Oil reservoir unit analysis-based oil reservoir identification method

Abstract

The invention belongs to the technical field of oil layer recognition in oilfield development, particularly relates to an oil layer recognition method based on oil reservoir unit analysis, and aims to solve the problem that a large number of II-type oil layers, surface layers and outer layers are difficult to effectively use due to the fact that oil layers cannot be accurately recognized in the prior art. The method comprises the following steps: constructing an initial map of an oil reservoir unit geologic model; the method comprises the following steps: carrying out three-dimensional description on an oil reservoir interlayer plane through a four-definite recent system lithologic oil finding technology sequence, and constructing an oil-water layer feature refining original electrical logging interpretation chart as a first chart; performing layer group division on the first plate again by fitting multiple parameters to obtain a second plate; calculating a carbon-oxygen ratio and calcium-silicon ratio envelope index, re-identifying an oil-water layer, and updating the reservoir water production rate parameter correlation chart; and in combination with the second chart and the reservoir water production rate parameter related chart, updating the reservoir unit geologic model initial map, and performing oil layer identification on the same reservoir unit after updating. According to the invention, fine oil reservoir unit depiction and accurate oil reservoir identification are realized.

Description

Technical Field

[0001] This invention belongs to the field of oil reservoir identification technology in oilfield development, and specifically relates to an oil reservoir identification method, system, electronic device, and computer-readable storage medium based on reservoir unit analysis. Background Technology

[0002] In the middle and late stages of reservoir development, vertical interaction between oil and water occurs, lateral phase transitions exist, and horizontal oil-water contradictions become prominent. Currently, the logging identification methods widely used in domestic oilfields for low-resistivity oil layers (such as saturation curve overlay method, logging data analysis method, logging accuracy interpretation and multi-well evaluation methods, etc.) cannot effectively address the low formation water salinity, resulting in high water resistivity and difficulty in distinguishing between oil and water layers, as exemplified by the Neogene. The Neogene, with its unique low-amplitude structural characteristics, can form reservoirs with slight undulations, and these low-amplitude traps are often overlooked or difficult to detect. Conventional logging curves cannot clearly identify low-resistivity layers or "thin and poor" layers, resulting in a large number of Class II and outer layers being difficult to effectively utilize.

[0003] Oil reservoirs are controlled by both structure and lithology, resulting in complex oil-water relationships and the contradiction of low oil content and high water content. Researchers have been continuously exploring methods for identifying oil layers, but relying solely on traditional techniques such as electrical logging and saturation logging cannot overcome this bottleneck. Therefore, this invention, based on fully utilizing existing data, meticulously dissects the reservoir, using sedimentary microfacies as constraints and combining dynamic and static data for comprehensive evaluation. It compiles structural maps of the top surface of oil layers at the sub-layer level and planar distribution maps of sand bodies at the sub-layer level. By examining logging interpretation conclusions from the perspective of the reservoir, a new potential grading and evaluation system is established using six elements: structure, sand bodies, logging, coring, development dynamic data, and saturation testing. This system enables refined oil layer identification based on the same reservoir unit, continuously revising and improving electrical logging interpretation conclusions, accurately describing the spatial distribution, boundary conditions, oil-water interface, and other basic attributes of each reservoir unit, thus achieving the goal of refined reservoir unit characterization and precise oil layer identification. Summary of the Invention

[0004] To address the aforementioned problems in the existing technology, namely, the inability of existing technologies to accurately identify oil layers, thus hindering the effective utilization of numerous Type II oil layers and outer layers, the present invention, in its first aspect, proposes an oil layer identification method based on reservoir unit analysis for identifying oil layers within reservoir units in Neogene strata. This method includes:

[0005] S10: Collect geological data of the reservoir unit and dynamic production data of the well after perforation repair. Construct the initial geological model of the reservoir unit using small layers as units.

[0006] S20, Combining the initial map of the reservoir unit geological model, the old area and new wells are three-dimensionally characterized by the interlayer plane of the reservoir using the four-dimensional Neogene lithology oil exploration technology sequence; Based on the three-dimensionally characterized reservoir unit, the oil-water layer characteristic refined original electrical logging interpretation map is constructed by intersection method, which serves as the first map; The first map is re-divided into layers by fitting multiple parameters to obtain the second map;

[0007] S30, calculate the carbon-oxygen ratio and calcium-silicon ratio envelope index, and re-identify the oil-water layer based on the carbon-oxygen ratio and calcium-silicon ratio envelope index; based on the oil-water layer identification results, update the reservoir water production parameter related charts; the reservoir water production parameter related charts include water production-porosity charts and water production-lithological oil-bearing index evaluation charts;

[0008] S40, combining the second map and the map related to the reservoir water production rate parameters, the initial map of the geological model of the reservoir unit is updated, and oil layers are identified for the same reservoir unit after the update.

[0009] In some preferred embodiments, the geological model map of the reservoir unit includes a sub-layer oil-bearing map, an oil body planar distribution map, and a sand body planar distribution map.

[0010] In some preferred embodiments, a three-dimensional characterization of the interlayer plane of the reservoir is performed using a four-dimensional Neogene lithological exploration technique sequence. The method is as follows:

[0011] Vertically, using sub-layers as units, we construct oil composition maps, sub-layer plan maps, and sand layer top structure maps to determine oil reservoir units;

[0012] Horizontally evaluate oil reservoirs, and systematically review the same oil reservoir unit following the principle of high oil content and low water content to clearly delineate the oil-water boundary;

[0013] On a planar surface, we conduct provenance analysis, sedimentary microfacies study, sand body morphology delineation, and reservoir prediction to determine the extent of sand bodies.

[0014] Three-dimensional source analysis is conducted to locate oil sources, identify faults, clarify migration channels, determine secondary migration of oil and gas within the reservoir after trap conditions are met, and determine the reservoir formation model.

[0015] In some preferred embodiments, the envelope index of the carbon-oxygen ratio and calcium-silicon ratio is calculated by the following method:

[0016] Full-spectrum residual oil saturation logging in non-elastic mode and full-spectrum residual oil saturation logging in trap mode were selected.

[0017] Calculate the carbon-oxygen ratio of the full-spectrum residual oil saturation logging in the non-elastic mode;

[0018] Calculate the silica-calcium ratio in the full-spectrum residual oil saturation logging of the capture mode;

[0019] Calculate the envelope index of the carbon-oxygen ratio and the calcium-silicon ratio based on the carbon-oxygen ratio and the silicon-calcium ratio.

[0020] In some preferred embodiments, the envelope index of the carbon-oxygen ratio and the calcium-silicon ratio is calculated based on the carbon-oxygen ratio and the silicon-calcium ratio, and the method is as follows:

[0021]

[0022] Wherein, ENcc represents the envelope index of the carbon-oxygen ratio and the calcium-silicon ratio, CO represents the carbon-oxygen ratio, and CO... MIN This represents the minimum carbon-to-oxygen ratio, CO. MAX CS represents the maximum carbon-oxygen ratio, and CS represents the calcium-silicon ratio. MIN CS represents the minimum calcium-to-silicon ratio. MAX This indicates the maximum calcium-to-silicon ratio.

[0023] In some preferred embodiments, the initial geological model map of the reservoir unit is updated by combining the second map and the map related to the reservoir water production parameters. After the update, oil layers are identified within the same reservoir unit. The method is as follows:

[0024] The initial map of the reservoir unit geological model is updated by combining the second map and the map related to the reservoir water production parameters.

[0025] Based on the updated initial map of the reservoir unit geological model, an oil layer type identification table is constructed; the oil layer type identification table is a mapping table between preset elements and preset oil layer types; the elements include potential level, structural location, production of adjacent wells, logging display, and oil-bearing level of wellbore coring;

[0026] The oil layer type identification table is used to match the elements of the same oil reservoir unit to obtain the oil layer type identification result.

[0027] In some preferred embodiments, the fitted multi-parameters include GRML (natural gamma), R4 (4-meter gradient), RT (resistivity), and AC (acoustic transit time).

[0028] In a second aspect, the present invention proposes an oil layer identification system based on reservoir unit analysis for identifying oil layers in reservoir units within Neogene strata. The system comprises:

[0029] The reservoir unit initial characterization module is configured to collect geological data of the reservoir unit and dynamic production data of the wells after perforation repair, and construct the initial geological model of the reservoir unit using small layers as units.

[0030] The strata re-division module is configured to combine the initial map of the reservoir unit geological model and use the four-dimensional Neogene lithology oil exploration technology sequence to perform a three-dimensional characterization of the interlayer plane of the reservoir in new wells in the old area; based on the three-dimensionally characterized reservoir unit, a refined original electrical logging interpretation map of oil and water layer characteristics is constructed using the intersection method, which serves as the first map; multiple parameters are fitted to the first map to re-divide the strata into a second map;

[0031] The map update module is configured to calculate the carbon-oxygen ratio and calcium-silicon ratio envelope index, and re-identify the oil-water layer based on the carbon-oxygen ratio and calcium-silicon ratio envelope index; based on the oil-water layer identification results, update the relevant maps for reservoir water production parameters; the relevant maps for reservoir water production parameters include water production-porosity maps and water production-lithological oil-bearing index evaluation maps.

[0032] The oil layer identification module is configured to update the initial map of the geological model of the reservoir unit by combining the second map and the map related to the reservoir water production rate parameters, and then identify the oil layers in the same reservoir unit after the update.

[0033] In a third aspect, the present invention provides an electronic device, the device comprising:

[0034] At least one processor, and a memory communicatively connected to at least one of the processors;

[0035] The memory stores instructions that can be executed by the processor to implement the above-described reservoir unit analysis-based oil layer identification method.

[0036] In a fourth aspect, the present invention provides a computer-readable storage medium storing computer instructions for execution by a computer to implement the above-described reservoir unit analysis-based oil layer identification method.

[0037] The beneficial effects of this invention are:

[0038] This invention enables fine reservoir unit characterization and accurate oil layer identification, solving the problem of the difficulty in effectively utilizing a large number of Class II oil layers and the outermost layer.

[0039] Based on existing data, this invention meticulously dissects oil reservoirs, using sedimentary microfacies as constraints and combining dynamic and static data for comprehensive evaluation. It compiles structural maps of the top surface of oil layers at the sub-layer level and planar distribution maps of sand bodies at the sub-layer level. It examines logging interpretation conclusions using the concept of an oil reservoir, and establishes a new potential classification using six elements: structure, sand bodies, logging, coring, development dynamic data, and saturation testing. It conducts fine-grained oil layer identification based on the same reservoir unit, continuously revising and improving electrical logging interpretation conclusions. It accurately describes the spatial distribution, boundary conditions, oil-water interface, and other basic attributes of each reservoir unit, achieving the goal of fine-grained reservoir unit characterization and precise oil layer identification. Attached Figure Description

[0040] Other features, objects, and advantages of this application will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings.

[0041] Figure 1 This is a flowchart illustrating an oil layer identification method based on reservoir unit analysis according to an embodiment of the present invention.

[0042] Figure 2 This is a detailed flowchart illustrating an oil layer identification method based on reservoir unit analysis according to an embodiment of the present invention.

[0043] Figure 3 This is a schematic diagram of a four-dimensional lithology oil exploration technology sequence according to an embodiment of the present invention;

[0044] Figure 4 This is a schematic diagram of a multi-parameter joint identification of oil and water layers in a new well in an old area according to an embodiment of the present invention;

[0045] Figure 5 This is a schematic diagram of a reservoir and stratification reconstruction and identification chart according to an embodiment of the present invention;

[0046] Figure 6 This is a schematic diagram of a quantitative oil-water layer identification chart according to an embodiment of the present invention;

[0047] Figure 7 This is a schematic diagram of the results of an outer layer review according to an embodiment of the present invention;

[0048] Figure 8 This is a schematic diagram of the production curve of an outer layer re-inspection well according to an embodiment of the present invention. Detailed Implementation

[0049] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions in the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this invention, not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0050] The present application will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the invention. Furthermore, it should be noted that, for ease of description, only the parts relevant to the invention are shown in the accompanying drawings.

[0051] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0052] A method for identifying oil layers based on reservoir unit analysis, according to a first embodiment of the present invention, is used for identifying oil layers in reservoir units within Neogene strata. Figure 1 As shown, it includes the following steps:

[0053] S10: Collect geological data of the reservoir unit and dynamic production data of the well after perforation repair. Construct the initial geological model of the reservoir unit using small layers as units.

[0054] S20, Combining the initial map of the reservoir unit geological model, the old area and new wells are three-dimensionally characterized by the interlayer plane of the reservoir using the four-dimensional Neogene lithology oil exploration technology sequence; Based on the three-dimensionally characterized reservoir unit, the oil-water layer characteristic refined original electrical logging interpretation map is constructed by intersection method, which serves as the first map; The first map is re-divided into layers by fitting multiple parameters to obtain the second map;

[0055] S30, calculate the carbon-oxygen ratio and calcium-silicon ratio envelope index, and re-identify the oil-water layer based on the carbon-oxygen ratio and calcium-silicon ratio envelope index; based on the oil-water layer identification results, update the reservoir water production parameter related charts; the reservoir water production parameter related charts include water production-porosity charts and water production-lithological oil-bearing index evaluation charts;

[0056] S40, combining the second map and the map related to the reservoir water production rate parameters, the initial map of the geological model of the reservoir unit is updated, and oil layers are identified for the same reservoir unit after the update.

[0057] To more clearly illustrate the oil layer identification method based on reservoir unit analysis of the present invention, the following description is in conjunction with the appendix. Figure 2 The steps of one embodiment of the method of the present invention will be described in detail below.

[0058] This invention, through reservoir analysis and refined fundamental research, identifies and delineates different reservoir units by studying structures, reservoirs, and sedimentary facies. It describes the spatial distribution, boundary conditions, oil-water interface, and other basic attributes of each reservoir unit. Combining well logging curves and saturation test results, a potential grading system is formed, enabling refined oil layer identification within the same reservoir unit. Details are as follows:

[0059] S10: Collect geological data of the reservoir unit and dynamic production data of the well after perforation repair. Construct the initial geological model of the reservoir unit using small layers as units.

[0060] In this embodiment, the reservoir unit is initially characterized as follows:

[0061] By conducting basic geological studies on structure, reservoir, and sedimentary facies (i.e., geological data), combined with the dynamic analysis of well production after perforation (i.e., dynamic production data of wells after perforation), we draw oil-bearing maps of small layers and planar distribution maps of oil and sand bodies, starting from the structural maps of small layers, to preliminarily characterize the reservoir units and obtain preliminary potential targets.

[0062] S20, Combining the initial map of the reservoir unit geological model, the old area and new wells are three-dimensionally characterized by the interlayer plane of the reservoir using the four-dimensional Neogene lithology oil exploration technology sequence; Based on the three-dimensionally characterized reservoir unit, the oil-water layer characteristic refined original electrical logging interpretation map is constructed by intersection method, which serves as the first map; The first map is re-divided into layers by fitting multiple parameters to obtain the second map;

[0063] With the increasing maturity of reservoir unit analysis, this embodiment focuses on new wells in old areas (old areas refer to newly constructed production or water injection wells in already exploited oilfields, whose significance lies in increasing or maintaining crude oil production; wells already developed in this stage are considered old wells). Based on reservoir units, a four-dimensional (vertical, horizontal, planar, and volumetric) Neogene lithological oil exploration technology sequence has been formed. Through integrated well logging and geology research from well to reservoir, the geological reservoir characteristics and reservoir effectiveness evaluation are deepened. The four-dimensional Neogene lithological oil exploration technology sequence includes, for example... Figure 3 As shown, the details are as follows:

[0064] Vertically, the comparison map, the plan view of the sub-layer, and the structural map of the top of the sand layer are clearly defined. That is, vertically, the oil composition map, the sub-layer map, and the sand layer map are constructed using the sub-layer as the unit to determine the oil reservoir unit; the oil composition map includes multiple sub-layer composition maps.

[0065] Horizontally evaluate oil reservoirs, and systematically review the same oil reservoir unit following the principle of high oil content and low water content to clearly delineate the oil-water boundary;

[0066] On a planar surface, we conduct provenance analysis, sedimentary microfacies study, sand body morphology delineation, and reservoir prediction to determine the extent of sand bodies; ultimately, we achieve a three-dimensional characterization of the interlayer plane of the reservoir (i.e., we conduct provenance analysis on a three-dimensional surface to find the oil source, identify faults, clarify migration channels, and determine the secondary migration of oil and gas within the reservoir after the trap conditions (necessary conditions for storing oil and gas) are met, thus determining the reservoir formation model).

[0067] Furthermore, given that traditional logging interpretation charts cannot accurately identify oil-bearing properties, this invention re-examines the relationship between the "four properties" (natural gamma ray, R4, RT, and AC). Targeting sensitive parameters GRML (natural gamma ray), R4 (4-meter gradient), RT (resistivity), and AC (acoustic transit time), and aiming to amplify differences, it fits dimensionless parameters. Based on reservoir unit studies, it refines the interpretation of remaining oil, and through cross-plotting, highlights oil-water layer characteristics to refine the original electrical logging interpretation chart. It then fits multiple parameters to jointly identify oil-water layers (such as...). Figure 4 As shown), conventional logging combined with reservoir unit subdivision and layer grouping was used to reconstruct and identify the map by reservoir and layer system (as shown). Figure 5 (As shown).

[0068] S30, calculate the carbon-oxygen ratio and calcium-silicon ratio envelope index, and re-identify the oil-water layer based on the carbon-oxygen ratio and calcium-silicon ratio envelope index; based on the oil-water layer identification results, update the reservoir water production parameter related charts; the reservoir water production parameter related charts include water production-porosity charts and water production-lithological oil-bearing index evaluation charts;

[0069] In this embodiment, based on the reservoir unit, the reservoir water production parameters are further improved by conventional electrical logging + saturation logging + relative permeability theory. Based on the original logging data, full-spectrum residual oil saturation logging (inelastic mode and trapping mode) is preferred. The carbon-oxygen ratio (not affected by formation water salinity, but greatly affected by porosity) is obtained by the inelastic mode, and the silica-calcium ratio (significant lithological reaction) is obtained by the trapping mode. The reservoir oil content is evaluated by calculating the carbon-oxygen ratio and calcium-silicon ratio envelope index (ENcc). As shown in formula (1):

[0070]

[0071] Wherein, ENcc represents the envelope index of the carbon-oxygen ratio and the calcium-silicon ratio, CO represents the carbon-oxygen ratio, and CO... MIN This represents the minimum carbon-to-oxygen ratio, CO. MAX CS represents the maximum carbon-oxygen ratio, and CS represents the calcium-silicon ratio. MIN CS represents the minimum calcium-to-silicon ratio. MAX This indicates the maximum calcium-to-silicon ratio.

[0072] Based on the carbon-oxygen ratio and calcium-silicon ratio envelope index, oil-water layers are re-identified; based on the oil-water layer identification results, the relevant charts for reservoir water production parameters are updated. For example, for Neogene low-salinity lithologic reservoirs, when the carbon-oxygen ratio is greater than a first set value (preferably 0.23 in this invention), the lithologic oil-bearing index is greater than a second set value (preferably 0.8 in this invention), and the water production rate is less than a first set percentage (preferably 20% in this invention), it is defined as an oil layer, achieving quantitative identification of oil-water layers, and thus establishing a complete evaluation chart of water production rate-porosity and water production rate-lithologic oil-bearing index, such as... Figure 6 As shown.

[0073] S40, combining the second map and the map related to the reservoir water production rate parameters, the initial map of the geological model of the reservoir unit is updated, and oil layers are identified for the same reservoir unit after the update.

[0074] In this embodiment, based on the in-depth geological research of S10, S20, and S30, reservoir units are characterized on the basis of sedimentary facies research. Combined with the fitting of sensitive parameters of conventional logging and quantitative identification of saturation logging, the reservoir units are further improved. The logging interpretation is examined from the perspective of reservoir concept. A potential classification system is established using six elements: "structure (i.e., structural location), sand body, logging (i.e., logging display), coring (i.e., wellbore coring), development dynamic data, and saturation testing". Then, an oil layer type identification table (i.e., a mapping relationship table between preset elements and preset oil layer types) is constructed, as shown in Table 1, and oil layer identification is carried out based on the same reservoir unit.

[0075] Table 1

[0076] In addition, S40 also includes: dividing potential layers into potential levels I, II, and III, and carrying out three-dimensional evaluation of "points, lines, surfaces, and volumes", as shown in Table 2, to guide the orderly conduct of oil layer review; ⑥ through production verification, continuously revising and improving electrical logging interpretation conclusions, accurately describing the basic attributes of each reservoir unit such as spatial distribution, boundary conditions, and oil-water interface, to achieve the purpose of fine reservoir unit characterization and accurate oil layer identification.

[0077] Table 2

[0078] In summary, this invention establishes a four-dimensional (vertical, horizontal, planar, and volumetric) lithological oil exploration technology sequence for Neogene lithology. It is further refined and improved through dynamic data analysis, well logging interpretation re-evaluation, and remaining oil saturation logging, enabling precise oil layer identification. Since its application, this method has achieved a success rate of 80.7% in the re-examination of oil layers in a Neogene reservoir, an improvement of 15 percentage points. Furthermore, since 2023, based on detailed reservoir unit characterization, and through comprehensive analysis of data from well logging, gas logging, saturation testing, and adjacent well production, the above-mentioned method has been used to re-examine the interpretation of outer layers. A total of 26 re-examination boreholes were drilled for outer layers, with 21 effective boreholes, re-examining 40 layers (108 meters) of outer layers, resulting in a daily oil increase of 128 tons and a cumulative oil increase of 22,900 tons. Figure 7 , 8 As shown.

[0079] A second embodiment of the present invention provides an oil layer identification system based on reservoir unit analysis for identifying oil layers in reservoir units within Neogene strata. The system includes:

[0080] The reservoir unit initial characterization module is configured to collect geological data of the reservoir unit and dynamic production data of the wells after perforation repair, and construct the initial geological model of the reservoir unit using small layers as units.

[0081] The strata re-division module is configured to combine the initial map of the reservoir unit geological model and use the four-dimensional Neogene lithology oil exploration technology sequence to perform a three-dimensional characterization of the interlayer plane of the reservoir in new wells in the old area; based on the three-dimensionally characterized reservoir unit, a refined original electrical logging interpretation map of oil and water layer characteristics is constructed using the intersection method, which serves as the first map; multiple parameters are fitted to the first map to re-divide the strata into a second map;

[0082] The map update module is configured to calculate the carbon-oxygen ratio and calcium-silicon ratio envelope index, and re-identify the oil-water layer based on the carbon-oxygen ratio and calcium-silicon ratio envelope index; based on the oil-water layer identification results, update the relevant maps for reservoir water production parameters; the relevant maps for reservoir water production parameters include water production-porosity maps and water production-lithological oil-bearing index evaluation maps.

[0083] The oil layer identification module is configured to update the initial map of the geological model of the reservoir unit by combining the second map and the map related to the reservoir water production rate parameters, and then identify the oil layers in the same reservoir unit after the update.

[0084] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working process and related descriptions of the system described above can be found in the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0085] It should be noted that the reservoir unit analysis-based oil layer identification system provided in the above embodiments is only an example of the division of the above functional modules. In practical applications, the above functions can be assigned to different functional modules as needed, that is, the modules or steps in the embodiments of the present invention can be further decomposed or combined. For example, the modules in the above embodiments can be merged into one module, or further divided into multiple sub-modules to complete all or part of the functions described above. The names of the modules and steps involved in the embodiments of the present invention are only for distinguishing the various modules or steps and are not considered as an improper limitation of the present invention.

[0086] A third embodiment of the present invention provides an electronic device comprising at least one processor and a memory communicatively connected to at least one of the processors; wherein the memory stores instructions executable by the processor, the instructions being executed by the processor to implement the above-described method for identifying oil layers based on reservoir unit analysis.

[0087] A computer-readable storage medium according to a fourth embodiment of the present invention stores computer instructions, which are executed by the computer to implement the above-described method for oil layer identification based on reservoir unit analysis.

[0088] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working process and related descriptions of the above-described electronic device and readable storage medium can be referred to the corresponding process in the foregoing method examples, and will not be repeated here.

[0089] Those skilled in the art will recognize that the modules and method steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. The programs corresponding to the software modules and method steps can be placed in random access memory (RAM), main memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disks, removable disks, CD-ROMs, or any other form of storage medium known in the art. To clearly illustrate the interchangeability of electronic hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in electronic hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the invention.

[0090] The terms “first,” “second,” “third,” etc., are used to distinguish similar objects, not to describe or indicate a specific order or sequence.

[0091] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of the present invention.

Claims

1. A method for identifying oil-bearing layers based on reservoir unit analysis, used for identifying oil-bearing layers in reservoir units of Neogene strata, characterized in that, The method includes: S10: Collect geological data of the reservoir unit and dynamic production data of the well after perforation repair. Construct the initial geological model of the reservoir unit using small layers as units. S20, Combining the initial map of the reservoir unit geological model, the old area and new wells are three-dimensionally characterized by the interlayer plane of the reservoir using the four-dimensional Neogene lithology oil exploration technology sequence; Based on the three-dimensionally characterized reservoir unit, the oil-water layer characteristic refined original electrical logging interpretation map is constructed by intersection method, which serves as the first map; The first map is re-divided into layers by fitting multiple parameters to obtain the second map; S30, calculate the carbon-oxygen ratio and calcium-silicon ratio envelope index, and re-identify the oil-water layer based on the carbon-oxygen ratio and calcium-silicon ratio envelope index; based on the oil-water layer identification results, update the reservoir water production parameter related charts; the reservoir water production parameter related charts include water production-porosity charts and water production-lithological oil-bearing index evaluation charts; S40, combining the second map and the map related to the reservoir water production rate parameters, the initial map of the geological model of the reservoir unit is updated, and oil layers are identified for the same reservoir unit after the update.

2. The method for identifying oil layers based on reservoir unit analysis according to claim 1, characterized in that, The geological model diagram of the reservoir unit includes a sub-layer oil-bearing map, an oil body planar distribution map, and a sand body planar distribution map.

3. The method for identifying oil layers based on reservoir unit analysis according to claim 2, characterized in that, The three-dimensional characterization of the interlayer plane of the reservoir is carried out using the four-dimensional Neogene lithological exploration technique sequence. The method is as follows: Vertically, using sub-layers as units, we construct oil composition maps, sub-layer plan maps, and sand layer top structure maps to determine oil reservoir units; Horizontally evaluate oil reservoirs, and systematically review the same oil reservoir unit following the principle of high oil content and low water content to clearly delineate the oil-water boundary; On a planar surface, we conduct provenance analysis, sedimentary microfacies study, sand body morphology delineation, and reservoir prediction to determine the extent of sand bodies. Three-dimensional source analysis is conducted to locate oil sources, identify faults, clarify migration channels, determine secondary migration of oil and gas within the reservoir after trap conditions are met, and determine the reservoir formation model.

4. The method for identifying oil layers based on reservoir unit analysis according to claim 3, characterized in that, The method for calculating the envelope index of the carbon-oxygen ratio and the calcium-silicon ratio is as follows: Full-spectrum residual oil saturation logging in non-elastic mode and full-spectrum residual oil saturation logging in trap mode were selected. Calculate the carbon-oxygen ratio of the full-spectrum residual oil saturation logging in the non-elastic mode; Calculate the silica-calcium ratio in the full-spectrum residual oil saturation logging of the capture mode; Calculate the envelope index of the carbon-oxygen ratio and the calcium-silicon ratio based on the carbon-oxygen ratio and the silicon-calcium ratio.

5. The method for identifying oil layers based on reservoir unit analysis according to claim 4, characterized in that, The envelope index of the carbon-oxygen ratio and the calcium-silicon ratio is calculated based on the carbon-oxygen ratio and the silicon-calcium ratio, using the following method: Wherein, ENcc represents the envelope index of the carbon-oxygen ratio and the calcium-silicon ratio, CO represents the carbon-oxygen ratio, and CO... MIN This represents the minimum carbon-to-oxygen ratio, CO. MAX CS represents the maximum carbon-oxygen ratio, and CS represents the calcium-silicon ratio. MIN This represents the minimum calcium-to-silicon ratio, CS. MAX This indicates the maximum calcium-to-silicon ratio.

6. The method for identifying oil layers based on reservoir unit analysis according to claim 5, characterized in that, Combining the second map and the relevant maps of the reservoir water production parameters, the initial map of the geological model of the reservoir unit is updated. After the update, oil layers are identified within the same reservoir unit. The method is as follows: The initial map of the reservoir unit geological model is updated by combining the second map and the map related to the reservoir water production parameters. Based on the updated initial map of the reservoir unit geological model, an oil layer type identification table is constructed; the oil layer type identification table is a mapping table between preset elements and preset oil layer types; the elements include potential level, structural location, production of adjacent wells, logging display, and oil-bearing level of wellbore coring; The oil layer type identification table is used to match the elements of the same reservoir unit to obtain the oil layer type identification result.

7. The method for identifying oil layers based on reservoir unit analysis according to claim 1, characterized in that, The fitting parameters include GRML, R4, RT, and AC.

8. A reservoir unit-based oil layer identification system for identifying oil layers in Neogene strata, characterized in that, The system includes: The reservoir unit initial characterization module is configured to collect geological data of the reservoir unit and dynamic production data of the wells after perforation repair, and construct the initial geological model of the reservoir unit using small layers as units. The strata re-division module is configured to combine the initial map of the reservoir unit geological model and use the four-dimensional Neogene lithology oil exploration technology sequence to perform a three-dimensional characterization of the interlayer plane of the reservoir in new wells in the old area; based on the three-dimensionally characterized reservoir unit, a refined original electrical logging interpretation map of oil and water layer characteristics is constructed using the intersection method, which serves as the first map; multiple parameters are fitted to the first map to re-divide the strata into a second map; The map update module is configured to calculate the carbon-oxygen ratio and calcium-silicon ratio envelope index, and re-identify the oil-water layer based on the carbon-oxygen ratio and calcium-silicon ratio envelope index; based on the oil-water layer identification results, update the relevant maps for reservoir water production parameters; the relevant maps for reservoir water production parameters include water production-porosity maps and water production-lithological oil-bearing index evaluation maps. The oil layer identification module is configured to update the initial map of the geological model of the reservoir unit by combining the second map and the map related to the reservoir water production rate parameters, and then identify the oil layers in the same reservoir unit after the update.

9. An electronic device, characterized in that, The device includes: At least one processor, and a memory communicatively connected to at least one of the processors; The memory stores instructions that can be executed by the processor to implement the reservoir unit analysis-based oil layer identification method according to any one of claims 1-7.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer instructions that are executed by a computer to implement the reservoir unit analysis-based oil layer identification method according to any one of claims 1-7.

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