Multi-thin-layer lamination favorable area optimization method based on three-dimensional earthquake and related equipment

Abstract

The invention discloses a three-dimensional earthquake-based multi-strata lamination favorable area optimization method and related equipment, and belongs to the technical field of natural gas development, and the method comprises the steps: based on a three-dimensional seismic exploration mode, recognizing a base, a cover stratum and a target stratum of a multi-strata gas reservoir through horizon interpretation, and obtaining a seismic attribute map corresponding to each horizon; the method comprises the following steps: respectively carrying out fracture interpretation on a base and a cover layer and carrying out distribution characteristic description on a target layer through a seismic attribute map to obtain a base fracture characteristic, a cover layer fracture characteristic and a reservoir sand body distribution characteristic which are used for establishing a target layer lamination favorable area optimization standard, and finally, carrying out reservoir sand body distribution analysis through the target layer lamination favorable area optimization standard. Carrying out optimization evaluation on the to-be-detected multi-thin-layer overlapping area; according to the method, a work area multi-layer series stratum is regarded as a whole, whether gas reservoir damage or natural gas dissipation exists in the whole multi-layer series reservoir in a certain area can be predicted only by determining the fracture development scale of a deep base and a shallow cover layer, and therefore optimization of a favorable area is efficiently and accurately completed.

Description

Technical Field

[0001] The invention belongs to the technical field of natural gas development, and in particular relates to a method for optimizing a favorable area of ​​multi-thin layer superposition based on three-dimensional seismic and related equipment. Background Art

[0002] At present, superimposed basins in some areas have experienced multi-stage tectonic changes and multi-cycle oil and gas accumulation. After the oil and gas accumulation, they have undergone adjustment, transformation and destruction of later tectonic changes, and the distribution pattern is very complex. The multi-layer tight sandstone represented by the gas field in the eastern part of the Ordos Basin has developed in-source, near-source and shallow gas reservoirs, with uneven spatial distribution and poor overall abundance, indicating that the accumulation process has undergone multi-stage migration and even escape. The development of multi-layer gas reservoirs in the basin has gone through "large cluster straight / directional well groups" to "single-layer horizontal well development in advantageous areas" and then to "three-dimensional horizontal well development exploration". The requirements for well type selection and deployment mode are constantly increasing. The horizontal well three-dimensional development well group is an important means to efficiently mobilize the geological reserves of multi-layer gas reservoirs and improve the recovery rate, and the optimization of superimposed favorable areas is the basis. Some areas are located in the basin margin fault zone, where the fault development is more complex and the sand body is smaller, resulting in higher difficulty in predicting superimposed favorable areas.

[0003] In response to the above problems, two types of methods are generally used. One is a qualitative favorable area prediction method based on the matching analysis of multiple reservoir-forming elements according to geological, seismic, logging and other data; the other is a quantitative favorable area prediction method that uses other parameters as weights to characterize the distribution of advantageous reservoirs or sedimentary phases. Although the first type of method has detailed and comprehensive reference content, it requires too much basic data and the implementation process is relatively complex. It is impossible to efficiently and quickly propose the optimal matching development method and is not suitable for fast-paced production and construction tasks; the second type of method only targets the distribution of single layers, and does not comprehensively consider the impact of the spatial configuration relationship of multi-layer reservoir sand body distribution, fault conduction, and caprock closure on the optimization of favorable areas, and the evaluation accuracy of multi-layer systems is poor. Summary of the invention

[0004] In order to overcome the shortcomings of the above-mentioned technology, the present invention provides a method and related equipment for optimizing favorable areas of multiple thin layers based on three-dimensional seismic, which can solve the technical problem that the existing method for optimizing favorable areas cannot quickly and accurately optimize and evaluate multi-layer areas.

[0005] In order to achieve the above object, the present invention adopts the following technical solution:

[0006] A method for selecting favorable areas based on three-dimensional seismic multi-thin layer superposition, comprising:

[0007] Based on 3D seismic exploration, the basement, caprock and target layer of multi-layer gas reservoirs are identified through stratum interpretation, and the seismic attribute map corresponding to each stratum is obtained;

[0008] Based on the seismic attribute map, the basement and caprock faults are interpreted to obtain the basement fault characteristics and caprock fault characteristics; the target layer is characterized to obtain the reservoir sand body distribution characteristics;

[0009] Based on the basement fault characteristics, cap rock fault characteristics and reservoir sand body distribution characteristics, the selection criteria for the favorable area of ​​target layer superposition are established;

[0010] Based on the optimization criteria for the favorable area of ​​target layer superposition, the multi-thin layer superposition area to be tested is optimized and evaluated.

[0011] Furthermore, the cap rock, target layer and basement are distributed from top to bottom; source rocks are also distributed between the basement and the target layer.

[0012] Furthermore, according to the location from the source rock, the target layer is divided into intra-source, near-source and far-source.

[0013] Furthermore, based on the coherence attributes, curvature attributes and dip attributes in the seismic attribute map, the basement and cover layer faults are interpreted to obtain the basement fault characteristics and cover layer fault characteristics.

[0014] Furthermore, the fault interpretation is characterized based on three dimensions: the nature of the fault in the work area, the period of fault activity, and the plane distribution of multiple-period faults.

[0015] Furthermore, based on the amplitude attributes in the seismic attribute map, the target layer is characterized for distribution characteristics, and the reservoir sand body distribution characteristics are obtained.

[0016] Furthermore, based on the spatial configuration relationship between the basement fault characteristics, cap rock fault characteristics and reservoir sand body distribution characteristics, the optimization criteria for the target layer superposition favorable area are established.

[0017] A system for optimizing favorable areas of multiple thin layers superimposed based on 3D seismic data, which is used to implement the steps of the above-mentioned method for optimizing favorable areas of multiple thin layers superimposed based on 3D seismic data, comprises:

[0018] The acquisition and identification module is used to identify the basement, cap layer and target layer of the multi-layer gas reservoir through layer interpretation based on the three-dimensional seismic exploration method, and obtain the seismic attribute map corresponding to each layer;

[0019] The interpretation module is used to interpret the basement and cover layers based on the seismic attribute map to obtain the basement fault characteristics and cover layer fault characteristics; the distribution characteristics of the target layer are characterized to obtain the reservoir sand body distribution characteristics;

[0020] The standard establishment module is used to establish the optimization standard of the favorable area of ​​target layer superposition based on the basement fault characteristics, cap rock fault characteristics and reservoir sand body distribution characteristics;

[0021] The optimization evaluation module is used to perform optimization evaluation on the multi-thin layer overlap area to be tested based on the optimization criteria of the target layer overlap favorable area.

[0022] A device comprising:

[0023] Memory for storing computer programs;

[0024] A processor is used to execute the steps of the above-mentioned method for selecting favorable areas based on three-dimensional seismic multi-thin layer superposition when executing the computer program.

[0025] A computer-readable storage medium stores a computer program, which, when executed by a processor, is used for the steps of the above-mentioned method for selecting a favorable area based on three-dimensional seismic multi-thin layer superposition.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] The present invention also provides a method for optimizing a favorable area of ​​multi-thin layer superposition based on three-dimensional seismic. The method is based on a three-dimensional seismic exploration method, and identifies the basement, cap rock and target layer of a multi-layer gas reservoir through stratum interpretation, and obtains a seismic attribute map corresponding to each stratum; through the seismic attribute map, the basement and cap rock are respectively interpreted for fractures, and the target layer is characterized for distribution characteristics, so as to obtain the basement fracture characteristics, cap rock fracture characteristics and reservoir sand body distribution characteristics for establishing a optimization standard for a favorable area of ​​target layer superposition, and finally, through the optimization standard for a favorable area of ​​target layer superposition, the multi-thin layer superposition area to be tested is optimized and evaluated; the method regards the multi-layer strata in the work area as a whole, and only needs to clarify the scale of fracture development of the deep basement and the shallow cap rock, so as to predict whether there is gas reservoir destruction or natural gas dissipation in the multi-layer reservoir as a whole in a certain area, thereby efficiently and accurately completing the optimization of favorable areas. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 The Mi-163 seismic profile and fault interpretation diagram provided by the embodiment of the present invention;

[0029] Figure 2 The fault distribution diagram corresponding to the Cambrian-Ordovician, Benxi Formation, Shiqianfengdi (Qian 5), and Triassic-Jurassic of Mi 163 provided in the embodiment of the present invention;

[0030] Figure 3 A schematic diagram of the fracture matching pattern between the cap layer and the substrate provided in an embodiment of the present invention;

[0031] Figure 4 A preferred schematic diagram of a superimposed favorable area provided in an embodiment of the present invention; wherein (a) is a seismic attribute map; (b) is an interpretation map of the seismic attribute map; (c) is a maximum wave crest attribute sand body prediction plane map; (d) is an effective sand body prediction plane map;

[0032] Figure 5 A flowchart of a method for selecting a favorable area for multi-thin layer superposition based on three-dimensional seismic provided by the present invention;

[0033] Figure 6 A schematic structural diagram of a system for selecting a favorable area for multiple thin layers superimposed on three-dimensional seismic data provided by the present invention. DETAILED DESCRIPTION

[0034] The present invention provides a method for selecting favorable areas based on three-dimensional seismic multi-thin layer superposition. Figure 5 As shown, the following steps are included:

[0035] S1: Based on the 3D seismic exploration method, the basement, cap rock and target layer of the multi-layer gas reservoir are identified through stratum interpretation, and the seismic attribute map corresponding to each stratum is obtained.

[0036] The cap rock, target rock and basement are distributed from top to bottom; among them, there are also source rocks distributed between the basement and the target rock.

[0037] According to the location from the source rock, the target layer is divided into intra-source, near-source and far-source.

[0038] S2: Based on the coherence attributes, curvature attributes and dip attributes in the seismic attribute map, the basement and cover layers are interpreted to obtain the basement fault characteristics and cover layer fault characteristics. The fault interpretation is based on the three dimensions of the fault nature of the work area, the fault activity period and the multi-period fault plane distribution.

[0039] Based on the amplitude attributes in the seismic attribute map, the distribution characteristics of the target layer are characterized to obtain the distribution characteristics of the reservoir sand body.

[0040] S3: Based on the spatial configuration relationship between the basement fault characteristics, cap rock fault characteristics and reservoir sand body distribution characteristics, the optimization criteria for the favorable area of ​​target layer superposition are established.

[0041] S4: Based on the optimization criteria for the favorable area of ​​target layer superposition, the multi-thin layer superposition area to be tested is optimized and evaluated.

[0042] like Figure 6As shown, the present invention also provides a system for optimizing favorable areas of multiple thin layers superimposed based on three-dimensional seismic, comprising: an acquisition and identification module, which is used to identify the basement, cap layer and target layer of a multi-layer gas reservoir through stratum interpretation based on a three-dimensional seismic exploration method, and obtain the seismic attribute map corresponding to each stratum; an interpretation module, which is used to interpret the basement and cap layer respectively based on the seismic attribute map to obtain the basement fault characteristics and the cap layer fault characteristics; to characterize the distribution characteristics of the target layer to obtain the reservoir sand body distribution characteristics; a standard establishment module, which is used to establish optimization criteria for favorable areas of target layer superposition based on the basement fault characteristics, the cap layer fault characteristics and the reservoir sand body distribution characteristics; and a preferred evaluation module, which is used to perform preferred evaluation on the multi-thin layer superposition area to be tested based on the optimization criteria for favorable areas of target layer superposition.

[0043] The present invention also provides a device, comprising: a memory for storing a computer program; a processor for implementing the steps of the method for selecting a favorable area for multiple thin layers superimposed based on three-dimensional seismic when executing the computer program.

[0044] When the processor executes the computer program, the above-mentioned steps of optimizing the favorable area of ​​multi-thin layer superposition based on three-dimensional seismic are implemented, for example: based on the three-dimensional seismic exploration method, the basement, cap layer and target layer of the multi-layer gas reservoir are identified through stratigraphic interpretation, and the seismic attribute map corresponding to each stratigraphic position is obtained; based on the seismic attribute map, the basement and cap layer are respectively interpreted for fractures to obtain the basement fracture characteristics and the cap layer fracture characteristics; the target layer is characterized for distribution characteristics to obtain the reservoir sand body distribution characteristics; based on the basement fracture characteristics, the cap layer fracture characteristics and the reservoir sand body distribution characteristics, the optimization criteria for the favorable area of ​​superposition of the target layer are established; based on the optimization criteria for the favorable area of ​​superposition of the target layer, the multi-thin layer superposition area to be tested is optimized and evaluated.

[0045] Alternatively, the processor implements the functions of each module in the above system when executing the computer program, for example: an acquisition and identification module, which is used to identify the basement, cap layer and target layer of a multi-layer gas reservoir through stratum interpretation based on a three-dimensional seismic exploration method, and obtain the seismic attribute map corresponding to each stratum; an interpretation module, which is used to interpret the basement and cap layer respectively based on the seismic attribute map to obtain the basement fault characteristics and cap layer fault characteristics; to characterize the distribution characteristics of the target layer to obtain the reservoir sand body distribution characteristics; a standard establishment module, which is used to establish the preferred standard for the target layer superposition favorable area based on the basement fault characteristics, cap layer fault characteristics and reservoir sand body distribution characteristics; a preferred evaluation module, which is used to perform preferred evaluation on the multi-thin layer superposition area to be tested based on the preferred standard for the target layer superposition favorable area.

[0046] Exemplarily, the computer program may be divided into one or more modules / units, which are stored in the memory and executed by the processor to complete the present invention. The one or more modules / units may be a series of computer program instruction segments capable of completing preset functions, and the instruction segments are used to describe the execution process of the computer program in the 3D seismic-based multi-thin layer superposition favorable zone optimization device. For example, the computer program can be divided into an acquisition and identification module, an interpretation module, a standard establishment module and a preferred evaluation module; the specific functions of each module are as follows: an acquisition and identification module, which is used to identify the basement, cap layer and target layer of a multi-layer gas reservoir through stratum interpretation based on a three-dimensional seismic exploration method, and obtain the seismic attribute map corresponding to each stratum; an interpretation module, which is used to interpret the basement and cap layer respectively based on the seismic attribute map to obtain the basement fault characteristics and cap layer fault characteristics; to characterize the distribution characteristics of the target layer to obtain the reservoir sand body distribution characteristics; a standard establishment module, which is used to establish the preferred standard for the target layer superposition favorable area based on the basement fault characteristics, cap layer fault characteristics and reservoir sand body distribution characteristics; a preferred evaluation module, which is used to perform preferred evaluation on the multi-thin layer superposition area to be tested based on the preferred standard for the target layer superposition favorable area.

[0047] The three-dimensional seismic-based multi-thin layer superposition favorable area optimization device can be a computing device such as a desktop computer, a notebook, a PDA and a cloud server. The three-dimensional seismic-based multi-thin layer superposition favorable area optimization device may include, but is not limited to, a processor and a memory. Those skilled in the art can understand that the above is an example of a three-dimensional seismic-based multi-thin layer superposition favorable area optimization device, and does not constitute a limitation on the three-dimensional seismic-based multi-thin layer superposition favorable area optimization device, and may include more components than the above, or a combination of certain components, or different components. For example, the three-dimensional seismic-based multi-thin layer superposition favorable area optimization device may also include input and output devices, network access devices, buses, etc.

[0048] The processor may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or the processor may be any conventional processor, etc. The processor is the control center of the three-dimensional seismic-based multi-thin layer superposition favorable area optimization, and uses various interfaces and lines to connect various parts of the entire three-dimensional seismic-based multi-thin layer superposition favorable area optimization device.

[0049] The memory can be used to store the computer program and / or module, and the processor realizes various functions of the three-dimensional seismic-based multi-thin layer superposition favorable area optimization device by running or executing the computer program and / or module stored in the memory and calling the data stored in the memory.

[0050] The memory may mainly include a program storage area and a data storage area, wherein the program storage area may store an operating system, an application required for at least one function (such as a sound playback function, an image playback function, etc.), etc.; the data storage area may store data created according to the use of the mobile phone (such as audio data, a phone book, etc.), etc. In addition, the memory may include a high-speed random access memory, and may also include a non-volatile memory, such as a hard disk, a memory, a plug-in hard disk, a smart memory card (Smart Media Card, SMC), a secure digital (Secure Digital, SD) card, a flash card (Flash Card), at least one disk storage device, a flash memory device, or other volatile solid-state storage devices.

[0051] The present invention also provides a computer-readable storage medium, which stores a computer program. When the computer program is executed by a processor, the steps of the method for selecting a favorable area for multiple thin layer superposition based on three-dimensional seismic are implemented.

[0052] If the module / unit of the integrated system of the preferred multi-thin layer superposition favorable area based on three-dimensional seismic is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium.

[0053] Based on such understanding, the present invention implements all or part of the processes in the above-mentioned method for selecting favorable areas for multiple thin layers superimposed based on 3D seismic, and can also be completed by instructing related hardware through a computer program, and the computer program can be stored in a computer-readable storage medium, and when the computer program is executed by a processor, the steps of the above-mentioned method for selecting favorable areas for multiple thin layers superimposed based on 3D seismic can be implemented. The computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or preset intermediate form, etc.

[0054] The computer-readable storage medium may include: any entity or device capable of carrying the computer program code, recording medium, USB flash drive, mobile hard disk, magnetic disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signal, telecommunication signal and software distribution medium, etc.

[0055] It should be noted that the content contained in the computer-readable storage medium can be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, computer-readable storage media do not include electrical carrier signals and telecommunication signals.

[0056] The present invention will be further described below in conjunction with the embodiments and drawings:

[0057] Example

[0058] In order to solve the problem mentioned in the background technology: Currently, two types of methods are used for the optimization and assessment of favorable areas in multi-layer systems. One is a qualitative favorable area prediction method based on the matching analysis of multiple reservoir-forming elements according to geological, seismic, logging and other data; the other is a quantitative favorable area prediction method that uses other parameters as weights to characterize the distribution of advantageous reservoirs or sedimentary phases. Although the first type of method has detailed and comprehensive reference content, it requires too much basic data and the implementation process is relatively complex. It is impossible to efficiently and quickly propose the optimal matching development method and is not suitable for fast-paced production and construction tasks; the second type of method only targets the distribution of single layers, and does not comprehensively consider the spatial configuration relationship of the multi-layer reservoir sand body distribution, fault conduction, and caprock closure on the optimization of favorable areas, and the assessment accuracy for multi-layer systems is poor.

[0059] This embodiment provides a method for selecting favorable areas for superposition of multiple thin layers based on 3D seismic. This method takes into account the inherited evolutionary development characteristics of multi-stage faults in a basin (e.g., the Ordos Basin), takes the matching relationship between cap rock faults and basement faults and the distribution of reservoir sand bodies as influencing factors, establishes evaluation criteria for superposition favorable areas, and then implements differentiated deployment of development well types. The specific steps are as follows:

[0060] Step 1: With the help of 3D seismic data in the work area, each layer is interpreted and analyzed based on the extracted seismic attributes, so as to identify the basement, source rock, multiple target layers (intra-source, near-source, far-source) and caprock corresponding to the work area.

[0061] Step 2: Complete the interpretation of the faults in the work area, focusing on the characterization and research of the fault properties, fault activity periods, and multi-period fault plane distribution in the work area.

[0062] Step 3: Combined with the research in step 2, use 3D seismic data to extract the attributes (coherence, curvature, dip) of the cover and basement in the work area, characterize the structure and fault characteristics and distribution of the shallow cover and deep basement in the work area, and obtain the basement fault characteristics and cover fault characteristics.

[0063] Step 4: Extract the seismic amplitude attribute body to characterize the distribution characteristics of multiple sets of sand bodies in the middle (i.e., the target layer). At the same time, in this step, geological and logging methods can be used for comparison and constraint, so as to more accurately characterize the distribution characteristics of the target layer and obtain the distribution characteristics of the reservoir sand body.

[0064] Step 5: Combine the spatial configuration relationship between the basement fault characteristics and the cap rock fault characteristics with the reservoir sand body distribution characteristics as influencing factors to establish the optimization criteria for the favorable area of ​​superposition of the target layer.

[0065] Step 6: Based on the optimization criteria for the favorable area of ​​target layer superposition, the multi-thin layer superposition area to be tested is optimized and evaluated.

[0066] The present invention is further explained below with reference to examples:

[0067] like Figure 1 and Figure 2 As shown, Mizhi Gas Field Mi 163 area (350km 2 ) In the Upper Paleozoic, there are multi-layered tight sandstone gas reservoirs. The 8# coal seam widely distributed at the bottom of the Permian is the main source rock. From the bottom to the top of the Permian, the Taiyuan Formation, Shanxi Formation (Shan 2), Shihezi Formation (He 8), Shiqianfeng Formation (Qian 5) may all develop reservoir sand bodies. The formations above Qian 5 to the Triassic can all serve as cap rocks. The structural faults in the above study area are extremely complex, and the multi-stage strike-slip faults developed are inherited and segmented. The vertical overlap of multi-stage faults can easily lead to the upward escape of natural gas or secondary accumulation.

[0068] like Figure 3As shown in the figure, the faults in the study area have three types of vertical overlap styles: a: the Ordovician and Triassic faults are large in scale, the strata are uplifted and broken, and the faults break through the central Permian strata; b: the Ordovician faults are small in scale, the Permian faults are small in scale, and no faults and broken zones are found in the Triassic; c: There are no faults in the Ordovician and Permian systems, and only the Triassic system has faults. Obviously, there are differences in the transport capacity of these three types of overlap styles, which weaken in the order of classification. The structural deformation of the Permian strata in the basin is weak, and the fault transport system between multiple thin layers is relatively complex, making it difficult to characterize reservoir faults. This patent regards the multi-layer strata in the work area as a whole. It only needs to clarify the scale of the development of the deep basement (Ordovician-Cambrian) and the shallow cover (Triassic) faults to predict whether there is gas reservoir destruction or natural gas dissipation in the multi-layer reservoir as a whole in a certain area. In addition, the plane distribution of river channel sand bodies in multiple strata is predicted by extracting three-dimensional seismic amplitude attributes. According to the following classification and matching relationship (i.e., the target layer superposition favorable area optimization criteria):

[0069] a: The basement fault is large in scale, and the cover rock is uplifted and broken.

[0070] b: The basement fault is small in scale and the cover rock is not uplifted or broken.

[0071] c: Basal fracture is not developed.

[0072] d: Multiple sets of target layer sand bodies are developed.

[0073] e: Sand bodies are developed in a certain target layer.

[0074] Among them, the judgment results of a certain area according to the target layer superposition favorable area selection standard are as follows:

[0075] If the area belongs to:

[0076] (1)b+d, the area is a Class I favorable area, and a three-dimensional horizontal well group can be directly deployed.

[0077] (2) b+e or c+d or c+e, then the area is a Class II favorable area, and it is recommended to deploy a vertical directional well + horizontal well group.

[0078] (3) a+d or a+e, the area is a Class III favorable area and it is not recommended to deploy a three-dimensional development well group.

[0079] Four favorable areas of type I+II superposition were selected in the study area, which have good superposition with the effective sand bodies of each layer. It can be seen that this method can accurately select favorable areas of multi-thin layer superposition with good reliability. Figure 4 As shown, specific reference Figure 4 (a) Attribute map, observe and analyze the distribution characteristics of the caprock and basement structural faults, and then prioritize the four favorable transport systems and caprock overlap areas, as follows: Figure 4(b); Based on the comprehensive analysis of seismic sand body attributes and geological effective sand bodies, see Figure 4 (c) and 4(d), it is clear that the Shan 2, He 8, and Qian 5 layers in these four areas all have channel sand bodies, which can be used as superimposed I+II favorable areas; according to the wellhead gas test results of adjacent wells and the actual drilling of sand bodies, the three well groups of Mi 34-36, Mi 42-44, and Mi 56 were selected for multi-layer three-dimensional development. Among them, the drilling results of effective sand bodies in multiple layers in the Mi 42-44 and Mi 34-36 well areas are good, and three-dimensional horizontal well groups can be deployed first.

[0080] Taking Mizhi gas field as an example, as a new development area with huge potential in Changqing gas field, the evaluation and production construction tasks are arduous. This method is used to preliminarily screen the Mi 163 area (350km 2 ) Four superimposed favorable areas were built. Two appraisal wells, Mi42-44 and Mi34-36C3, were drilled in two of the favorable areas. Multiple gas-bearing layers were encountered in both wells. The thickness of the Shan2, He8, Taiyuan and Qian5 gas layers exceeded 8m. In the Mi42-44 well area, 15km of superimposed favorable areas were identified. 2 , with a reserve of 1.56 billion cubic meters. This method is highly practical. It can carry out differentiated deployment for tight gas reservoirs with multiple thin layers, increase the number of three-dimensional horizontal wells, thereby improving the utilization of reserves and recovery rate, and the scale of development benefits will be greatly increased.

[0081] In summary, the present invention provides a method for selecting favorable areas based on three-dimensional seismic multi-thin layer superposition. Compared with the existing methods for selecting favorable areas, this method has the following advantages:

[0082] This method is based on a three-dimensional seismic exploration method. Through stratum interpretation, the basement, caprock and target layer of a multi-layer gas reservoir are identified, and the seismic attribute map corresponding to each stratum is obtained. Through the seismic attribute map, the basement and caprock are interpreted for faults, and the target layer is characterized for distribution characteristics, so as to obtain the basement fault characteristics, caprock fault characteristics and reservoir sand body distribution characteristics for establishing the target layer superposition favorable area optimization standard. Finally, through the target layer superposition favorable area optimization standard, the multi-thin layer superposition area to be tested is optimized and evaluated. This method regards the multi-layer strata in the work area as a whole. It only needs to clarify the scale of fracture development in the deep basement and shallow caprock, so as to predict whether there is gas reservoir destruction or natural gas dissipation in the multi-layer reservoir as a whole in a certain area, thereby efficiently and accurately completing the optimization of favorable areas.

[0083] The above embodiment is only one of the implementation methods that can realize the technical solution of the present invention. The scope of protection claimed by the present invention is not limited only to this embodiment, but also includes changes, replacements and other implementation methods that can be easily thought of by any technician familiar with the technical field within the technical scope disclosed by the present invention.

Claims

1. A method for selecting favorable areas based on three-dimensional seismic multi-thin layer superposition, characterized in that: include: Based on 3D seismic exploration, the basement, caprock and target layer of multi-layer gas reservoirs are identified through stratum interpretation, and the seismic attribute map corresponding to each stratum is obtained; Based on the seismic attribute map, the basement and cover faults are interpreted respectively to obtain the basement fault characteristics and cover fault characteristics; Characterize the distribution characteristics of the target layer and obtain the distribution characteristics of the reservoir sand body; Based on the basement fault characteristics, cap rock fault characteristics and reservoir sand body distribution characteristics, the selection criteria for the favorable area of ​​target layer superposition are established; Based on the optimization criteria for the favorable area of ​​target layer superposition, the multi-thin layer superposition area to be tested is optimized and evaluated.

2. The method for selecting favorable areas based on 3D seismic multi-thin layer superposition according to claim 1, characterized in that: in, The cap rock, target layer and basement are distributed from top to bottom; there are also source rocks between the basement and the target layer.

3. The method for selecting favorable areas based on 3D seismic multi-thin layer superposition according to claim 2, characterized in that: According to the location from the source rock, the target layer is divided into intra-source, near-source and far-source.

4. The method for selecting favorable areas based on 3D seismic multi-thin layer superposition according to claim 1, characterized in that: Based on the coherence attributes, curvature attributes and dip attributes in the seismic attribute map, the basement and cover layer faults are interpreted to obtain the basement fault characteristics and cover layer fault characteristics.

5. The method for selecting favorable areas based on 3D seismic multi-thin layer superposition according to claim 4, characterized in that: Fault interpretation is characterized based on three dimensions: the nature of the faults in the work area, the stages of fault activity, and the plane distribution of multiple-stage faults.

6. The method for selecting favorable areas based on three-dimensional seismic multi-thin layer superposition according to claim 1 is characterized in that: Based on the amplitude attributes in the seismic attribute map, the distribution characteristics of the target layer are characterized to obtain the distribution characteristics of the reservoir sand body.

7. The method for selecting favorable areas based on 3D seismic multi-thin layer superposition according to claim 1, characterized in that: Based on the spatial configuration relationship between the basement fault characteristics, cap rock fault characteristics and reservoir sand body distribution characteristics, the optimization criteria for the favorable area of ​​target layer superposition are established.

8. A system for optimizing favorable areas of multiple thin layers superimposed based on 3D seismic, used to implement the steps of the method for optimizing favorable areas of multiple thin layers superimposed based on 3D seismic according to any one of claims 1 to 7, characterized in that: include: The acquisition and identification module is used to identify the basement, cap layer and target layer of the multi-layer gas reservoir through layer interpretation based on the three-dimensional seismic exploration method, and obtain the seismic attribute map corresponding to each layer; The interpretation module is used to interpret the basement and cover fractures based on the seismic attribute map to obtain the basement fracture characteristics and cover fracture characteristics; Characterize the distribution characteristics of the target layer and obtain the distribution characteristics of the reservoir sand body; The standard establishment module is used to establish the optimization standard of the favorable area of ​​the target layer superposition based on the basement fault characteristics, cap rock fault characteristics and reservoir sand body distribution characteristics; The optimization evaluation module is used to perform optimization evaluation on the multi-thin layer overlap area to be tested based on the optimization criteria of the target layer overlap favorable area.

9. A device, characterized in that: include: Memory for storing computer programs; A processor is used to implement the steps of the method for selecting favorable areas for multi-thin layer superposition based on three-dimensional seismic as described in any one of claims 1 to 7 when executing the computer program.

10. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, it is used to implement the steps of the method for optimizing favorable areas based on three-dimensional seismic multi-thin layer superposition as described in any one of claims 1-7.

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