, a fracture branch index, a fracture network length, an apparent stress, a stress index, a diffusion index and a plasticity index based on the seismic source positioning information.

[0102] The parameter processing module is used for obtaining a fracturing result of a remaining oil enrichment zone based on the above parameters, adjusting construction parameters according to the fracturing result of the remaining oil enrichment zone, and realizing repeated fracturing fracture morphology and parameter system construction.

[0103] The terminal device provided in the embodiment comprises a processor, a memory and a computer program stored in the memory and executable on the processor. The processor implements the steps in each method embodiment when executing the computer program. Alternatively, the processor implements the functions of each module / unit in each device embodiment when executing the computer program.

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

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

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

[0107] The memory can be configured to store the computer programs and / or modules, and the processor realizes various functions of the terminal device by running or executing the computer programs and / or modules stored in the memory, and calling data stored in the memory.

[0108] The modules / units integrated in the terminal device, if realized in the form of software function units and sold or used as independent products, can be stored in a computer readable storage medium. Based on such understanding, all or part of the processes in the above-mentioned embodiment methods can also be completed by a computer program instructing related hardware, and the computer program can be stored in a computer readable storage medium. The computer program can realize the steps of the above-mentioned various method embodiments when executed by a processor. The computer program includes computer program code, which can be in the form of source code, object code, executable file or some intermediate form. The computer readable medium can include any entity or device capable of carrying the computer program code, recording medium, U disk, mobile hard disk, magnetic disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signal, telecommunication signal and software distribution medium, etc. It should be noted that the computer readable medium can include or exclude contents 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 only describes the preferred embodiments of the present application and is not used to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for optimizing fracturing parameters based on repeating fracturing fracture morphology, characterized in that, The method comprises the following steps: 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 source positioning information; obtaining source crack length, crack width, crack height, crack branch index, crack network length, apparent stress, stress index, diffusion index and plasticity index based on the source positioning information; obtaining a fracturing result of a remaining oil enrichment zone based on the above parameters, adjusting operation parameters according to the fracturing result of the remaining oil enrichment zone, and realizing fracturing parameter optimization of repeated fracturing crack morphology; The obtained fracturing result of the remaining oil enrichment zone is as follows: When the source crack length is less than one-half of the well spacing, the crack width is less than 5 mm, the crack height is less than 10 meters, and the stress index is less than 0.2, the sand and liquid amounts are increased to 130% of the fractured well. When the crack branch index is less than 4 and the crack network length is less than 500, the sand and liquid amounts are increased to 140% of the fractured well parameters during fracturing construction in the same research area. When the apparent stress logarithmic value is less than 5, a multi-stage temporary plugging is added during fracturing construction in the same research 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 liquid amounts are reduced to 80% of the fractured well. When the plasticity index is greater than 0.2, the sand and liquid amounts are increased to 130% of the fractured well. The to-time difference method based on P wave and S wave first arrival information is used for microseismic event positioning, the source vector is calculated by combining P wave polarization analysis, the microseismic source inversion positioning is performed according to the picked-up P wave and S wave first arrivals, the Geiger positioning method and the grid search method, the ray tracing forward is combined in the positioning process, and the theoretical and actual P wave and S wave time residuals and the angle residuals of the source vector are used for constraint to obtain the source positioning information. The method comprises:

2. The method for fracturing parameter optimization based on repeating fracturing fracture morphology of claim 1, wherein, a model establishing module, which is used for 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 source positioning information; 3. The method for fracturing parameter optimization based on repeating fracturing fracture morphology of claim 1, wherein, Method for obtaining stress index The method is as follows: where, is the cumulative seismic efficiency of the clustered events; c is a coefficient for different lithologies, times, and volumes; and DI is the diffusion index.

4. The method for fracturing parameter optimization based on repeating fracturing fracture morphology of claim 1, wherein, A method of obtaining a plasticity index is as follows: wherein, G is the dynamic shear modulus, is the cumulative seismic efficiency of clustered events.

5. The method for fracturing parameter optimization based on repeating fracturing fracture morphology of claim 1, wherein, Method of acquiring a diffusion index The method is as follows: wherein, is the square of the average distance of clustered events, t is the average time interval of clustered events.

6. A fracturing parameter optimization system based on repeating fracturing fracture morphology, characterized in that, a parameter obtaining module, which is used for obtaining source crack length, crack width, crack height, crack branch index, crack network length, apparent stress, stress index, diffusion index and plasticity index based on the source positioning information; ​ ​ A parameter processing module is configured to obtain a remaining oil enrichment zone fracturing result based on the parameters, adjust the operation parameters according to the remaining oil enrichment zone fracturing result, and realize fracturing parameter optimization of the repeated fracturing fracture morphology. The obtained remaining oil enrichment zone fracturing result is as follows: When the source fracture length is less than one-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 amounts are increased to 130% of the fractured well parameters; When the fracture branch index is less than 4, the fracture network length is less than 500, the apparent stress value is less than 5, and the diffusion index is greater than 0.4, the sand and liquid amounts are increased to 140% of the fractured well parameters; When the apparent stress logarithmic value is less than 5, the plastic index is greater than 0.2, and the diffusion index is greater than 0.4, the sand and liquid amounts are reduced to 80% of the fractured well parameters; The processor executes the computer program to realize the steps of the fracturing parameter optimization method based on the repeated fracturing fracture morphology according to any one of claims 1 to 5. The processor executes the computer program to realize the steps of the fracturing parameter optimization method based on the repeated fracturing fracture morphology according to any one of claims 1 to 5. ​ ​ 7.A computer device, comprising a memory and a processor, wherein the memory stores a computer program, and the computer device is configured to perform the method according to any one of claims 1-6 when the computer program is executed by the processor. ​

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