Method and system for evaluating the activity of strike-slip fault overlapping zones

Abstract

The present invention discloses a method for evaluating the activity of the overlapping area of strike-slip faults, which includes: performing fault interpretation on 3D seismic data of ultra-deep carbonate rocks containing the target fault zone, and collecting activity data of the overlapping area; according to the activity data of the overlapping area, plotting a graph representing the variation of the activity data of the overlapping area at each depth within the depth range of the target fault zone along the fault strike, and respectively analyzing the activity intensities of the overlapping area in the direction perpendicular to the strike of the strike-slip fault, the vertical direction of the fault, and the vertical direction of the fault zone fold, to form a comprehensive evaluation map of the activity of the overlapping area; according to the comprehensive evaluation map of the activity of the overlapping area, obtaining evaluation indicators for representing the development status of oil and gas reservoirs corresponding to different overlapping segments, and evaluating the fault-controlled oil and gas reservoir accumulation ability of each overlapping segment. The present invention has good applicability and popularization, and guides the evaluation of fault zones and oil and gas accumulation conditions.

Description

Technical Field

[0001] The present invention relates to the technical field of structural geology, and in particular, to a method and system for evaluating the activity of strike-slip fault overlapping zones in ultra-deep carbonate rocks. Background Art

[0002] The existing evaluation of strike-slip fault activity is mainly applied to currently active faults to predict natural earthquakes, and mainly uses three-dimensional seismic data to evaluate the activity of ultra-deep carbonate strike-slip fault zones. Among them, the main methods are: (1) multi-layer vertical offset superposition analysis; (2) statistical analysis of fault slip distance by the method of inclined formation in-phase axis offset; (3) analysis of fault activity using the maximum amplitude attribute of three-dimensional seismic data; (4) sectional research using local stress differences of faults.

[0003] The overlapping zone is a complex tectonic phenomenon generated by the interference of stress fields at the ends of two or more strike-slip faults. Its planar geometric morphological characteristics and internal fracture patterns are controlled by multiple aspects such as the lithology of the developed rock layers, the arrangement of strike-slip faults, and the intensity of strike-slip activity. Limited by research data, there are the following difficulties in analyzing the activity of overlapping zones in ultra-deep strike-slip fault systems with growth and development characteristics: (1) fine interpretation of ultra-deep strike-slip fault systems and identification of overlapping zones; (2) identification of internal fracture patterns in overlapping zones; (3) determination of comprehensive evaluation indicators for the activity of overlapping zones.

[0004] Furthermore, the current research on evaluating the activity of overlapping zones in ultra-deep strike-slip fault systems is still in its infancy, including: (1) using physical simulation methods to study the tectonic deformation of the superimposed tensile zone; (2) quantitative analysis of horizontal slip distance using the equal volume method of deformation in the overlapping uplift zone. The above methods are all effective research means for solving the structural geological problems of single strike-slip faults or overlapping zones.

[0005] Therefore, the existing technology urgently needs a technical solution for a method for evaluating the activity of strike-slip fault overlapping zones in ultra-deep carbonate rocks, which can solve the problem that the existing methods only evaluate the single-sided activity of faults and lack the evaluation of the overall activity of overlapping zones. Summary of the Invention

[0006] To solve the above technical problems, the present invention provides a method for evaluating the activity of the strike-slip fault overlapping area, which is located in ultra-deep carbonate rocks, and the method includes the following steps: performing fault interpretation on the 3D seismic data of ultra-deep carbonate rocks containing the target fault zone, and collecting the data of the activity of the overlapping area; according to the data of the activity of the overlapping area, drawing a map showing the variation of the data of the activity of the overlapping area along the fault strike at each depth within the depth range of the target fault zone, and based on this, analyzing the activity intensity of the overlapping area in the direction perpendicular to the fault strike, the vertical direction of the fault, and the vertical direction of the fault zone fold respectively to form a comprehensive evaluation map of the activity of the overlapping area; according to the comprehensive evaluation map of the activity of the overlapping area, obtaining evaluation indicators for representing the development status of the oil and gas reservoirs corresponding to different overlapping segments, and based on this, evaluating the oil and gas reservoir controlling and accumulating ability of each overlapping segment.

[0007] Preferably, the data of the activity of the overlapping area includes: the width of the fracture zone in the overlapping area, the vertical throw of a single fault in the overlapping area, and the vertical amplitude change of the reflection interface caused by the geomorphic change.

[0008] Preferably, in the step of evaluating the oil and gas reservoir controlling and accumulating ability of each fault layer according to the evaluation indicators, it includes: calculating the evaluation index of the control of the reservoir by the structural activity of the overlapping area according to the evaluation indicators of the current overlapping segment, so as to use the evaluation index of the control of the reservoir by the structural activity of the overlapping area to reflect the oil and gas reservoir controlling and accumulating ability under the current overlapping segment, wherein the evaluation indicators include: the maximum width of the fracture zone in the overlapping area, the maximum vertical amplitude change of the reflection interface, the seismic velocity of ultra-deep carbonate rocks, the fracture development abundance coefficient, the number of fractures developed in the overlapping area, and the maximum vertical throw of the main fault.

[0009] Preferably, the following expression is used to calculate the evaluation index of the control of the reservoir by the structural activity of the overlapping area:

[0010] I R =W max +V0·△T max +N n ·N+V0·D max

[0011] Wherein, I R represents the evaluation index of the control of the reservoir by the structural activity of the overlapping area, W max represents the maximum width of the fracture zone in the overlapping area, V0 represents the seismic velocity of ultra-deep carbonate rocks, △T max represents the maximum vertical amplitude change of the reflection interface, N n represents the fracture development abundance coefficient, N represents the number of fractures developed in the overlapping area, D max represents the maximum vertical throw of the main fault.

[0012] Preferably, according to the evaluation index of hydrocarbon reservoir control by the tectonic activity of each overlapping section in the target fault zone, the hydrocarbon reservoir capacity is divided into different aggregation levels, the evaluation index range of each aggregation level is determined, and further, the hydrocarbon reservoir control capacity of the faults in each overlapping section is evaluated according to the levels.

[0013] Preferably, the method further includes: sorting out and analyzing the collected activity data of the overlapping area, including: taking the absolute value of the vertical throw of the main fault collected, so as to draw corresponding maps using the processed data; when the overlapping area is uplifted due to the interference of strike-slip faults, the vertical amplitude change of the reflection interface is represented by a positive value; when the overlapping area is pulled apart due to the interference of strike-slip faults, the vertical amplitude change of the reflection interface is represented by a negative value.

[0014] Preferably, in the steps of fracture interpretation of the 3D seismic data of the ultra-deep carbonate rock containing the target fault zone and collecting the activity data of the overlapping area, it includes: according to the 3D seismic data, conducting fracture interpretation on the strike-slip fault system, determining the planar tectonic pattern and seismic profile characteristics of the development of the strike-slip faults, and based on this, establishing a spatial model of the fault system; using the sampling interval, scanning the spatial model of the fault system along the north-south direction of the fault zone to identify the overlapping area and collect the activity data of the overlapping area at different fracture depths.

[0015] On the other hand, the present invention also provides a system for evaluating the activity of the strike-slip fault overlapping area, the strike-slip fault overlapping area is located in the ultra-deep carbonate rock, and the system includes: a data collection module configured to conduct fracture interpretation on the 3D seismic data of the ultra-deep carbonate rock containing the target fault zone and collect the activity data of the overlapping area; a comprehensive analysis module configured to draw a map representing the variation of the activity data of the overlapping area at each depth within the depth range of the target fault zone along the fault strike according to the activity data of the overlapping area, and based on this, respectively analyze the activity intensities of the overlapping area in the direction perpendicular to the strike of the strike-slip fault, the vertical direction of the fault, and the vertical direction of the fold of the fault zone to form a comprehensive evaluation map of the activity of the overlapping area; a reservoir capacity evaluation module configured to obtain evaluation indicators representing the development status of hydrocarbon reservoirs corresponding to different overlapping sections according to the comprehensive evaluation map of the activity of the overlapping area, and based on this, evaluate the hydrocarbon reservoir control capacity of the faults in each overlapping section.

[0016] Preferably, the reservoir capacity evaluation module is further configured to calculate an evaluation index of the control of hydrocarbon accumulation by the tectonic activity in the overlapping area according to the evaluation indexes of the current overlapping section, so as to reflect the hydrocarbon accumulation control ability under the current overlapping section by using the evaluation index of the control of hydrocarbon accumulation by the tectonic activity in the overlapping area. Among them, the evaluation indexes include: the width of the largest fracture zone in the overlapping area, the vertical amplitude change of the largest reflection interface, the seismic velocity of ultra-deep carbonate rocks, the fracture development abundance coefficient, the number of fractures developed in the overlapping area, and the vertical throw of the largest main fracture.

[0017] Preferably, in the reservoir capacity evaluation module, the following expression is used to calculate the evaluation index of the control of hydrocarbon accumulation by the tectonic activity in the overlapping area:

[0018] I R =W max +V0·△T max +N n ·N+V0·D max

[0019] Among them, I R represents the evaluation index of the control of hydrocarbon accumulation by the tectonic activity in the overlapping area, W max represents the width of the largest fracture zone in the overlapping area, V0 represents the seismic velocity of ultra-deep carbonate rocks, △T max represents the vertical amplitude change of the largest reflection interface, N n represents the fracture development abundance coefficient, N represents the number of fractures developed in the overlapping area, and D max represents the vertical throw of the largest main fracture.

[0020] Compared with the prior art, one or more embodiments of the above solution may have the following advantages or beneficial effects:

[0021] The present invention discloses a method and a system for evaluating the activity of a strike-slip fault overlapping area. The method and the system propose a method for evaluating the tectonic activity of an overlapping area of an ultra-deep and complex carbonate rock strike-slip fault system based on 3D seismic data and a method for grading and evaluating hydrocarbon reservoirs by using an activity comprehensive analysis index. The present invention has good applicability and popularization on the basis of existing data, the research ideas and technical methods are highly feasible, and it guides the evaluation of fracture zones and hydrocarbon accumulation conditions.

[0022] Other features and advantages of the present invention will be described in the following specification, and, in part, will be obvious from the specification, or will be understood by implementing the present invention. The objectives and other advantages of the present invention can be realized and obtained by the structures specifically pointed out in the specification, the claims, and the drawings. Description of the Drawings

[0023] The accompanying drawings are used to provide a further understanding of the present invention, and constitute a part of the specification. They are used together with the embodiments of the present invention to explain the present invention, and do not constitute a limitation to the present invention. In the accompanying drawings:

[0024] Figure 1 is a step diagram of the method for evaluating the activity of the strike-slip fault overlapping area in the embodiment of the present application.

[0025] Figure 2 is a specific flowchart of the method for evaluating the activity of the strike-slip fault overlapping area in the embodiment of the present application.

[0026] Figure 3 is a schematic diagram of the principle for collecting the activity data of the overlapping area in the method for evaluating the activity of the strike-slip fault overlapping area in the embodiment of the present application.

[0027] Figure 4 is a rendering diagram of the drawing of the variation diagram of the activity data of the overlapping area of each exploration horizon along the strike of the fault zone in the method for evaluating the activity of the strike-slip fault overlapping area in the embodiment of the present application.

[0028] Figure 5 is a rendering diagram of the drawing of the comprehensive evaluation diagram of the activity of the overlapping area in the method for evaluating the activity of the strike-slip fault overlapping area in the embodiment of the present application.

[0029] Figure 6 is a schematic diagram of the calculation results of the evaluation indexes of each overlapping area and the corresponding evaluation index of the control of reservoir formation by the structural activity of the overlapping area in the method for evaluating the activity of the strike-slip fault overlapping area in the embodiment of the present application.

[0030] Figure 7 is a block diagram of the modules of the system for evaluating the activity of the strike-slip fault overlapping area in the embodiment of the present application. Detailed implementation manners

[0031] The following will detail the implementation manners of the present invention in conjunction with the accompanying drawings and embodiments, so as to fully understand how the present invention uses technical means to solve technical problems and achieve the implementation process of technical effects and implement accordingly. It should be noted that as long as there is no conflict, the various embodiments in the present invention and the various features in each embodiment can be combined with each other, and the formed technical solutions are all within the protection scope of the present invention.

[0032] In addition, the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions. And although the logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in a different order than here.

[0033] The existing evaluation of strike-slip fault activity is mainly applied to currently active faults to predict natural earthquakes, and mainly uses three-dimensional seismic data to evaluate the activity of ultra-deep carbonate strike-slip fault zones. Among them, the main methods are: (1) Multi-layer vertical offset superposition analysis; (2) Using the method of tilted formation in-phase axis offset segments to statistically analyze the fault slip distance; (3) Analyzing the fault activity using the maximum amplitude attribute of three-dimensional seismic data; (4) Conducting segmental research using the local stress difference of the fault.

[0034] The overlapping area is a complex tectonic phenomenon generated by the interference of stress fields at the ends of two or more strike-slip faults. Its planar geometric morphological characteristics and internal fracture patterns are controlled by multiple factors such as the lithology of the developed rock layers, the arrangement of strike-slip faults, and the intensity of strike-slip activity. Limited by research data, there are the following difficulties in analyzing the activity of the overlapping area in the strike-slip fault system with growth and development characteristics in ultra-deep layers: (1) Fine interpretation of the ultra-deep strike-slip fault system and identification of the overlapping area; (2) Identification of the internal fracture patterns in the overlapping area; (3) Determination of the comprehensive evaluation index for the activity of the overlapping area.

[0035] Furthermore, the current research on evaluating the activity of the overlapping area in the ultra-deep strike-slip fault system is still in its infancy, including: (1) Using physical simulation methods to study the tectonic deformation of the superimposed tensile area; (2) Using the equal volume method of deformation in the overlapping uplift area for quantitative analysis of the horizontal slip distance. The above methods are all effective research means for solving the tectonic geological problems of single strike-slip faults or overlapping areas.

[0036] To solve the above technical problems, the present invention proposes a method and system for evaluating the activity of the strike-slip fault overlapping area. This method and system first perform fault interpretation on three-dimensional seismic data containing target fault zone information and collect activity data of the overlapping area; then, based on these activity data, draw maps reflecting the activity of the strike-slip fault system, and based on this, comprehensively evaluate the activity of the strike-slip fault overlapping area and the hydrocarbon accumulation conditions. The present invention is mainly applied to the evaluation of the activity of the ultra-deep complex carbonate strike-slip fault overlapping area and the evaluation of related hydrocarbon accumulation conditions, can evaluate the overall activity of the overlapping area, has good applicability and popularization on the basis of existing data, and has strong feasibility, thus playing a certain guiding role in the evaluation of the fault zone and hydrocarbon accumulation conditions.

[0037] In addition, the method for evaluating the tectonic activity of the overlapping area of the ultra-deep carbonate strike-slip fault system provided by the present invention also uses the comprehensive activity analysis index to conduct hierarchical evaluation of hydrocarbon reservoirs, thereby improving the economic benefits of exploration and development.

[0038] Figure 1 It is a step diagram of the method for evaluating the activity of the strike-slip fault overlapping area in the embodiment of the present application. Figure 2It is a specific flowchart of the method for evaluating the activity of the strike-slip fault overlapping zone in the embodiments of the present application. The following will be combined with Figure 1 and Figure 2 to illustrate the implementation process of the method for evaluating the activity of the strike-slip fault overlapping zone (hereinafter referred to as the "overlapping zone activity evaluation method") described in the present invention. It should be noted that the overlapping zone activity evaluation method described in the present invention is applied to the ultra-deep carbonate rock scenario. Further, the strike-slip fault zone (the overlapping zone therein) is the strike-slip fault zone within the ultra-deep carbonate rock.

[0039] As Figure 1 shown, in step S110, fracture interpretation is performed on the 3D seismic data of the ultra-deep carbonate rock containing the target fault zone, and the overlapping zone activity data is collected.

[0040] In step S110, first, it is necessary to obtain the 3D seismic data of the ultra-deep (target) carbonate rock containing the target fault zone. Among them, the target fault zone refers to the fault zone to be evaluated and with an overlapping zone. After obtaining the 3D seismic data of the target carbonate rock, fracture interpretation is performed on the target carbonate rock within the target carbonate rock to determine the planar structural pattern corresponding to the strike-slip fault development area of the target fault zone and the 3D seismic profile characteristics corresponding to the current strike-slip fault development area. The planar structural pattern reflects different types of tectonic activities contained within the area where the target fault zone belongs. The 3D seismic profile characteristics, on the other hand, reflect the characteristics of the fracture zone in the area where the target fault zone belongs. Further, in the embodiments of the present invention, after obtaining the 3D seismic profile characteristics of the target fault zone, coherent body identification can also be performed on the area where the target fault zone belongs based on the seismic profile characteristics to obtain coherent body data slice information.

[0041] Then, based on the planar structural pattern and 3D seismic profile characteristics corresponding to the strike-slip fault development area of the target fault zone, a spatial three-dimensional model of the fault system is established to facilitate the identification of the fault overlapping zone and obtain the overlapping zone activity data of the fracture activity intensity within the overlapping zone. Then, using the sampling interval, combined with the coherent body data slice information, the spatial model of the fault system that can characterize the structural pattern characteristics and seismic profile characteristics of the target fault zone is scanned along the north-south direction of the fault zone to identify the overlapping zone within the target fault zone, and the overlapping zone activity data at different fracture depths is collected during the identification process. For example: during the collection of the overlapping zone activity data, it is mainly based on the high-precision 3D seismic profile and coherent data volume slice information, and the data reading is performed at a sampling interval of 200m along the north-south direction of the fault zone.

[0042] Figure 3This is a schematic diagram of the principle for collecting the activity data of the overlapping area in the method for evaluating the activity of the strike-slip fault overlapping area according to the embodiments of the present application. In the embodiments of the present invention, the activity data of the overlapping area includes, but is not limited to: the width of the fracture zone in the overlapping area, the vertical throw of a single fault in the overlapping area, and the vertical amplitude change of the reflection interface caused by geomorphic changes. Specifically, ① the width of the fracture zone in the overlapping area (W) refers to the width of the fracture zone near the seismic reflection interface caused by the interaction of two main strike-slip faults. When obtaining the width of the fracture zone in the overlapping area at the corresponding fault depth, it is necessary to combine with the flat-section characteristics of the fault interpretation and refer to Figure 3 , first, select the main fault that controls the development of the overlapping area within the current fault depth range on the seismic profile in the east-west direction; then, measure the straight-line distance between the two main faults on the selected coherence cube slice, so as to calculate the width data of the fracture zone in the overlapping area at this fault depth. ② The vertical throw of a single fault refers to the vertical throw (D) of the main fault that controls the development of the overlapping area. In the actual application process, (refer to Figure 3 ) for a strike-slip fault zone with growth and development characteristics, generally, the fault zone is composed of multiple strike-slip faults. Therefore, there may be multiple main fault layers within a certain fault depth range. Thus, when collecting the vertical throw of a single fault corresponding to the current fault depth range, the vertical throw of a single fault will be obtained for each main fault. ③ The vertical amplitude change of the reflection interface refers to the vertical amplitude change (ΔT) of the reflection interface caused by the uplift or pull-apart phenomenon in the overlapping area due to the interference of the strike-slip fault. Since the amplitude change characteristics of the reflection interface are simultaneously controlled by the geological background and the main faults in the overlapping area, in the embodiments of the present invention, the vertical amplitude change of the reflection interface is the data of the formation uplift amount or pull-apart amount after excluding the influence of the geological structure background. Specifically, the amplitude change of the reflection interface is the difference between the maximum / minimum value (T1) of the reflection interface in the overlapping area and the horizontal reflection interface (T2) outside the overlapping area.

[0043] In addition, after collecting the activity data of the overlapping area at different fracture depths, the method for evaluating the activity of the overlapping area according to the embodiments of the present invention further includes: sorting and analyzing the collected activity data of the overlapping area. Further, in the embodiments of the present invention, the collected activity data of the overlapping area is summarized in an Excel table. Specifically, first, when scanning the three-dimensional spatial model of the fracture system corresponding to different fracture depth ranges, combined with the coherent body data, the width of the fractured zone in the overlapping area corresponding to the corresponding fracture depth range is directly statistically calculated. Then, the absolute values of the vertical displacement of several (one or more) single faults corresponding to each fracture depth range collected are uniformly processed, so as to draw corresponding diagrams using the processed data. Finally, the vertical amplitude change of the reflection interface corresponding to each fracture depth collected is analyzed according to the geomorphic feature categories. When the overlapping area bulges due to the interference of the strike-slip fault, the vertical amplitude change of the current reflection interface is represented by a positive value; when the overlapping area is pulled apart due to the interference of the strike-slip fault (the amplitude change of the reflection interface in the overlapping area is lower than the amplitude change of the reflection interface outside the main fault), the vertical amplitude change of the current reflection interface is represented by a negative value.

[0044] In this way, after completing the task of collecting the activity data of the overlapping area that characterizes the fracture zone characteristics and structural style characteristics of the target fracture zone in the seismic profile, it enters step S120.

[0045] According to the activity data of the overlapping area collected in step S110, step S120 draws diagrams showing the variation of the activity data of the overlapping area along the fracture strike at each fracture depth (i.e., each exploration horizon or each fracture horizon) within the depth range of the target fracture zone, and analyzes the activity intensity of the overlapping area in the direction perpendicular to the strike of the strike-slip fault, the vertical direction of the fracture, and the vertical direction of the fold in the fracture zone respectively based on all the diagrams, so as to form a comprehensive evaluation diagram of the activity of the overlapping area.

[0046] Since the width of the fractured zone in the overlapping area, the vertical displacement of several single faults, and the vertical amplitude change of the reflection interface at different fracture depths are collected in step S110, therefore, in step S120, first, according to all the data collected in step S110, a (first) diagram showing the variation of the width of the fractured zone in the overlapping area along the fracture strike within the depth range of the target fracture zone, a (second) diagram showing the variation of the vertical displacement of each single fault corresponding to each fracture in the fracture zone along the fracture strike, and a (third) diagram showing the variation of the vertical amplitude change data of the reflection interface along the fracture strike need to be drawn respectively. Figure 4 It is the rendering effect diagram of the diagram showing the variation of the activity data of the overlapping area at each exploration horizon along the fracture zone strike in the method for evaluating the activity of the strike-slip fault overlapping area according to the embodiments of the present application. In Figure 4In it, Figure a shows the first diagram of the variation of the width of the overlapping zone fracture zone along the strike of the fault zone; Figure b shows the second diagram of the variation of the vertical offset of each single fault corresponding to each fault in the overlapping zone of the fault zone along the strike of the fault zone, where different styles of curves are used in Figure b to distinguish different faults in the overlapping zone; Figure c shows the third diagram of the variation of the vertical amplitude change data of the reflection interface along the strike of the fault zone.

[0047] Furthermore, after completing the drawing of the diagrams, step S120 will also perform a comprehensive analysis of the activity of the strike-slip fault overlapping zone based on all the drawn diagrams to obtain a comprehensive evaluation diagram of the activity of the overlapping zone. Among them, during the comprehensive analysis process, step S120 will first perform linear fitting on all the diagrams and then perform integration processing, and analyze the activity intensity of the overlapping zone in the direction perpendicular to the strike of the strike-slip fault, the activity intensity of a single fault in the vertical direction, and the activity intensity of the folds in the fault zone in the vertical direction, so as to form a comprehensive evaluation diagram of the activity of the overlapping zone. More specifically, a fracture zone width change curve is formed according to the above first diagram, a vertical offset change curve is formed according to the above second diagram, and a terrain amplitude change curve is formed according to the above third diagram. Therefore, in the embodiment of the present invention, the above comprehensive evaluation diagram of the activity of the overlapping zone at least includes: a fracture zone width change curve, a vertical offset change curve, the reflection interface coherence body data of the target fault zone, and a terrain amplitude change curve. In this way, it is convenient to evaluate the oil and gas storage capacity of the subsequent fault zone reservoir space based on the comprehensive evaluation diagram of the activity of the overlapping zone.

[0048] Figure 5 It is the rendering effect diagram of the comprehensive evaluation diagram of the activity of the overlapping zone in the method for evaluating the activity of the strike-slip fault overlapping zone in the embodiment of the present application. Figure 5 It shows the formation effect of the comprehensive evaluation diagram of the activity of the overlapping zone, where the fracture zone width change curve, the vertical offset change curve, the reflection interface coherence body data of the target fault zone, and the terrain amplitude change curve are shown from left to right respectively.

[0049] Specifically, in step S120, a comprehensive evaluation of the activity characteristics of the overlapping area is required to evaluate the reservoir storage capacity using the evaluation results. Among them, the comprehensive activity evaluation includes: (1) In the actual application process, the fracture zone width change curve formed by the first map generated based on the fracture zone width data of the overlapping area is jointly affected by the position of the main fault controlling the development of the overlapping area and the mechanical properties of the surrounding rock. In the fracture zone width change curve, the data corresponding to different fracture depths reflect the activity intensity of the strike-slip fault zone in the direction perpendicular to the strike of the strike-slip fault. (2) The vertical displacement change curve formed by the second map generated based on the single-fault vertical displacement data corresponding to several faults in the overlapping area, and each data point reflects the vertical activity intensity of a single fault. Among them, a single fault includes two fault modes: fault fold and fold fault. Fault fold means that fractures first exist at the ends of two strike-slip faults and then the vertical displacement changes during the development of the overlap; fold fault means that folding occurs first until the rock reaches the fracture strength and then the displacement increases. In Figure 5 , it reflects two structural modes in the strike-slip fault zone, namely the development of a single strike-slip fault within the strike-slip fault zone and the overlap area formed by the interference of the ends of two or more strike-slip faults. (3) The topographic amplitude change curve formed by the third map generated based on the vertical amplitude change data of the reflection interface, and each data point therein reflects the vertical activity intensity of the folds within the fault zone. Specifically, positive landforms reflect a compressive stress background, negative landforms reflect a tensile background, and strike-slip segments without topographic fluctuations generally indicate the development of a single strike-slip fault without the interference of multiple faults.

[0050] Furthermore, in the embodiment of the present invention, during the generation of the comprehensive activity evaluation map of the overlapping area, the overlapping area with a certain depth within the target fault zone is also segmented, so as to form several overlapping segments with different fracture depths according to the spatial relationship of the strike-slip faults within the target strike-slip fault zone. The several overlapping segments divide the strike-slip fault zone along the strike into the main fault segment where a single strike-slip fault develops and the overlapping area. In Figure 5 the target strike-slip fault zone to be studied, 11 overlapping areas formed by the interference of multiple strike-slip faults are identified, and the main fault segments are developed between the overlapping areas.

[0051] In this way, after generating the comprehensive activity evaluation map of the overlapping area, it enters step S130.

[0052] Continue to refer to Figure 1 and Figure 2 , step S130 obtains evaluation indicators representing the development status of oil and gas reservoirs corresponding to different overlapping segments according to the comprehensive activity evaluation map of the overlapping area formed in step S120, and evaluates the fracture-controlled oil and gas storage capacity of each overlapping segment within the target fault zone based on the currently calculated evaluation indicators.

[0053] In the embodiments of the present invention, the carbonate rock oil and gas reservoirs controlled by ultra-deep strike-slip faults are mainly evaluated from aspects such as source rocks, physical properties of carbonate rocks, migration, and preservation. Specifically, first, the width of the fracture zone in the overlapping area and the variation range of the landform (topography) determine the lateral distribution range of the reservoir body and affect the spatial size of oil and gas accumulation. Second, the variation range of the reflection interface is positively correlated with the variation range of the landform, reflecting the stress environment during the tectonic activity period. Specifically, in a tensile environment, faults can serve as the dominant transport system for oil and gas migration, while fault zones can serve as the dominant oil and gas accumulation and preservation areas in a compressive environment. Third, the strike-slip fault system is a fault dissolution body formed by weathering leaching or dissolution modification, which is the main type of oil and gas reservoir in ultra-deep carbonate rocks. Therefore, the fracture abundance in the overlapping area of the strike-slip fault zone also affects the number of developed oil and gas reservoirs, and further, there is a positive correlation between the two. Fourth, the vertical throw reflects the vertical activity intensity of the strata caused by fault activity.

[0054] Furthermore, based on the above analysis results of the influence relationship between ultra-deep strike-slip fault control and carbonate rock oil and gas reservoirs, in order to comprehensively evaluate oil and gas migration and accumulation in terms of the activity intensity of the fractures in the overlapping area from the above different perspectives, the embodiments of the present invention propose a tectonic activity reservoir control evaluation index I R for the overlapping area of the strike-slip fault. In the embodiments of the present invention, the tectonic activity reservoir control evaluation index for the overlapping area represents the control effect of the activity intensity of different overlapping segments in the space of the overlapping area of the target strike-slip fault zone on oil and gas accumulation.

[0055] Furthermore, the evaluation indexes described in the embodiments of the present invention (corresponding to each overlapping segment) at least include: the maximum width of the fracture zone in the overlapping area (in the current overlapping segment), the maximum vertical amplitude change of the reflection interface (in the current overlapping segment), the seismic velocity of ultra-deep carbonate rocks, the fracture development abundance coefficient (in the current overlapping segment), the number of developed fractures in the overlapping area (to which the current overlapping segment belongs), and the maximum vertical throw of the main fault (in the current overlapping segment). Figure 6 is a schematic diagram of the calculation results of the evaluation indexes for each overlapping area and the corresponding tectonic activity reservoir control evaluation index in the method for evaluating the activity of the overlapping area of the strike-slip fault in the embodiments of the present application. Refer to Figure 6 , in step S130, the embodiments of the present invention will calculate the tectonic activity reservoir control evaluation index for the overlapping area according to the evaluation indexes corresponding to the current overlapping segment, so as to use the tectonic activity reservoir control evaluation index corresponding to each overlapping segment to characterize the oil and gas reservoir control ability under the current overlapping segment.

[0056] Among them, in step S130, the tectonic activity reservoir control evaluation index corresponding to each overlapping segment is calculated using the following expression:

[0057] I R = Wmax +V0·△T max +N n ·N + V0·D max (1)

[0058] Among them, I R represents the evaluation index for controlling hydrocarbon storage by the structural activity of the overlapping zone; W max represents the width of the fracture zone in the maximum overlapping zone, with the unit of meter (m); V0 represents the seismic velocity of ultra-deep carbonate rocks, with the unit of meter per second (m / s); △T max represents the vertical amplitude change of the maximum reflection interface, with the unit of millisecond (ms); N n represents the fracture development abundance coefficient; N represents the number of fractures developed in the overlapping zone; D max represents the vertical throw of the maximum main fracture, with the unit of millisecond (ms). In addition, in the process of using the above expression (1) to calculate the evaluation index for controlling hydrocarbon storage by the structural activity of the overlapping zone of each overlapping segment, step S130 will continuously adjust the fracture development abundance coefficient to determine the fracture development abundance coefficient that conforms to the geological characteristics of the current overlapping segment, so as to eliminate the influence brought by the dimensionless parameter of the number of fractures developed in the overlapping zone.

[0059] In this way, the present invention quantitatively evaluates the storage capacity of hydrocarbon reservoirs in the overlapping segments of different depth ranges in the target fracture zone by using step S130, thereby quantitatively evaluating the development status of hydrocarbon reservoirs in the overlapping zone of the target fracture zone.

[0060] In addition, in order to visually compare and evaluate the degree of controlling hydrocarbon storage capacity corresponding to different overlapping segments in the overlapping zone of the target fracture zone, the embodiment of the present invention will also evaluate the hydrocarbon storage control ability of each overlapping segment by grade in step S130. Specifically, according to the evaluation index for controlling hydrocarbon storage by the structural activity of the overlapping zone corresponding to each overlapping segment in the target fracture zone, the hydrocarbon storage capacity is divided into different aggregation levels, and the evaluation index range of each aggregation level is determined. Then, according to the evaluation index for controlling hydrocarbon storage by the structural activity of the overlapping zone corresponding to each overlapping segment in the target fracture zone, and using the evaluation index range corresponding to each aggregation level, the fracture-controlled hydrocarbon storage capacity corresponding to each overlapping segment is evaluated by grade.

[0061] In the embodiment of the present invention, if the evaluation index for controlling hydrocarbon storage by the structural activity of the overlapping zone is larger, it indicates that the structural activity of the overlapping zone is stronger, and the ability of fractures in the overlapping zone to control hydrocarbon storage is better. It should be noted that the embodiment of the present invention does not specifically limit the number of aggregation levels, and those skilled in the art can set it according to actual needs. For example: the overlapping zone is divided into three levels according to the evaluation index I for controlling hydrocarbon storage by the structural activity R : Level I hydrocarbon-rich area; Level II hydrocarbon-accumulating area; Level III poor hydrocarbon-accumulating area.

[0062] Example 1

[0063] Apply the method for evaluating the activity of the overlapping area of the present invention to the Shunbei No. 5 strike-slip fault zone developed in the Shuntuogole low uplift of the Tarim Basin. The following describes the evaluation process of the activity of the overlapping area of the Shunbei No. 5 strike-slip fault zone:

[0064] The Shunbei No. 5 strike-slip fault zone is a typical ultra-deep carbonate strike-slip fault. Four distinct stages of tectonic activity can be divided according to the differences in vertical tectonic styles. Among them, the northern section of the Shunbei No. 5 zone has obvious vertical zoning characteristics and also has great differences in planar tectonic styles: the bottom interface of the Lower Cambrian Yurtus Formation is a sub-salt structure; the bottom interface of the Middle-Upper Cambrian Lower Qiulitage Formation develops a supra-salt structure, which appears as a discontinuous fault zone on the plane; the strike-slip fault styles on the top surface of the Middle-Lower Ordovician Yijianfang Formation are rich, developing various tectonic styles such as braided, lenticular, horsetail-shaped, and en echelon, with the characteristics of growth faults, and the overlapping area is developed; the strike-slip fault on the top surface of the Middle-Upper Ordovician Sangtamu Mudstone shows en echelon normal fault characteristics.

[0065] This method is applied to the overlapping area on the top surface of the Middle-Lower Ordovician Yijianfang Formation in the Shunbei No. 5 strike-slip fault zone. The analysis results show that: the overlapping areas developed in this area are mainly of the compression type, affected by the arrangement position and movement mode of the strike-slip faults. The paleogeomorphology of the overlapping area generally has the law of "single peak" type. The width of the pull-apart overlapping fracture zone has the characteristics of "big at both ends and small in the middle", while the width of the compression overlapping fracture zone is "small at both ends and big in the middle". According to the seismic data of this work area, the seismic velocity V0 of this carbonate formation is 6350 m / s. Thus, time-depth conversion can be carried out for parameters such as terrain amplitude and vertical throw. The width range of the fault zone is 0 - 2000 m, the terrain amplitude varies between -40 - 100 ms (250 - 640 m), generally the number of faults is between 2 - 5, and N n is set to 50; the vertical throw of the main fault varies within a large range. The vertical throw of the vertical strike-slip section is near 0 ms, and the maximum vertical throw can reach 50 ms (320 m) under the action of tensile-shear and compressive-shear stresses.

[0066] According to the evaluation index I R for controlling hydrocarbon accumulation in the structural activity of the overlapping area provided in the present invention Figure 6 , I R The minimum value of the value is 701.55, the maximum value is 1918.32, and the average value is 1177.10. According to the evaluation index I R for grading and evaluating the overlapping area: Grade I hydrocarbon-rich area (1500 < I R ); Grade II hydrocarbon accumulation area (1000 < I R<1500); It is a Class III differential hydrocarbon accumulation area (I R <850).

[0067] On the other hand, based on the above-mentioned evaluation method for the activity of the overlapping area, the present invention also proposes a system for evaluating the activity of the strike-slip fault overlapping area (hereinafter referred to as the "activity evaluation system of the overlapping area"). Figure 7 It is a block diagram of the module of the system for evaluating the activity of the strike-slip fault overlapping area in the embodiment of the present application. As Figure 7 shown, the activity evaluation system of the overlapping area described in the present invention includes: a data collection module 71, a comprehensive analysis module 72, and a reservoir capacity evaluation module 73.

[0068] Furthermore, the data collection module 71 is implemented according to the method described in the above step S110, and is configured to perform fracture interpretation on the 3D seismic data of the ultra-deep carbonate rock containing the target fault zone, and collect the activity data of the overlapping area. The comprehensive analysis module 72 is implemented according to the method described in the above step S120, and is configured to draw a graph representing the variation of the activity data of the overlapping area along the strike of the fault at each fracture depth within the depth range of the target fault zone based on the collected activity data of the overlapping area, and analyze the activity intensity of the overlapping area in the direction perpendicular to the strike of the strike-slip fault, the vertical direction of the fault, and the vertical direction of the fold of the fault zone according to all the graphs, so as to form a comprehensive evaluation graph of the activity of the overlapping area. The reservoir capacity evaluation module 73 is implemented according to the method described in the above step S130, and is configured to obtain evaluation indicators representing the development status of the oil and gas reservoirs corresponding to different overlapping segments based on the comprehensive evaluation graph of the activity of the overlapping area, and evaluate the fracture-controlled oil and gas reservoir capacity of each overlapping segment according to the evaluation indicators.

[0069] Furthermore, the reservoir capacity evaluation module 73 is also configured to calculate the evaluation index of the structure activity control of the overlapping area according to the evaluation indicators of the current overlapping segment, so as to reflect the oil and gas reservoir capacity control under the current overlapping segment by using the evaluation index of the structure activity control of the overlapping area. Among them, the evaluation indicators include: the maximum width of the fracture zone in the overlapping area, the vertical amplitude change of the maximum reflection interface, the seismic velocity of the ultra-deep carbonate rock, the fracture development abundance coefficient, the number of fractures developed in the overlapping area, and the vertical throw of the maximum main fracture.

[0070] Furthermore, in the reservoir capacity evaluation module 73, the following expression is used to calculate the evaluation index of the structure activity control of the overlapping area corresponding to each overlapping segment:

[0071] I R =W max +V0·△T max +N n ·N+V0·D max

[0072] where, I RIndicates the evaluation index for controlling hydrocarbon accumulation by the tectonic activity of the overlapping zone, W max Indicates the maximum width of the fracture zone in the overlapping zone, V0 represents the seismic velocity of ultra-deep carbonate rocks, △T max Indicates the vertical amplitude change of the maximum reflection interface, N n Indicates the fracture development abundance coefficient, N represents the number of fractures developed in the overlapping zone, D max Indicates the vertical throw of the maximum main fracture.

[0073] The present invention discloses a method and system for evaluating the activity of the overlapping zone of strike-slip faults. The method and system are as follows: First, fracture interpretation is carried out in a DSG (Decision&Space Geosciences) workstation, and the overlapping zone is identified based on the fracture plane tectonic style and the characteristics of the fracture zone reflected from the seismic section (related fractures develop at the tail of the strike-slip fault and have geometric or dynamic connections with the tails of other strike-slip faults), and data related to fracture activity is collected; Second, data sorting and analysis work is carried out on the collected data of the overlapping zone activity; Third, maps reflecting the activity of the strike-slip fault system and a comprehensive evaluation map of the overlapping zone activity are made; Fourth, a comprehensive evaluation is carried out on the activity of the strike-slip fault overlapping zone and the hydrocarbon accumulation conditions based on the statistical chart results. The present invention proposes a method for evaluating the tectonic activity of the overlapping zone of the ultra-deep and complex carbonate rock strike-slip fault system based on 3D seismic data and a method for grading and evaluating hydrocarbon reservoirs using the comprehensive analysis index of activity. It has good applicability and popularization on the existing data basis, the research ideas and technical methods are highly feasible, and it guides the evaluation of fracture zones and hydrocarbon accumulation conditions.

[0074] As described above, only the preferred specific embodiments of the present invention are given, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

[0075] It should be understood that the embodiments disclosed in the present invention are not limited to the specific structures, processing steps or materials disclosed herein, but should extend to equivalent alternatives of these features understood by those of ordinary skill in the relevant art. It should also be understood that the terms used herein are only for the purpose of describing specific embodiments and do not mean to limit.

[0076] The "one embodiment" or "embodiment" mentioned in the specification means that the specific features, structures or characteristics described in combination with the embodiment are included in at least one embodiment of the present invention. Therefore, the phrases "one embodiment" or "embodiment" appearing throughout the specification do not necessarily all refer to the same embodiment.

[0077] Although the embodiments disclosed in the present invention are as above, the content described is only an embodiment adopted for the convenience of understanding the present invention and is not used to limit the present invention. Any person skilled in the art within the technical field to which the present invention pertains may make any modifications and changes in the form of implementation and details without departing from the spirit and scope disclosed by the present invention. However, the scope of patent protection of the present invention shall still be subject to the scope defined by the appended claims.

Claims

1. A method for evaluating the activity of a strike-slip fault overlapping area, characterized in that, The strike-slip fault overlapping area is located in ultra-deep carbonate rocks, and the method includes the following steps: Conduct fault interpretation on the 3D seismic data of ultra-deep carbonate rocks containing the target fault zone, and collect the activity data of the overlapping area; According to the activity data of the overlapping area, draw a map showing the variation of the activity data of the overlapping area along the fault strike at each depth within the depth range of the target fault zone. Based on this, analyze the activity intensity of the overlapping area in the direction perpendicular to the strike of the strike-slip fault, the vertical direction of the fault, and the vertical direction of the fault zone fold, and form a comprehensive evaluation map of the activity of the overlapping area; According to the comprehensive evaluation map of the activity of the overlapping area, obtain evaluation indicators representing the development status of oil and gas reservoirs corresponding to different overlapping segments. Based on this, evaluate the fault-controlled oil and gas reservoir accumulation capacity of each overlapping segment.

2. The method according to claim 1, wherein The activity data of the overlapping area includes: the width of the fracture zone in the overlapping area, the vertical offset of a single fault within the overlapping area, and the vertical amplitude change of the reflection interface caused by geomorphic changes.

3. The method according to claim 1, wherein In the step of evaluating the fault-controlled oil and gas reservoir accumulation capacity of each fault layer according to the evaluation indicators, it includes: According to the evaluation indicators of the current overlapping segment, calculate the evaluation index of the structure activity control of the overlapping area on reservoir formation to reflect the fault-controlled oil and gas reservoir accumulation capacity under the current overlapping segment. Among them, the evaluation indicators include: the maximum width of the fracture zone in the overlapping area, the maximum vertical amplitude change of the reflection interface, the seismic velocity of ultra-deep carbonate rocks, the fracture development abundance coefficient, the number of fractures developed in the overlapping area, and the maximum vertical offset of the main fault.

4. The method according to claim 3, wherein Calculate the evaluation index of the structure activity control of the overlapping area on reservoir formation using the following expression: I R = W max + V0·ΔT max + N n ·N + V0·D max Among them, I R represents the evaluation index for controlling hydrocarbon accumulation by the tectonic activity of the overlapping zone, W max represents the width of the fracture zone in the maximum overlapping zone, V0 represents the seismic velocity of ultra-deep carbonate rocks, ΔT max represents the vertical amplitude change of the maximum reflection interface, N n represents the fracture development abundance coefficient, N represents the number of fractures developed in the overlapping zone, D max represents the vertical throw of the maximum main fracture.

5. The method according to claim 3, wherein According to the evaluation index of the structure activity control of the overlapping area on reservoir formation corresponding to each overlapping segment within the target fault zone, divide the oil and gas reservoir accumulation capacity into different aggregation levels, determine the evaluation index range of each aggregation level, and further evaluate the fault-controlled oil and gas reservoir accumulation capacity of each overlapping segment by level.

6. The method according to claim 2, wherein The method further includes: sorting out and analyzing the activity data of the overlapping area collected, which includes: Take the absolute value of the collected vertical offset of the main fault to draw the corresponding map using the processed data; When the overlapping area is uplifted due to the interference of the strike-slip fault, the vertical amplitude change of the reflection interface is represented by a positive value; When the overlapping area is stretched due to the interference of the strike-slip fault, the vertical amplitude change of the reflection interface is represented by a negative value.

7. The method according to any one of claims 1 to 6, characterized in that, In the step of conducting fault interpretation on the 3D seismic data of ultra-deep carbonate rocks containing the target fault zone and collecting the activity data of the overlapping area, it includes: According to the 3D seismic data, conduct fault interpretation on the strike-slip fault system, determine the planar structural pattern and seismic profile characteristics of the strike-slip fault development, and based on this, establish a spatial model of the fault system; Use the sampling interval to scan the spatial model of the fault system along the north-south direction of the fault zone, identify the overlapping area and collect the activity data of the overlapping area at different fault depths.

8. A system for evaluating the activity of a strike-slip fault overlapping area, characterized in that, The strike-slip fault overlapping area is located in ultra-deep carbonate rocks, and the system includes: A data collection module configured to perform fracture interpretation on 3D seismic data of ultra-deep carbonate rocks containing a target fracture zone and collect data on the activity of the overlapping area; A comprehensive analysis module configured to draw a graph showing the variation of the activity data of the overlapping area along the fracture strike at each depth within the depth range of the target fracture zone based on the activity data of the overlapping area, and based on this, analyze the activity intensity of the overlapping area in the direction perpendicular to the fracture strike, the vertical direction of the fracture, and the vertical direction of the fracture zone fold respectively, to form a comprehensive evaluation map of the activity of the overlapping area; A reservoir capacity evaluation module configured to obtain evaluation indicators representing the development status of oil and gas reservoirs corresponding to different overlapping segments based on the comprehensive evaluation map of the activity of the overlapping area, and based on this, evaluate the fracture-controlled oil and gas reservoir capacity of each overlapping segment.

9. The system according to claim 8, wherein the reservoir capacity evaluation module is further configured to calculate a reservoir control evaluation index for the structural activity of the overlapping area according to the evaluation index of the current overlapping segment, so as to use the reservoir control evaluation index for the structural activity of the overlapping area to reflect the fracture-controlled oil and gas reservoir capacity under the current overlapping segment, wherein the evaluation index includes: the maximum width of the fracture zone in the overlapping area, the vertical amplitude change of the maximum reflection interface, the seismic velocity of ultra-deep carbonate rocks, the fracture development abundance coefficient, the number of fractures developed in the overlapping area, and the vertical throw of the maximum main fracture.

10. The system according to claim 9, wherein In the reservoir capacity evaluation module, the following expression is used to calculate the reservoir control evaluation index for the structural activity of the overlapping area: I R = W max + V0·ΔT max + N n ·N + V0·D max Among them, I R represents the evaluation index for controlling hydrocarbon accumulation by the tectonic activity of the overlapping zone, W max represents the width of the fracture zone in the largest overlapping zone, V0 represents the seismic velocity of ultra-deep carbonate rocks, ΔT max represents the vertical amplitude change of the maximum reflection interface, N n represents the fracture development abundance coefficient, N represents the number of fractures developed in the overlapping zone, D max represents the vertical throw of the maximum main fault.

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