Method and system for identifying deep oil gas by using gravity anomaly in combination with earthquake

Abstract

The invention discloses a method and a system for identifying deep oil gas by using gravity anomaly in combination with earthquake. The method comprises the following steps: establishing a stratigraphic division comparison framework of a target area; performing gravity and earthquake joint inversion interpretation on the basis of stratigraphic division comparison to obtain first interpretation data; based on the database and the first interpretation data, carrying out joint inversion interpretation on the gravity of the regional target strata series to obtain a geophysical comprehensive interpretation profile; according to the preset rock physical property of the target geological horizon and the corresponding Bouguer gravity anomaly, constraining the inverted model; performing density inversion of gravity anomalies on the constrained model based on data of a geophysical comprehensive interpretation profile to obtain a geophysical comprehensive model; and comparing and verifying a hydrocarbon source rock analysis result with data in the geophysical comprehensive model, and screening an area meeting a first preset condition as an exploration target. Quantitative description of deep oil and gas geological conditions is achieved, and the purposes of improving exploration precision and reducing exploration cost are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of oil and gas geophysical exploration, and in particular to a method and system for identifying deep oil and gas by combining gravity anomaly with seismic. Background Art

[0002] With the continuous expansion of the oil and gas exploration and development field and the continuous advancement of detection technology, searching for oil and gas resources in deeper and older formations has become an important goal for oil and gas companies. In recent years, global deep oil and gas exploration and development have made important progress, and deep oil and gas resources have become the main body of proven reserves growth in recent years. With the continuous advancement of deep oil and gas exploration and development theory and technology, my country's deep and ultra-deep oil and gas exploration and development have made important progress, and also demonstrated the huge potential of deep oil and gas, which has broadened new areas for the development of my country's petroleum industry. In the near future, deep oil and gas will surely become a realistic field for increasing my country's oil and gas exploration and development efforts. This can not only support the needs of sustainable development of major oil fields, but also has important strategic significance for national economic development and national energy security.

[0003] In the process of deep oil and gas exploration, increasingly complex geological conditions and increasing development difficulties are important challenges and practical problems that need to be solved urgently. The detailed description of the structure is the first technical challenge, which is of great significance for improving the success rate of exploration and reducing exploration costs. In the process of deep oil and gas exploration, the serious attenuation of seismic signals makes the study of the development and distribution characteristics of deep structures, source rocks and reservoirs face huge challenges. Summary of the invention

[0004] The embodiments of the present invention provide a method and system for identifying deep oil and gas by using gravity anomalies in combination with seismic data, thereby at least partially solving the technical problem of the difficulty in deep oil and gas exploration in the prior art and achieving the technical effect of quantitatively describing the geological conditions of deep oil and gas.

[0005] In the first aspect, to solve the above technical problems, the embodiments of the present invention provide the following technical solutions:

[0006] A method for identifying deep oil and gas by combining gravity anomaly with seismic data, comprising:

[0007] According to the data in the database, establish the stratigraphic division and comparison framework of the target area;

[0008] Based on the stratigraphic division and comparison framework and single well data, gravity and seismic joint inversion interpretation is performed on the basis of stratigraphic division and comparison to obtain the first interpretation data;

[0009] Based on the above database and the first interpretation data, the gravity of the target layer in the region is jointly inverted and interpreted to obtain a geophysical comprehensive interpretation profile;

[0010] The inversion model is constrained by the preset rock properties of the target geological layer and the corresponding Bouguer gravity anomaly; the constrained model is used to perform density inversion of the gravity anomaly based on the data of the above-mentioned geophysical comprehensive interpretation profile to obtain a geophysical comprehensive model;

[0011] The results of the source rock analysis in the target area are compared and verified with the data in the above-mentioned comprehensive geophysical model, and the areas that meet the first preset conditions are selected as exploration targets.

[0012] Optionally, the step of establishing a stratigraphic division and comparison grid for the target area further includes:

[0013] Using multiple stratigraphic division and comparison methods, the development characteristics of the geological strata in the above target area are obtained;

[0014] Based on the above development characteristics, determine the corresponding stratigraphic structure and lithology;

[0015] Based on the above structures and lithologies, a regional comprehensive column chart is constructed, and a stratigraphic division and comparison framework of the target area is established accordingly.

[0016] Optionally, the step of performing gravity and seismic joint inversion interpretation based on stratigraphic division and comparison further includes:

[0017] Conduct single-section or single-well sedimentary facies analysis on the target geological horizon;

[0018] Screen out typical sections or wells that meet the preset second condition and establish sedimentary environment comparison sections;

[0019] Based on the above sedimentary environment comparison profile, the sedimentary facies belt that meets the preset third condition is screened out;

[0020] Based on the above sedimentary facies belts and the above stratigraphic division and comparison framework, a gravity and seismic joint inversion interpretation is carried out.

[0021] Optionally, the above-mentioned step of performing joint inversion interpretation on the gravity of the target strata in the region further includes:

[0022] Based on the above database, the gravity inversion is constrained using geophysical parameters obtained by the preset geophysical exploration method;

[0023] Carry out gravity inversion on the target layer system in the region to obtain the gravity inversion profile;

[0024] Through the correspondence between the above gravity inversion profile and the above first interpretation data, a geophysical comprehensive interpretation profile is obtained.

[0025] Optionally, the above-mentioned geophysical exploration method is electrical method and / or magnetic method.

[0026] Optionally, the step of constraining the inversion model further includes:

[0027] Measure the measured gravity effect value of the above target area;

[0028] The Bouguer gravity anomaly is obtained by subtracting the gravity effect value of the material above the preset reference surface from the above measured gravity effect value;

[0029] Based on the Bouguer gravity anomaly, the gravity effect value of the horizon other than the target geological horizon is subtracted to obtain the gravity effect value of the target geological horizon;

[0030] The Bouguer gravity anomaly range that meets the preset rock properties is screened, and the gravity inversion model is constrained based on the Bouguer gravity anomaly range.

[0031] Optionally, after obtaining the gravity effect value of the target stratum layer, the method further includes:

[0032] Generate characteristic curves based on the changes in different rock properties and logging curves;

[0033] By using the characteristic curve, the distribution range of the rock formations serving as reservoirs and the corresponding gravity anomaly range are screened out in the formations other than the target geological formations;

[0034] The above inversion model is constrained based on the above gravity anomaly range and fitted with the above inversion results.

[0035] In a second aspect, a system for identifying deep oil and gas by combining gravity anomaly with seismic is provided, comprising:

[0036] A comparison grid establishment module is used to establish a stratigraphic division comparison grid for the target area based on the data in the database;

[0037] The primary inversion module performs gravity and seismic joint inversion interpretation based on the stratigraphic division and comparison framework and single well data to obtain the first interpretation data;

[0038] The secondary inversion module performs a joint inversion interpretation of the gravity of the target layer in the region based on the above database and the above first interpretation data to obtain a geophysical comprehensive interpretation profile;

[0039] The inversion model correction module is used to constrain the inversion model through the preset rock properties of the target geological layer and the corresponding Bouguer gravity anomaly; the constrained model is used to perform density inversion of the gravity anomaly based on the data of the above-mentioned geophysical comprehensive interpretation profile to obtain a geophysical comprehensive model;

[0040] The exploration target result module is used to compare and verify the results of the source rock analysis in the target area with the data in the above-mentioned geophysical comprehensive model, and select the area that meets the first preset condition as the exploration target.

[0041] In a third aspect, an electronic device is provided, comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps corresponding to the method of the first aspect when executing the computer program.

[0042] In a fourth aspect, a computer-readable storage medium is provided, on which a computer program is stored, and when the program is executed by a processor, the steps corresponding to the above method in the first aspect are implemented.

[0043] One or more technical solutions provided in the embodiments of the present invention have at least the following technical effects or advantages:

[0044] In view of the deep structure and stratigraphic characteristics of the basin, combined with gravity data, which has a good reflection of the deep basement structure, and seismic data, which can more finely reflect the characteristics of the shallow stratigraphic structure, the combined research technology of gravity and seismic is applied to conduct comprehensive and integrated detection to achieve a quantitative description of deep oil and gas geological conditions. This overcomes the limitations of low imaging accuracy, multiple solutions and large uncertainty of traditional single methods, thereby achieving the purpose of improving exploration accuracy and reducing exploration costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0046] Figure 1 A flow chart of a method for identifying deep oil and gas by combining gravity anomaly with seismic provided by the present invention;

[0047] Figure 2 It is a columnar profile of the regional geological prediction section in the present invention;

[0048] Figure 3 This is a comparative diagram of the stratigraphic division of the Yixian Formation (segment) in the region of the present invention;

[0049] Figure 4 This is the comparative grid table of the stratigraphic division of Kailu and surrounding areas in the present invention;

[0050] Figure 5 It is the J53 single well phase in Kailu area in the present invention;

[0051] Figure 6The lithofacies paleogeography of Kailu area and its surrounding areas in this invention;

[0052] Figure 7 This is a plan view of the lithofacies distribution of the Yixian Formation in the depression of the present invention;

[0053] Figure 8 It is the combined gravity-seismic model for stratigraphic division and comparison in the present invention;

[0054] Fig. 9 For the comprehensive seismic interpretation combining gravity and seismic data in the present invention;

[0055] Fig.10 It is the regional gravity anomaly and gravity three-dimensional inversion profile in the present invention;

[0056] Fig.11 This is the geophysical comprehensive interpretation profile of Kailu and surrounding areas in the present invention;

[0057] Fig.12 This is the Bouguer gravity anomaly map of Zhonglu and surrounding areas in the present invention;

[0058] Fig.13 The rock properties and logging curve characteristics of Kailu and surrounding areas in the present invention;

[0059] Fig.14 To carry out inversion interpretation based on the stratigraphic division and comparison in the present invention;

[0060] Fig.15 This is a schematic diagram of the geochemical evaluation of Jurassic source rocks in the northern Songliao Basin around Kailu in the present invention;

[0061] Fig.16 The deep source rock characteristics of Songliao Basin in this invention;

[0062] Fig.17 The target area distribution map for the oil and gas exploration review requirement in the central Shandong region of the present invention;

[0063] Fig.18 A schematic diagram of the system structure for identifying deep oil and gas by combining gravity anomalies with seismic data provided by the present invention. DETAILED DESCRIPTION

[0064] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0065] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0066] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0067] It should be understood that the embodiments of the present invention and the specific features in the embodiments are detailed descriptions of the technical solutions of the present application, rather than limitations of the technical solutions of the present application. In the absence of conflict, the embodiments of the present application and the technical features in the embodiments may be combined with each other.

[0068] In addition, the term "and / or" in this article is only a description of the association relationship of the associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0069] The technical solution of the embodiment of the present invention is to solve the above technical problems, and the overall idea is as follows:

[0070] Taking advantage of the fact that gravity exploration has a good reflection of deep basement structure, a joint gravity and seismic study is conducted on the basis of ground gravity area measurement and seismic exploration, which complements the seismic data and obtains more accurate deep geological information, thereby achieving the purpose of finely describing the deep structure and stratigraphic distribution characteristics.

[0071] In an embodiment of the present invention, there is provided Figure 1 A method for identifying deep oil and gas by combining gravity anomaly with seismic is shown, and the method includes steps S101 to S103:

[0072] Step S101, establishing a stratigraphic division and comparison framework for the target area according to the data in the database;

[0073] It should be noted that the data in the database include existing basic geological, geophysical, drilling, seismic data, drilling data and regional geological data in the target area. In detail, the steps of establishing the stratigraphic division and comparison framework of the target area also include: using multiple stratigraphic division and comparison methods to obtain the development characteristics of the geological strata in the target area; based on the development characteristics, determine the corresponding stratigraphic structure and lithology; construct a regional comprehensive columnar diagram based on the structure and lithology, such as Figure 2As shown, a stratigraphic division comparison grid is established for the target area, such as Figure 3 and 4 As shown. Among them, the multiple stratigraphic division and correlation method refers to dividing the strata into different groups and sections according to lithology, paleontology, sedimentary environment, geochemistry and other methods, and conducting stratigraphic correlation to obtain the development characteristics of the geological strata in the target area. Taking the outcrop of the Yixian Formation in western Liaoning as an example, the vertical sedimentary sequence of the Yixian Formation sedimentary layer in the Yixian Basin was analyzed, and it was concluded that the sedimentary environment of the Yixian Basin was alluvial fan-braided river-meandering river-lake deposition, and the river deposition model and lake deposition model were established. Based on the stratigraphic study of the Yixian Formation in the Sihetun area, the sedimentary environment of this period was analyzed, and 12 lithofacies types were identified in the Lujiatun and Jianshangou sections, which were divided into volcaniclastic fan depositional assemblages and lake depositional assemblages. The sedimentary model of the lake during this period was established, and it was believed that the Yixian Formation deposition was divided into 4 stages. The results show that the Yixian Formation is widely developed in the southern Songliao Basin and western Liaoning. It is mainly a set of volcanic rocks intercalated with sedimentary layers, and the sedimentary layers are discontinuous. In the southern Songliao Basin, it mainly exists in the Lujiabao, Zhezhong, Naiman and other depressions and Xiushui Basin. In western Liaoning, it is mainly distributed in the Fuxin-Yixian Basin, Jianchang Basin, Lingyuan Basin, Jinyang Basin and other basins. It is a "Thousand Island Lake" type in the region, which is a catchment lake basin formed in the depression area during the volcanic intermission period. The above content can be analyzed through artificial field surveys and analysis, or by using existing drilling and outcrop data and multiple stratigraphic data such as rock stratigraphy, biostratigraphy, chemical stratigraphy, and chronostratigraphy, using MapGIS software for analysis.

[0074] Step S102, based on the stratigraphic division and comparison framework and the single well data, gravity and seismic joint inversion interpretation is performed on the basis of stratigraphic division and comparison to obtain first interpretation data;

[0075] It should be noted that the main purpose of the stratigraphic division comparison framework and single well data is to conduct sedimentary environment analysis. Taking the Yixian Formation in Kailu area as an example, a single profile or single well sedimentary facies analysis is conducted on the target geological stratum. Figure 5 As shown; select typical sections or wells that meet the preset second condition and establish sedimentary environment comparison sections; its purpose is to clarify the regional macroscopic lithofacies paleogeography paleo-sedimentary environment, such as Figure 6 As shown in the figure, for specific typical profiles or drilling screening, the selection is mainly based on the research purpose, geographical location and other factors. For example, if the sedimentary environment and rock type are of interest, then sedimentary rock is set as the preset second condition for drilling or profile. Then, based on the sedimentary environment comparison profile, the sedimentary facies belt that meets the preset third condition is selected, such as Figure 7As shown; Taking the Lujiapu area in Kailu area as an example, because the maximum depression area is 1740km2; the Yixian Formation is thick, and the final thickness can reach 2100m; the burial depth is deep, the deepest is about 5200m; the preservation conditions are good, the Yixian Formation interior and deep exploration are low, and the lower Permian in the Mesozoic depression development area is relatively intact. Among them, the Lujiapu Depression is characterized by: the boundary fault controls the development of volcanic rocks, the downthrown plate is dominated by volcanic rock accumulation, the seismic phase is chaotic reflection, and the seismic phase in the slope area is medium-strong amplitude, parallel-subparallel relatively continuous reflection, reflecting the lake phase fan delta deposition system, which has good exploration prospects. Therefore, the regional parameters and characteristics with good exploration prospects are used as the preset third condition for screening, that is, the proportion and distribution position of various rocks are set. Finally, based on the sedimentary facies belt, on the basis of the stratigraphic division and comparison framework, gravity and seismic joint inversion interpretation is carried out. The inversion model can adopt horizontal layered inversion model, vertical layered inversion model, density inversion model, etc.

[0076] Step S103, based on the database and the first interpretation data, the gravity of the target layer in the region is jointly inverted and interpreted to obtain a geophysical comprehensive interpretation profile;

[0077] It should be noted that the purpose of this step is to invert gravity, because low gravity anomalies are mainly caused by sedimentary depressions or low-density granite intrusions, and high gravity anomalies are mainly caused by the uplift of the basement Paleozoic. In detail, using the gravity profiles and seismic data, drilling data, and regional geological data in the database, a method combining basin-inside and basin-outside data is used, including basin-inside data analysis, basin-outside data analysis, basin-inside and basin-outside data comparison, and joint inversion and comprehensive interpretation analysis. Joint inversion and comprehensive interpretation analysis are carried out for the regional target strata, namely the Jurassic and Permian systems, such as Figure 8 and Fig. 9 As shown in the figure, the geophysical comprehensive interpretation profile and comprehensive interpretation results are obtained, such as Fig.10 and Fig.11 shown.

[0078] Furthermore, in the step of joint inversion interpretation of the gravity of the target layer in the region, it also includes: constraining the gravity inversion based on the database and using the geophysical parameters obtained by the preset geophysical exploration method; performing gravity inversion on the target layer in the region to obtain the gravity inversion profile; and obtaining the geophysical comprehensive interpretation profile through the correspondence between the gravity inversion profile and the first interpretation data. Among them, the purpose of constraining the gravity inversion is to improve the accuracy of the inversion results and obtain more accurate information on the structure and properties of the underground rock formations; specifically, the geophysical parameters obtained by the geophysical exploration method of the electrical method or / and the magnetic method, that is, the electrical method or / and the magnetic method are used to obtain the conductivity, magnetism, wave velocity density and elasticity and other data of the underground rock formations.

[0079] Step S104, constraining the inverted model through the preset rock properties of the target geological layer and the corresponding Bouguer gravity anomaly; performing density inversion of the gravity anomaly on the constrained model based on the data of the geophysical comprehensive interpretation profile to obtain a geophysical comprehensive model;

[0080] It should be noted that because the gravity anomaly measured on the ground is the superposition of the gravitational effects of field sources at different depths underground, the Bouguer gravity anomaly is used to constrain the inversion model in order to provide the accuracy of the inversion model. In detail, the steps for constraining the inversion model include measuring the measured gravity effect value of the target area; subtracting the gravity effect value of the material above the preset reference plane from the measured gravity effect value to obtain the Bouguer gravity anomaly; in detail, the measured gravity value is obtained by eliminating the gravity effect value of the material above the geoid (for example, sea level). Then, based on the Bouguer gravity anomaly, the gravity effect value of the layer other than the target geological layer is subtracted to obtain the gravity effect value of the target stratigraphic layer; among them, the layers other than the target geological layer are mainly middle and shallow layers, and the purpose of this step is to eliminate the influence of middle and shallow layers on the calculation. Finally, the Bouguer gravity anomaly range that meets the preset rock properties is screened, and the gravity inversion model is constrained based on the Bouguer gravity anomaly range. That is, using the difference in rock properties as a bridge, such as Fig.13 As shown, the Bouguer gravity anomaly range that meets the preset rock properties is screened, and the gravity inversion model is constrained based on the Bouguer gravity anomaly range. The preset rock properties mainly refer to porosity and permeability. The porosity and permeability ranges required for production are selected, and the Bouguer gravity anomaly range is selected to constrain the gravity inversion model.

[0081] Specifically, the formula for calculating the Bouguer gravity anomaly Δg is:

[0082] Δg=g 测 -g 高 -g 中 -g 纬 -g 形 -g

[0083] The deep gravity anomaly is: g 深 =Δg-g 正 ;

[0084] The corrected deep gravity anomaly is: g 校 =g 深 ×(Δg-δ) / Δg;

[0085] Among them, g 测 is the measured result by the gravimeter; g 纬 g is the latitude-corrected gravity effect value; 高 is the value of gravity effect correction for height; g 中 Corrected gravity effect value for the middle layer; g形 is the value of terrain-corrected gravity effect; g is the normal gravity value; g 正 is the gravity effect value of the middle and shallow geological bodies; δ is the difference value of rock physical properties.

[0086] Furthermore, after obtaining the gravity effect value of the target stratum layer, it also includes:

[0087] Based on the changes of different rock properties and logging curves, a characteristic curve is generated; the distribution range of rock formations and the corresponding gravity anomaly range as reservoirs are screened out in the layers other than the target geological layers through the characteristic curve; the inversion model is constrained based on the gravity anomaly range and fitted with the inversion results. This reduces the error value caused by changes in formation physical properties and further improves accuracy. In detail, it is essentially to use the known layer (middle and shallow) data other than the target geological layer to make an analogy with the target geological layer. The middle and shallow data of multiple known areas around the target geological layer can be used for analogy, or the data of the known area closest to the target geological layer can be used for analogy.

[0088] Based on the above method, the density inversion of the final gravity anomaly is as follows: Fig.14 shown.

[0089] Step S105, comparing and verifying the results of the source rock analysis in the target area with the data in the geophysical comprehensive model, and selecting areas that meet the first preset conditions as exploration targets.

[0090] It should be noted that source rock analysis mainly uses existing outcrop profiles, drilling, logging, and analytical data to analyze the geochemical characteristics of single profiles or single well source rocks in the target group and deep-seated systems. Taking the Yixian Formation in Kailu area as an example, Fig.15 As shown in the figure; generate data on the development, distribution and hydrocarbon generation potential of source rocks in Kailu area, such as Fig.16 As shown in Table 1 below.

[0091]

[0092] Table 1

[0093] After clarifying the oil and gas geological conditions of the main target strata based on the above figures and data, select favorable exploration target areas, such as Fig.17As shown in detail, firstly, the thickness of source rock is one of the main factors that determine the retention height of oil and gas in source rock. The greater the thickness, the more favorable it is for the accumulation of oil and gas. In Kailu and surrounding areas, the source rock types of Carboniferous-Permian and Yixian Formation are mainly mudstone source rocks. According to the geological data in historical data and the evaluation of oil and gas geology by other scholars, it is very favorable for the accumulation of mudstone when the oil-producing layer is selected as mudstone with a thickness greater than 1000m. Secondly, the thickness of reservoir and formation is an important indicator for the evaluation of oil and gas resources in the basin. The accumulation of oil and gas is mainly controlled by reservoir thickness and reservoir physical properties. A large reservoir thickness, good lateral continuity and wide distribution are conducive to the storage of oil and gas. It is known that the Permian sandstone, fracture and Yixian Formation sandstone and volcanic reservoirs all have good storage capacity. Their thickness can be obtained through detailed interpretation of seismic profiles, but the seismic reflection profile quality is required to be very high. Since the seismic profiles in Kailu area are mostly for medium and shallow oil and gas, and there are few for the deep Yixian Formation and Carboniferous-Permian, it is impossible to accurately determine the specific thickness of the reservoir. Through this patent, the seismic data are interpreted and inverted by gravity to characterize the thickness of the reservoir base layer. Third: Fault activity not only controls the sedimentary structure in the basin, but also has a close relationship with oil and gas accumulation. The activation of the Paleozoic reverse faults in the Kailu area in the late Yanshan Movement caused the Yixian Formation and Linxi Formation to form a relatively closed system, which is different from the open system above the Jiufotang Formation. The volcanic rocks at the top of the Cretaceous Yixian Formation have upper generation and lower storage, the interior has self-generation and self-storage, and the lower part has the potential for oil and gas accumulation; the Permian Linxi Formation has a self-generation and self-storage accumulation combination. Fourth: Geochemical indicators, the vitrinite reflectance Ro of the source rocks in the Songliao Basin is above 1.09%-3.45%, showing the overall evolution characteristics of high maturity-overmature. The cumulative thickness of the mudstone encountered in the Heifudi 1 well of the Linxi Formation is 276m, the total organic carbon (TOC) is distributed between 0.013 and 1.56%, the average is 1.058%, the organic matter type is type II, and most of them are medium source rocks. The maximum hydrocarbon generation temperature (Tmax) is mostly >450℃, Ro: 1.5∽3.76%, indicating a high maturity-overmature stage. The optimization criteria obtained are shown in Table 2.

[0094]

[0095]

[0096] Table 2

[0097] The optimization criteria are used as the first preset condition to select the area as the exploration target, such as Fig.17 Finally, well location deployment recommendations are made based on the exploration objectives.

[0098] Based on the same inventive concept, the embodiment of the present invention provides a system for identifying deep oil and gas by combining gravity anomaly with seismic. Fig.18 As shown, including:

[0099] A comparison grid establishment module is used to establish a stratigraphic division comparison grid for the target area based on the data in the database;

[0100] The primary inversion module performs gravity and seismic joint inversion interpretation based on stratigraphic division and comparison framework and single well data to obtain the first interpretation data;

[0101] The secondary inversion module performs a joint inversion interpretation of the gravity of the target strata in the region based on the database and the first interpretation data to obtain a geophysical comprehensive interpretation profile;

[0102] The inversion model correction module is used to constrain the inversion model through the preset rock properties of the target geological layer and the corresponding Bouguer gravity anomaly; the constrained model is used to perform density inversion of the gravity anomaly based on the data of the geophysical comprehensive interpretation profile to obtain a geophysical comprehensive model;

[0103] The exploration target result module is used to compare and verify the results of the source rock analysis in the target area with the data in the geophysical comprehensive model, and select the areas that meet the first preset conditions as exploration targets.

[0104] Based on the same inventive concept, an embodiment of the present invention provides an electronic device, including: a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, a method for identifying deep oil and gas by combining gravity anomalies with seismic data is implemented.

[0105] Based on the same inventive concept, this embodiment provides a computer-readable storage medium on which a computer program is stored, characterized in that when the program is executed by a processor, a method for identifying deep oil and gas by using gravity anomalies in combination with seismic data is implemented.

[0106] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0107] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0108] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A method for identifying deep oil and gas using gravity anomaly combined with seismic, characterized in that: The method comprises: According to the data in the database, establish the stratigraphic division and comparison framework of the target area; Based on the stratigraphic division and comparison framework and the single well data, gravity and seismic joint inversion interpretation is performed on the basis of stratigraphic division and comparison to obtain first interpretation data; Based on the database and the first interpretation data, a joint inversion interpretation is performed on the gravity of the target layer in the region to obtain a geophysical comprehensive interpretation profile; The inverted model is constrained by the preset rock properties of the target geological layer and the corresponding Bouguer gravity anomaly; the constrained model is subjected to density inversion of the gravity anomaly based on the data of the geophysical comprehensive interpretation profile to obtain a geophysical comprehensive model; The results of the source rock analysis in the target area are compared and verified with the data in the geophysical comprehensive model, and the areas that meet the first preset conditions are selected as exploration targets.

2. The method according to claim 1, characterized in that The step of establishing a stratigraphic division and comparison grid for the target area also includes: Using multiple stratigraphic division and comparison methods, the development characteristics of the geological strata in the target area are obtained; Based on the development characteristics, determine the corresponding stratigraphic structure and lithology; A regional comprehensive columnar diagram is constructed based on the structure and lithology, and a stratigraphic division and comparison framework of the target area is established accordingly.

3. The method according to claim 1, characterized in that The step of performing gravity and seismic joint inversion interpretation based on stratum division and comparison also includes: Conduct single-section or single-well sedimentary facies analysis on the target geological horizon; Screen out typical sections or wells that meet the preset second condition and establish sedimentary environment comparison sections; Based on the sedimentary environment comparison profile, screening out the sedimentary facies belt that meets the preset third condition; Based on the sedimentary facies belts and the stratigraphic division and comparison framework, gravity and seismic joint inversion interpretation is performed.

4. The method according to claim 1, characterized in that The step of performing joint inversion interpretation on the gravity of the regional target strata also includes: Based on the database, the gravity inversion is constrained using geophysical parameters obtained by a preset geophysical exploration method; Carry out gravity inversion on the target layer system in the region to obtain the gravity inversion profile; A geophysical comprehensive interpretation profile is obtained through the correspondence between the gravity inversion profile and the first interpretation data.

5. The method according to claim 4, characterized in that The geophysical prospecting method is an electrical method or / and a magnetic method.

6. The method according to claim 4, characterized in that The step of constraining the inversion model further includes: measuring the measured gravity effect value of the target area; The Bouguer gravity anomaly is obtained by subtracting the gravity effect value of the material above the preset reference surface from the measured gravity effect value; Based on the Bouguer gravity anomaly, the gravity effect value of the horizon other than the target geological horizon is subtracted to obtain the gravity effect value of the target geological horizon; The Bouguer gravity anomaly range that meets the preset rock properties is screened, and the gravity inversion model is constrained based on the Bouguer gravity anomaly range.

7. The method according to claim 6, characterized in that After obtaining the gravity effect value of the target stratum layer, the method further includes: Generate characteristic curves based on the changes in different rock properties and logging curves; Screening out the distribution range of rock formations serving as reservoirs and the corresponding gravity anomaly range in the formations other than the target geological formations through the characteristic curve; The inversion model is constrained based on the gravity anomaly range and fitted with the inversion result.

8. A system for identifying deep oil and gas using gravity anomalies combined with seismic data, characterized in that: The system comprises: A comparison grid establishment module is used to establish a stratigraphic division comparison grid for the target area based on the data in the database; A primary inversion module, based on the stratigraphic division and comparison framework and the single well data, performs gravity and seismic joint inversion interpretation on the basis of stratigraphic division and comparison to obtain first interpretation data; A secondary inversion module performs a joint inversion interpretation of the gravity of the target layer in the region based on the database and the first interpretation data to obtain a geophysical comprehensive interpretation profile; The inversion model correction module is used to constrain the inversion model through the preset rock properties of the target geological layer and the corresponding Bouguer gravity anomaly; the constrained model is used to perform density inversion of the gravity anomaly based on the data of the geophysical comprehensive interpretation section to obtain a geophysical comprehensive model; The exploration target result module is used to compare and verify the results of the source rock analysis in the target area with the data in the geophysical comprehensive model, and select the area that meets the first preset condition as the exploration target.

9. An electronic device, characterized in that: The electronic device comprises: a memory, a processor and a computer program stored in the memory and executable on the processor, and the processor implements the method steps described in any one of claims 1 to 7 when executing the computer program.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the steps corresponding to the method according to any one of claims 1 to 7 are implemented.

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