Quantitative identification method and system of fluvial-lacustrine facies based on paleoecological habit reconstruction

Abstract

This invention provides a method and system for quantitative identification of fluvial and lacustrine facies based on paleontological ecological habit reconstruction, comprising: collecting target samples from a target area within a target well; determining that the target samples do not contain ostracods and gastropods; obtaining the plant species of aquatic plant pollen, the algal species of algal pollen, the quantity of plant pollen of each aquatic plant genus, and the quantity of algal pollen of each algal genus in the target samples; quantitatively calculating paleoenvironmental identification indicators based on the plant species, algal species, plant pollen quantity, and algal pollen quantity; and determining the fluvial and lacustrine sedimentary environment of the target area based on the paleoenvironmental identification indicators. This invention overcomes the drawbacks of traditional qualitative methods that are "highly subjective and rely on experience-based judgment," is more effective, does not require extensive and expensive geochemical analysis and testing, is not limited by specific oxidation / reduction environments of strata or subsequent alterations, and has wider applicability.

Description

Technical Field

[0001] This invention belongs to the field of fluvial-lacustrine facies identification technology, and particularly relates to a quantitative fluvial-lacustrine facies identification method and system based on paleontological ecological habit reconstruction. Background Technology

[0002] Fluvial facies sand bodies are continuous and possess excellent physical properties along the source direction, while mudstone provides lateral sealing perpendicular to the source direction, thus forming effective lithological traps; they are important targets for oil and gas exploration both domestically and internationally. Statistics show that fluvial facies lithological traps account for nearly half of the proven and developed oil and gas reserves. Rivers and lakes often alternate frequently in time and are spatially associated, making it difficult to effectively distinguish fluvial sand bodies from lacustrine sand bodies, which severely restricts the effective identification of fluvial facies lithological traps. "How to accurately and effectively identify fluvial and lacustrine sedimentary environments and sedimentary facies" is the "core key" to fluvial facies lithological trap exploration; however, existing "qualitative identification methods for fluvial and lacustrine facies" have poor effectiveness, and "quantitative identification methods for fluvial and lacustrine facies" have narrow applicability.

[0003] Currently, there are two main types of methods for identifying fluvial and lacustrine facies: qualitative identification methods based on sedimentary characteristics and quantitative identification methods based on geochemical indicators. The qualitative identification method based on sedimentary characteristics is a technique that uses sedimentary structures (such as horizontal bedding and cross-bedding) and petrological characteristics (such as mudstone color, sandstone grain size, and sorting / rounding) to identify fluvial and lacustrine sedimentary environments and facies. However, this method heavily relies on the experience of practitioners (for example, some geologists consider horizontal bedding to be a distinguishing feature of fluvial sandstone, while others consider it a distinguishing feature of lacustrine sandstone), resulting in a high degree of subjectivity and poor effectiveness.

[0004] The "quantitative identification method of fluvial and lacustrine facies based on geochemical indicators" is a technical method for identifying fluvial and lacustrine sedimentary environments and sedimentary facies based on geochemical parameters (such as GDGPs, lipid compounds, major and trace elements, etc.). However, this method heavily relies on geochemical analysis and testing data. It not only depends on a large number of expensive analytical tests but is also only applicable to reducing environments unaffected by later alterations, resulting in a narrow applicability. Therefore, existing quantitative identification methods of fluvial and lacustrine facies suffer from the drawbacks of "poor effectiveness and narrow applicability." Summary of the Invention

[0005] The main objective of this invention is to propose a quantitative identification method and system for river and lake facies based on paleontological ecological habit reconstruction, aiming to solve the technical problems of poor effectiveness and narrow applicability of existing quantitative identification methods for river and lake facies.

[0006] To achieve the above objectives, this invention provides a method for quantitative identification of fluvial and lacustrine facies based on paleontological ecological habit reconstruction. The method includes: Collect target samples from the target area within the target well; Determine that the target sample does not contain ostracods and gastropods, and obtain the plant species of aquatic plant pollen, the algal species of algal pollen, the number of plant pollen of each aquatic plant genus, and the number of algal pollen of each algal genus in the target sample. Based on the plant species, algae species, plant pollen quantity, and algae pollen quantity, paleoenvironmental identification indicators are quantitatively calculated. The lacustrine and fluvial sedimentary environment of the target area is determined based on the paleoenvironmental identification indicators.

[0007] In this embodiment of the invention, paleoenvironmental identification indicators are quantitatively calculated based on the plant species, the algal species, the quantity of plant pollen, and the quantity of algal pollen, including: Obtain a pre-stored paleoenvironmental parameter library, which includes at least a preset paleontological species and the paleoenvironmental parameters corresponding to the preset paleontological species; Based on the plant species, the algae species, and the paleoenvironmental parameter database, determine the paleoenvironmental parameters corresponding to different species of aquatic plants and algae; Based on the quantity of plant pollen and algal pollen, determine the parameter weights of preset paleoenvironmental parameters for different species of aquatic plants and algae; Based on the paleoenvironmental parameters and their weights, paleoenvironmental identification indicators are quantitatively calculated.

[0008] In this embodiment of the invention, the parameter weights of preset paleoenvironmental parameters for different species of aquatic plants and algae are determined according to the following formula:

[0009]

[0010] in: Let be the parameter weights for the pollen of the s-th aquatic plant; Let be the parameter weights of the s-th type of algal pollen; s represents the species or genus of aquatic plant pollen or algal pollen; n represents the total number of species of aquatic plant pollen or algal pollen.

[0011] In this embodiment of the invention, paleoenvironmental identification indicators are quantitatively calculated based on the paleoenvironmental parameters and the parameter weights, including: Based on the paleoenvironmental parameters and the parameter weights, the cumulative paleoenvironmental parameters of aquatic plants and algae are calculated. Based on the cumulative paleoenvironmental parameters of aquatic plants and algae, paleoenvironmental identification indicators are quantitatively calculated.

[0012] In this embodiment of the invention, the cumulative paleoenvironmental parameters of aquatic plants and algae are calculated according to the following formulas: ( s= 1, 2, 3...n) ( s =1, 2, 3...n) in: For the cumulative paleoenvironmental parameters of aquatic plants; These are the cumulative paleoenvironmental parameters for algae; The paleoenvironmental parameters of the pollen of the s-th aquatic plant; Paleoenvironmental parameters of pollen from the sth algae; Let be the parameter weights for the pollen of the s-th aquatic plant; Let be the parameter weights of the s-th type of algal pollen; s represents the species or genus of aquatic plant pollen or algal pollen; n represents the total number of species of aquatic plant pollen or algal pollen.

[0013] In this embodiment of the invention, the paleoenvironment identification index is calculated according to the following formula:

[0014] in: Indicators for paleoenvironmental identification; For the cumulative paleoenvironmental parameters of aquatic plants; These are the cumulative paleoenvironmental parameters for algae.

[0015] In this embodiment of the invention, the method for quantitative identification of fluvial and lacustrine facies based on paleontological ecological habit reconstruction further includes: The target sample is determined to contain ostracods but not gastropods. The plant species of aquatic plant pollen, the algal species of algal pollen, the number of plant pollen of each aquatic plant genus, the number of algal pollen of each algal genus, and the developmental characteristics of ostracods in the target sample are obtained. Based on the plant species, the algal species, the number of plant pollen, the number of algal pollen, and the developmental characteristics of ostracods, paleoenvironmental identification indicators are quantitatively calculated. The target sample was determined to contain gastropods and ostracods. The plant species of aquatic plant pollen, the algal species of algal pollen, the quantity of plant pollen of each aquatic plant genus, the quantity of algal pollen of each algal genus, the developmental characteristics of ostracods and gastropods were obtained from the target sample. Based on the plant species, algal species, quantity of plant pollen, quantity of algal pollen, developmental characteristics of ostracods and gastropods, paleoenvironmental identification indicators were quantitatively calculated.

[0016] In this embodiment of the invention, paleoenvironmental identification indicators are quantitatively calculated based on the plant species, the algal species, the quantity of plant spores and pollen, the quantity of algal spores and pollen, and the developmental characteristics of ostracods, including: Obtain a pre-stored paleoenvironmental parameter library, which includes at least preset developmental characteristics of ostracods and the corresponding paleoenvironmental parameters. Based on the developmental characteristics of ostracods and the paleoenvironmental parameter database, the paleoenvironmental parameters corresponding to the ostracods in the target sample are determined. The paleoenvironment identification index is calculated using the following formula:

[0017] in: Indicators for paleoenvironmental identification; For the cumulative paleoenvironmental parameters of aquatic plants; These are the cumulative paleoenvironmental parameters for algae; Paleoenvironmental parameters of ostracods

[0018] In this embodiment of the invention, paleoenvironmental identification indicators are quantitatively calculated based on the plant species, the algal species, the quantity of plant spores and pollen, the quantity of algal spores and pollen, the developmental characteristics of ostracods, and the developmental characteristics of gastropods, including: Obtain a pre-stored paleoenvironmental parameter library, which includes at least preset developmental characteristics of ostracods and gastropods and the paleoenvironmental parameters corresponding to the preset developmental characteristics; Based on the developmental characteristics of ostracods and gastropods, and the paleoenvironmental parameter database, the paleoenvironmental parameters corresponding to ostracods and gastropods in the target sample are determined. The paleoenvironment identification index is calculated using the following formula:

[0019] in: Indicators for paleoenvironmental identification; For the cumulative paleoenvironmental parameters of aquatic plants; These are the cumulative paleoenvironmental parameters for algae; These are paleoenvironmental parameters for ostracods; These are paleoenvironmental parameters for gastropods.

[0020] This invention also proposes a quantitative discrimination system for fluvial-lacustrine facies based on paleontological ecological habit reconstruction, applied to the fluvial-lacustrine facies quantitative discrimination method based on paleontological ecological habit reconstruction as described above. The fluvial-lacustrine facies quantitative discrimination system based on paleontological ecological habit reconstruction includes: The sample acquisition unit is used to collect target samples from the target area within the target well. The sample identification unit is used to determine that the target sample does not contain ostracods and gastropods, and to obtain the plant species of aquatic plant pollen, the algal species of algal pollen, the number of plant pollen of each aquatic plant genus, and the number of algal pollen of each algal genus in the target sample. The calculation unit is used to quantitatively calculate paleoenvironment identification indicators based on the plant species, the algae species, the plant pollen quantity, and the algae pollen quantity. The output unit is used to determine the lacustrine and fluvial sedimentary environment of the target area based on the paleoenvironmental identification indicators.

[0021] Through the above technical solutions, the quantitative identification method for fluvial and lacustrine facies based on paleontological ecological habit reconstruction provided by the embodiments of the present invention has the following beneficial effects: Once the target area within the target well is identified, sampling can be performed to obtain target samples. Paleontological identification of these samples is then conducted to determine the plant species of aquatic plant pollen, the algal species of algal pollen, the quantity of plant pollen for each genera, and the quantity of algal pollen for each genera. Based on the different developmental characteristics of paleontology under varying sedimentary environments and water depths—for example, in plain-shallow water sedimentary environments—the assemblage of paleontological species includes floating plants such as *Azolla* and *Azolla*, and near-water plants such as *Quercus* and *Ulmus*. By combining the plant species, algal species, plant pollen quantity, and algal pollen quantity with the paleontological ecological habits (sedimentary environment and water depth), the assemblage characteristics under different sedimentary environments can be fully considered, and paleoenvironmental identification indicators can be quantitatively calculated, avoiding heavy reliance on the experience of practitioners. The quantitative identification method for fluvial-lacustrine facies based on paleontological ecological behavior reconstruction in this embodiment, compared with the existing "qualitative identification method for fluvial-lacustrine facies based on sedimentary characteristics", can use the plant species, algal species, plant pollen quantity, and algal pollen quantity to identify the fluvial-lacustrine sedimentary environment by calculating paleoenvironmental evaluation indicators. This overcomes the drawbacks of traditional qualitative methods that are "subjective and rely on experience-based judgment". The quantitative identification method for fluvial-lacustrine facies based on paleontological ecological behavior reconstruction is more effective. Compared with the existing "quantitative identification method for fluvial-lacustrine facies based on geochemical indicators", this invention does not require a large number of expensive geochemical analysis tests, is not limited by specific oxidation / reduction environments of strata or subsequent modifications, and has wider applicability.

[0022] Other features and advantages of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0023] The accompanying drawings are provided to illustrate the invention and form part of the specification. They are used together with the following detailed description to explain the invention, but do not constitute a limitation thereof. In the drawings: Figure 1 This is a flowchart illustrating a method for quantitative identification of fluvial and lacustrine facies based on paleontological ecological habit reconstruction according to an embodiment of the present invention. Figure 2 According to one embodiment of the present invention, the lithological profile, paleontological identification results, and paleoenvironmental identification indicators of the target area are used. Figure 3 This refers to the lithological profile, paleontological identification results, and paleoenvironmental identification indicators of the target area according to another embodiment of the present invention; Figure 4 This refers to the lithological profile, paleontological identification results, and paleoenvironmental identification indicators of the target area in another embodiment of the present invention. Detailed Implementation

[0024] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0025] The following description, with reference to the accompanying drawings, describes a quantitative method for identifying fluvial and lacustrine facies based on paleontological ecological habit reconstruction according to the present invention.

[0026] In embodiments of the present invention, the method for quantitative identification of fluvial and lacustrine facies based on paleontological ecological habit reconstruction includes: Collect target samples from the target area within the target well; Determine that the target sample does not contain ostracods and gastropods, and obtain the plant species of aquatic plant pollen, the algal species of algal pollen, the number of plant pollen of each aquatic plant genus, and the number of algal pollen of each algal genus in the target sample. Based on plant species, algal species, plant pollen quantity, and algal pollen quantity, paleoenvironmental identification indicators are quantitatively calculated. The lacustrine and fluvial sedimentary environment of the target area is determined based on paleoenvironmental identification indicators.

[0027] It should be noted that when sampling the target area, it is necessary to select fine-grained sedimentary rocks (such as mudstone with horizontal bedding, silty mudstone, etc.) in the original sedimentary strata of the target well, avoid coarse-grained clastic rocks transported and deposited in other locations, ensure that the samples are fresh and have not been modified by later, and protect the target samples to prevent them from being contaminated by the external environment. At the same time, it is necessary to ensure that the strata sampling is relatively continuous.

[0028] Once the target area within the target well is identified, sampling can be performed to obtain target samples. Paleontological identification of these samples is then conducted to determine the plant species and algal species of aquatic plant pollen, the quantity of plant pollen for each genera, and the quantity of algal pollen for each genera. Based on the different developmental characteristics of various paleontologists under different sedimentary environments and water depths—for example, in plain-shallow water sedimentary environments, the pollen species assemblage of paleontologists includes floating plants such as *Azolla* and *Azolla*, and near-water plants such as *Quercus* and *Ulmus*—by combining plant species, algal species, plant pollen quantity, and algal pollen quantity with paleontological ecological habits (sedimentary environment and water depth), the paleontological assemblage characteristics under different sedimentary environments can be fully considered. Furthermore, paleoenvironmental identification indicators can be quantitatively calculated, avoiding heavy reliance on the experience of practitioners. The quantitative identification method for fluvial-lacustrine facies based on paleontological ecological behavior reconstruction in this embodiment, compared with the existing "qualitative identification method for fluvial-lacustrine facies based on sedimentary characteristics", can use plant species, algal species, plant pollen quantity, and algal pollen quantity to identify fluvial-lacustrine sedimentary environments by calculating paleoenvironmental evaluation indicators. This overcomes the drawbacks of traditional qualitative methods that are "subjective and rely on experience-based judgment". The quantitative identification method for fluvial-lacustrine facies based on paleontological ecological behavior reconstruction is more effective. Compared with the existing "quantitative identification method for fluvial-lacustrine facies based on geochemical indicators", this invention does not require a large number of expensive geochemical analysis tests, is not limited by specific oxidation / reduction environments of strata or subsequent modifications, and has wider applicability.

[0029] In one embodiment, paleoenvironmental identification indicators are quantitatively calculated based on plant species, algal species, plant pollen quantity, and algal pollen quantity, including: Obtain a pre-stored paleoenvironmental parameter library, which includes at least a preset paleontological species and the corresponding paleoenvironmental parameters. Based on plant species, algae species, and paleoenvironmental parameter databases, the paleoenvironmental parameters corresponding to different species of aquatic plants and algae were determined. Based on the amount of plant and algal pollen, the parameter weights of the preset paleoenvironmental parameters for different species of aquatic plants and algae are determined. Based on paleoenvironmental parameters and parameter weights, paleoenvironmental identification indicators are quantitatively calculated.

[0030] Aquatic plants ( ) and algae ( Ecological Habits (Sedimentary Environment and Water Depth) - Paleoenvironmental Parameter Database

[0031] Table 1 The paleoenvironmental parameter database can classify aquatic plants into five ecological habits according to their corresponding water depth: lacustrine, lacustrine or shallow lake, shallow lake, floodplain or wetland, and floodplain. The paleoenvironmental parameter database can classify algae into three ecological habits: lacustrine, shallow lake, and semi-deep lake to deep lake.

[0032] It should be noted that the pre-stored paleoenvironmental parameter library, as shown in Table 1, can include paleoenvironmental parameters corresponding to different preset paleontological (aquatic plant and algae) species. Based on the quantity of plant and algal pollen, the parameter weights of preset paleoenvironmental parameters for different species of aquatic plants and algae are determined, with larger quantities resulting in larger parameter weights. Based on the paleoenvironmental parameters and parameter weights, paleoenvironmental identification indicators are quantitatively calculated. This embodiment fully considers the paleoenvironmental parameters of different paleontological species and the proportion of different paleontological species, making the calculation of paleoenvironmental identification indicators more accurate and comprehensive.

[0033] It should be noted that the parameter weights for the preset paleoenvironmental parameters of different species of aquatic plants and algae are determined according to the following formula:

[0034]

[0035] in: Let be the parameter weights for the pollen of the s-th aquatic plant; Let be the parameter weights of the s-th type of algal pollen; s represents the species or genus of aquatic plant pollen or algal pollen; n represents the total number of species of aquatic plant pollen or algal pollen.

[0036] In this embodiment, the parameter weights of pollen and algae of each genus of aquatic plants can be accurately calculated using the above formula, making the calculation of paleoenvironment identification indicators more accurate.

[0037] In one embodiment, paleoenvironmental identification indicators are quantitatively calculated based on paleoenvironmental parameters and parameter weights, including: Based on paleoenvironmental parameters and parameter weights, the cumulative paleoenvironmental parameters of aquatic plants and algae are calculated. Based on the cumulative paleoenvironmental parameters of aquatic plants and algae, paleoenvironmental identification indicators are quantitatively calculated.

[0038] In this embodiment, by combining paleoenvironmental parameters and parameter weights, the species type and pollen quantity ratio in the target sample can be combined to obtain cumulative paleoenvironmental parameters. Based on the sample type present in the target sample, the corresponding calculation formula is called. If only aquatic plants and algae are present in the target sample, a pre-stored first preset formula can be called, and the paleoenvironmental identification index is quantitatively calculated by combining the cumulative paleoenvironmental parameters of aquatic plants and algae. If aquatic plants, algae, and ostracods are present in the target sample, a pre-stored second preset formula can be called, and the paleoenvironmental identification index is quantitatively calculated by combining the cumulative paleoenvironmental parameters of aquatic plants and algae. If aquatic plants, algae, ostracods, and gastropods are present in the target sample, a pre-stored third preset formula can be called, and the paleoenvironmental identification index is quantitatively calculated by combining the cumulative paleoenvironmental parameters of aquatic plants and algae. In this embodiment, different calculation formulas are called according to the sample type in the target sample to calculate the paleoenvironmental identification index, which can be fully applied to the quantitative determination of fluvial and lacustrine facies under different sample types.

[0039] Specifically, the cumulative paleoenvironmental parameters of aquatic plants and algae are calculated using the following formulas: ( s= 1, 2, 3...n) ( s =1, 2, 3...n) in: For the cumulative paleoenvironmental parameters of aquatic plants; These are the cumulative paleoenvironmental parameters for algae; The paleoenvironmental parameters of the pollen of the s-th aquatic plant; Paleoenvironmental parameters of pollen from the sth algae; Let be the parameter weights for the pollen of the s-th aquatic plant; Let be the parameter weights of the s-th type of algal pollen; s represents the species or genus of aquatic plant pollen or algal pollen; n represents the total number of species of aquatic plant pollen or algal pollen.

[0040] In one embodiment, the paleoenvironment identification index is calculated according to the following formula:

[0041] in: Indicators for paleoenvironmental identification; For the cumulative paleoenvironmental parameters of aquatic plants; These are the cumulative paleoenvironmental parameters for algae.

[0042] When the target sample consists only of aquatic plants and algae, paleoenvironmental identification indicators can be calculated by using the cumulative paleoenvironmental parameters of aquatic plants and algae. This allows for precise consideration of the species and pollen counts of aquatic plants and algae, making the calculation of paleoenvironmental identification indicators more accurate.

[0043] In this embodiment of the invention, the method for quantitative identification of fluvial and lacustrine facies based on paleontological ecological habit reconstruction further includes: The target sample was determined to contain ostracods but not gastropods. The plant species of aquatic plant pollen, the algal species of algal pollen, the number of plant pollen of each aquatic plant genus, the number of algal pollen of each algal genus, and the developmental characteristics of ostracods were obtained from the target sample. Based on the plant species, algal species, number of plant pollen, number of algal pollen, and developmental characteristics of ostracods, paleoenvironmental identification indicators were quantitatively calculated. The target sample was determined to contain gastropods and ostracods. The plant species of aquatic plant pollen, the algal species of algal pollen, the quantity of plant pollen of each aquatic plant genus, the quantity of algal pollen of each algal genus, the developmental characteristics of ostracods and gastropods were obtained from the target sample. Based on the plant species, algal species, quantity of plant pollen, quantity of algal pollen, developmental characteristics of ostracods and gastropods, paleoenvironmental identification indicators were quantitatively calculated.

[0044] In this embodiment, it is specifically determined whether the sample type in the target sample includes aquatic plants, algae, ostracods and gastropods. Then, paleoenvironmental identification indicators are calculated based on different data. This can fully take into account the ecological habits in the fluvial and lacustrine sedimentary environment, making the determination of the fluvial and lacustrine sedimentary environment of the target area more accurate.

[0045] In this embodiment of the invention, paleoenvironmental identification indicators are quantitatively calculated based on plant species, algal species, plant pollen quantity, algal pollen quantity, and ostracod developmental characteristics, including: Obtain a pre-stored paleoenvironmental parameter library, which includes at least the preset developmental characteristics of ostracods and the corresponding paleoenvironmental parameters. Based on the developmental characteristics of ostracods and the paleoenvironmental parameter database, the paleoenvironmental parameters corresponding to the ostracods in the target sample were determined. The paleoenvironment identification index is calculated using the following formula:

[0046] in: Indicators for paleoenvironmental identification; For the cumulative paleoenvironmental parameters of aquatic plants; These are the cumulative paleoenvironmental parameters for algae; Paleoenvironmental parameters of ostracods

[0047] Specifically, the calculation methods for the cumulative paleoenvironmental parameters of aquatic plants and algae are shown above.

[0048] In this embodiment of the invention, paleoenvironmental identification indicators are quantitatively calculated based on plant species, algal species, plant pollen quantity, algal pollen quantity, developmental characteristics of ostracods, and developmental characteristics of gastropods, including: Obtain a pre-stored paleoenvironmental parameter library, which includes at least preset developmental characteristics of ostracods and gastropods and the corresponding paleoenvironmental parameters. Based on the developmental characteristics of ostracods and gastropods, and the paleoenvironmental parameter database, the paleoenvironmental parameters corresponding to ostracods and gastropods in the target sample were determined. The paleoenvironment identification index is calculated using the following formula:

[0049] in: Indicators for paleoenvironmental identification; For the cumulative paleoenvironmental parameters of aquatic plants; These are the cumulative paleoenvironmental parameters for algae; These are paleoenvironmental parameters for ostracods; These are paleoenvironmental parameters for gastropods.

[0050] Specifically, the calculation methods for the cumulative paleoenvironmental parameters of aquatic plants and algae are shown above.

[0051] Ostracods ( ) and gastropods ( Ecological Habits (Sedimentary Environment and Water Depth) - Paleoenvironmental Parameter Database

[0052] Table 2 Osphronemes can be classified into five ecological habits based on their corresponding water depths: plains, lakeside, shallow lakes, semi-deep lakes, and deep lakes. According to the paleoenvironmental parameter database, gastropods appeared in deep lake sedimentary environments. If gastropods are present, the paleoenvironmental identification index is increased by 1 (not included in the weighting).

[0053] Among them, the paleoenvironmental parameters for ostracods can be taken as the average water depth. In lacustrine sedimentary environments, ostracods are "few in species but abundant in individuals." Affected by hydrodynamic fluctuations and salinity changes, only 1-5 dominant species with strong resilience can reproduce in large numbers, with the number of individuals generally ≥100, and no difference in lake basin size. In shallow lacustrine sedimentary environments, ostracods are "moderate in species and abundant in number." Due to the moderate environmental gradient in shallow lacustrine sedimentary environments, the number of suitable species increases, but there is no single dominant species monopolizing the habitat. The number of species is 6-15, and the number of individuals is 50-200. In semi-deep lacustrine sedimentary environments, ostracods are "abundant in species and abundant in number." Due to the weakly reducing environment and abundant nutrients in semi-deep lacustrine sedimentary environments, it is the most suitable habitat for ostracods. Regardless of the size of the lake basin, the diversity is ≥15 species, and the abundance is ≥150 individuals, which is the peak value for the entire lake. Ostracods in deep-lake sedimentary environments exhibit "medium individual size and medium species diversity." Due to the low dissolved oxygen in deep-lake sedimentary environments, diversification decreases (6-12 species), but hypoxia-tolerant dominant species can still reproduce in large numbers, with individuals ≥80. There is no core difference caused by lake basin size. Ostracods in brackish / saline-water sedimentary environments exhibit "few species but large numbers." Due to salinity stress in brackish / saline-water sedimentary environments, diversification drops sharply (≤3 species), but euryhaline species (such as *Spodoptera exigua* and *Spodoptera uniguagua*) dominate reproduction, with significantly higher individual numbers than in freshwater lakes.

[0054] In one embodiment, target samples can be collected from the target area within the target well to obtain sample information. The sample information specifically includes sample type (the first type includes only aquatic plants and algae, the second type includes aquatic plants, algae, and ostracods, and the third type includes aquatic plants, algae, ostracods, and gastropods). The sample information of the three sample types is matched with a pre-set paleoenvironment identification index calculation formula. In the case of the first type, the sample information also includes plant species, algae species, plant pollen quantity, and algae pollen quantity. Based on the plant species, algae species, plant pollen quantity, and algae pollen quantity, the paleoenvironment identification index is quantitatively calculated. Among them, the paleoenvironmental parameters of different types of paleontology can be determined by combining the pre-stored paleoenvironmental parameter database: the sample information of the target sample is compared with the "ecological habits-paleoenvironmental parameter database" in Table 2 to determine the corresponding paleoenvironmental parameters.

[0055] Among them, aquatic plants and algae are mainly compared based on the characteristics of their respective pollen assemblages to determine the corresponding paleoenvironmental parameters, while ostracods and gastropods are mainly compared based on their developmental characteristics (whether they are developed and their individual abundance and diversity) to determine the corresponding paleoenvironmental parameters.

[0056] The paleoenvironmental parameter weights of aquatic plants and algae can be calculated using Formula 1 based on the number and total number of different species of aquatic plants and algae in the target sample. The paleoenvironmental parameter weights of algae were calculated using Formula 2. ):

[0057]

[0058] In the formula: The paleoenvironmental parameters of the pollen of the s-th aquatic plant are weighted. The paleoenvironmental parameters of the pollen of the s-th algae are weighted. s represents the species or genus of aquatic plant pollen or algal pollen; n represents the total number of species of aquatic plant pollen or algal pollen.

[0059] In this step, the cumulative paleoenvironmental parameters of aquatic plants and algae are obtained. The paleoenvironmental parameters of aquatic plants and algae obtained in the previous steps, along with their calculated weights, are used to calculate the cumulative paleoenvironmental parameters of aquatic plants using Formula 3, and the cumulative paleoenvironmental parameters of algae are calculated using Formula 4. ( s= 1, 2, 3...n)

[0060] ( s =1, 2, 3...n)

[0061] In the formula: For the cumulative paleoenvironmental parameters of aquatic plants; These are the cumulative paleoenvironmental parameters for algae; The paleoenvironmental parameters of the pollen of the s-th aquatic plant; Paleoenvironmental parameters of pollen from the sth algae; The paleoenvironmental parameters of the pollen of the s-th aquatic plant are weighted. The paleoenvironmental parameters of the pollen of the s-th algae are weighted. s represents the species or genus of aquatic plant pollen or algal pollen; n represents the total number of species of aquatic plant pollen or algal pollen.

[0062] S4: Calculate paleoenvironmental identification indicators at the proposed restoration depth As shown above, based on different types of paleontological assemblages, three different working conditions are defined: Develop gastropods and ostracods; It does not develop gastropods or ostracods; It does not develop gastropods but does develop ostracods. Using the quantitative calculation formula of paleoenvironmental identification indicators, the paleoenvironmental identification indicators of the target area are calculated. ):

[0063] In the formula: To identify paleoenvironmental indicators for the proposed restoration of in-depth treatment; For the cumulative paleoenvironmental parameters of aquatic plants; These are the cumulative paleoenvironmental parameters for algae; These are paleoenvironmental parameters for ostracods; These are paleoenvironmental parameters for gastropods.

[0064] In one embodiment, the fluvial-lacustrine sedimentary environment of the target area can be quantitatively determined based on paleoenvironmental identification indicators (PLERI). Using 2.50 as a boundary, determine the sedimentary environment type of the target area at the proposed recovery depth: when" When this is the case, the target area is a riverine sedimentary environment; when" "When the target area is a lacustrine sedimentary environment, then the target area is a lacustrine sedimentary environment.

[0065] Compared to existing methods for qualitative identification of fluvial-lacustrine facies based on sedimentary characteristics, this embodiment utilizes paleontological data to identify fluvial-lacustrine sedimentary environments by calculating paleoenvironmental evaluation indicators, thereby overcoming the drawbacks of traditional qualitative methods that are "highly subjective and rely on experience-based judgments." This embodiment is more effective. Compared to existing methods for quantitative identification of fluvial-lacustrine facies based on geochemical indicators, this embodiment does not require extensive and expensive geochemical analysis and is not limited by specific oxidation / reduction environments or subsequent alterations in the strata; therefore, this invention has wider applicability.

[0066] In one embodiment, based on the method for quantitative identification of fluvial and lacustrine facies reconstructed from paleontological ecological habits, paleoenvironmental identification indicators and fluvial and lacustrine facies were calculated and quantitatively identified at different depths (1560m in well PL15-2-7, 1340m in well BZ29-6-3, and 1250m in well KL10-2-7) from three wells in the lower section of the Late Miocene Minghuazhen Formation in the Bohai Sea, in order to verify the effectiveness of the present invention. Samples were taken from wells PL15-2-7 at a depth of 1560m, BZ29-6-3 at a depth of 1340m, and KL10-2-7 at a depth of 1250m. Paleontological identification of the target samples was performed, and the results are shown in Tables 3, 4, and 5. The results of the paleontological identification were compared with the ecological habits-paleoenvironmental parameter database in Tables 2 and 3 to obtain the paleoenvironmental parameters corresponding to aquatic plants, algae, ostracods, and gastropods (see Tables 3, 4, and 5 for details).

[0067] Among them, aquatic plants and algae were mainly compared and their corresponding paleoenvironmental parameters were determined based on the characteristics of their respective pollen assemblages, while ostracods and gastropods were mainly compared and their corresponding paleoenvironmental parameters were determined based on their developmental characteristics.

[0068] Based on the paleontological identification results at depths of 1560m in well PL15-2-7, 1340m in well BZ29-6-3, and 1250m in well KL10-2-7, the quantity of aquatic plants and algae was determined. The weights of paleoenvironmental parameters for aquatic plants were calculated using Formula 1. The weights of paleoenvironmental parameters of algae were calculated using Formula 2 (the results are detailed in Tables 3, 4 and 5).

[0069] Based on the calculation of the paleoenvironmental parameters of aquatic plants and algae and the weights of the paleoenvironmental parameters of aquatic plants and algae, the cumulative paleoenvironmental parameters of aquatic plants were calculated using Formula 3 and the cumulative paleoenvironmental parameters of algae were calculated using Formula 4 at depths of 1560m in well PL15-2-7, 1340m in well BZ29-6-3 and 1250m in well KL10-2-7 (the results are detailed in Tables 3, 4 and 5).

[0070] No gastropods or ostracods were found at depth 1560m in well PL15-2-7. Using the quantitative calculation formula for paleoenvironmental identification indicators, the paleoenvironmental identification indicators were calculated as follows: =0.5×(0.15+0+0+0+0.46)+0.5×(3.00+0+0)=1.81 Gastropods and ostracods were found at depth 1340m in well BZ29-6-3. The paleoenvironmental identification indicators were calculated using a quantitative formula: =1 / 3 × (1.14 + 0.03 + 0.14 + 0.14 + 0.16) + 1 / 3 × (2.82 + 0.43 + 0) + 1 / 3 × 4 + 1 = 3.95 Well KL10-2-7 at depth 1250m does not contain gastropods but does contain ostracods. Using a quantitative formula for paleoenvironmental identification indicators, the paleoenvironmental identification indicators were calculated as follows: =1 / 3 × (0.82 + 0 + 0.53 + 0.41 + 0.15) + 1 / 3 × (2.25 + 0 + 2.50) + 1 / 3 × 4 = 3.55 S5: Quantitatively identifying fluvial and lacustrine sedimentary environments The calculation results show that: (1) Paleoenvironmental identification index at 1560m in well PL15-2-7 =1.81 < 2.50, quantitatively identified as a fluvial sedimentary environment ( Figure 2 ); (2) Paleoenvironmental identification indicators at 1340m in well BZ29-6-3 =3.95≥2.50, quantitatively identified as a lacustrine sedimentary environment ( Figure 3 ); (3) Paleoenvironmental identification indicators at 1250m in well KL10-2-7 =3.55≥2.50, quantitatively identified as a lacustrine sedimentary environment ( Figure 4 ).

[0071] By repeating the above steps, the depth range of "PL15-2-7 well, 1428.00~1819.00m" can be quantitatively recovered. Figure 2 ), the depth range of well BZ29-6-3 from 843.50 to 1440.00 m ( Figure 3 ) and KL10-2-7 well 911.00~1265.50m ( Figure 4 Paleoenvironmental identification indicators.

[0072] Pollen assemblage and paleontological development characteristics at a depth of 1560m in well PL15-2-7, along with corresponding paleoenvironmental parameters and weights:

[0073] Table 3 Paleozoic assemblage and paleontological development characteristics at a depth of 1340m in well BZ29-6-3, along with corresponding paleoenvironmental parameters and weights.

[0074] Table 4 Paleozoic and pollen assemblage and paleontological development characteristics at a depth of 1250m in well KL10-2-7, along with corresponding paleoenvironmental parameters and weights.

[0075] Table 5 This invention also proposes a quantitative discrimination system for fluvial-lacustrine facies based on paleontological ecological habit reconstruction, applied to the above-mentioned quantitative discrimination method for fluvial-lacustrine facies based on paleontological ecological habit reconstruction. The quantitative discrimination system for fluvial-lacustrine facies based on paleontological ecological habit reconstruction includes: The sample acquisition unit is used to collect target samples from the target area within the target well. The sample identification unit is used to determine that the target sample does not contain ostracods and gastropods, and to obtain the plant species of aquatic plant pollen, the algal species of algal pollen, the number of plant pollen of each aquatic plant genus, and the number of algal pollen of each algal genus in the target sample. The calculation unit is used to quantitatively calculate paleoenvironment identification indicators based on plant species, algal species, plant pollen quantity, and algal pollen quantity. The output unit is used to determine the lacustrine and fluvial sedimentary environment of the target area based on paleoenvironmental identification indicators.

[0076] In the description of this invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0077] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0078] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0079] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A quantitative method for identifying fluvial and lacustrine facies based on paleontological ecological habit reconstruction, characterized in that, The quantitative discrimination method for fluvial and lacustrine facies based on paleontological ecological habit reconstruction includes: Collect target samples from the target area within the target well; Determine that the target sample does not contain ostracods and gastropods, and obtain the plant species of aquatic plant pollen, the algal species of algal pollen, the number of plant pollen of each aquatic plant genus, and the number of algal pollen of each algal genus in the target sample. Based on the plant species, algae species, plant pollen quantity, and algae pollen quantity, paleoenvironmental identification indicators are quantitatively calculated. The lacustrine and fluvial sedimentary environment of the target area is determined based on the paleoenvironmental identification indicators.

2. The method for quantitative identification of fluvial and lacustrine facies based on paleontological ecological habit reconstruction according to claim 1, characterized in that, Based on the plant species, algal species, plant pollen quantity, and algal pollen quantity, paleoenvironmental identification indicators are quantitatively calculated, including: Obtain a pre-stored paleoenvironmental parameter library, which includes at least a preset paleontological species and the paleoenvironmental parameters corresponding to the preset paleontological species; Based on the plant species, the algae species, and the paleoenvironmental parameter database, determine the paleoenvironmental parameters corresponding to different species of aquatic plants and algae; Based on the quantity of plant pollen and algal pollen, determine the parameter weights of preset paleoenvironmental parameters for different species of aquatic plants and algae; Based on the paleoenvironmental parameters and their weights, paleoenvironmental identification indicators are quantitatively calculated.

3. The method for quantitative identification of fluvial and lacustrine facies based on paleontological ecological habit reconstruction according to claim 2, characterized in that, The parameter weights for preset paleoenvironmental parameters of different species of aquatic plants and algae are determined according to the following formula: in: Let be the parameter weights for the pollen of the s-th aquatic plant; Let be the parameter weights of the s-th type of algal pollen; s represents the species or genus of aquatic plant pollen or algal pollen; n represents the total number of species of aquatic plant pollen or algal pollen.

4. The method for quantitative identification of fluvial and lacustrine facies based on paleontological ecological habit reconstruction according to claim 3, characterized in that, Based on the paleoenvironmental parameters and their weights, paleoenvironmental identification indicators are quantitatively calculated, including: Based on the paleoenvironmental parameters and the parameter weights, the cumulative paleoenvironmental parameters of aquatic plants and algae are calculated. Based on the cumulative paleoenvironmental parameters of aquatic plants and algae, paleoenvironmental identification indicators are quantitatively calculated.

5. The method for quantitative identification of fluvial and lacustrine facies based on paleontological ecological habit reconstruction according to claim 4, characterized in that, The cumulative paleoenvironmental parameters of aquatic plants and algae were calculated using the following formulas: （ s= 1、2、3……n） （ s =1、2、3……n） in: For the cumulative paleoenvironmental parameters of aquatic plants; These are the cumulative paleoenvironmental parameters for algae; The paleoenvironmental parameters of the pollen of the s-th aquatic plant; Paleoenvironmental parameters of pollen from the sth algae; Let be the parameter weights for the pollen of the s-th aquatic plant; Let be the parameter weights of the s-th type of algal pollen; s represents the species or genus of aquatic plant pollen or algal pollen; n represents the total number of species of aquatic plant pollen or algal pollen.

6. The method for quantitative identification of fluvial and lacustrine facies based on paleontological ecological habit reconstruction according to claim 5, characterized in that, The paleoenvironment identification index is calculated using the following formula: in: Indicators for paleoenvironmental identification; For the cumulative paleoenvironmental parameters of aquatic plants; These are the cumulative paleoenvironmental parameters for algae.

7. The method for quantitative identification of fluvial and lacustrine facies based on paleontological ecological habit reconstruction according to any one of claims 1 to 6, characterized in that, The method for quantitative identification of fluvial and lacustrine facies based on paleontological ecological habit reconstruction also includes: The target sample is determined to contain ostracods but not gastropods. The plant species of aquatic plant pollen, the algal species of algal pollen, the number of plant pollen of each aquatic plant genus, the number of algal pollen of each algal genus, and the developmental characteristics of ostracods in the target sample are obtained. Based on the plant species, the algal species, the number of plant pollen, the number of algal pollen, and the developmental characteristics of ostracods, paleoenvironmental identification indicators are quantitatively calculated. The target sample was determined to contain gastropods and ostracods. The plant species of aquatic plant pollen, the algal species of algal pollen, the quantity of plant pollen of each aquatic plant genus, the quantity of algal pollen of each algal genus, the developmental characteristics of ostracods and gastropods were obtained from the target sample. Based on the plant species, algal species, quantity of plant pollen, quantity of algal pollen, developmental characteristics of ostracods and gastropods, paleoenvironmental identification indicators were quantitatively calculated.

8. The method for quantitative identification of fluvial and lacustrine facies based on paleontological ecological habit reconstruction according to claim 7, characterized in that, Based on the plant species, algal species, pollen quantity of the plant, pollen quantity of the algae, and developmental characteristics of ostracods, paleoenvironmental identification indicators are quantitatively calculated, including: Obtain a pre-stored paleoenvironmental parameter library, which includes at least preset developmental characteristics of ostracods and the corresponding paleoenvironmental parameters. Based on the developmental characteristics of ostracods and the paleoenvironmental parameter database, the paleoenvironmental parameters corresponding to the ostracods in the target sample are determined. The paleoenvironment identification index is calculated using the following formula: in: Indicators for paleoenvironmental identification; For the cumulative paleoenvironmental parameters of aquatic plants; These are the cumulative paleoenvironmental parameters for algae; These are paleoenvironmental parameters for ostracods.

9. The method for quantitative identification of fluvial and lacustrine facies based on paleontological ecological habit reconstruction according to claim 7, characterized in that, Based on the plant species, algal species, plant pollen quantity, algal pollen quantity, developmental characteristics of ostracods, and developmental characteristics of gastropods, paleoenvironmental identification indicators are quantitatively calculated, including: Obtain a pre-stored paleoenvironmental parameter library, which includes at least preset developmental characteristics of ostracods and gastropods and the paleoenvironmental parameters corresponding to the preset developmental characteristics; Based on the developmental characteristics of ostracods and gastropods, and the paleoenvironmental parameter database, the paleoenvironmental parameters corresponding to ostracods and gastropods in the target sample are determined. The paleoenvironment identification index is calculated using the following formula: in: Indicators for paleoenvironmental identification; For the cumulative paleoenvironmental parameters of aquatic plants; These are the cumulative paleoenvironmental parameters for algae; These are paleoenvironmental parameters for ostracods; These are paleoenvironmental parameters for gastropods.

10. A quantitative identification system for fluvial and lacustrine facies based on paleontological ecological habit reconstruction, applied to the quantitative identification method for fluvial and lacustrine facies based on paleontological ecological habit reconstruction as described in any one of claims 1 to 9, characterized in that, The quantitative discrimination system for fluvial and lacustrine facies based on paleontological ecological habit reconstruction includes: The sample acquisition unit is used to collect target samples from the target area within the target well. The sample identification unit is used to determine that the target sample does not contain ostracods and gastropods, and to obtain the plant species of aquatic plant pollen, the algal species of algal pollen, the number of plant pollen of each aquatic plant genus, and the number of algal pollen of each algal genus in the target sample. The calculation unit is used to quantitatively calculate paleoenvironment identification indicators based on the plant species, the algae species, the plant pollen quantity, and the algae pollen quantity. The output unit is used to determine the lacustrine and fluvial sedimentary environment of the target area based on the paleoenvironmental identification indicators.

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