Shale gas monitoring method and system based on microseismic fracturing

Abstract

The application discloses a shale gas monitoring method based on microseismic fracturing, which comprises the following steps: S1, establishing a three-dimensional well trajectory model; S2, marking in the well trajectory model to reflect the relationship of 'fracturing section-fracturing time-fracturing event-fracturing energy'; S3, adding a two-dimensional shale layer seismic profile at the fracturing position of the horizontal section of the well trajectory to obtain a comprehensive model of'shale layer+well trajectory+fracturing event' formed on the three-dimensional well trajectory model along the fracturing event of the well trajectory; S4, adding various two-dimensional shale layer 'dessert' attribute profiles along the well trajectory in the comprehensive model to form a comprehensive three-dimensional visualization model of 'dessert' profile+well trajectory+fracturing event for real-time fracturing effect comprehensive analysis of the fracturing section of the well trajectory; and S5, analyzing the microseismic fracturing effect on the 'dessert' profile through the comprehensive three-dimensional visualization model. The application combines the fracturing event with the seismic profile and the 'dessert' attribute profile of the shale layer, and can better monitor the shale gas.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of shale gas exploration and development, and particularly relates to a shale gas monitoring method and system based on microseismic fracturing. BACKGROUND

[0002] Shale gas refers to unconventional natural gas existing in organic matter-rich shale and its interbeds in the form of adsorption and free state, and the main component is methane and other hydrocarbons. It is a clean and efficient energy source. It can be generated in various stages of organic origin, and mainly exists in the form of free phase in fractures, pores and other reservoir spaces, and in the form of adsorption on kerogen, clay particles and pore surfaces, and a small amount in the form of dissolution in kerogen, bitumen and oil. The "sweet spot" is an important part of shale gas evaluation. Based on the logging response characteristics and rock physics analysis of shale reservoirs, the sensitive parameters of shale reservoir porosity and TOC are determined as the longitudinal wave velocity and density, and the quantitative relationship and seismic prediction model are established. Then, according to the quantitative relationship, the pre-stack simultaneous inversion of seismic data is carried out, so as to predict the porosity, TOC and brittleness index of the shale reservoir. Finally, the prediction results of the core parameters such as porosity, TOC, fracture and brittleness of the shale reservoir are comprehensively analyzed and evaluated, and on this basis, the well trajectory design and perforation fracturing design are carried out.

[0003] The shale gas horizontal well formation dip angle while drilling monitoring method mainly analyzes the change of the natural gamma curve while drilling, and predicts the actual formation change in advance, adjusts the drilling trajectory, and ensures that the wellbore passes through the target formation. Figure 1 The middle A target point is a theoretically designed target point, which is adjusted to a new slightly deeper position according to the change of the natural gamma curve while drilling. Figure 2 The middle A target point and the B target point are actual drilling target points, and the corresponding relationship between the well section between the A target point and the B target point and the two-dimensional seismic depth profile reflects the change of the actual formation natural gamma curve.

[0004] Hydraulic fracturing technology is the main technology for shale gas exploitation. Hydraulic fracturing technology pours a large amount of water mixed with chemicals into shale layers for hydraulic crushing to release natural gas. Figure 2 From the middle B end to the A end, it is divided into unequal fracturing sections of about 70-100m. In each section, a target gun is used for spiral perforation to produce fractures in the shale formation, and then a sand liquid proppant is used to fill the fracturing gap, and a soluble bridge plug is used to block to complete one after another different fracturing sections. During fracturing, perforation will produce many rupture events in the circular shale layer around the well trajectory. The field fracturing event characteristics mainly include time, position, energy, etc. A fracturing event in a section is collected in real time by the fracturing monitoring system, and is processed and displayed in about 2 minutes.

[0005] The monitoring of microseismic fracturing event occurrence is in the same way as seismic data acquisition, the source signal (event) of underground formation rupture is received by 408, 428 and other seismic instruments, and the microseismic information propagated after the event occurrence is received by a conventional seismic velocity detector with a main frequency of 10 Hz. Figure 3 A radial fracturing monitoring observation system is shown, Figure 4 A propagation path of microseismic waves generated by the vibration of underground formation rupture when a fracturing event occurs is shown, and the distribution position of the detector receiving the microseismic signal is also shown. Figure 5 A microseismic data processing flow is shown, because the vibration energy generated by fracturing is very weak, the source scanning stacking technology is adopted in the processing to improve the imaging effect of microseismic events, and the field requirements are as follows Figure 3 Such a multi-point and multi-line receiving of weak signals improves the signal-to-noise ratio and imaging convergence effect of weak signals through processing.

[0006] Figure 6 The right shows a source scanning stacking process of a source event, and the right figure is the receiving channel sorted by offset; the figure is the stacked channel of different offset channel sets, and it can be seen that the energy of the near arrangement is higher; the left figure is the fracturing event result inverted through processing, and the position and energy are well converged.

[0007] The current field microseismic fracturing monitoring work focuses on the spatial position distribution of underground formation fracturing events and the change of energy size, judges the fracturing stress direction, guides the ball plugging process during field perforation fracturing, prevents leakage, changes the stress direction, and achieves the effect of omnidirectional fracturing. Figure 7 The green small columnar body (event) reflects the frequency of fracturing events in this period, and the red (casing pressure), blue (displacement), and black line (sand concentration) are real-time acquisition curves in the field fracturing engineering, the event (field microseismic fracturing monitoring unit responsible) in this figure and the corresponding mapping of casing pressure, displacement, and sand concentration (field perforation fracturing unit responsible) are provided after 1-2 hours of fracturing event occurrence, which cooperates with the analysis of the perforation fracturing effect, Figure 7 The field microseismic monitoring suggests that the ball diameter test is carried out at about 10:40, and 20 balls (with a particle size of 16 mm) are used for fracturing. Figure 8 The temporary plugging and diversion effect of microseismic events is shown, the third section, stage 1 shows that the microseismic events are mainly distributed on the upper side of the wellbore, and the third section, stage 2 after balling shows that the microseismic events gradually move to the lower side of the wellbore, indicating that the vertical downward fracturing effect after balling is obvious. Figure 9Three-dimensional display of all fracturing events during the entire fracturing process, because the fracturing cycle is generally about 2 weeks, which is the data processing after the fracturing is completed. From the service provided by the entire fracturing monitoring site, the service content mainly proves that the formation rupture and rupture frequency occurred during the fracturing process, and the ability to participate in the evaluation of the overall effect of the fracturing is insufficient.

[0008] Fracturing is a key technology for shale gas development, and the gas production effect is closely related to the process control of fracturing. In the past, the microseismic monitoring process provided by the site can prove that the fracturing event is rich, which can show whether the fracturing process meets the perforation fracturing design requirements, but lacks participation. SUMMARY

[0009] The main purpose of the present application is to analyze the principal stress distribution characteristics of the fracturing event, study the physical factors of the rupture energy size, and pay attention to the event frequency of the target gas production part on the basis of the original shale gas fracturing construction, improve the fracturing guidance role of the site microseismic monitoring, and solve the disconnection problem of microseismic monitoring and shale gas final production effect analysis.

[0010] The technical scheme adopted by the present application is:

[0011] A shale gas monitoring method based on microseismic fracturing is provided, comprising the following steps:

[0012] S1, import the inclined well horizontal fracturing data, and use the three-dimensional well trajectory model established by the geodetic data, well trajectory azimuth angle and vertical depth data;

[0013] S2, mark the fracturing section position on the drilling trajectory of the three-dimensional well trajectory model, display the fracturing event position and the energy size of the fracturing around the fracturing section, and reflect the relationship between the “fracturing section-fracturing time-fracturing event-fracturing energy” in the well trajectory model;

[0014] S3, add a two-dimensional shale layer seismic profile at the horizontal section fracturing position of the well trajectory to obtain a “shale layer+well trajectory+fracturing event” comprehensive model formed on the three-dimensional well trajectory model along the well trajectory fracturing event; the control effect of the comprehensive model on the spatial distribution of the small faults or fractures to the fracturing event is analyzed;

[0015] S4, add various two-dimensional shale layer “sweet spot” attribute profiles along the well trajectory in the comprehensive model to form a “sweet spot” profile+well trajectory+fracturing event comprehensive three-dimensional visualization model for real-time fracturing effect comprehensive analysis of the well trajectory fracturing section;

[0016] S5, analyze the microseismic fracturing effect on the “sweet spot” profile through the comprehensive three-dimensional visualization model.

[0017] According to the technical scheme, in step S2, a cube with a corresponding color is used to display the fracturing event position and the energy size of fracturing around the fracturing section.

[0018] According to the technical scheme, in step S2, a three-dimensional visualization technology is used to directly determine the event phenomenon and the richness of the event occurrence between the fracturing sections.

[0019] According to the technical scheme, in step S2, a grid scaling and texture alignment method is used to add a two-dimensional shale layer seismic profile at the fracturing position of the well trajectory horizontal section, so as to display the relationship between the fracturing event position and the target position on the profile.

[0020] According to the technical scheme, in step S3, the space distribution control effect includes that the events of small faults and fractures will develop along the cracks, causing pressure loss; and the cracks are beneficial to form a fractured system for gas production.

[0021] According to the technical scheme, the "sweet spot" of the shale layer is a reservoir with good gas content in geology, high brittleness index in engineering, and easy-to-form volume cracks in fracturing; and the evaluation parameters of the shale gas geological "sweet spot" mainly include total organic carbon content, porosity, gas content and natural fractures; and the evaluation parameters of the engineering "sweet spot" mainly include rock mineral composition and rock mechanics parameters.

[0022] The application further provides a shale gas monitoring system based on microseismic fracturing, which comprises:

[0023] A three-dimensional well trajectory model establishment module is used to import the horizontal fracturing data of the deviated well, and a three-dimensional well trajectory model is established by using geodetic survey data, well trajectory azimuth angle and vertical depth data;

[0024] A relationship marking module is used to mark the fracturing section position on the drilling trajectory of the three-dimensional well trajectory model, display the fracturing event position and the energy size of fracturing around the fracturing section, and reflect the "fracturing section-fracturing time-fracturing event-fracturing energy" relationship in the well trajectory model;

[0025] A seismic profile fusion module is used to add a two-dimensional shale layer seismic profile at the fracturing position of the well trajectory horizontal section, so as to obtain a comprehensive model of "shale layer+well trajectory+fracturing event" formed on the three-dimensional well trajectory model along the fracturing event of the well trajectory; and the space distribution control effect of the small fault or crack on the fracturing event is analyzed through the comprehensive model.

[0026] A target profile fusion module is used to add various two-dimensional shale layer "sweet spot" attribute profiles along the well trajectory in the comprehensive model, so as to form a comprehensive three-dimensional visualization model of the shale layer "sweet spot" profile+well trajectory+fracturing event for real-time fracturing effect comprehensive analysis of the well trajectory fracturing section.

[0027] A monitoring module is configured to analyze microseismic fracturing effects on the sweet spot profile through the final comprehensive three-dimensional visualization model.

[0028] According to the above technical solution, the seismic profile fusion module specifically adopts a grid scaling and texture alignment method to add a two-dimensional shale layer seismic profile at a fracturing position of a horizontal section of a well trajectory, and display the relationship between the fracturing event position and the target position on the profile.

[0029] The present application also provides a computer storage medium, which stores a computer program executable by a processor, and the computer program executes the microseismic fracturing based shale gas monitoring method according to the above technical solution.

[0030] The present application has the following beneficial effects: the present application expands the field service range on the basis of the previous use of field monitoring of fracturing events to guide specific perforation fracturing construction, and makes fracturing events evenly distributed in shale layers, combines the fracturing events with seismic profiles and shale layer sweet spot attribute profiles, analyzes the rationality of the fracturing event occurrence position by using 3D visualization technology, analyzes the principal stress direction distribution characteristics of the fracturing events, studies the physical property factors of the breaking energy size, pays attention to the event frequency of the target gas production position, and the like, and does not blindly pursue the distribution balance of the fracturing events, thereby improving the fracturing guidance role of the field microseismic monitoring, providing more comprehensive microseismic fracturing monitoring and analysis technology for the optimized exploitation of shale gas, solving the disconnection problem between the microseismic monitoring and the final exploitation effect analysis of shale gas, and achieving the real service of the field and reducing the post-production type of explanation. BRIEF DESCRIPTION OF DRAWINGS

[0031] The present application will be further described below in combination with the drawings and examples, and the drawings show:

[0032] Figure 1 is a horizontal well near A target point stratum inclination detection model adjustment schematic view;

[0033] Figure 2 is a two-dimensional shale layer seismic profile corresponding to a horizontal well actual drilling A target point to B target point well section;

[0034] Figure 3 is a radial fracturing monitoring observation system schematic view;

[0035] Figure 4 is a fracturing event corresponding ray path distribution schematic view;

[0036] Figure 5 is a microseismic data processing flow chart;

[0037] Figure 6 is a seismic source scanning superposition (right) and event inversion position (left) schematic view;

[0038] Figure 7is a comparison chart of the frequency of fracturing events and real-time curves of fracturing sleeve pressure, displacement, and lifting displacement on site;

[0039] Figure 8 is a comparison chart of fracturing event distribution in stage 1 and stage 2;

[0040] Figure 9 is a fracturing event distribution chart along the well trajectory;

[0041] Figure 10 is a schematic diagram of a three-dimensional model of a well trajectory;

[0042] Figure 11 is a fracturing microseismic event distribution chart along the well trajectory

[0043] Figure 12 is a three-dimensional comprehensive model of “shale layer + well trajectory + fracturing event” (front view);

[0044] Figure 13 is a three-dimensional comprehensive model of “shale layer + well trajectory + fracturing event” (oblique view);

[0045] Figure 14 is a three-dimensional comprehensive model of “shale layer + well trajectory + fracturing event” (side view);

[0046] Figure 15 is a total organic carbon content inversion profile of a pre-stack shale gas geology “sweet spot”;

[0047] Figure 16 is a brittleness index inversion profile chart of an engineering “sweet spot”;

[0048] Figure 17 is a comprehensive three-dimensional visualization model of a controlled source electromagnetic CR method “sweet spot” profile + well trajectory + fracturing event (front + side view);

[0049] Figure 18 is a flowchart of a shale gas monitoring method based on microseismic fracturing according to an embodiment of the present application;

[0050] Figure 19 is a comparison chart of a conventional microseismic fracturing monitoring process and the microseismic monitoring process of the present application. DETAILED DESCRIPTION

[0051] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and do not limit the present application.

[0052] As shown in Figure 18 , the shale gas monitoring method based on microseismic fracturing of the present application mainly includes the following main steps:

[0053] S1, import the horizontal fracturing data of the inclined shaft, use the three-dimensional well trajectory model established by the geodetic data, well trajectory azimuth angle and vertical depth data;

[0054] S2, mark the fracturing section position on the drilling trajectory of the three-dimensional well trajectory model, display the fracturing event position and the fracturing energy around the fracturing section, and embody the relationship of "fracturing section-fracturing time-fracturing event-fracturing energy" in the well trajectory model;

[0055] S3, add the two-dimensional shale layer seismic profile at the fracturing position of the well trajectory horizontal section to obtain a comprehensive model of "shale layer+well trajectory+fracturing event" formed on the three-dimensional well trajectory model where the fracturing event is located; the control effect of the small fault or fracture on the spatial distribution of the fracturing event is analyzed through the comprehensive model;

[0056] S4, add various two-dimensional shale layer "sweet spot" attribute profiles along the well trajectory in the comprehensive model to form a comprehensive three-dimensional visualization model of shale layer "sweet spot" profile+well trajectory+fracturing event for real-time fracturing effect comprehensive analysis of the well trajectory fracturing section;

[0057] S5, analyze the microseismic fracturing effect on the "sweet spot" profile through the comprehensive three-dimensional visualization model.

[0058] Step S1 is mainly three-dimensional modeling along the microseismic fracturing event of the well trajectory:

[0059] 1) adopt the three-dimensional model coordinate alignment and superposition method, use the vector lofting modeling technology, import the horizontal fracturing data of the inclined shaft, and use the well trajectory model established by the geodetic data, well trajectory azimuth angle and vertical depth data, as shown in Figure 10 .

[0060] 2) mark the fracturing section position on the drilling trajectory, display the fracturing event position and the fracturing energy around the fracturing section with a cube with corresponding color, construct all and part of the corresponding events around the well trajectory according to the relationship of fracturing section-time-event-energy, and directly judge the event phenomenon and the richness of the event occurrence between the fracturing sections by using the three-dimensional visualization technology, as shown in Figure 11 . The data fusion of this step is mainly to correspond the fracturing event with the fault position of the shale layer, the development and distribution of the original fracture of the shale layer, and the low-amplitude structural part of the shale layer.

[0061] Step S2 is mainly cutting into the two-dimensional shale layer seismic profile along the well trajectory, which can specifically adopt the grid scaling and texture alignment method to cut into (i.e. add) the two-dimensional shale layer seismic profile at the fracturing position of the well trajectory horizontal section, and display the relationship between the position of the fracturing event and the target position on the profile. As shown in Figure 12As shown, a comprehensive model of "shale layer + well trajectory + event" is formed by inserting a two-dimensional seismic profile of shale layer depth into a three-dimensional model of the fracturing event along the well trajectory. Figure 12 , 13 As shown in Figure 14, this model can be used to analyze the spatial distribution control of small faults or fractures on fracturing events (small faults and fractures will develop along the fractures, causing pressure loss; fractures are conducive to the formation of fracture systems and gas production). It can also be used to determine and verify whether suspected small and low-amplitude strata are small fractures (events developing along the fractures are more concentrated, and the effect of fracturing is reduced), which helps to improve the interpretation accuracy of seismic acquisition data.

[0062] Two-dimensional shale seismic profiles are primarily obtained through the following methods: Typically, 3D seismic data acquisition is performed in shale gas development areas to obtain subsurface 3D seismic geological bodies. Technicians then use existing drilling logging data from large-scale drilling operations, such as core samples, porosity data, electrical conductivity curves, mineralization, and gamma ray curves, to analyze various geological attributes on these 3D geological bodies, forming new 3D attribute volumes. This process identifies favorable shale gas enrichment areas or the variations in mining conditions along shale layers in each horizontal direction around the central well location of a large-scale drilling operation. The well trajectory positions in each direction are designed. Simultaneously, the 2D shale seismic profiles along the well trajectory in any direction are extracted, and the corresponding 3D attribute volumes are also obtained. Similarly, displaying the "sweet spot" attributes of the shale layers on these 2D geological profiles yields various 2D shale layer "sweet spot" profiles.

[0063] The target locations of 2D shale layer seismic profiles primarily include fault locations, low-amplitude structural locations, and well trajectory variations along the shale layer (because actual drilling trajectories may differ slightly from the designed ones, and the sweet spot encountered may also vary). The location of the shale layer is obtained through geological outcrops, core sampling interpretation, tectonic interpretation, and seismic profile tracking interpretation. Currently, 2D seismic profile data is in SEGY format, which is very large and requires specialized expertise to open; this is not yet feasible. Because the constructed 3D well trajectory model is composed of spatial depth points, the 2D shale layer seismic profile is captured as a screenshot, assigning depth coordinates to the image—specifically, the depth control coordinates of four points—thus matching the two.

[0064] Step S3 is mainly to cut in (i.e., add) the "sweet spot" profile of various two-dimensional shale layers along the well trajectory, the "sweet spot" of the shale layer refers to the reservoir with good gas content in geology, high brittleness index in engineering, and easy to form volume fractures in fracturing. Mainly including geological "sweet spot" and engineering "sweet spot". The w(TOC: pre-stack total organic carbon content inversion profile) predicted by the earthquake, porosity and fracture development are used as the geological "sweet spot" to express the range of high-yield enrichment area and fracturing quality area of the shale gas in the research area.

[0065] The selection of "sweet spot" plays a crucial role in shale gas development, which can to some extent judge the size of the possibility of shale gas layer after fracturing. The prediction of shale gas geological "sweet spot area" and engineering "sweet spot area" can realize the economic and effective exploitation of shale gas in the research area. The evaluation parameters of shale gas geological "sweet spot" mainly include total organic carbon content (such as Figure 15 ), porosity, gas content, natural fracture, etc. The evaluation parameters of engineering "sweet spot" mainly include rock mineral composition and rock mechanics parameters. Therefore, the TOC, porosity and fracture development predicted by the earthquake are used as the geological "sweet spot", and the brittleness index (such as Figure 16 ) is used as the engineering "sweet spot" to express the range of high-yield enrichment area and fracturing quality area of the shale gas in the research area. It is generally believed that when the brittleness index is greater than 30%, the reservoir is easier to fracture, and the brittleness index is better at this time.

[0066] The evaluation method of geological "sweet spot": total organic carbon content is the main index for evaluating the abundance and hydrocarbon generation capacity of shale organic matter, which affects the organic matter porosity and gas content of shale gas reservoir. Only when the average content of total organic carbon reaches a certain threshold value, can commercial gas flow be obtained. At present, in addition to the analysis and test of geological samples, the evaluation of w(TOC) mainly adopts logging evaluation methods, mainly including bulk density logging method, limited mineral model method, BP neural network method, natural gamma logging method, multiple regression analysis method, acoustic time difference and resistivity method.

[0067] The evaluation method of engineering "sweet spot": the commonly used brittleness index prediction methods at home and abroad mainly include two categories of rock brittleness prediction methods, namely mineral composition method and elastic parameter method. The first method mainly characterizes the brittleness of rock by calculating the proportion of brittle minerals, which can obtain relatively objective brittle mineral distribution of the whole well section, but this method can only evaluate the brittleness of outcrop and drilled well vertical layer, and the actual application of this method is very limited due to the small number of coring wells in the research area and the limited core in the well. The second method is to calculate the elastic modulus and Poisson's ratio by using the vertical and horizontal wave velocities obtained by logging or seismic inversion, and then the brittleness index can be calculated. Through comprehensive analysis of the two methods, it is considered that the second method can more effectively reflect the brittleness of the formation.

[0068] Fracture plays an important role in shale gas development, which not only increases the reservoir space, but also effectively improves the permeability of shale reservoir. The fractures and micro-fractures are relatively developed in the research area, and the gas content is better when the fractures are developed in the reservoir. Under the action of large-scale fracturing, the fractures are relatively easy to open, thereby forming a fracture system which is favorable for fracturing and release of free gas.

[0069] In order to promote the fusion of the field processing and interpretation results of microseismic fracturing monitoring and perforation fracturing design, and enhance the suggestion role of microseismic fracturing monitoring to field fracturing engineering, the application combines various "sweet spot" attribute profiles of shale gas development design with real-time fracturing events to form a real-time fracturing effect comprehensive analysis three-dimensional visualization system along the well trajectory fracturing section. The application increases the "sweet spot" profile three-dimensional real-time corresponding analysis function, improves the analysis ability of fracturing monitoring events, makes the analysis results of event development characteristics more convincing, and closely links the whole fracturing process from design to construction and then to results. The application can improve the field guidance role of fracturing monitoring, improve the technical content and added value of microseismic fracturing monitoring, and also provide intermediate technology for moving the "attribute" technology of shale gas exploitation forward to the field.

[0070] The non-seismic controllable source electromagnetic CR method can also be used to find the "sweet spot" area of shale layer rich in gas. The gas-rich area is often accompanied by pyrite, so that the resistivity polarization rate of the shale layer will change along the layer. The area with large polarization rate value is often the area where pyrite is distributed more. The position of pyrite is brittle and easy to be fractured. The fracturing events are more and the fracture network is developed during perforation fracturing, which indicates that the fracturing effect is good, and the actual gas production can be guaranteed or increased.

[0071] As shown in Figure 17 , it is a comprehensive three-dimensional visualization model of controllable source electromagnetic CR method "sweet spot" profile + well trajectory + fracturing event. The red area near the well trajectory is the event point distribution area that needs to be concerned during perforation fracturing. The more fracturing events in the area, the better.

[0072] As shown in Figure 19 , it is the difference and advantage of the conventional microseismic fracturing monitoring process and the microseismic monitoring fracturing process of the application. In the past, the field mainly focused on and provided real-time fracturing event position and energy which changed with time, so as to research and judge the principal stress direction and fracture direction of the fracturing event, provide reference opinions for field ball plugging work, ensure uniform fracturing around the perforation, and play a supporting role in perforation fracturing effect. Figure 19The existing fracturing monitoring field suggestion has a single role, and the role in participating in the control of the entire fracturing process is not strong, and the role is biased towards the later summary and verification. The various attribute reasons for generating the fracturing event cannot be actively provided, and the correction of the sleeve pressure, lifting, sand adding, and displacement of the field perforation fracturing cannot be actively cooperated and participated in, which will more or less affect the final fracturing gas production effect. The part in the dashed box is the main innovation of the present application, and the present application makes up the "sweet spot" factor analysis process of microseismic fracturing monitoring, so that the "sweet spot" factor runs through the entire microseismic monitoring, from the perforation fracturing design to the summary of the fracturing monitoring effect, and there is no disconnection. In turn, the reliability of various "sweet spots" can be verified. Through the improvement of the understanding of "sweet spots", the effect analysis and evaluation means of microseismic fracturing monitoring are enriched, and the role of microseismic monitoring in the entire shale gas development process is highlighted.

[0073] The present application also provides a shale gas monitoring system based on microseismic fracturing, comprising:

[0074] A three-dimensional well trajectory model establishment module is used to import the deviated well horizontal fracturing data, and a three-dimensional well trajectory model is established by using geodetic data, well trajectory azimuth angle and vertical depth data;

[0075] A relationship marking module is used to mark the fracturing section position on the drilling trajectory of the three-dimensional well trajectory model, display the fracturing event position and the fracturing energy size around the fracturing section, and embody the "fracturing section-fracturing time-fracturing event-fracturing energy" relationship in the well trajectory model;

[0076] A seismic profile fusion module is used to add a two-dimensional shale layer seismic profile at the well trajectory horizontal section fracturing position to obtain a "shale layer+well trajectory+fracturing event" comprehensive model formed on the three-dimensional well trajectory model along the well trajectory fracturing event; the control effect of a small fault or crack on the spatial distribution of the fracturing event is analyzed through the comprehensive model;

[0077] A target profile fusion module is used to add various two-dimensional shale layer "sweet spot" attribute profiles along the well trajectory in the comprehensive model to form a shale layer "sweet spot" profile+well trajectory+fracturing event comprehensive three-dimensional visualization model for the real-time fracturing effect comprehensive analysis of the well trajectory fracturing section;

[0078] A monitoring module is used to analyze the microseismic fracturing effect on the "sweet spot" profile through the final comprehensive three-dimensional visualization model.

[0079] Further, the seismic profile fusion module specifically adopts a grid scaling and texture alignment method to add a two-dimensional shale layer seismic profile at the well trajectory horizontal section fracturing position to display the relationship between the position of the fracturing event and the target position on the profile.

[0080] The application further provides a computer readable storage medium, such as a flash memory, a hard disk, a multimedia card, a card memory (for example, an SD or DX memory, etc.), a random access memory (RAM), a static random access memory (SRAM), a read-only memory (ROM), an electrically erasable programmable read-only memory (EEPROM), a programmable read-only memory (PROM), a magnetic memory, a magnetic disk, an optical disk, a server, an App application store, etc., which stores a computer program, and the program is executed by a processor to realize corresponding functions. The computer readable storage medium of the embodiment is used to realize the microseismic fracturing based shale gas monitoring method of the method embodiment when executed by the processor.

[0081] In summary, the application introduces the seismic "sweet spot" attribute information, combines the microseismic fracturing event with the effect of fracturing engineering, and makes the shale gas exploration and exploitation form a closed-loop comprehensive analysis and verification effect process. The 3D model display analysis mode is used, and the real-time dynamic analysis technology is used, so that the field fracturing process and the "sweet spot" attribute are combined together, the fracturing effect and the gas production prediction are combined together, and the effect of the original fracturing monitoring is significantly improved.

[0082] It should be understood that, for those skilled in the art, improvements or changes can be made according to the above description, and all these improvements and changes shall belong to the protection scope of the appended claims of the application.

Claims

1. A shale gas monitoring method based on microseismic fracturing, characterized in that, Includes the following steps: S1. Import the horizontal fracturing data of the deviated well and establish a three-dimensional well trajectory model using geodetic data, well trajectory azimuth angle and vertical depth data; S2. Mark the location of the fracturing section on the drilling trajectory of the three-dimensional well trajectory model, display the location of the fracturing event and the energy of the fracturing around the fracturing section, and reflect the relationship of "fracturing section - fracturing time - fracturing event - fracturing energy" in the well trajectory model. S3. Add a two-dimensional seismic profile of the shale layer to the fracturing location in the horizontal section of the well trajectory to obtain a comprehensive model of "shale layer + well trajectory + fracturing event" formed on the three-dimensional well trajectory model where the fracturing event occurs along the well trajectory; analyze the spatial distribution control effect of small faults or fractures on the occurrence of fracturing events through this comprehensive model; S4. Add "sweet spot" attribute profiles of various two-dimensional shale layers along the well trajectory to the integrated model to form a comprehensive three-dimensional visualization model of "sweet spot" profile + well trajectory + fracturing event for real-time fracturing effect analysis of the well trajectory fracturing section. S5. Analyze the microseismic fracturing effect on the "sweet spot" profile using this comprehensive three-dimensional visualization model.

2. The shale gas monitoring method based on microseismic fracturing according to claim 1, characterized in that, In step S2, cubes of corresponding colors are used to display the location of fracturing events and the energy magnitude of fracturing around the fracturing section.

3. The shale gas monitoring method based on microseismic fracturing according to claim 1, characterized in that, In step S2, three-dimensional visualization technology is used to directly determine the event phenomena and the richness of events between fracturing sections.

4. The shale gas monitoring method based on microseismic fracturing according to claim 1, characterized in that, In step S2, a two-dimensional shale seismic profile is added to the fracturing location in the horizontal section of the well trajectory using a grid scaling and texture alignment method, showing the relationship between the location of the fracturing event and the target location on the profile.

5. The shale gas monitoring method based on microseismic fracturing according to claim 1, characterized in that, In step S3, the spatial distribution control effect includes small faults and fractures that develop along the fractures, causing pressure loss; the fractures are conducive to the formation of a fracture system for gas production.

6. The shale gas monitoring method based on microseismic fracturing according to claim 1, characterized in that, The "sweet spot" of shale formations refers to reservoirs that are geologically well-filled with gas, have a high brittleness index in engineering applications, and are prone to forming volumetric fractures when subjected to hydraulic fracturing. Evaluation parameters for shale gas geological "sweet spots" include total organic carbon content, porosity, gas content, and natural fractures. Evaluation parameters for engineering "sweet spots" mainly include rock mineral composition and rock mechanical parameters.

7. A shale gas monitoring system based on microseismic fracturing, characterized in that, include: The 3D well trajectory model building module is used to import horizontal fracturing data from deviated wells and build a 3D well trajectory model using geodetic data, well trajectory azimuth angle, and vertical depth data. The relationship annotation module is used to annotate the location of the fracturing section on the drilling trajectory of the 3D well trajectory model, display the location of the fracturing event and the energy of the fracturing around the fracturing section, and reflect the relationship of "fracturing section-fracturing time-fracturing event-fracturing energy" in the well trajectory model; The seismic profile fusion module is used to add two-dimensional shale layer seismic profiles to the fracturing location in the horizontal section of the well trajectory, resulting in a comprehensive model of "shale layer + well trajectory + fracturing event" formed on the three-dimensional well trajectory model where the fracturing event occurs. This comprehensive model is used to analyze the spatial distribution control effect of small faults or fractures on the occurrence of fracturing events. The target profile fusion module is used to add various two-dimensional shale layer "sweet spot" attribute profiles along the well trajectory to the comprehensive model, forming a comprehensive three-dimensional visualization model of shale layer "sweet spot" profile + well trajectory + fracturing event for real-time fracturing effect analysis of the well trajectory fracturing section; The monitoring module is used to analyze the microseismic fracturing effect on the "sweet spot" profile through this comprehensive three-dimensional visualization model.

8. The shale gas monitoring system based on microseismic fracturing according to claim 7, characterized in that, The seismic profile fusion module specifically uses grid scaling and texture alignment methods to add two-dimensional shale layer seismic profiles at the fracturing location in the horizontal section of the well trajectory, showing the relationship between the location of the fracturing event and the target location on the profile.

9. A computer storage medium, characterized in that, It contains a computer program that can be executed by a processor, which performs the shale gas monitoring method based on microseismic fracturing as described in any one of claims 1-6.

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