Shale formation framework establishment method and device, electronic equipment and storage medium
By selecting key wells in shale formations for core sampling and elemental geochemical analysis, the problems of small lithological variations and difficulty in identifying sequence boundaries were solved, thus enabling the effective establishment of the shale formation framework and accurate identification of sweet spots.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- CHINA PETROLEUM & CHEMICAL CORP
- Filing Date
- 2023-05-08
- Publication Date
- 2026-06-23
AI Technical Summary
Existing technologies are insufficient to effectively establish shale stratigraphic frameworks where lithological variations are minimal and typical sequence boundaries are difficult to identify, making traditional methods difficult to apply.
By selecting key wells in the target shale strata of the study area, core samples were taken and elemental geochemical analysis was performed. Elemental geochemical information was obtained using techniques such as inductively coupled plasma optical emission spectrometry, and the elemental distribution characteristics were statistically analyzed to determine the characteristic values of enriched minerals, thus establishing a well-connected profile and stratigraphic framework.
It has enabled the establishment of an effective framework for shale strata with little lithological variation and difficult identification of typical sequence boundaries, thereby improving the ability of geological evaluation and sweet spot identification.
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Figure CN118911684B_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of geological exploration technology, specifically to a method, apparatus, electronic device, and storage medium for establishing a shale stratigraphic framework. Background Technology
[0002] With the continuous development of oil and gas exploration and development both domestically and internationally, unconventional oil and gas has become one of the most important resources for increasing reserves and production. The tremendous success of shale oil and gas in North America has attracted numerous global oil and gas companies seeking similar resources. Stratigraphic frameworks can separate strata of different sedimentary periods and characteristics, which is of great significance for studying sedimentary evolution processes, controlling factors, and oil and gas geological characteristics. However, unfortunately, compared to other conventional oil and gas reservoirs, shale reservoirs typically have finer grains, making it difficult to widely apply traditional sequence stratigraphy methods for establishing stratigraphic frameworks.
[0003] Currently, commonly used methods for establishing shale stratigraphic frameworks include gamma-ray spectrometry logging, paleontology, well logging, mineral composition, lithofacies and their assemblages, geochemical characteristics, source rock heterogeneity, astronomical cycles, sequence stratigraphic control factor analysis, and multi-method comprehensive analysis. Among these, using mineral composition, lithofacies and their assemblages to determine sea-level changes and thus sequence stratigraphy is a relatively common method, but it faces challenges in terms of core length and descriptive accuracy, and identification of fine-grained lithofacies remains difficult. Scanning electron microscopy, energy dispersive spectroscopy, and scattered electron imaging are also increasingly being applied in this area, yielding some results. Simultaneously, the application of organic geochemistry and isotopic chemistry characteristics can reflect redox conditions and changes relative to sea-level, also contributing to the division and establishment of stratigraphic frameworks. Paleontological data can be used to determine different paleontological development periods, assisting in the establishment of sequence stratigraphic frameworks. Furthermore, combining the above methods for comprehensive research on shale strata to establish sequence stratigraphic frameworks is also a practical and effective approach.
[0004] However, for some shale strata with little variation in lithology (mainly mudstone) and where typical sequence boundaries are difficult to identify, there is little clear reflection in lithofacies, paleontology, and well logging, making it quite difficult to establish a stratigraphic framework. Summary of the Invention
[0005] In view of this, this application provides a method, apparatus, electronic device and storage medium for establishing a shale stratigraphic framework, in order to solve the problem in the prior art that it is difficult to establish a stratigraphic framework for some shale strata with little lithological variation (mainly mudstone) and where typical sequence boundaries are not easy to identify.
[0006] In a first aspect, embodiments of this application provide a method for establishing a shale stratigraphic framework, including:
[0007] Key wells for coring were selected from the target shale strata in the study area;
[0008] Core samples were systematically and regularly taken from the core of the key core well to obtain core experimental analysis samples of the target shale strata in the study area;
[0009] Elemental geochemical analysis was performed on the experimental samples to obtain elemental geochemical information of the target shale strata in the study area;
[0010] Based on the elemental geochemical information, statistical analysis was conducted to identify the distribution characteristics of various elemental geochemical data in the target shale strata of the study area.
[0011] Based on the distribution characteristics of the geochemical data of various elements, the elemental composition and characteristic values of enriched minerals of the target shale strata in the study area are determined, and different strata are divided according to the vertical variation characteristics of the characteristic values of the enriched minerals to obtain the strata division results.
[0012] For the key core wells, establish a series of well profiles, and based on the series of well profiles, the characteristic values of the enriched minerals, and the stratigraphic division results, establish a stratigraphic framework.
[0013] In one possible implementation, the selection rules for the coring key well include:
[0014] The target shale strata in the study area have been drilled through, and core samples have been partially or completely taken from the target strata, covering the entire study area.
[0015] In one possible implementation, the systematic and regular sampling of core samples from the core of the key core well to obtain core samples for experimental analysis of the target shale strata in the study area includes:
[0016] Based on the scope and precision of the study section, core samples are taken from the core of the key core well at preset intervals to obtain core experimental analysis samples of the target shale strata in the study area.
[0017] In one possible implementation, the systematic and regular sampling of core samples from the core of the key core well to obtain core samples for experimental analysis of the target shale strata in the study area further includes:
[0018] If a marker mineral layer or rock layer is present, then the marker mineral layer or rock layer shall be sampled in a targeted manner.
[0019] In one possible implementation, the elemental geochemical analysis of the experimental sample to obtain elemental geochemical information of the target shale strata in the study area includes:
[0020] Elemental geochemical analysis of the experimental samples was performed using inductively coupled plasma optical emission spectrometry, inductively coupled plasma optical emission mass spectrometry, and / or X-ray fluorescence spectrometry to obtain elemental geochemical information of the target shale strata in the study area.
[0021] In one possible implementation, the distribution characteristics of the various elemental geochemical data are used to determine the interrelationships between different elements, thereby identifying enriched minerals that control key elements and element ratios.
[0022] Secondly, embodiments of this application provide a shale formation framework establishment device, comprising:
[0023] The core sampling key well selection module is used to select key core wells for the target shale formation in the study area;
[0024] The sampling module is used to systematically and regularly sample the cores of the key core wells to obtain core experimental analysis samples of the target shale strata in the study area.
[0025] The elemental geochemical analysis module is used to perform elemental geochemical analysis on the experimental analysis samples to obtain elemental geochemical information of the target shale strata in the study area.
[0026] The statistical analysis module is used to statistically analyze the distribution characteristics of various elemental geochemical data in the target shale strata of the study area based on the elemental geochemical information.
[0027] The eigenvalue determination and stratigraphic division module is used to determine the elemental composition and enriched mineral characteristics of the target shale strata in the study area based on the distribution characteristics of the geochemical data of various elements, and to divide different stratigraphic segments based on the vertical variation characteristics of the enriched mineral characteristics to obtain stratigraphic division results.
[0028] The stratigraphic framework establishment module is used to establish a well-connected profile for the cored key wells, and to establish a stratigraphic framework based on the well-connected profiles, the characteristic values of the enriched minerals, and the stratigraphic division results.
[0029] Thirdly, embodiments of this application provide an electronic device, including:
[0030] processor;
[0031] Memory;
[0032] And a computer program, wherein the computer program is stored in the memory, the computer program including instructions that, when executed by the processor, cause the electronic device to perform the method described in any one of the first aspects.
[0033] Fourthly, embodiments of this application provide a computer-readable storage medium including a stored program, wherein, when the program is executed, it controls the device where the computer-readable storage medium is located to perform the method described in any one of the first aspects.
[0034] In this embodiment, based on the elemental geochemical characteristics of different segments in key wells of shale formations, geostatistical methods are used to screen characteristic values and establish a shale stratigraphic framework through well-to-well correlation based on the differences in elemental geochemical characteristics among different segments. This method is particularly suitable for shale formations with minimal lithological variation and where typical sequence boundaries are difficult to identify. It can provide effective guidance for subsequent geological evaluation, identification of favorable sweet spots, and enhance geological understanding. Attached Figure Description
[0035] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0036] Figure 1 A flowchart illustrating a method for establishing a shale stratigraphic framework, provided as an embodiment of this application;
[0037] Figure 2 This is a schematic diagram of the elemental geochemical information of the target shale stratigraphic position in a basin study area provided in an embodiment of this application.
[0038] Figure 3 A schematic diagram illustrating the distribution characteristics of geochemical data of various elements in the target shale strata of a basin study area provided in this application embodiment;
[0039] Figure 4 A schematic diagram of the stratigraphic division results of the target shale strata in a basin study area provided in this application embodiment;
[0040] Figure 5 A schematic diagram of the stratigraphic framework of a well-connected profile of the target shale strata in a basin study area provided for an embodiment of this application;
[0041] Figure 6 A structural block diagram of a shale formation framework establishment device is also provided in this application;
[0042] Figure 7 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application. Detailed Implementation
[0043] To better understand the technical solution of this application, the embodiments of this application will be described in detail below with reference to the accompanying drawings.
[0044] It should be understood that the described embodiments are merely some, not all, of the embodiments in this application. All other embodiments obtained by those skilled in the art based on the embodiments in this application without inventive effort are within the scope of protection of this application.
[0045] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. The singular forms “a,” “the,” and “the” used in the embodiments of this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.
[0046] It should be understood that the term "and / or" used 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.
[0047] Identifying and establishing a shale stratigraphic framework is one of the most fundamental tasks for in-depth evaluation of shale reservoirs and selection of favorable sweet spots. Although many scholars and companies have conducted extensive research and developed numerous evaluation methods, establishing a stratigraphic framework remains challenging for shale formations with minimal lithological variation (primarily mudstone) and difficult-to-identify typical sequence boundaries. Lithofacies, paleontology, and well logging data often provide clear indications. Therefore, this application provides a method for establishing a shale stratigraphic framework. Based on the elemental geochemical characteristics of different intervals in key wells of shale formations, geostatistical methods are used to screen characteristic values. The framework is then established through well-to-well comparison based on the differences in elemental geochemical characteristics across different intervals. This method is particularly suitable for shale formations with minimal lithological variation and difficult-to-identify typical sequence boundaries, providing effective guidance for subsequent geological evaluation and identification of favorable sweet spots, thus enhancing geological understanding. Detailed explanations are provided below with specific embodiments.
[0048] See Figure 1 This is a flowchart illustrating a method for establishing a shale stratigraphic framework according to an embodiment of this application. Figure 1 As shown, it mainly includes the following steps.
[0049] Step S101: Select key wells for coring the target shale strata in the study area.
[0050] In practice, the selected key coring wells should penetrate the target shale strata in the study area as much as possible, have partially or completely completed coring of the target strata, and cover the entire study area in order to reflect the structural pattern distribution of the study area.
[0051] Step S102: Systematically and regularly sample the cores of the key core wells to obtain core experimental analysis samples of the target shale strata in the study area.
[0052] In one possible implementation, based on the scope and precision of the study section, core samples are taken from the core of the key core well at predetermined intervals to obtain core samples for experimental analysis of the target shale strata in the study area. For example, samples are taken from the core of the key core well at 1-meter intervals. If core samples are missing, adjustments can be made according to the actual geological conditions.
[0053] In one possible implementation, if a marker mineral layer or rock layer exists, the marker mineral layer or rock layer is sampled in a targeted manner to more accurately reflect the sedimentary environment and stratigraphic correlation.
[0054] Step S103: Perform elemental geochemical analysis on the experimental analysis sample to obtain elemental geochemical information of the target shale strata in the study area.
[0055] In one possible implementation, the experimental analysis samples can be subjected to elemental geochemical analysis using inductively coupled plasma optical emission spectrometry (ICPOES), inductively coupled plasma optical emission mass spectrometry (ICPMS), and / or X-ray fluorescence spectrometry (XRF) to obtain elemental geochemical information of the target shale strata in the study area.
[0056] The elemental geochemical information includes data on more than 50 elements obtained through elemental geochemical analysis, such as SiO2, TiO2, Al2O3, MgO, MnO, CaO, Na2O, K2O, and P2O5. For example, some data from the elemental geochemical information of the target shale strata in a certain basin study area are shown below. Figure 2 As shown.
[0057] Step S104: Statistically analyze the distribution characteristics of various elemental geochemical data in the target shale strata of the study area based on the elemental geochemical information.
[0058] Specifically, the distribution characteristics of various elemental geochemical data are used to determine the relationships between different elements, and thus identify enriching minerals that control key elements and element ratios. For example, the distribution characteristics of various elemental geochemical data in the target shale strata of a certain basin study area are as follows: Figure 3 As shown.
[0059] Step S105: Based on the distribution characteristics of the geochemical data of various elements, determine the elemental composition and characteristic values of the enriched minerals of the target shale strata in the study area, and divide different strata according to the vertical variation characteristics of the characteristic values of the enriched minerals to obtain the strata division results.
[0060] Specifically, the characteristic values of the elemental composition of the target shale strata in the study area can be determined first based on the distribution characteristics of various elemental geochemical data. Then, based on the characteristic values of the elemental composition, the enriched minerals can be identified, and subsequently, the characteristic values of the representative elements corresponding to the enriched minerals can be determined, i.e., the characteristic values of the enriched minerals can be determined. The representative elements corresponding to the enriched minerals can be some of the elements in the elemental composition of the target shale strata in the study area.
[0061] For example, the stratigraphic division results of the target shale strata in a certain basin study area are as follows: Figure 4 As shown.
[0062] Step S106: Establish a connecting well profile for the core sampling key well, and establish a stratigraphic framework based on the connecting well profile, the characteristic values of the enriched minerals, and the stratigraphic division results.
[0063] For example, the stratigraphic framework of the target shale strata in a certain basin study area is as follows: Figure 5 As shown.
[0064] In this embodiment, based on the elemental geochemical characteristics of different segments in key wells of shale formations, geostatistical methods are used to screen characteristic values and establish a shale stratigraphic framework through well-to-well correlation based on the differences in elemental geochemical characteristics among different segments. This method is particularly suitable for shale formations with minimal lithological variation and where typical sequence boundaries are difficult to identify. It can provide effective guidance for subsequent geological evaluation, identification of favorable sweet spots, and enhance geological understanding.
[0065] Corresponding to the above embodiments, this application also provides a shale formation framework establishment device.
[0066] See Figure 6 This application also provides a structural block diagram of a shale formation framework establishment device. Figure 6 As shown, it mainly includes the following modules.
[0067] The core sampling key well selection module 601 is used to select the key core wells for the target shale strata in the study area.
[0068] The sampling module 602 is used to systematically and regularly sample the cores of the key core well to obtain core experimental analysis samples of the target shale strata in the study area.
[0069] The elemental geochemical analysis module 603 is used to perform elemental geochemical analysis on the experimental analysis sample to obtain elemental geochemical information of the target shale strata in the study area.
[0070] Statistical analysis module 604 is used to statistically analyze the distribution characteristics of various elemental geochemical data in the target shale strata of the study area based on the elemental geochemical information.
[0071] The eigenvalue determination and stratigraphic division module 605 is used to determine the elemental composition and enriched mineral characteristic values of the target shale stratigraphic position in the study area based on the distribution characteristics of the geochemical data of various elements, and to divide different stratigraphic segments according to the vertical variation characteristics of the elemental geochemical characteristics to obtain the stratigraphic segment division results.
[0072] The stratigraphic framework establishment module 606 is used to establish a well-connected profile for the cored key well, and to establish a stratigraphic framework based on the well-connected profile, the characteristic values of the enriched minerals, and the stratigraphic division results.
[0073] In this embodiment, based on the elemental geochemical characteristics of different segments in key wells of shale formations, geostatistical methods are used to screen characteristic values and establish a shale stratigraphic framework through well-to-well correlation based on the differences in elemental geochemical characteristics among different segments. This method is particularly suitable for shale formations with minimal lithological variation and where typical sequence boundaries are difficult to identify. It can provide effective guidance for subsequent geological evaluation, identification of favorable sweet spots, and enhance geological understanding.
[0074] It should be noted that the specific content involved in the embodiments of this application can be found in the description of the above method embodiments, and will not be repeated here for the sake of brevity.
[0075] Corresponding to the above embodiments, this application also provides an electronic device.
[0076] See Figure 7 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application. Figure 7 As shown, the electronic device 700 may include a processor 701, a memory 702, and a communication unit 703. These components communicate via one or more buses. Those skilled in the art will understand that the electronic device structure shown in the figures does not constitute a limitation on the embodiments of this application. It may be a bus topology or a star topology, and may include more or fewer components than shown, or combine certain components, or have different component arrangements.
[0077] The communication unit 703 is used to establish a communication channel, thereby enabling the electronic device to communicate with other devices.
[0078] The processor 701 serves as the control center of the electronic device, connecting various parts of the device via various interfaces and lines. It executes software programs and / or modules stored in the memory 702, and calls data stored in the memory to perform various functions and / or process data. The processor can be composed of integrated circuits (ICs), such as a single packaged IC or multiple packaged ICs with the same or different functions connected together. For example, the processor 701 may consist only of a central processing unit (CPU). In this embodiment, the CPU may have a single processing core or include multiple processing cores.
[0079] Memory 702 is used to store the execution instructions of processor 701. Memory 702 can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic storage, flash memory, magnetic disk or optical disk.
[0080] When the execution instructions in memory 702 are executed by processor 701, the electronic device 700 is able to perform some or all of the steps in the above method embodiments.
[0081] Corresponding to the above embodiments, this application also provides a computer-readable storage medium, wherein the computer-readable storage medium may store a program, wherein when the program runs, it can control the device where the computer-readable storage medium is located to execute some or all of the steps in the above method embodiments. Specifically, the computer-readable storage medium may be a magnetic disk, an optical disk, read-only memory (ROM), or random access memory (RAM), etc.
[0082] Corresponding to the above embodiments, this application also provides a computer program product containing executable instructions that, when executed on a computer, cause the computer to perform some or all of the steps in the above method embodiments.
[0083] In this application embodiment, "at least one" refers to one or more, and "more than one" refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent the existence of A alone, the simultaneous existence of A and B, or the existence of B alone. A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one of the following" and similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one of a, b, and c can represent: a, b, c, ab, ac, bc, or abc, where a, b, and c can be single or multiple.
[0084] Those skilled in the art will recognize that the units and algorithm steps described in the embodiments disclosed herein can be implemented using electronic hardware, computer software, or a combination of electronic hardware and software. Whether these functions are implemented in 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 this application.
[0085] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.
[0086] In the several embodiments provided in this application, any function, if implemented as a software functional unit and sold or used as an independent product, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.
[0087] The above description is merely a specific embodiment of this application. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the protection scope of this application. The protection scope of this application should be determined by the protection scope of the claims.
Claims
1. A method for establishing a shale stratigraphic framework, characterized in that, include: Key wells for coring were selected from the target shale strata in the study area; Core samples were systematically and regularly taken from the core of the key core well to obtain core experimental analysis samples of the target shale strata in the study area; Elemental geochemical analysis was performed on the experimental samples to obtain elemental geochemical information of the target shale strata in the study area; Based on the elemental geochemical information, statistical analysis was conducted to identify the distribution characteristics of various elemental geochemical data in the target shale strata of the study area. Based on the distribution characteristics of the geochemical data of various elements, the elemental composition and characteristic values of enriched minerals of the target shale strata in the study area are determined, and different strata are divided according to the vertical variation characteristics of the characteristic values of the enriched minerals to obtain the strata division results. For the key core wells, establish a series of well profiles, and based on the series of well profiles, the characteristic values of the enriched minerals, and the stratigraphic division results, establish a stratigraphic framework.
2. The method according to claim 1, characterized in that, The selection rules for the key coring wells include: The target shale strata in the study area have been drilled through, and core samples have been partially or completely taken from the target strata, covering the entire study area.
3. The method according to claim 1, characterized in that, The systematic and regular sampling of core samples from the key core wells to obtain core samples for experimental analysis of the target shale strata in the study area includes: Based on the scope and precision of the study section, core samples are taken from the core of the key core well at preset intervals to obtain core experimental analysis samples of the target shale strata in the study area.
4. The method according to claim 3, characterized in that, The systematic and regular sampling of core samples from the key core wells to obtain core samples for experimental analysis of the target shale strata in the study area also includes: If a marker mineral layer or rock layer is present, then the marker mineral layer or rock layer shall be sampled in a targeted manner.
5. The method according to claim 1, characterized in that, The elemental geochemical analysis of the experimental samples to obtain elemental geochemical information of the target shale strata in the study area includes: Elemental geochemical analysis of the experimental samples was performed using inductively coupled plasma optical emission spectrometry, inductively coupled plasma optical emission mass spectrometry, and / or X-ray fluorescence spectrometry to obtain elemental geochemical information of the target shale strata in the study area.
6. The method according to claim 1, characterized in that, The distribution characteristics of the geochemical data of various elements are used to determine the interrelationships between different elements, and then to identify enriched minerals that control key elements and element ratios.
7. A shale stratigraphic framework establishment device, characterized in that, include: The core sampling key well selection module is used to select key core wells for the target shale formation in the study area; The sampling module is used to systematically and regularly sample the cores of the key core wells to obtain core experimental analysis samples of the target shale strata in the study area. The elemental geochemical analysis module is used to perform elemental geochemical analysis on the experimental analysis samples to obtain elemental geochemical information of the target shale strata in the study area. The statistical analysis module is used to statistically analyze the distribution characteristics of various elemental geochemical data in the target shale strata of the study area based on the elemental geochemical information. The eigenvalue determination and stratigraphic division module is used to determine the elemental composition and enriched mineral characteristics of the target shale strata in the study area based on the distribution characteristics of the geochemical data of various elements, and to divide different stratigraphic segments based on the vertical variation characteristics of the enriched mineral characteristics to obtain stratigraphic division results. The stratigraphic framework establishment module is used to establish a well-connected profile for the cored key wells, and to establish a stratigraphic framework based on the well-connected profiles, the characteristic values of the enriched minerals, and the stratigraphic division results.
8. An electronic device, characterized in that, include: processor; Memory; And a computer program, wherein the computer program is stored in the memory, the computer program including instructions that, when executed by the processor, cause the electronic device to perform the method of any one of claims 1 to 6.
9. A computer-readable storage medium, characterized in that, The computer-readable storage medium includes a stored program, wherein, when the program is executed, it controls the device on which the computer-readable storage medium is located to perform the method according to any one of claims 1 to 6.