Method and system for identifying deep oil and gas by combining gravity anomaly and earthquake

Abstract

The application discloses a method and system for identifying deep oil and gas by combining gravity anomaly and earthquakes, which comprises the following steps: establishing a stratigraphic division contrast framework of a target area; performing gravity and earthquake combined inversion interpretation on the basis of stratigraphic division contrast to obtain first interpretation data; performing combined inversion interpretation on the gravity of the target layer system of the area based on a database and the first interpretation data to obtain a geophysical comprehensive interpretation profile; constraining the inverted model by preset rock physical properties of a target geological horizon and corresponding Bouguer gravity anomaly; performing density inversion of the gravity anomaly based on the data of the geophysical comprehensive interpretation profile of the constrained model to obtain a geophysical comprehensive model; comparing and verifying the results of hydrocarbon source rock analysis with the data in the geophysical comprehensive model to screen regions meeting a first preset condition as exploration targets. The method realizes quantitative description of deep oil and gas geological conditions and achieves the purposes of improving exploration accuracy and reducing exploration cost.

Description

Technical Field

[0001] This invention relates to the field of oil and gas geophysical exploration technology, and in particular to a method and system for identifying deep oil and gas formations using gravity anomalies combined with seismic activity. Background Technology

[0002] With the continuous expansion of oil and gas exploration and development and the advancement of detection technologies, searching for oil and gas resources in deeper and older strata has become a key objective for oil and gas companies. In recent years, significant progress has been made in global deep oil and gas exploration and development, with deep oil and gas resources becoming the main driver of the increase in proven reserves. With the continuous advancement of theories and technologies in deep oil and gas exploration and development, my country has also made significant progress in deep and ultra-deep oil and gas exploration and development, demonstrating the enormous potential of deep oil and gas and expanding new areas for the development of my country's petroleum industry. In the near future, deep oil and gas will undoubtedly become a real area for increasing my country's oil and gas exploration and development efforts. This will not only support the sustainable development needs of major oilfields but also have significant strategic importance for national economic development and national energy security.

[0003] In the exploration of deep oil and gas, increasingly complex geological conditions and ever-increasing development difficulties are significant challenges and pressing issues that need to be addressed. Therefore, detailed characterization of the geological structure is the first technical challenge, crucial for improving exploration success rates and reducing costs. Furthermore, the severe attenuation of seismic signals during deep oil and gas exploration poses a significant challenge to the study of the development and distribution characteristics of deep structures, source rocks, and reservoirs. Summary of the Invention

[0004] The embodiments of the present invention provide a method and system for identifying deep oil and gas using gravity anomalies combined with seismic data, which at least partially solves the technical problem of the difficulty in deep oil and gas exploration in the prior art, and achieves the technical effect of quantitative description of the geological conditions of deep oil and gas.

[0005] Firstly, to solve the above-mentioned technical problems, embodiments of the present invention provide the following technical solutions:

[0006] A method for identifying deep oil and gas formations using gravity anomalies combined with seismic activity includes:

[0007] Based on the data in the database, a stratigraphic correlation framework for the target area was established.

[0008] Based on the stratigraphic correlation framework and single-well data mentioned above, gravity and seismic joint inversion interpretation were performed on the basis of stratigraphic correlation to obtain the first interpretation data;

[0009] Based on the aforementioned database and the aforementioned first interpretation data, a joint inversion interpretation of the gravity of the target stratigraphic system in the region was performed to obtain a geophysical comprehensive interpretation profile.

[0010] The inverted model is constrained by the preset rock properties of the target geological strata and the corresponding Bouguer gravity anomaly; the constrained model is then used to perform gravity anomaly density inversion based on the data from the above geophysical integrated interpretation profile to obtain the geophysical integrated model.

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

[0012] Optionally, the steps of establishing a stratigraphic correlation framework for the target area described above further include:

[0013] The development characteristics of geological strata in the target area were obtained by using the multiple stratigraphic division and correlation method.

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

[0015] Based on the above-mentioned structural and lithological regional integrated columnar section, a corresponding stratigraphic correlation framework for the target area was established.

[0016] Optionally, the steps of performing joint gravity and seismic inversion interpretation based on stratigraphic correlation also include:

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

[0018] Typical profiles or wells that meet the preset second condition are selected to establish a sedimentary environment comparison profile.

[0019] Based on the above comparative profile of sedimentary environments, sedimentary facies zones that meet the preset third condition were selected.

[0020] Based on the aforementioned sedimentary facies zones and the stratigraphic correlation framework, a joint gravity and seismic inversion interpretation was performed.

[0021] Optionally, the steps for the joint inversion interpretation of gravity in the target stratigraphic region mentioned above further include:

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

[0023] Gravity inversion is performed on the target stratigraphic system in the region to obtain the gravity inversion profile;

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

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

[0026] Optionally, the steps for constraining the inverted model described above further include:

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

[0028] Subtracting the gravity effect value of the material above the preset reference plane from the above measured gravity effect value yields the Bouguer gravity anomaly.

[0029] The gravity effect value of the target geological stratum is obtained by subtracting the gravity effect value of the strata other than the target geological stratum from the above Bouguer gravity anomaly.

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

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

[0032] Based on the different rock properties and well logging curve variations, characteristic curves are generated;

[0033] By using the aforementioned characteristic curves, the distribution range of rock strata that can serve as reservoirs and the corresponding gravity anomaly range can be screened out in strata other than the target geological strata.

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

[0035] Secondly, a system for identifying deep oil and gas formations using gravity anomalies combined with seismic activity is provided, comprising:

[0036] The stratigraphic comparison grid creation module is used to create a stratigraphic comparison grid for the target area based on data from the database.

[0037] The primary inversion module, based on the stratigraphic correlation framework and single-well data mentioned above, performs gravity and seismic joint inversion interpretation on the basis of stratigraphic correlation to obtain the first interpretation data;

[0038] The second-level inversion module, based on the aforementioned database and the aforementioned first interpretation data, performs a joint inversion interpretation of the gravity of the target stratigraphic system in the region, and obtains a geophysical comprehensive interpretation profile;

[0039] The inversion model correction module is used to constrain the inverted model by using the preset rock properties of the target geological strata and the corresponding Bouguer gravity anomaly; the constrained model is then used to perform gravity anomaly density inversion based on the data of the above geophysical integrated interpretation profile to obtain the geophysical integrated model.

[0040] The exploration target results module is used to compare and verify the results of source rock analysis in the target area with the data in the above-mentioned geophysical integrated model, and select areas that meet the first preset conditions as exploration targets.

[0041] Thirdly, 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 executes the computer program to perform the steps corresponding to the method described in the first aspect.

[0042] Fourthly, a computer-readable storage medium is provided having a computer program stored thereon, which, when executed by a processor, performs the steps corresponding to the method described in the first aspect.

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

[0044] Targeting the deep structural and stratigraphic characteristics of the basin, this study combines gravity data, which provides a good reflection of the deep basement structure, and seismic data, which can more precisely reflect the shallow stratigraphic structure. A comprehensive, integrated approach using both gravity and seismic data is employed to achieve a quantitative description of deep oil and gas geological conditions. This overcomes the limitations of traditional single-method approaches, such as low imaging accuracy, multiple interpretations, and high uncertainty, thereby improving exploration accuracy and reducing exploration costs. Attached Figure Description

[0045] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0046] Figure 1 A flowchart of a method for identifying deep oil and gas formations using gravity anomalies combined with seismic activity, provided by this invention;

[0047] Figure 2 This is a columnar cross-section of the regional geological prediction profile in this invention;

[0048] Figure 3 This is a stratigraphic correlation diagram of the Yixian Formation (segmented) in the region used in this invention;

[0049] Figure 4 This is a stratigraphic correlation grid table for the Kailu and surrounding areas in this invention;

[0050] Figure 5 This refers to the single-well facies of J53 in the Kailu area of ​​this invention;

[0051] Figure 6This invention pertains to the lithofacies paleogeography of the Kailu region and its surrounding areas.

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

[0053] Figure 8 This is the combined stratigraphic correlation gravity-seismic model used in this invention;

[0054] Figure 9 This invention combines gravity and seismic data for comprehensive seismic interpretation.

[0055] Figure 10 This is the regional gravity anomaly and three-dimensional gravity inversion profile in this invention;

[0056] Figure 11 This is the geophysical comprehensive interpretation profile of Kailu and surrounding areas in this invention;

[0057] Figure 12 This is a Bouguer gravity anomaly map of Shandong and surrounding areas in this invention;

[0058] Figure 13 This invention describes the rock properties and well logging curve characteristics of Kailu and surrounding areas.

[0059] Figure 14 This invention is based on the stratigraphic division and correlation to conduct inversion interpretation;

[0060] Figure 15 This is a schematic diagram illustrating the geochemical evaluation of Jurassic source rocks in the northern Songliao Basin surrounding Kailu in this invention.

[0061] Figure 16 This invention describes the characteristics of deep hydrocarbon source rocks in the Songliao Basin.

[0062] Figure 17 This is a map showing the distribution of target areas required for oil and gas exploration verification in the Shandong region in this invention.

[0063] Figure 18 This invention provides a schematic diagram of a system structure for identifying deep oil and gas formations using gravity anomalies combined with seismic activity. Detailed Implementation

[0064] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0065] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0066] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[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 this application, rather than limitations on the technical solutions of this application. Unless otherwise specified, the embodiments of the present application and the technical features in the embodiments can be combined with each other.

[0068] Furthermore, the term "and / or" in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

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

[0070] Utilizing the characteristic that gravity exploration can better reflect the deep basement structure, and based on ground gravity area measurement and seismic exploration, a joint study of gravity and seismic data is conducted to complement seismic data and obtain more accurate deep geological information, thereby achieving the goal of finely describing the deep structure and stratigraphic distribution characteristics.

[0071] In this embodiment of the invention, the following are provided: Figure 1 The method shown is for identifying deep oil and gas formations using gravity anomalies combined with seismic data. The method includes steps S101 to S103:

[0072] Step S101: Based on the data in the database, establish a stratigraphic correlation framework for the target area;

[0073] It should be noted that the data in the database includes existing basic geological, geophysical, drilling, seismic, well data, and regional geological data for the target area. Specifically, the steps in establishing a stratigraphic correlation framework for the target area include: using multiple stratigraphic correlation methods to obtain the development characteristics of geological strata in the target area; based on these development characteristics, determining the corresponding stratigraphic structure and lithology; and constructing a comprehensive regional columnar section based on the structure and lithology, such as... Figure 2As shown, a stratigraphic correlation framework for the target area was established accordingly, such as... Figure 3 and 4 As shown. Among them, the multiple stratigraphic division and correlation method refers to dividing strata into different groups and sections based on multiple methods such as lithology, paleontology, sedimentary environment, and geochemistry, and then conducting stratigraphic correlation to obtain the development characteristics of geological strata in the target area. Taking the Yixian Formation outcrop in western Liaoning as an example, the vertical sedimentary sequence of the Yixian Formation sedimentary layers in the Yixian Basin was analyzed, revealing that the sedimentary environment of the Yixian Basin was alluvial fan-braided river-meandering river-lacustrine sedimentation, and establishing fluvial and lacustrine sedimentary models. Based on the stratigraphic study of the Yixian Formation in the Sihetun area, the sedimentary environment of this period was analyzed. Twelve lithofacies types were identified in the Lujiatun and Jianshangou sections, divided into volcanic clastic fan sedimentary assemblages and lacustrine sedimentary assemblages, establishing a lacustrine sedimentary model for this period, and concluding that the Yixian Formation deposition was divided into four stages. The Yixian Formation is widely developed in the southern Songliao Basin and western Liaoning Province. It consists mainly of a set of volcanic rocks interbedded with sedimentary layers, and the sedimentary layers are discontinuous. In the southern Songliao Basin, it is mainly found in the Lujiabao, Zhezhong, and Naiman depressions and the Xiushui Basin. In western Liaoning, it is mainly distributed in the Fuxin-Yixian Basin, Jianchang Basin, Lingyuan Basin, and Jinyang Basin. Regionally, it exhibits a "Thousand Island Lake" type, representing a catchment lake basin formed in the depression area during a volcanic intercalation period. The above findings can be obtained through field surveys and analysis, or by utilizing existing borehole and outcrop data, as well as multiple stratigraphic data including lithostratigraphy, biostratigraphy, chemical stratigraphy, and chronostratigraphy, and analyzing them using MapGIS software.

[0074] Step S102: Based on the stratigraphic correlation framework and single-well data, gravity and seismic joint inversion interpretation is performed on the basis of stratigraphic correlation to obtain the first interpretation data;

[0075] It should be noted that, based on stratigraphic correlation frameworks and single-well data, the main focus is on sedimentary environment analysis. Taking the Yixian Formation in the Kailu area as an example, single-section or single-well sedimentary facies analysis is conducted on the target geological strata. Figure 5 As shown; typical profiles or wells that meet the preset second condition are selected to establish a sedimentary environment comparison profile; the purpose is to clarify the macroscopic lithofacies paleogeography and paleosedimentary environment of the region, such as Figure 6 As shown; however, the selection of specific typical profiles or wells is mainly based on factors such as research objectives and geographical location. For example, if the focus is on sedimentary environment and rock type, then sedimentary rocks are set as the second preset condition for drilling or profile selection. Then, based on the sedimentary environment comparison profile, sedimentary facies zones that meet the third preset condition are selected, such as... Figure 7As shown, taking the Lujiabao area in the Kailu region as an example, the depression has the largest area of ​​1740 km², the Yixian Formation is thick, reaching up to 2100 m, and is deeply buried, with a maximum depth of about 5200 m. It has good preservation conditions, but the exploration of the inner and deeper layers of the Yixian Formation is low, and the lower Permian strata in the Mesozoic depression development area are relatively well preserved. The Lujiabao depression exhibits the following characteristics: boundary faults control volcanic rock development, the downthrown block is dominated by volcanic rock accumulation, the seismic facies are chaotic reflections, and the slope area shows medium-to-strong amplitude, relatively continuous parallel-to-subparallel reflections, reflecting a predominantly lacustrine fan deltaic sedimentary system, indicating good exploration potential. Therefore, regional parameters and characteristics with good exploration potential are used as the third pre-set condition for screening, i.e., setting the proportion and distribution location of various rocks. Finally, based on sedimentary facies zones and a stratigraphic correlation framework, gravity and seismic joint inversion interpretation is performed. The inversion model can employ horizontal stratification inversion models, vertical stratification inversion models, density inversion models, etc.

[0076] Step S103: Based on the database and the first interpretation data, the gravity of the target stratigraphic system in the region is jointly inverted and interpreted to obtain a geophysical integrated interpretation profile;

[0077] It should be noted that the purpose of this step is to perform gravity inversion, because low gravity anomalies are mainly caused by sedimentary depressions or low-density granite intrusions, while high gravity anomalies are mainly caused by the uplift of the Paleozoic strata at the basement level. In detail, utilizing gravity profiles, seismic data, drilling data, and regional geological data from the database, a combined intra-basin and extra-basin approach is employed, including intra-basin data analysis, extra-basin data analysis, intra-basin and extra-basin data comparison, and joint inversion and comprehensive interpretation analysis. Joint inversion and comprehensive interpretation analysis are conducted on the target stratigraphic systems in the region, namely the Jurassic and Permian systems, such as... Figure 8 and Figure 9 As shown, the geophysical integrated interpretation profile and integrated interpretation results are obtained, as follows: Figure 10 and Figure 11 As shown.

[0078] Furthermore, the joint inversion interpretation of gravity in the target stratigraphic system of the region also includes: constraining the gravity inversion based on a database and using geophysical parameters obtained by pre-defined geophysical exploration methods; performing gravity inversion on the target stratigraphic system of the region to obtain a gravity inversion profile; and obtaining a comprehensive geophysical interpretation profile by comparing the gravity inversion profile with the first interpretation data. The purpose of constraining the gravity inversion is to improve the accuracy of the inversion results and obtain more precise information on the structure and properties of underground rock strata; specifically, geophysical parameters obtained using electrical and / or magnetic geophysical exploration methods are used, i.e., data on the electrical conductivity, magnetism, wave velocity density, and elasticity of underground rock strata are obtained using electrical and / or magnetic methods.

[0079] Step S104: Constrain the inverted model by using the preset rock properties of the target geological strata and the corresponding Bouguer gravity anomaly; and perform gravity anomaly density inversion on the constrained model based on the data of the geophysical integrated interpretation profile to obtain the geophysical integrated model.

[0080] It should be noted that because the measured gravity anomaly on the ground is a superposition of the gravitational effects of field sources at different depths underground, the Bouguer gravity anomaly is used to constrain the inversion model, aiming to improve the accuracy of the inversion model. Specifically, the steps for constraining the inversion model include: measuring the measured gravity effect value of the target area; subtracting the gravity effect value of materials above the preset reference surface from the measured gravity effect value to obtain the Bouguer gravity anomaly; specifically, eliminating the gravity effect value of materials above the geoid (e.g., using sea level) from the measured gravity value to obtain the Bouguer gravity anomaly. Then, based on the Bouguer gravity anomaly, the gravity effect value of layers outside the target geological layer is obtained by subtracting the gravity effect value of layers outside the target geological layer; these layers outside the target geological layer are mainly middle and shallow layers, and this step aims to eliminate the influence of middle and shallow layers on the calculation. Finally, a Bouguer gravity anomaly range that conforms to the preset rock properties is selected, and the gravity inversion model is constrained based on the Bouguer gravity anomaly range. That is, using differences in rock properties as a bridge, such as... Figure 13 As shown, a Bouguer gravity anomaly range that meets the preset rock properties is selected, 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 required porosity and permeability ranges for production are 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] Deep gravity anomalies are: g 深 =Δg-g 正 ;

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

[0085] Among them, g 测 The result is obtained through actual measurement using a gravimeter; g 纬 Latitude-corrected gravity effect value; g 高 To highly correct for the gravitational effect; g 中 Correction for gravity effect value for intermediate layer; g形 g is the terrain-corrected gravity effect value; g is the normal gravity value; g 正 δ represents the gravity effect value of the middle and shallow geological bodies; δ represents the difference in rock physical properties.

[0086] Furthermore, after obtaining the gravity effect values ​​of the target stratigraphic level, the following is also included:

[0087] Based on variations in rock properties and logging curves, characteristic curves are generated. These characteristic curves are then used to screen for reservoir-like rock formations and their corresponding gravity anomaly ranges in formations outside the target geological strata. The gravity anomaly ranges are then used to constrain the inversion model, which is then fitted to the inversion results. This reduces errors caused by variations in formation properties, further improving accuracy. In essence, this involves using known data from formations outside the target geological strata (intermediate and shallow layers) to draw an analogy with the target geological strata. This analogy can be made using intermediate and shallow layer data from multiple existing areas surrounding the target geological strata, or it can be made using data from the area closest to the target geological strata.

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

[0089] Step S105: Compare and verify the results of the source rock analysis in the target area with the data in the geophysical integrated model, and select areas that meet the first preset conditions as exploration targets.

[0090] It should be noted that source rock analysis mainly utilizes existing outcrop profiles, drilling data, logging data, and analytical test data to analyze the geochemical characteristics of source rocks in the target group and deep strata from single profiles or wells. Taking the Yixian Formation in the Kailu area as an example, for instance... Figure 15 As shown; generate data on the development, distribution, and hydrocarbon generation potential of source rocks in the Kailu area, such as... Figure 16 As shown in Table 1 below.

[0091]

[0092] Table 1

[0093] Based on the above-mentioned attached figures and data, and after clarifying the main target stratigraphic geological conditions for oil and gas, favorable exploration target areas are selected from them, such as... Figure 17As shown; in detail, firstly, the thickness of the source rock is one of the main factors determining the retention level of oil and gas within it; the greater the thickness, the more favorable it is for oil and gas accumulation and reservoir formation. In the Carboniferous-Permian and Yixian Formations of Kailu and surrounding areas, the source rocks are mainly argillaceous. Based on historical geological data and other scholars' evaluations of oil and gas geology, a thickness greater than 1000m is highly favorable for oil and gas accumulation when the source layer is mudstone. Secondly, reservoir and stratigraphic thickness is an important indicator for evaluating basin oil and gas resources. Oil and gas accumulation is mainly controlled by reservoir thickness and reservoir properties. Larger reservoir thickness, better lateral continuity, and wider distribution are conducive to oil and gas storage. It is known that Permian sandstone, fractured rock, and Yixian Formation sandstone and volcanic rock reservoirs all possess good reservoir capacity. Their thickness can be obtained through detailed interpretation of seismic profiles, but this requires high-quality seismic reflection profiles. Since seismic profiles in the Kailu area are mostly for shallow and medium-depth hydrocarbons, and few for the deeper Yixian Formation and Carboniferous-Permian strata, the specific thickness of the reservoirs cannot be accurately determined. This patent utilizes gravity-based joint interpretation and inversion of seismic data to characterize the thickness of the base strata of the reservoirs. Thirdly, fault activity not only controls the sedimentary structures within the basin but is also closely related to hydrocarbon accumulation. The Paleozoic reverse faults in the Kailu area were activated during the late Yanshanian orogeny, creating a relatively closed system for the Yixian and Linxi Formations, unlike the open system above the Jiufotang Formation. The top volcanic rocks of the Cretaceous Yixian Formation possess upper generation and lower reservoir characteristics, with internal self-generation and self-reservoir characteristics, and the lower part has the potential for lower generation and upper reservoir hydrocarbon accumulation; the Permian Linxi Formation possesses a self-generation and self-reservoir combination. Fourthly, geochemical indicators show that the vitrinite reflectance (Ro) of the source rocks in the Songliao Basin ranges from 1.09% to 3.45%, exhibiting an overall highly mature to over-mature evolutionary characteristic. The Linxi Formation's Heifudi 1 well encountered 276m of mudstone and shale with a total organic carbon (TOC) distribution between 0.013% and 1.56%, averaging 1.058%. The organic matter type is Type II, with the majority being medium-grade source rocks. The maximum hydrocarbon generation temperature (Tmax) is mostly >450℃, and Ro is 1.5%–3.76%, indicating a highly mature to over-mature stage. The resulting selection criteria are shown in Table 2.

[0094]

[0095]

[0096] Table 2

[0097] Using the selection criteria as the first preset condition, the selected area is used as the exploration target, such as... Figure 17 As shown in the diagram. Finally, well location recommendations are proposed based on the exploration objectives.

[0098] Based on the same inventive concept, embodiments of the present invention provide a system for identifying deep oil and gas formations using gravity anomalies combined with seismic activity, such as... Figure 18 As shown, it includes:

[0099] The stratigraphic comparison grid creation module is used to create a stratigraphic comparison grid for the target area based on data from the database.

[0100] The primary inversion module, based on stratigraphic correlation framework and single-well data, performs joint gravity and seismic inversion interpretation on the basis of stratigraphic correlation to obtain the first interpretation data;

[0101] The second-level inversion module, based on the database and the first interpretation data, performs a joint inversion interpretation of the gravity of the target stratigraphic system in the region to obtain a geophysical comprehensive interpretation profile;

[0102] The inversion model correction module is used to constrain the inverted model by using the preset rock properties of the target geological strata and the corresponding Bouguer gravity anomaly; the constrained model is then used to perform gravity anomaly density inversion based on the data of the geophysical integrated interpretation profile to obtain the geophysical integrated model.

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

[0104] Based on the same inventive concept, embodiments of the present invention provide 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, it implements a method for identifying deep oil and gas using gravity anomalies combined with seismic activity.

[0105] Based on the same inventive concept, this embodiment provides a computer-readable storage medium storing a computer program thereon, characterized in that the program, when executed by a processor, implements a method for identifying deep oil and gas using gravity anomalies combined with seismic activity.

[0106] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0107] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0108] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A method for identifying deep oil and gas formations using gravity anomalies combined with seismic activity, characterized in that, The method includes: Based on the data in the database, a stratigraphic correlation framework for the target area was established. Based on the stratigraphic correlation framework and single-well data, gravity and seismic joint inversion interpretation are performed on the basis of stratigraphic correlation to obtain the first interpretation data; Based on the database and the first interpretation data, the gravity of the target stratigraphic system in the region is jointly inverted and interpreted to obtain a comprehensive geophysical interpretation profile. The step of jointly inverting and interpreting the gravity of the target stratigraphic system in the region further includes: constraining the gravity inversion using geophysical parameters obtained from a preset geophysical exploration method based on the database; performing gravity inversion on the target stratigraphic system in the region to obtain a gravity inversion profile; and obtaining the comprehensive geophysical interpretation profile by establishing the correspondence between the gravity inversion profile and the first interpretation data. The inverted model is constrained by pre-defined rock properties and corresponding Bouguer gravity anomalies of the target geological strata. The constrained model is then used to perform gravity anomaly density inversion based on data from the geophysical integrated interpretation profile to obtain a geophysical integrated model. The step of constraining the inverted model further includes: measuring the measured gravity effect value of the target area; subtracting the gravity effect value of materials above the pre-defined reference surface from the measured gravity effect value to obtain the Bouguer gravity anomaly; and subtracting the gravity effect value of strata outside the target geological strata from the Bouguer gravity anomaly. The method further includes: obtaining the gravity effect value of the target formation; screening Bouguer gravity anomaly ranges that conform to preset rock properties; constraining the gravity inversion model based on the Bouguer gravity anomaly ranges; and, after obtaining the gravity effect value of the target formation, generating characteristic curves based on different rock properties and well logging curve variations; screening out the distribution range of rock formations that serve as reservoirs and their corresponding gravity anomaly ranges in formations other than the target geological formation using the characteristic curves; constraining the inversion model based on the gravity anomaly ranges and fitting it with the inversion results. The results of the source rock analysis in the target area are compared and verified with the data in the geophysical integrated model, and areas that meet the first preset conditions are selected as exploration targets.

2. The method as described in claim 1, characterized in that, The step of establishing a stratigraphic correlation framework for the target area also includes: The development characteristics of geological strata in the target area were obtained by using a multiple stratigraphic division and correlation method. Based on the aforementioned developmental characteristics, determine the corresponding stratigraphic structure and lithology; Based on the aforementioned structure and lithology, a comprehensive columnar section was constructed for the region, and a corresponding stratigraphic correlation framework for the target area was established.

3. The method as described in claim 1, characterized in that, The steps for joint gravity and seismic inversion interpretation based on stratigraphic correlation also include: Perform single-section or single-well sedimentary facies analysis on the target geological strata; Typical profiles or wells that meet the preset second condition are selected to establish a sedimentary environment comparison profile. Based on the aforementioned sedimentary environment comparison profile, sedimentary facies zones that meet the preset third condition are selected; Based on the sedimentary facies zones, and on the basis of the stratigraphic correlation framework, a joint gravity and seismic inversion interpretation is performed.

4. The method as described in claim 1, characterized in that, The geophysical exploration method is electrical and / or magnetic.

5. A system for identifying deep oil and gas formations using gravity anomalies combined with seismic activity, characterized in that, The system includes: The stratigraphic comparison grid creation module is used to create a stratigraphic comparison grid for the target area based on data from the database. The primary inversion module, based on the stratigraphic correlation framework and single-well data, performs gravity and seismic joint inversion interpretation on the basis of stratigraphic correlation to obtain the first interpretation data; The secondary inversion module, based on the database and the first interpretation data, performs a joint inversion interpretation of the gravity of the target stratigraphy in the region to obtain a comprehensive geophysical interpretation profile. The step of performing the joint inversion interpretation of the gravity of the target stratigraphy in the region further includes: constraining the gravity inversion using geophysical parameters obtained from a preset geophysical exploration method based on the database; performing gravity inversion on the target stratigraphy in the region to obtain a gravity inversion profile; and obtaining the comprehensive geophysical interpretation profile through the correspondence between the gravity inversion profile and the first interpretation data. The inversion model correction module is used to constrain the inverted model using preset rock properties of the target geological stratum and the corresponding Bouguer gravity anomaly; the constrained model is then used to perform gravity anomaly density inversion based on data from the geophysical integrated interpretation profile to obtain a geophysical integrated model; wherein, the step of constraining the inverted model further includes: measuring the measured gravity effect value of the target area; subtracting the gravity effect value of the material above the preset reference surface from the measured gravity effect value to obtain the Bouguer gravity anomaly; and subtracting the gravity effect value of the strata outside the target geological stratum from the Bouguer gravity anomaly... The gravity effect value of the target stratum is obtained; the Bouguer gravity anomaly range that conforms to the preset rock properties is selected, and the gravity inversion model is constrained based on the Bouguer gravity anomaly range; after obtaining the gravity effect value of the target stratum, the inversion model correction module is also used to: generate characteristic curves based on different rock properties and well logging curve changes; select the distribution range of rock strata as reservoirs and the corresponding gravity anomaly range in strata other than the target geological stratum using the characteristic curves; constrain the inversion model based on the gravity anomaly range and fit it with the inversion result; The exploration target results module is used to compare and verify the results of source rock analysis in the target area with the data in the geophysical integrated model, and select areas that meet the first preset conditions as exploration targets.

6. An electronic device, characterized in that, The electronic device includes: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of the method according to any one of claims 1 to 4.

7. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the program is executed by the processor, it implements the steps corresponding to the method as described in any one of claims 1 to 4.

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