A method for determining the uranium content of a well logging formation based on a sedimentary facies belt

Abstract

The application discloses a method for determining the uranium content of a well logging stratum based on a sedimentary facies belt, and comprises the following steps: S1, drawing a sedimentary facies and a sedimentary microfacies diagram of a target layer; S2, analyzing rock properties by using a core; S3, dividing stratum lithology by using logging data; and S4, calculating the uranium content of the stratum according to the rock properties and the stratum lithology and by using the uranium-radium balance coefficient.

Description

Technical Field

[0001] This invention relates to the field of uranium geological exploration and development technology, and in particular to a method for determining the uranium content of formations based on well logging based on sedimentary facies zones. Background Technology

[0002] In the field of uranium exploration, especially in the field of sandstone-type uranium exploration, since the implementation of "dual exploration of oil and uranium" and "dual exploration of coal and uranium", natural gamma, gamma spectroscopy logging and quantitative gamma logging have played an important role in delineating uranium mineralization zones, determining their depth, grade and spatial distribution, and estimating the uranium content of the formation.

[0003] The most common method for determining uranium content is to use core samples and analyze them using one or more methods to obtain the uranium content (Jiao Cangwen, 2021, Research on the Application of Gamma Spectrometry Logging Technology in Uranium Resource Estimation). Using well logging interpretation to submit uranium resource estimates is a nationally recognized method. Methods for estimating uranium resource estimates using well logging interpretation results can be roughly classified into two types: indirect uranium logging (including total gamma and gamma spectral logging) and direct uranium logging (including transient fission neutron logging (PFN) and delayed fission neutron logging (DFN)).

[0004] Indirect uranium determination calculates uranium content by measuring the intensity of gamma rays emitted by uranium decay products (mainly 214Pb and 214Bi). This assumes the ore's radioactivity is in equilibrium (Jiao Cangwen, 2021, Application Research of Gamma Spectrometry Logging Technology in Uranium Resource Estimation). Alternatively, it uses core (rock) analysis to determine formation uranium content, directly establishing a quantitative relationship between uranium content and natural gamma rays and natural gamma spectral density values. This model is then used to calculate formation uranium content. Five-point deconvolution and three-point deconvolution methods are also commonly used methods for calculating uranium content (Li Guodong). 2016, Application of gamma logging in uranium exploration; Jiao Cangwen, 2021, Research on the application of gamma spectroscopy logging technology in uranium resource estimation; Yu Reng'an, 2022, Research on uranium resource evaluation method based on natural gamma logging data), this method often requires uranium-radium balance coefficient correction; due to limitations such as low count rate and low logging efficiency, direct uranium logging technology is currently mainly used to obtain the "uranium-radium-radon" balance coefficient of gamma logging, and has not been widely used alone for formation uranium content calculation (Ye Hao, 2022, Current status of domestic research on logging technology for sandstone-type uranium deposits).

[0005] Sandstone-type uranium deposits are mostly distributed in the basin margins or the intersection of uplifts and depressions within the basin. They often develop alluvial fans, diluvial fans, deltas, and other sedimentary facies, characterized by rapid facies changes and significant lithological differences. The gamma background values ​​or the proportions of U, Th, and K radioactivity contributions vary in different sedimentary facies zones, and the uranium-radium balance coefficients of different sedimentary microfacies also differ (Zhao Xigang, 2002, Study on geophysical parameters in calculating the reserves of leached sandstone-type uranium deposits; Xiao Cheng, 2020, Study on uranium-radium balance coefficients in the middle section of the Qian IV section of the Qianjiadian uranium deposit and comparison with gamma logging; Miao Chenruo, 2022, Characteristics and geological significance of uranium-radium balance coefficients in the upper section of the Xishanyao Formation in the Kuosigal area of ​​the Ili Basin). The calculation of formation uranium content using well logging data has a large error, which restricts the application of well logging data in calculating formation uranium content.

[0006] Numerous studies, both domestically and internationally, have focused on calculating formation uranium content using well logging data, primarily natural gamma ray (GR) and natural gamma ray spectroscopy, resulting in a small number of patent applications. Patent application number 202210985454.3 describes a method for quantitative prediction of sandstone-type uranium deposits based on comprehensive well logging big data. The method involves: 1) establishing the relationship between natural gamma ray data from coalfield and oilfield boreholes and quantitative gamma ray data from verification boreholes; 2) determining the grade and thickness of the ore layer; 3) performing lithological interpretation using well logging data; and 4) batch processing of data. However, this method does not consider sedimentary facies zones and requires a large amount of sample data, which is sometimes unavailable. Patent application number CN114545515A discloses a gamma logging interpretation method for in-situ leaching sandstone-type uranium deposits, which includes well logging data input / output, input parameter types, and well logging interpretation output content. This method primarily focuses on well logging data and related data processing methods, without addressing the interpretation model. Patent application number 201811580620.1 describes a method for calculating the porosity of sandstone-type uranium deposits based on optimized well logging interpretation. It analyzes the relationship and influencing factors between experimental uranium content data from core samples and gamma-ray spectroscopy logging U, covering aspects such as instrument calibration, three-property assurance, and well logging applications. It also summarizes exploratory work in recent years and explains its potential application areas and advantages. This method does not consider the influence of sedimentary facies zones on calculation errors.

[0007] Sedimentary facies and sedimentary microfacies exhibit geological, petrological, and mineralogical regularities and uniformity. Under the control of sedimentary facies zones, errors in uranium content calculation caused by differences in rock composition, radioactive element content, and the amount of radioactive elements adsorbed due to differences in rock grain size can be reduced.

[0008] In summary, the existing publicly available technologies do not take into account the errors introduced by sedimentary facies in calculating the uranium content of the formation. Summary of the Invention

[0009] In view of the above problems, the present invention is proposed to provide a method for determining the uranium content of formations based on sedimentary facies zones, which overcomes or at least partially solves the above problems.

[0010] According to one aspect of the present invention, a method for determining the uranium content of a formation based on sedimentary facies zones through well logging is provided, the method comprising:

[0011] Step S1: Draw the sedimentary facies and sedimentary microfacies diagrams of the target layer;

[0012] Step S2: Analyze rock properties using core samples;

[0013] Step S3: Use well logging data to classify stratigraphic lithology;

[0014] Step S4: Calculate the uranium-radium balance coefficient based on rock properties and stratigraphic lithology, and calculate the uranium content of the stratigraphic strata.

[0015] Optionally, the statistical calculation of the uranium-radium balance coefficient based on rock properties and stratigraphic lithology specifically includes:

[0016] Using natural gamma spectroscopy logging, the relationship between natural gamma and parameter variations was determined;

[0017] Statistical uranium-radium balance coefficients for phase zones.

[0018] Optionally, the calculation of the formation uranium content specifically includes: calculating the formation uranium content based on the uranium-radium balance coefficient.

[0019] Optionally, step S1: drawing the sedimentary facies and sedimentary microfacies diagram of the target layer specifically includes:

[0020] Based on geological research results and rock information, sedimentary facies and sedimentary microfacies maps of the target layer were drawn.

[0021] Optionally, the rock information specifically includes: rock core, rock fragment lithology, well logging curves, and seismic sand body prediction maps.

[0022] Optionally, step S2: analyzing rock properties using core samples specifically includes:

[0023] Core analysis was used to determine rock composition, clay type, and content.

[0024] Statistical analysis of rock composition, clay type and content in facies zones.

[0025] Optionally, step S3: using well logging data to classify stratigraphic lithology specifically includes:

[0026] By using well logging data to classify stratigraphic lithology, statistical analysis of natural gamma values ​​in the absence of uranium anomalies in different facies zones, and determination of background radioactivity values ​​in various facies zones, we can identify the lithological characteristics of the formations.

[0027] Optionally, the determination of the relationship between natural gamma and parameter variations using natural gamma spectral logging specifically includes:

[0028] Using natural gamma spectroscopy logging, U, Th, and K values ​​were statistically analyzed by lithology and facies zone to determine the range of variation and background values ​​of U, Th, and K under conditions without uranium anomalies.

[0029] When Th and K are more than twice the background value of the same phase band, they are defined as high anomalies, and the relationship between natural gamma and the changes of U, Th, and K is determined.

[0030] Optionally, the phase-separation zone statistical uranium-radium balance coefficient specifically includes:

[0031] Collect core samples from each sedimentary microfacies layer in a balanced manner;

[0032] The uranium-radium balance coefficient is determined using laboratory or radioactive instruments, and the uranium-radium balance coefficient is statistically analyzed by phase zone.

[0033] Optionally, the calculation of the formation uranium content based on the uranium-radium balance coefficient specifically includes:

[0034] The formula for calculating the uranium content of strata is formula (1), calculated by sedimentary facies zone:

[0035] U=D*(A*(GR-GR 本底值 )-B*K 高异常 -C*Th 高异常 )) / Kp+E (1)

[0036] Among them, K 高异常 =KK 本底值 ;Th 高异常 =Th-Th 本底值 ;GR 本底值 K 本底值 ,Th 本底值 —Background values ​​for different sedimentary facies zones; Kp—Radium-uranium balance coefficient; K 高异常 ,Th 高异常 — K and Th values ​​greater than twice the background value are considered high anomalies, while values ​​less than twice the background value are considered normal; A, B, C, D, and E are coefficients to be determined.

[0037] This invention provides a method for determining the uranium content of formations based on sedimentary facies zones through well logging. The method includes: Step S1: drawing sedimentary facies and sedimentary microfacies diagrams of the target layer; Step S2: analyzing rock properties using core samples; Step S3: classifying formation lithology using well logging data; Step S4: calculating the uranium-radium balance coefficient based on rock properties and formation lithology, and calculating the formation uranium content. This establishes an accurate geophysical well logging calculation method.

[0038] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and in order to make the above and other objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described below. Attached Figure Description

[0039] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0040] Figure 1 A flowchart illustrating a method for determining uranium content in formations based on sedimentary facies zones, provided as an embodiment of the present invention;

[0041] Figure 2 This is a single-well sedimentary microfacies partitioning diagram provided in an embodiment of the present invention;

[0042] Figure 3 The sedimentary microfacies and uranium mineralization zone distribution map provided for embodiments of the present invention;

[0043] Figure 4 This is a graph showing the relationship between GR and uranium content after correction of sedimentary phase parameters, provided in an embodiment of the present invention.

[0044] Figure 5 The single-well sedimentary facies, GR, and gamma spectral characteristics are provided for embodiments of the present invention. Detailed Implementation

[0045] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0046] The terms "comprising" and "having," and any variations thereof, in the specification, embodiments, claims, and drawings of this invention are intended to cover non-exclusive inclusion, such as including a series of steps or units.

[0047] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0048] This invention proposes a method for calculating formation uranium content based on geophysical logging of sedimentary facies zones. This method involves dividing the sedimentary microfacies of the area to be evaluated, analyzing rock components of different sedimentary microfacies, determining background radioactivity, identifying the proportions of U, Th, and K radioactivity contributions, and measuring the uranium-radium balance coefficient. Based on the identification of characteristic values ​​of different facies zones, a quantitative relationship is established between experimental or measured values ​​of formation uranium content and logging curves for each facies zone. Corresponding calculation models are used for different facies zones within the exploration area. This method is mainly applied to uranium geological exploration and development, calculating formation uranium resources, providing technical support for uranium exploration and development plans, and improving the economic benefits of uranium exploration and development.

[0049] Example 1

[0050] Geological research was conducted using the first experimental area.

[0051] First, we collected geological research results, core images, core experiments, lithological descriptions, well logging data, seismic data, and seismic processing and interpretation results for the example area.

[0052] Analyzing existing geological research findings, particularly the topography, paleoclimate, and regional sedimentary environment during the depositional period of the target layer, we can preliminarily determine the possible sedimentary facies types. The example area has a gentle terrain, with orogenic belts in the west and south, which can provide sedimentary sources. The orogenic belt contains rocks such as granite, rhyolite, tuff, and andesite. Among these, the highly radioactive granite, rhyolite, and tuff can provide uranium sources for the target layer. The climate is humid, and sedimentary facies such as alluvial fans, alluvial fans, underwater deltas, and shallow lacustrines may be developed.

[0053] The target reservoir is a clastic reservoir, mainly composed of conglomerate and gravelly sandstone, followed by medium sandstone and fine sandstone. The lithology varies considerably, with porosity ranging from 15% to 41% and permeability from 10 to 3000 × 10⁻⁶. -3 μm 2 It is basically a high-porosity, high-permeability reservoir. The target layer can be divided into three sand layer groups, each of which is basically a single sand body.

[0054] Single-well facies studies were conducted using drilling cores, cuttings, and grain size analysis of the example area. This area is a braided river delta sedimentary facies, with sedimentary microfacies including deltaic underwater distributary channels, braided river delta fronts, fan delta plains, and clastic flows.

[0055] Based on the results of core and lithic debris sedimentary microfacies classification, see Figure 2 Columns 5 and 6 describe the study of sedimentary facies characteristics obtained from well logging. A model for identifying sedimentary facies and microfacies using well logging curves was established. Sedimentary microfacies were classified in the study area. The sedimentary facies and microfacies in the example area were further classified using seismic target layer attribute maps and inversion maps. Figure 3 Distribution map of sedimentary microfacies.

[0056] Rock components, clay types and their contents were analyzed using core samples from wells and well walls. The rock components, clay types and their contents were statistically analyzed by facies zone, as shown in Table 1. Table of rock components and clay types and contents in different sedimentary facies zones.

[0057] Well logging data were used to classify stratigraphic lithology, and natural gamma (GR) values ​​were statistically analyzed for facies zones without uranium anomalies to determine the background radioactivity values ​​of strata in different facies zones, as shown in Table 1.

[0058]

[0059]

[0060] Using natural gamma spectral logging in the example area, U, Th, and K values ​​were statistically analyzed by lithology and facies zone to determine the range of variation and background values ​​of U, Th, and K under the absence of uranium anomalies. No well sections with Th and K values ​​exceeding twice the background value appeared in the same facies zone, i.e., there were no high anomaly values. The relationship between natural gamma and the variation of U, Th, and K was not analyzed.

[0061] Based on the available core and cuttings data and as needed, core samples from the target layer are collected evenly from each sedimentary microfacies. Appropriate samples are taken from each sedimentary microfacies according to standards. Uranium content and uranium-radium balance coefficients are determined using laboratory or radioactive instruments, and uranium-radium balance coefficients are statistically analyzed by phase zone.

[0062] Formula (2) is used to calculate the uranium content of the strata, and calculations are performed by sedimentary facies zone to determine the undetermined coefficients:

[0063] U = 0.3038 * (GR - GR) 本底值 ) / Kp+31.081 (2)

[0064] Wherein: GR 本底值 —Background values ​​for different sedimentary facies zones; Kp —Radium-uranium balance coefficient.

[0065] Where: K 高异常 =KK 本底值 ;Th 高异常 =Th-Th 本底值 ;GR 本底值 K 本底值 ,Th 本底值 —Background values ​​for different sedimentary facies zones; Kp—Radium-uranium balance coefficient; K 高异常 ,Th 高异常 — K and Th values ​​greater than twice the background value are considered high anomalies, while values ​​less than twice the background value are considered normal; A, B, C, D, and E are coefficients to be determined.

[0066] Figure 4A graph showing the relationship between GR values ​​corrected for sedimentary microfacies zoning and uranium content from core analysis is presented. A strong correlation is observed between the two. Comparison shows that calculating uranium content using sedimentary microfacies zoning data reduces the error rate by 6.5% compared to methods that do not consider sedimentary facies zoning.

[0067] Example 2

[0068] Geological research was conducted using the second experimental area.

[0069] First, we collected geological research results, core images, core experiments, lithological descriptions, well logging data, seismic data, and seismic processing and interpretation results for the example area.

[0070] According to existing geological research, the climate was humid during the deposition period of the target layer, and the topography was high in the north and low in the south. The source rocks were gneiss, granitic gneiss, and clastic rocks. The granitic gneiss could provide a large amount of uranium source for the target layer. The area near the uplift was conducive to the formation of alluvial fans, alluvial fans, and underwater deltas, while the area away from the uplift was prone to the formation of shallow lacustrine sedimentary facies.

[0071] The target reservoir is a clastic reservoir, mainly composed of conglomerate and gravelly sandstone, followed by medium sandstone and fine sandstone. The lithology varies considerably, with porosity primarily ranging from 15% to 39% and permeability from 100 to 3500 × 10⁻⁶. -3 μm 2 It is basically a high-porosity, high-permeability reservoir. The target layer can be divided into 4 sand layer groups, each consisting of 1-3 individual sand bodies.

[0072] Using core samples, cuttings, and grain size analysis from the example area, single-well facies studies were conducted. The sedimentary types in the uranium-developing area are mainly fan delta and braided river delta sedimentary facies. The microfacies of fan delta sedimentary facies include channel runoff, channel deposits, debris flow lobes, and natural debris flow levees. The microfacies of braided river delta sedimentary facies include deltaic underwater distributary channels, sheet sands, fan delta plains, estuary bars, and interdistributary bays.

[0073] Based on the results of core and lithic debris sedimentary microfacies classification, a well logging sedimentary facies characteristic study was conducted. A well logging curve identification model for sedimentary facies and sedimentary microfacies recognition was established. The sedimentary microfacies of the study area were classified. Combined with seismic target layer attribute maps and inversion maps, the sedimentary facies and sedimentary microfacies of the example area were further classified. Figure 5 Columns 5 and 6 are sedimentary microfacies and sedimentary subfacies.

[0074] Rock composition, clay type, and content were analyzed using core samples from wells and wellbore. The rock composition, clay type, and content were statistically analyzed by facies zoning. In Example 2, the provenance of the sediments in the alluvial fan depositional area was high-radioactive gneiss and granitic gneiss, while the provenance in the braided river delta was low-radioactive clastic rocks. The sandstone and conglomerate layers derived from high-radioactive gneiss and granitic gneiss exhibited high K, Th, and low U characteristics, with a boundary depth of 1257m. (See...) Figure 5 Logging curves in columns 1, 9, 10, and 11.

[0075] Well logging data was used to classify stratigraphic lithology, and natural gamma (GR) values ​​were statistically analyzed for facies zones without uranium anomalies. The background radioactivity values ​​of strata in different facies zones were determined, with alluvial fans having a GR background value of 110 API and deltas having a background value of 60 API.

[0076] Using natural gamma spectral logging in the example area, U, Th, and K values ​​were statistically analyzed by lithology and facies zone to determine the range and background values ​​of U, Th, and K in the absence of uranium anomalies. No well sections in the same facies zone showed values ​​exceeding twice the background value for Th and K, indicating no high anomalies. Therefore, the relationship between natural gamma spectral logging and the variations in U, Th, and K was not analyzed. The background value of K in the alluvial fan was 3.5%, and Th was 15 ppm. Statistically, a small number of well sections reached the high anomaly value standard for K. A formula for the relationship between GR and K anomalies was established and used when gamma spectral logging was not performed.

[0077] K 高异常 =0.0814*(GR-GR) 本底值 +3.65 (3)

[0078] Wherein: GR 本底值 —Background values ​​for different sedimentary facies zones;

[0079] Based on the available core and cuttings data and as needed, core samples from the target layer are collected evenly from each sedimentary microfacies. Appropriate samples are taken from each sedimentary microfacies according to standards. Uranium content and uranium-radium balance coefficients are determined using laboratory or radioactive instruments, and uranium-radium balance coefficients are statistically analyzed by phase zone.

[0080] Formula 1 was used to calculate the uranium content of the formation, and calculations were performed by sedimentary facies zone, with undetermined coefficients identified.

[0081] U = (0.4121*(GR-GR)) 本底值 -1.32*K 高异常 ) / Kp+28.13 (4)

[0082] Wherein: GR 本底值 —Background values ​​for different sedimentary facies zones; GR 本底值 K 本底值 —Background values ​​for different sedimentary facies zones; Kp —Radium-uranium balance coefficient.

[0083] By comparison, the error rate of calculating uranium content using sedimentary microfacies zoning data was reduced by 8.6% compared to the original method.

[0084] Example 3

[0085] Geological research was conducted using the third experimental area.

[0086] First, we collected geological research results, core images, core experiments, lithological descriptions, well logging data, seismic data, and seismic processing and interpretation results for the example area.

[0087] Based on existing geological research, the climate during the depositional period of the target layer alternated between relatively humid and relatively arid, with humid conditions predominating. The topography is characterized by high elevations in the northeast and west, and low elevations in the southwest and west. The source rock area consists of intermediate-acidic volcanic rocks, which provided the uranium source for the target layer. The relatively flat terrain was conducive to the formation of large braided river delta deposits.

[0088] The target layer is a clastic reservoir, primarily composed of medium-sized sandstone and gravelly sandstone, followed by fine sandstone. Porosity ranges from 8% to 25%, and permeability ranges from 10 to 1200 × 10⁻³ μm², essentially classifying it as a medium-low porosity, medium-low permeability reservoir. The target layer can be divided into four sandstone groups, each consisting of 2-5 individual sand bodies.

[0089] Using core samples, cuttings, and grain size analysis from the example area, single-well facies studies were conducted. The sedimentary type in the uranium ore development area is braided river deltaic sedimentary facies, and the sedimentary microfacies include deltaic underwater distributary channels, sheet sands, mouth bars, and interdistributary bays.

[0090] Using the results of core and rock fragment sedimentary microfacies classification, we conducted a study on the characteristics of sedimentary facies from well logging, established a model for identifying sedimentary facies and sedimentary microfacies using well logging curves, classified the sedimentary microfacies in the study area, and classified the sedimentary facies and sedimentary microfacies in the example area by combining the seismic target layer attribute map and inversion map.

[0091] Rock components, clay types, and their contents were analyzed using core samples from drilling and wellbore samples. Phase zoning was also performed to statistically analyze the rock components, clay types, and their contents. In Example 3, the source material showed relatively little variation, with K and Th exhibiting relatively stable values.

[0092] By using well logging data to classify stratigraphic lithology, statistical analysis of natural gamma (GR) values ​​in the absence of uranium anomalies in different facies zones, and determination of the background radioactivity values ​​of strata in different facies zones, it was found that the differences in GR background values ​​among the sedimentary facies zones were small and insufficient to cause significant errors, so a unified value could be used for calculation.

[0093] Using natural gamma spectral logging in the example area, U, Th, and K values ​​were statistically analyzed by lithology and facies zone to determine the range of variation and background values ​​of U, Th, and K under the absence of uranium anomalies. No well sections with Th and K values ​​exceeding twice the background value appeared in the same facies zone, i.e., there were no high anomaly values. The relationship between natural gamma and the variation of U, Th, and K was not analyzed.

[0094] Based on the available core and cuttings data and as needed, core samples from the target layer are collected evenly from each sedimentary microfacies. Appropriate samples are taken from each sedimentary microfacies according to standards. Uranium content and uranium-radium balance coefficients are determined using laboratory or radioactive instruments, and uranium-radium balance coefficients are statistically analyzed by phase zone.

[0095] Formula 1 was used to calculate the uranium content of the formation, and calculations were performed by sedimentary facies zone, with undetermined coefficients identified.

[0096] U = 0.4314 * (GR - GR) 本底值 ) / Kp+24.13 (5)

[0097] Wherein: GR 本底值 —Background values ​​for different sedimentary facies zones; GR 本底值 —Background values ​​for different sedimentary facies zones; Kp —Radium-uranium balance coefficient.

[0098] Beneficial Effects: This invention proposes a method for calculating formation uranium content based on geophysical logging of sedimentary facies zones. This method involves dividing the sedimentary microfacies of the area to be evaluated, analyzing rock components of different sedimentary microfacies, determining background radioactivity, identifying the proportions of U, Th, and K radioactivity contributions, and measuring the uranium-radium balance coefficient. Based on the identification of characteristic values ​​of different facies zones, a quantitative relationship is established between experimental or measured values ​​of formation uranium content and logging curves for each facies zone. Corresponding calculation models are used for different facies zones within the exploration area. This method is mainly applied to uranium geological exploration and development, calculating formation uranium resources, providing technical support for uranium exploration and development plans, and improving the economic benefits of uranium exploration and development.

[0099] The above specific embodiments further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for determining the uranium content of formations based on sedimentary facies zones through well logging, characterized in that, The determination method includes: Step S1: Draw the sedimentary facies and sedimentary microfacies diagrams of the target layer; Step S2: Analyze rock properties using core samples; Step S3: Use well logging data to classify stratigraphic lithology; Step S4: Calculate the uranium-radium balance coefficient based on rock properties and stratigraphic lithology, and calculate the uranium content of the stratigraphic strata.

2. The method for determining the uranium content of a formation based on sedimentary facies zones according to claim 1, characterized in that, The statistical calculation of uranium-radium balance coefficients based on rock properties and stratigraphic lithology specifically includes: Using natural gamma spectroscopy logging, the relationship between natural gamma and parameter variations was determined; Statistical uranium-radium balance coefficients for phase zones.

3. The method for determining the uranium content of a formation based on sedimentary facies zones according to claim 2, characterized in that, The calculation of the uranium content of the formation specifically includes: calculating the uranium content of the formation based on the uranium-radium balance coefficient.

4. The method for determining the uranium content of a formation based on sedimentary facies zones according to claim 1, characterized in that, Step S1: Drawing the sedimentary facies and sedimentary microfacies diagram of the target layer specifically includes: Based on geological research results and rock information, sedimentary facies and sedimentary microfacies maps of the target layer were drawn.

5. The method for determining the uranium content of a formation based on sedimentary facies zones according to claim 4, characterized in that, The rock information specifically includes: core samples, rock fragment lithology, well logging curves, and seismic sand body prediction maps.

6. The method for determining the uranium content of a formation based on sedimentary facies zones according to claim 1, characterized in that, Step S2: Analyzing rock properties using core samples specifically includes: Core analysis was used to determine rock composition, clay type, and content. Statistical analysis of rock composition, clay type and content in facies zones.

7. The method for determining the uranium content of a formation based on sedimentary facies zones according to claim 1, characterized in that, Step S3: Determining formation lithology using well logging data specifically includes: By using well logging data to classify stratigraphic lithology, statistical analysis of natural gamma values ​​in the absence of uranium anomalies in different facies zones, and determination of background radioactivity values ​​in various facies zones, we can identify the lithological characteristics of the formations.

8. The method for determining the uranium content of a formation based on sedimentary facies zones according to claim 2, characterized in that, The method of using natural gamma spectroscopy logging to determine the relationship between natural gamma and parameter variations specifically includes: Using natural gamma spectroscopy logging, U, Th, and K values ​​were statistically analyzed by lithology and facies zone to determine the range of variation and background values ​​of U, Th, and K under conditions without uranium anomalies. When Th and K are more than twice the background value of the same phase band, they are defined as high anomalies, and the relationship between natural gamma and the changes of U, Th, and K is determined.

9. The method for determining the uranium content of a formation based on sedimentary facies zones according to claim 2, characterized in that, The phase-separation zone statistical uranium-radium balance coefficients specifically include: Collect core samples from each sedimentary microfacies layer in a balanced manner; The uranium-radium balance coefficient is determined using laboratory or radioactive instruments, and the uranium-radium balance coefficient is statistically analyzed by phase zone.

10. The method for determining the uranium content of a formation based on sedimentary facies zones according to claim 3, characterized in that, The calculation of the uranium content of the formation based on the uranium-radium balance coefficient specifically includes: The formula for calculating the uranium content of strata is formula (1), calculated by sedimentary facies zone: U=D*(A*(GR-GR 本底值 )-B*K 高异常 -C*Th 高异常 )) / Kp+E (1) Among them, K 高异常 =KK 本底值 ;Th 高异常 =Th-Th 本底值 ;GR 本底值 K 本底值 ,Th 本底值 —Background values ​​for different sedimentary facies zones; Kp—Radium-uranium balance coefficient; K 高异常 ,Th 高异常 — K and Th values ​​greater than twice the background value are considered high anomalies, while values ​​less than twice the background value are considered normal; A, B, C, D, and E are coefficients to be determined.

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