A method for prospecting a lithium-potassium-boron deposit of a brine type in a foreland basin carbonate rock stratum

Abstract

The application provides a prospecting method for a halide type lithium-potassium-boron deposit in a foreland basin carbonate rock formation, comprising the following steps: determining a type of a metallogenic potential tectonic unit; determining a type of a metallogenic halide supply potential source; determining a type of a favorable metallogenic tectonic unit; calculating a comprehensive evaluation coefficient of the tectonic unit, screening a favorable exploration tectonic unit; analyzing a metallogenic halide carbonate rock reservoir of the favorable exploration tectonic unit, and delineating a favorable exploration target area; and drilling and verifying the favorable exploration target area, and evaluating the economic value of the favorable exploration target area. The application realizes multi-level prospecting prediction from the selection of a tectonic unit at a whole basin scale to fine evaluation of a local target area, and significantly improves the exploration efficiency and success rate of the halide type lithium-potassium-boron deposit.

Description

Technical Field

[0001] This application relates to the field of geological exploration technology for potassium-lithium-boron deposits, specifically to a prospecting method for brine-type lithium-potassium-boron deposits in carbonate rock formations in foreland basins. Background Technology

[0002] With the rapid development of new energy, modern agriculture, and high-end manufacturing, the demand for strategic mineral resources such as lithium, potassium, and boron has experienced explosive growth. Traditional solid mineral deposits face severe challenges to resource supply due to factors such as declining grades and ecological constraints. However, deep brine-type liquid mineral deposits, with their advantages of in-situ green mining characteristics and low environmental disturbance, have become a crucial breakthrough in the transformation of the resource supply system. Foreland basin carbonate strata are the dominant host for brine-type minerals. Through tectonic compression and hydrothermal circulation coupling, they form a continuous system of dissolution pores and fractures combined with gypsum-salt caprock, constituting an integrated "transport-reservoir-closure" metallogenic geological structure for brine-type minerals. However, deep brine ore bodies lack surface geochemical markers, rendering traditional mineral exploration target delineation methods ineffective. Therefore, it is necessary to focus on key ore-controlling elements and select appropriate exploration methods to achieve accurate discovery of deep brine resources, which has significant scientific and engineering value. Summary of the Invention

[0003] To address the problems existing in the prior art, this application provides a prospecting method for brine-type lithium, potassium, and boron deposits in carbonate strata of foreland basins, comprising:

[0004] Analyze carbonate strata at the whole basin scale to determine the types of tectonic units with mineralization potential;

[0005] Analyze the sources of mineralized brine at the basin scale to determine the types of potential sources of mineralized brine supply.

[0006] Analyze the migration paths of mineralized brine at the basin scale to determine the types of favorable mineralized tectonic units;

[0007] Based on the mineralization potential structural unit type, the mineralization brine supply potential source type, and the favorable mineralization structural unit type, the comprehensive evaluation coefficient of the structural unit is calculated, and favorable exploration structural units are selected.

[0008] Analyze the mineralized brine carbonate reservoirs in favorable exploration structural units and delineate favorable exploration target areas;

[0009] Drilling is conducted to verify favorable exploration target areas and to evaluate their economic value.

[0010] Furthermore, the types of tectonic units with metallogenic potential are identified as follows:

[0011] Obtain global paleoclimate data to identify target mineral exploration layers in foreland basins;

[0012] Remote sensing interpretation of the foreland basin, field outcrop surveys and analysis, and establishment of the correspondence between outcrops and subsurface strata;

[0013] Seismic and well logging data from the foreland basin were analyzed to characterize the distribution, lithological assemblage, and reservoir space of carbonate strata.

[0014] A comprehensive evaluation of the development characteristics and mineralization potential of carbonate strata was conducted to determine the types of tectonic units with mineralization potential in the foreland basin.

[0015] Furthermore, the target mineral exploration layers in the foreland basin include:

[0016] Acquire global paleoclimate data to screen drought events and their durations during the formation and evolution of foreland basins;

[0017] If the carbonate rock strata were formed in an extremely arid paleoclimate environment, then the carbonate rock strata are high-quality mineral exploration target layers.

[0018] If the carbonate rock strata were formed in an arid to semi-arid paleoclimate environment, then the carbonate rock strata are good target layers for mineral exploration.

[0019] If a carbonate rock formation was formed in a warm and humid paleoclimate environment, then that carbonate rock formation is a potential mineral exploration target layer.

[0020] Furthermore, the types of tectonic units that determine the metallogenic potential of foreland basins include:

[0021] For shallow carbonate rock strata with a burial depth of less than 200m, structural units with large-scale exposure of high-quality prospecting target layers and well-developed fractures and dissolution pores are identified as a1-type metallogenic potential structural units; structural units with partial exposure of high-quality prospecting target layers and accompanied by medium to low permeability are identified as b1-type metallogenic potential structural units; structural units with large-scale exposure of good prospecting target layers and well-developed fractures and dissolution pores are identified as b2-type metallogenic potential structural units; structural units with partial exposure of good prospecting target layers and accompanied by medium to low permeability are identified as c1-type metallogenic potential structural units; and structural units with large-scale exposure of potential prospecting target layers and well-developed fractures and dissolution pores are identified as c2-type metallogenic potential structural units.

[0022] For medium-deep buried carbonate rock strata at depths of 200-500m, structural units with locally exposed high-quality prospecting target layers and widespread development at depth are designated as a1-type metallogenic potential structural units; structural units with widely developed high-quality prospecting target layers at depth, excluding a1-type metallogenic potential structural units, are designated as a2-type metallogenic potential structural units; structural units with locally developed high-quality prospecting target layers at depth are designated as b1-type metallogenic potential structural units; structural units with widely developed good prospecting target layers at depth are designated as b2-type metallogenic potential structural units; structural units with locally developed good prospecting target layers at depth are designated as c1-type metallogenic potential structural units; and structural units with widely developed potential prospecting target layers at depth are designated as c2-type metallogenic potential structural units.

[0023] For deep carbonate rock formations at depths greater than 500m, the following structural units are defined: those with widely developed high-quality mineral exploration target layers at depth are classified as a1-type mineralization potential structural units; those with locally developed high-quality mineral exploration target layers at depth are classified as b1-type mineralization potential structural units; those with widely developed good mineral exploration target layers at depth are classified as b2-type mineralization potential structural units; those with locally developed good mineral exploration target layers at depth are classified as c1-type mineralization potential structural units; and those with widely developed potential mineral exploration target layers at depth are classified as c2-type mineralization potential structural units.

[0024] Furthermore, the types of potential sources of mineralized brine supply were identified as including:

[0025] Identify normal faults and deep faults in the foreland basin;

[0026] Geothermal analysis was conducted on the tectonic units containing normal faults and deep faults to determine the types of favorable metallogenic tectonic units.

[0027] By combining normal faults and deep faults with favorable metallogenic tectonic unit types, the types of potential sources of mineralized brine supply are determined.

[0028] Furthermore, geothermal analysis was conducted on the tectonic units containing normal faults and deep faults to determine the types of favorable metallogenic tectonic units, specifically:

[0029] The normal temperature of the target mineral layer is calculated based on the burial depth of the target mineral layer and the annual average surface temperature.

[0030] Collect geophysical logging data of tectonic units containing normal faults and deep faults, analyze the well temperature data, and determine the well temperature of the target mineral exploration layer;

[0031] If the well temperature of the target mineral layer is greater than 140% of the normal temperature, the structural unit where the normal fault and deep fault are located is classified as a dominant and favorable mineralization structural unit.

[0032] If the well temperature of the target mineral layer is greater than 120% of the normal temperature but less than or equal to 140% of the normal temperature, then the structural unit where the normal fault and deep fault are located is classified as a favorable mineralization structural unit.

[0033] If the well temperature of the target mineral layer is less than or equal to 120% of the normal temperature, then the structural unit where the normal fault and deep fault are located is classified as a generally favorable mineralization structural unit.

[0034] Furthermore, by combining normal faults and deep faults with favorable metallogenic tectonic unit types, the types of potential sources of ore-forming brine supply are determined, specifically:

[0035] If deep faults and normal faults are well-developed within and around a favorable ore-forming tectonic unit, then the deep part of the tectonic unit is determined to be a potential source of ore-forming brine (type a1).

[0036] If deep faults and normal faults are not developed within and around the advantageous metallogenic tectonic unit, then the deep part of the tectonic unit is determined to be a potential source of metallogenic brine supply of type b1.

[0037] If deep faults and normal faults are well-developed within and around a favorable ore-forming tectonic unit, then the deep part of the tectonic unit is determined to be a potential source of ore-forming brine (type b2).

[0038] If deep faults and normal faults are not developed within and around a favorable ore-forming tectonic unit, then the deep part of the tectonic unit is determined to be a potential source of ore-forming brine (C1 type).

[0039] If deep faults and normal faults are well-developed within and around a potentially favorable ore-forming tectonic unit, then the deep part of the tectonic unit is determined to be a potential source of ore-forming brine (C2 type).

[0040] Furthermore, the types of favorable metallogenic tectonic units include:

[0041] Tectonic units that have been located in low-lying areas along the migration path since the formation of carbonate rock strata are classified as type a1 favorable mineralization tectonic units.

[0042] Tectonic units in which carbonate rock strata were located in low-lying areas along their migration paths during formation were classified as type b1 favorable mineralization tectonic units.

[0043] The structural units traversed by the migration path of the ore-forming brine are classified as favorable mineralization structural units of type C1.

[0044] Furthermore, the selection of favorable exploration structural units includes:

[0045] The comprehensive evaluation coefficient of the structural unit is calculated as follows:

[0046]

[0047] in, This represents the comprehensive evaluation coefficient of the structural unit; The type of tectonic unit representing the mineralization potential is assigned a value; This indicates the type of source that represents the potential supply of mineralized brine. This indicates the type of favorable metallogenic tectonic unit assigned.

[0048] Based on the comprehensive evaluation coefficient of structural units, favorable exploration structural units are selected. If 4 < M If the value is ≤5, then the mineralization potential evaluation of this structural unit can be prioritized; if 3 < M If ≤4, then the tectonic unit can be evaluated for its mineralization potential; if 2 < M If the value is ≤3, then no mineralization potential evaluation is required for this structural unit; structural units that can be given priority for mineralization potential evaluation and those that can be evaluated for mineralization potential are favorable exploration structural units.

[0049] Furthermore, delineating favorable exploration target areas includes: conducting geological interpretation of seismic data of favorable exploration tectonic units, identifying key tectonic features, detecting fracture development zones and lithological changes using attribute analysis techniques, and making preliminary predictions of porosity development zones using impedance spectroscopy; screening tectonic transition zones, paleogeographic highs, and special tectonic assemblages, and then verifying the reservoir conditions and capping effectiveness of tectonic transition zones, paleogeographic highs, and special tectonic assemblages using regional geological data, ultimately delineating favorable exploration target areas with tectonic-reservoir configuration advantages.

[0050] Based on the above-mentioned invention, compared with the prior art, this application proposes a "source-migration-reservoir" prospecting method for brine-type lithium, potassium, and boron deposits in carbonate strata of foreland basins. By combining structural analysis with geochemical analysis, a coupled structural-fluid-reservoir evaluation system is established. This method breaks through the traditional prospecting model, and for the first time systematically considers the controlling effect of foreland basin tectonic features on brine migration and enrichment. Combined with the evaluation of carbonate reservoir properties and sealing, it achieves multi-level prospecting prediction from selecting structural units at the whole basin scale to fine evaluation of local target areas, significantly improving the exploration efficiency and success rate of brine-type lithium, potassium, and boron deposits. Attached Figure Description

[0051] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0052] Figure 1 This is a schematic flowchart of a prospecting method for brine-type lithium, potassium, and boron deposits in carbonate rock formations in a foreland basin, provided in an embodiment of this application. Detailed Implementation

[0053] To better understand the technical solution of the present invention, the embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0054] It should be understood that the described embodiments are merely some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention. Example

[0055] See Figure 1 This is a schematic flowchart illustrating a prospecting method for brine-type lithium, potassium, and boron deposits in carbonate strata of a foreland basin, provided by an embodiment of the present invention. Figure 1 As shown, the method specifically includes:

[0056] Step S1: Analyze carbonate strata at the whole basin scale to determine the type of tectonic unit with mineralization potential. Specifically, this includes:

[0057] Step S11: Obtain global paleoclimate data to determine the target mineral exploration layers in the foreland basin. Specifically:

[0058] By integrating regional geological maps, borehole data, and paleontological data, the basin stratigraphic sequence framework of the foreland basin was determined, and the vertical distribution and lateral spread of carbonate rock strata (such as limestone and dolomite) were clarified.

[0059] We acquire global paleoclimate data and filter drought events and their durations during the formation and evolution of foreland basins.

[0060] If the carbonate rock strata were formed in an extremely arid paleoclimate environment, then the carbonate rock strata are identified as high-quality mineral exploration target layers.

[0061] If the carbonate rock strata were formed in an arid to semi-arid paleoclimate environment, then the carbonate rock strata are considered to be good prospecting target layers.

[0062] If a carbonate rock formation was formed in a warm and humid paleoclimate environment, then that carbonate rock formation is considered a potential mineral exploration target layer.

[0063] Step S12: Perform remote sensing interpretation of the foreland basin, conduct field outcrop surveys and analysis, and establish the correspondence between outcrops and subsurface strata. Specifically:

[0064] Sentinel-2 data and SRTM DEM topographic data of the foreland basin were acquired. Guided by the basin stratigraphic sequence framework, hyperspectral remote sensing was used to extract the spectral characteristics of calcite (2.35 μm) and dolomite (2.32 μm). Combined with DEM topographic data, karst landforms were identified, and the distribution of surface carbonate outcrops was quickly delineated to establish remote sensing interpretation target areas. This stage transforms macroscopic geological data into spatial target areas, which can effectively guide the formulation of field outcrop survey routes.

[0065] Based on the remote sensing interpretation target area, field verification was carried out, and field outcrops were investigated. Rock lithology identification and sedimentary structure observation were conducted on the field outcrops to verify the accuracy of remote sensing interpretation. The survey data was used to back-calibrate the remote sensing interpretation target area and the basin stratigraphic sequence framework to form a closed loop of "data → remote sensing → outcrops".

[0066] Through systematic field outcrop surveys, the outcrop exposure of carbonate rock strata in different tectonic units was determined.

[0067] Detailed observation of the outcrop's micro-geological properties was conducted to determine the density of fractures and the degree of solution pore development.

[0068] By comparing the measured lithology and sedimentary sequence of the outcrops with previously collected stratigraphic data (such as borehole columnar sections and paleontological assemblages), the stratigraphic unit corresponding to the outcrops can be identified, and the correspondence between outcrops and subsurface strata can be established. By establishing the correspondence between outcrops and subsurface strata, the strata corresponding to the subsurface strata exposed on the surface can be determined.

[0069] Preferably, the Sentinel-2 data can be downloaded from the Copernicus Open Access Hub; the SRTM DEM terrain data can be obtained from the USGS EarthExplorer.

[0070] Preferably, the hyperspectral remote sensing is ASTER.

[0071] Step S13: Analyze seismic and well logging data from the foreland basin to characterize the distribution, lithological assemblage, and reservoir space of carbonate strata. Specifically:

[0072] Based on natural gamma and sonic transit time logging data, a lithological identification template for carbonate formations was established. Through comparative analysis of seismic and logging data, the physical properties of carbonate formations were determined. The amplitude, frequency, and coherence properties of carbonate formations were extracted to identify their unique structures. Under accurate seismic-logging calibration, the top and bottom interfaces of carbonate formations were calibrated and traced using continuous strong reflection axes, thereby characterizing the stratigraphic distribution, lithological assemblage, and reservoir space of carbonate formations.

[0073] Step S14: Conduct a comprehensive evaluation of the development characteristics and mineralization potential of carbonate strata to determine the type of tectonic unit with mineralization potential in the foreland basin. Specifically:

[0074] Evaluation methods for carbonate rock formations need to be developed based on burial depth classification: shallow carbonate rock formations with a burial depth of less than 200m are often exposed over large areas due to tectonic compression, and the focus is on outcrop investigation, with particular emphasis on analyzing lithology, fractures, and dissolution characteristics; medium-deep carbonate rock formations with a burial depth of 200-500m are only partially exposed, and a comprehensive evaluation requires combining outcrop observation, seismic data, and well logging data; deep carbonate rock formations with a burial depth of more than 500m have no surface outcrops, and the evaluation relies on seismic attribute analysis and well logging data, using well-seismic joint modeling to characterize the spatial distribution of the reservoir.

[0075] For shallow carbonate rock formations, the potential for brine mineralization in different tectonic units of the basin is preliminarily evaluated based on outcrop exposure and the classification of carbonate rock formations as target layers for mineral exploration.

[0076] The structural units with large-scale exposure of high-quality mineral exploration target layers and well-developed fractures and dissolution pores are identified as a1-type mineralization potential structural units.

[0077] The structural units with localized exposure of high-quality mineral exploration target layers and accompanied by medium to low permeability are identified as B1 type mineralization potential structural units.

[0078] Tectonic units with large-scale exposure of good prospecting target layers and well-developed fractures and dissolution pores are identified as B2 type metallogenic potential tectonic units.

[0079] Structural units with localized exposure of promising mineral exploration target layers and low to medium permeability are identified as C1 type mineralization potential structural units.

[0080] The structural unit with a large area of ​​potential mineral exploration target layer exposed and with well-developed fractures and dissolution pores was identified as a C2 type mineralization potential structural unit.

[0081] For medium-deep buried carbonate rock strata, based on outcrop exposure, geophysical exploration and analysis results, and the classification of carbonate rock strata as target layers for mineral exploration, the potential for brine mineralization in different tectonic units of the basin is preliminarily evaluated.

[0082] The structural units in which high-quality mineral exploration target layers are partially exposed and widely developed at depth are identified as a1-type metallogenic potential structural units.

[0083] The structural units in which high-quality mineral exploration target layers are widely developed at depth are identified as a2 type metallogenic potential structural units.

[0084] The structural units in which high-quality mineral exploration target layers are locally developed at depth are identified as B1 type mineralization potential structural units.

[0085] Tectonic units in which good prospecting target layers are widely developed at depth are identified as B2 type metallogenic potential tectonic units;

[0086] Tectonic units in which promising mineral exploration target layers are locally developed at depth are identified as C1 type mineralization potential tectonic units;

[0087] The structural units in which the potential mineral exploration target layer is widely developed at depth are identified as C2 type mineralization potential structural units;

[0088] For deep carbonate rock formations, based on geophysical exploration and analysis results and the classification of carbonate rock formations as target layers for mineral exploration, the potential for brine mineralization in different tectonic units of the basin is preliminarily evaluated.

[0089] The structural unit in which high-quality mineral exploration target layers are widely developed at depth is identified as a1 type metallogenic potential structural unit;

[0090] The structural units in which high-quality mineral exploration target layers are locally developed at depth are identified as B1 type mineralization potential structural units.

[0091] Tectonic units in which good prospecting target layers are widely developed at depth are identified as B2 type metallogenic potential tectonic units;

[0092] Tectonic units in which promising mineral exploration target layers are locally developed at depth are identified as C1 type mineralization potential tectonic units;

[0093] Tectonic units with extensive development of potential mineral exploration target layers at depth were identified as C2 type mineralization potential tectonic units.

[0094] Step S2: Conduct a basin-scale analysis of ore-forming brine sources to determine the types of potential ore-forming brine supply sources. Specifically:

[0095] Step S21: Identify normal faults and deep faults in the foreland basin. Specifically:

[0096] By interpreting linear structures (such as tonal anomalies and hydrological faults) using high-resolution remote sensing images and analyzing topographic slope abrupt change zones (such as fault scarps and steep slopes) using DEM, the boundaries of the foreland basin and the deep faults controlling the basin can be preliminarily identified.

[0097] Further data processing and geological interpretation of the 2D seismic overlay profiles were conducted. Fault locations were identified using reflection phase axis misalignment and fault wave characteristics, and fault strike and dip were verified through cross-tracking. Seismic coherence attributes (adjacent trace similarity analysis) and instantaneous frequency attributes (low-frequency attenuation indicating fracture zones) were extracted to enhance fault plane continuity identification. Extensional tectonic features on the seismic profiles (such as graben structures and abrupt changes in stratum thickness) were analyzed to identify normal faults. Fault properties were determined by combining the regional stress field direction (maximum principal stress is orthogonal to fault strike), further confirming the distribution of deep and large faults.

[0098] Step S22: Perform geothermal analysis on the structural units where normal faults and deep faults are located to determine the types of favorable mineralization structural units.

[0099] The normal temperature of the target mineral layer is calculated based on the burial depth of the target mineral layer and the annual average surface temperature.

[0100] The formula for calculating the normal temperature of the target mineral layer is as follows:

[0101]

[0102] in, This indicates the normal temperature of the target mineral layer; Indicates the burial depth of the target mineral layer; This represents the geothermal gradient. The geothermal gradient in a rift basin is generally 30-35℃ / km. In this example, we take 33℃ / km. It represents the annual average temperature of the Earth's surface.

[0103] Collect geophysical logging data from tectonic units containing normal faults and deep faults, analyze the well temperature data, and determine the well temperature of the target mineral exploration layer.

[0104] If the well temperature of the target mineral layer is greater than 140% of the normal temperature, the structural unit where the normal fault and deep fault are located is classified as a dominant and favorable mineralization structural unit.

[0105] If the well temperature of the target mineral layer is greater than 120% of the normal temperature but less than or equal to 140% of the normal temperature, then the structural unit where the normal fault and deep fault are located is classified as a favorable mineralization structural unit.

[0106] If the well temperature of the target mineral layer is less than or equal to 120% of the normal temperature, then the structural unit where the normal fault and deep fault are located is classified as a generally favorable mineralization structural unit.

[0107] Step S23: Combine normal faults and deep faults with favorable metallogenic tectonic unit types to determine the source type of potential brine supply for mineralization.

[0108] If deep faults and normal faults are well-developed within and around a favorable ore-forming tectonic unit, then the deep part of the tectonic unit is determined to be a potential source of ore-forming brine (type a1).

[0109] If deep faults and normal faults are not developed within and around the advantageous metallogenic tectonic unit, then the deep part of the tectonic unit is determined to be a potential source of metallogenic brine supply of type b1.

[0110] If deep faults and normal faults are well-developed within and around a favorable ore-forming tectonic unit, then the deep part of the tectonic unit is determined to be a potential source of ore-forming brine (type b2).

[0111] If deep faults and normal faults are not developed within and around a favorable ore-forming tectonic unit, then the deep part of the tectonic unit is determined to be a potential source of ore-forming brine (C1 type).

[0112] If deep faults and normal faults are well-developed within and around a potentially favorable ore-forming tectonic unit, then the deep part of the tectonic unit is determined to be a potential source of ore-forming brine (C2 type).

[0113] Step S3: Conduct ore-forming brine migration path analysis at the basin scale to determine the types of favorable ore-forming tectonic units.

[0114] Currently, the key prospecting areas for brine-type lithium, potassium, and boron deposits are foreland basins formed under compressional tectonic activity. The formation of these foreland basins is a result of the Himalayan orogeny caused by the collision of the Indian and Eurasian plates. Under the influence of regional compressional tectonic stress fields, tectonic uplift occurred at the basin margins, and differentiated development occurred among the various tectonic units within the basins. Therefore, it is necessary to conduct brine migration path analysis at the basin scale.

[0115] To obtain tectonic-stratigraphic data of the target foreland basin, and through regional geological surveys and existing research results, to clarify the spatial distribution pattern and boundary characteristics of first-order tectonic units (such as uplifts and depressions), second-order tectonic units (such as depressions and slope zones), and third-order tectonic units (such as local structures and fault zones) within the basin.

[0116] Based on basin-level tectonic grid seismic profiles, we conducted detailed tectonic and sedimentary interpretations, focusing on comparative analysis of differences between adjacent tectonic units in terms of tectonic deformation intensity (e.g., fault density, fold amplitude) and stratigraphic development characteristics (e.g., stratigraphic thickness, sedimentary facies zones). Through stratigraphic contact relationships, growth stratigraphic analysis, and fault-related fold studies, we determined the nature of tectonic activities (e.g., extension, compression, or strike-slip) experienced during the formation of different sedimentary strata and their corresponding tectonic stress field directions (e.g., the orientation of the maximum principal stress).

[0117] Specifically targeting carbonate rock strata, this study analyzes in detail the tectonic activity periods (such as the development stage of the marine transgressive systems tract) and the later alteration stages (such as the tectonic uplift stage) of each period, including the Caledonian and Indosinian periods, and the changes in their stress field direction (such as the shift from NE-SW compression to NW-SE extension). Furthermore, based on the opening and closing of faults at the boundaries of tectonic units, the spatial configuration of permeable and impermeable layers, and the distribution of fluid potential fields driven by paleotectonic stress fields, the study comprehensively determines the dominant migration paths of ore-forming brines at the basin scale (such as vertical migration along inherited faults, lateral migration along high-permeability layers, or convergence in tectonic transition zones).

[0118] Tectonic units that have been located in low-lying areas along the migration path since the formation of carbonate rock strata are classified as type a1 favorable mineralization tectonic units.

[0119] Tectonic units in which carbonate rock strata were located in low-lying areas along their migration paths during formation were classified as type b1 favorable mineralization tectonic units.

[0120] The structural units traversed by the migration path of the ore-forming brine are classified as favorable mineralization structural units of type C1.

[0121] Step S4: Calculate the comprehensive evaluation coefficient of the structural unit based on the type of structural unit with mineralization potential, the type of source of mineralization brine supply potential, and the type of favorable mineralization structural unit, and screen out favorable exploration structural units.

[0122] The formula for calculating the comprehensive evaluation coefficient of the structural unit is:

[0123] ,

[0124] in, This represents the comprehensive evaluation coefficient of the structural unit; The type of tectonic unit representing the mineralization potential is assigned a value; This indicates the type of source that represents the potential supply of mineralized brine. This indicates the type of favorable mineralized tectonic unit to be assigned.

[0125] ,

[0126] ,

[0127] ,

[0128] Based on the comprehensive evaluation coefficient of the structural units, favorable structural units for exploration are selected.

[0129] If 4 < M If the value is ≤5, then the mineralization potential evaluation of this structural unit can be carried out first.

[0130] If 3 < M If the value is ≤4, then the mineralization potential of the structural unit can be evaluated.

[0131] If 2 < M If the value is ≤3, then no mineralization potential evaluation is required for this structural unit.

[0132] Among them, the tectonic units that can be given priority for mineralization potential evaluation and the tectonic units that can be evaluated for mineralization potential are the favorable exploration tectonic units.

[0133] Step S5: Conduct mineralized brine carbonate reservoir analysis on favorable exploration structural units to delineate favorable exploration target areas. Specifically:

[0134] Geological interpretation is conducted on seismic data of favorable exploration structural units to identify key structural features (such as fault systems, unconformities, and fold structures). Attribute analysis techniques (such as coherence volume and instantaneous amplitude) are used to detect fracture development zones and lithological changes. Impedance inversion is used to preliminarily predict porosity development zones. Structural transition zones (such as fault intersections and slope transition zones), paleogeographic highs (such as the periphery of paleo-uplifts), and special structural assemblages (such as the hanging wall of thrust faults) are screened. These areas typically exhibit seismic response characteristics such as phase axis faulting, abrupt changes in reflected wave groups, or amplitude anomalies. Regional geological data is then used to verify the reservoir conditions and capping effectiveness of tectonic transition zones, paleogeographic highs, and special structural assemblages. Finally, favorable exploration target areas with structural-reservoir configuration advantages are delineated.

[0135] The method for evaluating the effectiveness of the sealing is as follows: Hydrogen (H2) molecules are small and diffuse rapidly, making them sensitive to sealing defects and capable of quickly detecting minute leaks. Based on its high diffusivity and its properties as a tracer gas, this embodiment uses hydrogen (H2) to detect structural sealing, assessing the sealing capability of geological structures by monitoring hydrogen migration or leakage. Specifically, this includes:

[0136] Survey lines were laid out perpendicular to the target structure, with a spacing of 50m between monitoring points. An ATG-300H portable hydrogen analyzer was used. Upon arrival at the monitoring point, personnel verified the point markings and recorded detailed information about the surface soil characteristics and surrounding environment. After drilling, the gas sampling device was quickly installed, and the soil around the conical structure at the top of the sampling probe was compacted to prevent external gas infiltration and dilution of the hydrogen sample, ensuring accurate and reliable data. Gas conduit connections must be completed beforehand, and equipment parameters adjusted to single-point soil detection mode. The detection program was started immediately after the sampling probe was installed. The standard sampling depth was controlled between 50-70 cm, with a single detection duration set to 120 seconds. Two sets of parallel data were collected at each monitoring point. If abnormal data was encountered during detection, the instrument's operating status was immediately checked, and a new borehole was drilled in the vicinity of the original location for retesting to verify hydrogen source abundance. When the detected values ​​showed an abnormally increasing trend, a special investigation was organized to determine the cause by increasing the density of monitoring points and conducting follow-up detection.

[0137] After data acquisition, the H2 concentration was analyzed using an ATG-300H portable hydrogen analyzer. If the H2 concentration inside the structure is significantly higher than that at the surface or in adjacent areas and remains stable over a long period, it indicates that the caprock effectively blocks gas migration and is a high-quality mineralized brine reservoir. If H2 is abnormally enriched in the fault zone near the structural trap, it reflects leakage in the structural sealing, and the risk of sealing failure needs to be comprehensively verified by combining lithological, pressure, and tectonic activity data.

[0138] Step S6: Conduct borehole verification of the favorable exploration target area and evaluate its economic value.

[0139] The borehole was deployed in a selected, favorable exploration target area for verification. The concentration gradients of K⁺, Li⁺, and B³⁺ were monitored in real time using fluid spectroscopy while drilling, supplemented by distributed optical fiber monitoring of formation pressure (accuracy ±0.1MPa) and temperature (±0.5℃).

[0140] Closed-loop drilling technology was used to collect brine samples from favorable exploration target areas in layers. ICP-MS was used to analyze the K, Li, and B contents, and the economic value was evaluated according to industrial standards. If the standards were met, resource development could be promoted by combining brine extraction and beneficiation experiments; otherwise, the target area model was optimized and re-validated.

[0141] Hydrogen and oxygen isotope δD and δ¹ content was analyzed in the laboratory of the collected brine samples. 8 O analysis, content testing and ratio calculation of halogen elements Cl, Br and I;

[0142] Using isotope ratio mass spectrometry to study the δD and δ100 of hydrogen and oxygen isotopes 18 O analysis, if the hydrogen and oxygen isotope composition is: δ 18 If O ≈ 0‰ SMOW and δD ≈ 0‰ SMOW, then the source is seawater; if δ 18 When O = +5‰~+10‰ and δD = -40‰~-80‰, it indicates a deep magma water source; if +5‰≤δ 18 If O ≤ +25‰ and δD is similar to that of magmatic water, then it is a source of metamorphic water; if the data point is located between seawater and magmatic / metamorphic water, it may reflect mixing or water-rock reaction.

[0143] Inductively coupled plasma mass spectrometry (ICP-MS) was used to determine the content of halogen elements Cl, Br, and I, and the Cl / Br ratio and I / Cl ratio were calculated. If Cl / Br ≈ 290, it is seawater; if Cl / Br > 1000 or < 100, it is deep hydrothermal fluid. If the I / Cl ratio is extremely low (~10), it is considered a deep hydrothermal vent. -6 If the I / Cl ratio is high, it is seawater; if the I / Cl ratio is high, it is brine from a sedimentary basin.

[0144] If discrepancies are found between the test results and the preliminary analysis of the source of the mineralized brine, adjustments will be made accordingly to improve the reliability of the prospecting method.

[0145] This application proposes a "source-migration-reservoir" prospecting method for brine-type lithium, potassium, and boron deposits in carbonate strata of foreland basins. By combining structural analysis with geochemical analysis, a coupled structural-fluid-reservoir evaluation system is established. This method breaks through traditional prospecting models, systematically considering for the first time the controlling role of foreland basin tectonic features on brine migration and enrichment. Combined with evaluation of carbonate reservoir properties and sealing characteristics, it achieves multi-level prospecting prediction from selecting structural units at the whole basin scale to fine-grained evaluation of local target areas, significantly improving the exploration efficiency and success rate of brine-type lithium, potassium, and boron deposits.

[0146] In this application embodiment, "at least one" refers to one or more, and "more than one" refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent the existence of A alone, the simultaneous existence of A and B, or the existence of B alone. A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one of the following" and similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one of a, b, and c can represent: a, b, c, ab, ac, bc, or abc, where a, b, and c can be single or multiple.

[0147] The above description is merely a specific embodiment of this application. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the protection scope of this application. The protection scope of this application should be determined by the protection scope of the claims.

Claims

1. A prospecting method for brine-type lithium, potassium, and boron deposits in carbonate strata of foreland basins, characterized in that, include: Analyze carbonate strata at the whole basin scale to determine the types of tectonic units with mineralization potential; Analyze the sources of mineralized brine at the basin scale to determine the types of potential sources of mineralized brine supply. Analyze the migration paths of mineralized brine at the basin scale to determine the types of favorable mineralized tectonic units; Based on the mineralization potential structural unit type, the mineralization brine supply potential source type, and the favorable mineralization structural unit type, the comprehensive evaluation coefficient of the structural unit is calculated, and favorable exploration structural units are selected. Analyze the mineralized brine carbonate reservoirs in favorable exploration structural units and delineate favorable exploration target areas; Drilling is conducted to verify favorable exploration target areas and to evaluate their economic value. The types of tectonic units with determined metallogenic potential include: Obtain global paleoclimate data to identify target mineral exploration layers in foreland basins; Remote sensing interpretation of the foreland basin, field outcrop surveys and analysis, and establishment of the correspondence between outcrops and subsurface strata; Seismic and well logging data from the foreland basin were analyzed to characterize the distribution, lithological assemblage, and reservoir space of carbonate strata. A comprehensive evaluation of the development characteristics and mineralization potential of carbonate rock strata was conducted to determine the type of tectonic unit with mineralization potential in the foreland basin. The types of sources for determining the potential supply of mineralized brine include: Identify normal faults and deep faults in the foreland basin; Geothermal analysis was conducted on the tectonic units containing normal faults and deep faults to determine the types of favorable metallogenic tectonic units. By combining normal faults and deep faults with the types of favorable metallogenic tectonic units, the types of potential sources of mineralized brine supply can be determined. The determination of favorable metallogenic tectonic unit types includes: Tectonic units that have been located in low-lying areas along the migration path since the formation of carbonate rock strata are classified as type a1 favorable mineralization tectonic units. Tectonic units in which carbonate rock strata were located in low-lying areas along their migration paths during formation were classified as type b1 favorable mineralization tectonic units. The structural units along the migration path of the ore-forming brine are classified as favorable mineralization structural units of type C1. The selection of favorable exploration structural units includes: The comprehensive evaluation coefficient of the structural unit is calculated as follows: ， in, This represents the comprehensive evaluation coefficient of the structural unit; The type of tectonic unit representing the mineralization potential is assigned a value; This indicates the type of source of potential supply for mineralized brine. This indicates the type of favorable metallogenic tectonic unit assigned. Based on the comprehensive evaluation coefficient of structural units, favorable exploration structural units are selected. If 4 < M If the value is ≤5, then the mineralization potential evaluation of this structural unit can be prioritized; if 3 < M If ≤4, then the tectonic unit can be evaluated for its mineralization potential; if 2 < M If the value is ≤3, then no mineralization potential evaluation is required for this structural unit; structural units that can be given priority for mineralization potential evaluation and those that can be evaluated for mineralization potential are favorable exploration structural units.

2. The method according to claim 1, characterized in that, The target mineral exploration layers in the foreland basin include: Acquire global paleoclimate data to screen drought events and their durations during the formation and evolution of foreland basins; If the carbonate rock strata were formed in an extremely arid paleoclimate environment, then the carbonate rock strata are high-quality mineral exploration target layers. If the carbonate rock strata were formed in an arid to semi-arid paleoclimate environment, then the carbonate rock strata are good target layers for mineral exploration. If a carbonate rock formation was formed in a warm and humid paleoclimate environment, then that carbonate rock formation is a potential mineral exploration target layer.

3. The method according to claim 2, characterized in that, The types of tectonic units that determine the metallogenic potential of foreland basins include: For shallow carbonate rock strata with a burial depth of less than 200m, structural units with large-scale exposure of high-quality prospecting target layers and well-developed fractures and dissolution pores are identified as a1-type metallogenic potential structural units; structural units with partial exposure of high-quality prospecting target layers and accompanied by medium to low permeability are identified as b1-type metallogenic potential structural units; structural units with large-scale exposure of good prospecting target layers and well-developed fractures and dissolution pores are identified as b2-type metallogenic potential structural units; structural units with partial exposure of good prospecting target layers and accompanied by medium to low permeability are identified as c1-type metallogenic potential structural units; and structural units with large-scale exposure of potential prospecting target layers and well-developed fractures and dissolution pores are identified as c2-type metallogenic potential structural units. For medium-deep buried carbonate rock strata at depths of 200-500m, structural units with locally exposed high-quality prospecting target layers and widespread development at depth are designated as a1-type metallogenic potential structural units; structural units with widely developed high-quality prospecting target layers at depth, excluding a1-type metallogenic potential structural units, are designated as a2-type metallogenic potential structural units; structural units with locally developed high-quality prospecting target layers at depth are designated as b1-type metallogenic potential structural units; structural units with widely developed good prospecting target layers at depth are designated as b2-type metallogenic potential structural units; structural units with locally developed good prospecting target layers at depth are designated as c1-type metallogenic potential structural units; and structural units with widely developed potential prospecting target layers at depth are designated as c2-type metallogenic potential structural units. For deep carbonate rock formations at depths greater than 500m, the following structural units are defined: those with widely developed high-quality mineral exploration target layers at depth are classified as a1-type mineralization potential structural units; those with locally developed high-quality mineral exploration target layers at depth are classified as b1-type mineralization potential structural units; those with widely developed good mineral exploration target layers at depth are classified as b2-type mineralization potential structural units; those with locally developed good mineral exploration target layers at depth are classified as c1-type mineralization potential structural units; and those with widely developed potential mineral exploration target layers at depth are classified as c2-type mineralization potential structural units.

4. The method according to claim 1, characterized in that, Geothermal analysis was conducted on the tectonic units containing normal faults and deep faults to determine the types of favorable metallogenic tectonic units, specifically: The normal temperature of the target mineral layer is calculated based on the burial depth of the target mineral layer and the annual average surface temperature. Collect geophysical logging data of tectonic units containing normal faults and deep faults, analyze the well temperature data, and determine the well temperature of the target mineral exploration layer; If the well temperature of the target mineral layer is greater than 140% of the normal temperature, the structural unit where the normal fault and deep fault are located is classified as a dominant and favorable mineralization structural unit. If the well temperature of the target mineral layer is greater than 120% of the normal temperature but less than or equal to 140% of the normal temperature, then the structural unit where the normal fault and deep fault are located is classified as a favorable mineralization structural unit. If the well temperature of the target mineral layer is less than or equal to 120% of the normal temperature, then the structural unit where the normal fault and deep fault are located is classified as a generally favorable mineralization structural unit.

5. The method according to claim 4, characterized in that, Based on the combination of normal faults, deep and large faults, and favorable metallogenic tectonic unit types, the types of potential sources of mineralized brine supply are determined as follows: If deep faults and normal faults are well-developed within and around a favorable ore-forming tectonic unit, then the deep part of the tectonic unit is determined to be a potential source of ore-forming brine (type a1). If deep faults and normal faults are not developed within and around the advantageous metallogenic tectonic unit, then the deep part of the tectonic unit is determined to be a potential source of metallogenic brine supply of type b1. If deep faults and normal faults are well-developed within and around a favorable ore-forming tectonic unit, then the deep part of the tectonic unit is determined to be a potential source of ore-forming brine (type b2). If deep faults and normal faults are not developed within and around a favorable ore-forming tectonic unit, then the deep part of the tectonic unit is determined to be a potential source of ore-forming brine (C1 type). If deep faults and normal faults are well-developed within and around a potentially favorable ore-forming tectonic unit, then the deep part of the tectonic unit is determined to be a potential source of ore-forming brine (C2 type).

6. The method according to claim 1, characterized in that, Delineating favorable exploration target areas includes: conducting geological interpretation of seismic data of favorable exploration tectonic units, identifying key tectonic features, detecting fracture development zones and lithological changes using attribute analysis techniques, and making preliminary predictions of porosity development zones using impedance spectroscopy; screening tectonic transition zones, paleogeographic highs, and special tectonic assemblages, and then verifying the reservoir conditions and capping effectiveness of tectonic transition zones, paleogeographic highs, and special tectonic assemblages using regional geological data, ultimately delineating favorable exploration target areas with structural-reservoir configuration advantages.

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