A precise positioning method for uranium-ore-forming sand bodies favorable for the coverage area

Abstract

The present invention belongs to the technical field of prediction of favorable uranium ore-forming sand bodies, and specifically relates to a precise positioning method for favorable uranium ore-forming sand bodies in covered areas, comprising the following steps: Step 1: Collect and analyze data to delineate key prospecting basin segments and regions with great potential; Step 2: Define favorable prospecting target horizons; Step 3: Supplement and collect borehole data of the boreholes that penetrate the favorable prospecting target horizons defined in Step 2, and statistically analyze the data of various ore-controlling factors of the target horizons; Step 4: Use Surfer software to draw maps of various ore-controlling factors of the target horizons and screen the most favorable ore-forming intervals of each factor; Step 5: Overlay and stack various types of maps to precisely locate favorable uranium ore-forming sand bodies. The present invention extracts the most favorable ore-forming intervals of various favorable ore-forming factors for overlay and stacking, thereby precisely locating the distribution characteristics of favorable uranium ore-forming sand bodies under covered areas and providing favorable support for subsequent prospecting work.

Description

Technical Field

[0001] The present invention belongs to the technical field of predicting favorable uranium ore-forming sand bodies, and particularly relates to a precise positioning method for favorable uranium ore-forming sand bodies in covered areas. Background Art

[0002] Sandstone-type uranium ore is an important industrial uranium mineralization type in China. With the proposal of the concepts of energy conservation, emission reduction, environmental protection and green development, it is crucial to provide economically recoverable uranium ore resources to meet the development of China's military industry and nuclear power. Sandstone-type uranium ore has entered a stage of all-round rapid development due to its shallow burial depth, easy mining, safety and environmental protection characteristics. Since the 1990s, China has made great breakthroughs in the Ordos, Erlian, Songliao, Yili and other basins, identified super-large uranium deposits such as Zaohuhao, Nalinggou, Daying, Qianjiadian, Mengqiguer, etc., and formed a series of prospecting methods, greatly enriching China's sandstone-type uranium resource reserves.

[0003] In recent years, with the continuous deepening of the exploration degree of sandstone-type uranium ore, it has been gradually recognized that the metallogenic mechanism of sandstone-type uranium ore is mostly of composite origin. However, the positioning and prediction technology of favorable ore-forming sand bodies is still the key technology for prospecting. Therefore, it is necessary to design a precise positioning technology method for favorable ore-forming sand bodies in covered areas to improve the technical problems of poor prediction accuracy in the existing positioning and prediction work of ore-forming sand bodies. Summary of the Invention

[0004] A precise positioning method for favorable uranium ore-forming sand bodies in covered areas designed by the present invention is used to solve the technical problems of poor positioning accuracy easily caused by the composite origin of the uranium ore metallogenic mechanism in the existing positioning and prediction work of ore-forming sand bodies.

[0005] The technical solution of the present invention:

[0006] A precise positioning method for favorable uranium ore-forming sand bodies in covered areas includes the following steps:

[0007] Step 1: Collect and analyze data, and delineate key prospecting basin segments and regions with great potential;

[0008] Step 1.1: Initially delineate key basin segments;

[0009] Step 1.2: On the basis of the key prospecting basin segments delineated in Step 1.1, delineate key regions;

[0010] Step 2: Define favorable prospecting target horizons;

[0011] Step 3: Supplement and collect borehole data of boreholes that penetrate the favorable prospecting target horizons defined in Step 2, and statistically analyze the data of various ore-controlling factors of the target horizons;

[0012] Step 4: Use Surfer software to draw maps of various ore-controlling factors for the target horizon, and screen the most favorable metallogenic intervals for each factor;

[0013] Step 5: Overlay and stack various types of maps to accurately locate favorable uranium metallogenic sand bodies.

[0014] In Step 1.1, initially delineate key basin segments, including: collect graphic and text materials such as regional geology and tectonic evolution of the studied basin, clarify elements such as basin type, sedimentary cover, basement lithology, and source area conditions, and delineate key prospecting basin segments with greater potential according to the first-level tectonic units:

[0015] For the first-level tectonic units of the compressional basin type, the piedmont slope zone is the first choice, and for the first-level tectonic units of the rift basin type, the uplift area is the first choice;

[0016] It is favorable if the sedimentary cover develops an interlayer oxidation zone and its thickness < 1000m;

[0017] For the lithology of the source area, granite is the first choice, followed by pyroclastic rock and acidic volcanic rock, and the uranium content ≥ 5ppm.

[0018] In Step 1.2, on the basis of the key prospecting basin segments delineated in Step 1.1, delineate key areas, including: focus on collecting and sorting out geological, tectonic, and seismic data of this basin segment, study and analyze elements such as the sedimentary system, paleoclimate evolution, and provenance-uranium source supply conditions of this basin segment, divide the second-level tectonic units and further delineate key favorable metallogenic areas accordingly: define the favorable metallogenic geological age range vertically according to the thickness of the favorable sedimentary cover in Step 1.1; integrate the existing previous research data, analyze the paleoclimate and sedimentary evolution characteristics of this basin segment, and determine that it is favorable vertically under semi-arid to semi-humid climate conditions and the sedimentary system is dominated by the river-delta system; comprehensively consider the above favorable elements, with the second-level tectonic units as the unit, ensure sufficient provenance-uranium source supply horizontally, and it is favorable to be close to the provenance area, source area, or tectonic erosion area, and then comprehensively judge and delineate key favorable metallogenic areas.

[0019] Step 2: Define favorable prospecting target horizons, including:

[0020] In Step 2.1, within the scope of the key areas delineated in Step 1, collect borehole data, and the collected borehole data cover data such as seismic profiles of the whole area;

[0021] Vertically, use the borehole data to establish multiple typical single-well columnar diagrams, combine data such as seismic profiles in the region to clarify the formation thickness, and establish a comprehensive columnar diagram of this key area; on this basis, analyze the lithological structure between and within each formation, and combine the existing previous research results to optimize the vertically favorable lithological combination, mainly the formation with a stable mud-sand-mud structure;

[0022] Step 2.3: Horizontally, draw the cross-well profile, further divide sedimentary facies zones, sand body development, interlayer oxidation zones and other elements by formation group, and determine braided river facies, meandering river channel subfacies, and braided river delta plain subfacies; multiple layers of sand bodies are developed with a single-layer sand body thickness of 5-15 m and good continuity; the horizons with large-scale development of interlayer oxidation zones are favorable target horizons.

[0023] In Step 3, supplement and collect borehole data of the favorable ore-prospecting target horizons defined in Step 2, and statistically analyze the data of various ore-controlling elements of the target horizons.

[0024] Step 3.1: Determine the boundaries of the key areas delineated in Step 1.2, revise the geological map of the key areas using Mapgis software based on previous research results, and make a table of the inflection point coordinates of the key area boundaries; Step 3.2: Based on a large amount of borehole data, statistically analyze the data of ore-controlling elements such as formation thickness, floor depth, sand body thickness, sand-to-ground ratio, oxidized sand body thickness, and reduced sand body thickness of the favorable ore-forming target horizons defined in Step 2 and their borehole coordinates, and statistically organize them in tabular form.

[0025] On the basis of the above steps, merge the key area boundary coordinates with the statistical data of each ore-controlling element in Step 3.2, and assign the key area boundary coordinates as 0, and organize them into independent tables for standby according to the ore-controlling elements.

[0026] In Step 4: Use Surfer software to draw maps of each ore-controlling element of the target horizon, and screen the most favorable ore-forming intervals for each element.

[0027] Step 4.1: Use Surfer software to import the data in Step 3.3 into the software and draw contour maps of each element of the target horizon.

[0028] Step 4.2: Use borehole data to identify the facies markers of the target horizon and revise the sedimentary facies distribution map of the target horizon.

[0029] Step 4.3: Summarize the threshold values of the favorable ore-forming element intervals of typical sandstone-type uranium deposits based on previous existing research data, and delimit the most favorable ore-forming intervals of the favorable ore-forming elements.

[0030] Step 4.4: According to the criteria in Step 4.2, screen the most favorable ore-forming intervals for each element, where the formation thickness > 80 m, the floor depth < 1000 m, the sand body thickness ≥ 60 m, the sand-to-ground ratio ≥ 0.5, the reduced sand body is best at 10-50 m, followed by 50-70 m, and the oxidized sand body thickness is 10-40 m.

[0031] Step 5: Overlay and stack various types of maps to accurately locate the favorable uranium ore-forming sand bodies.

[0032] Step 5.1: Use Mapgis or CorelDRAW software to overlay each element map of the most favorable metallogenic interval screened in Step 4.3 on the sedimentary facies base map;

[0033] Step 5.2: On the basis of Step 5.1, delimit the area where the overlap is more than 80% as the most favorable metallogenic sand body according to the coincidence probability of each favorable element, and the area with an overlap of 65 - 80% is the next best.

[0034] Advantages of the present invention:

[0035] Based on the in-depth analysis of the key basin segments (regions), the method of the present invention integrates and statistically analyzes a large amount of borehole data to compile a series of favorable metallogenic element maps, extracts the most favorable metallogenic intervals of each favorable metallogenic element for overlay, so as to accurately locate the distribution characteristics of favorable uranium metallogenic sand bodies under the covering area and provide favorable support for subsequent prospecting work.

[0036] Under the guidance of theories such as sequence stratigraphy, sedimentary petrology, uranium geology, and lithogeochemical characteristics, the present invention uses a large amount of borehole data to compile a series of favorable metallogenic element maps. The data source is true and reliable, and the maps have high accuracy. In addition, according to the most favorable metallogenic element intervals divided by the existing technical data, the compiled maps are screened and overlapped to determine the distribution of favorable metallogenic sand bodies. The method of the present invention has practical guiding significance for delineating favorable metallogenic sand bodies, has high accuracy, can directly guide actual prospecting work, and solves the key technology of positioning and predicting favorable metallogenic sand bodies; in addition, it can also be used to evaluate the uranium ore potential of a certain area and predict the resource volume. Description of the drawings

[0037] Figure 1 It is a flow chart of the method for accurately positioning favorable uranium metallogenic sand bodies in the covering area designed by the present invention;

[0038] Figure 2 It is a map of the location of favorable metallogenic sand bodies in the embodiment of the present invention. Detailed implementation manners

[0039] The following combines the drawings and embodiments to detail a method for accurately positioning favorable uranium metallogenic sand bodies in the covering area of the present invention.

[0040] A method for accurately positioning favorable uranium metallogenic sand bodies in the covering area includes the following steps:

[0041] Step 1: Collect and analyze data, and delimit key prospecting basin segments and regions with greater potential;

[0042] Step 1.1: Initially delimit key basin segments;

[0043] Step 1.2: Based on the key ore prospecting basin segments delineated in Step 1.1, delineate key areas;

[0044] Step 2: Define favorable ore prospecting target horizons;

[0045] Step 3: Supplement and collect borehole data that penetrate the favorable ore prospecting target horizons defined in Step 2, and statistically analyze the data of various ore-controlling elements in the target horizons;

[0046] Step 4: Use Surfer software to draw maps of various ore-controlling elements in the target horizons, and screen the most favorable metallogenic intervals for each element;

[0047] Step 5: Overlay and stack various types of maps to accurately locate favorable uranium metallogenic sand bodies.

[0048] The above-mentioned Step 1.1: Initially delineate key basin segments, including: collecting graphic materials such as regional geology and geotectonic evolution of the studied basin, clarifying elements such as basin type, sedimentary cover, basement lithology, and provenance area conditions, and delineating key ore prospecting basin segments with greater potential according to the first-level tectonic units:

[0049] For the first-level tectonic units of the compressive basin type, the piedmont slope zone is the first choice, and for the first-level tectonic units of the rift basin type, the uplift area is the first choice;

[0050] The sedimentary cover is favorable when it develops an interlayer oxidation zone and the thickness < 1000 m;

[0051] The lithology of the provenance area preferably is granite, followed by pyroclastic rocks and acidic volcanic rocks, with a uranium content ≥ 5 ppm.

[0052] The above-mentioned Step 1.2: Based on the key ore prospecting basin segments delineated in Step 1.1, delineate key areas, including: focusing on collecting and sorting out the geological, tectonic, and seismic data of this basin segment, studying and analyzing elements such as the sedimentary system, paleoclimate evolution, and provenance-uranium source supply conditions of this basin segment, dividing the second-level tectonic units and further delineating favorable ore-forming key areas accordingly: vertically define the favorable ore-forming geological age range based on the thickness of the favorable sedimentary cover in Step 1.1; integrate the existing previous research materials, analyze the paleoclimate and sedimentary evolution characteristics of this basin segment, and determine that the semi-arid to semi-humid climate conditions are favorable vertically and the river-delta system is favorable for the sedimentary system; comprehensively considering the above favorable elements, taking the second-level tectonic units as units, ensuring sufficient provenance-uranium source supply horizontally, and being favorable near the provenance area, the source area, or the tectonic denudation area, and then comprehensively judge and delineate the favorable ore-forming key areas.

[0053] Step 2: Defining favorable ore prospecting target horizons includes:

[0054] Step 2.1: Within the scope of the key areas delineated in Step 1, collect borehole data, and the collected borehole data cover data such as seismic profiles of the whole area;

[0055] Step 2.2: Vertically, establish multiple typical single-well columnar diagrams using borehole data, clarify the formation thickness by combining data such as seismic profiles in the area, and establish a comprehensive columnar diagram for this key area; on this basis, analyze the lithologic structure between various formations and within formation groups, and combine with previous research results to optimize the favorable lithologic combination in the vertical direction to develop strata mainly with a stable mud-sand-mud structure.

[0056] Step 2.3: Horizontally, draw a cross-well profile, further divide sedimentary facies belts, sand body development, interlayer oxidation zones and other elements in units of formation groups, and determine braided river facies, meandering river channel subfacies, and braided river delta plain subfacies; multiple sand bodies are developed, with the thickness of a single sand body being 5 - 15 m and good continuity; the horizons with large-scale development of interlayer oxidation zones are favorable target horizons.

[0057] In Step 3, supplement and collect borehole data of the boreholes that penetrate the favorable ore-prospecting target horizons defined in Step 2, and statistically analyze the data of various ore-controlling elements in the target horizons.

[0058] Step 3.1: Determine the boundary of the key area delineated in Step 1.2, revise the geological map of the key area using Mapgis software based on previous research results, and make a coordinate table of the inflection points of the key area boundary; Step 3.2: Based on a large amount of borehole data, statistically analyze the data of ore-controlling elements such as formation thickness, floor depth, sand body thickness, sand-to-shale ratio, oxidized sand body thickness, and reduced sand body thickness of the favorable ore-forming target horizons defined in Step 2 and their borehole coordinates, and statistically organize them in tabular form.

[0059] On the basis of the above steps, merge the boundary coordinates of the key area with the statistical data of each ore-controlling element in Step 3.2 respectively, and assign the boundary coordinates of the key area as 0, and organize them into independent tables for standby according to ore-controlling elements.

[0060] In Step 4: Use Surfer software to draw maps of each ore-controlling element of the target horizon and screen the most favorable ore-forming intervals for each element.

[0061] Step 4.1: Import the data in Step 3.3 into Surfer software and draw contour maps of each element of the target horizon.

[0062] Use borehole data to identify the facies markers of the target horizon and revise the sedimentary facies distribution map of the target horizon.

[0063] According to previous research data, summarize the threshold values of the favorable ore-forming element intervals of typical sandstone-type uranium deposits and delimit the most favorable ore-forming intervals of favorable ore-forming elements.

[0064] Step 4.4: Screen the most favorable metallogenic intervals for each element according to the criteria in Step 4.2, where the formation thickness > 80 m, the bottom plate burial depth < 1000 m, the sand body thickness ≥ 60 m, the sand-to-ground ratio ≥ 0.5, the best reduction sand body is 10 - 50 m, followed by 50 - 70 m, and the oxidation sand body thickness is 10 - 40 m.

[0065] Step 5: Overlay and stack various types of maps to accurately locate the favorable uranium metallogenic sand bodies;

[0066] Step 5.1: Use Mapgis or CorelDRAW software to overlay and stack the element maps of the most favorable metallogenic intervals screened in Step 4.3 in the sedimentary facies base map;

[0067] Step 5.2: On the basis of Step 5.1, delimit the area where the coincidence rate is more than 80% as the most favorable metallogenic sand body according to the coincidence probability of each favorable element, and the area with a coincidence rate of 65 - 80% is the second best.

[0068] The above has made a detailed description of the embodiments of the present invention. The present invention is not limited to the above examples, and various changes can be made without departing from the gist of the present invention within the knowledge scope of those of ordinary skill in the art.

Claims

1. A precise positioning method for uranium ore-forming sand bodies favorable in the coverage area, characterized in that, It includes the following steps: Step 1: Collect and analyze data, and delineate key prospecting basin segments and regions with great potential; Step 1.1: Preliminarily delineate key basin segments; Step 1.2: On the basis of the key prospecting basin segments delineated in Step 1.1, delineate key regions; Step 2: Define favorable ore-prospecting target horizons; Step 3: Supplement and collect borehole data drilling through the favorable ore-prospecting target horizons defined in Step 2, and statistically analyze data of various ore-controlling factors of the target horizons; Step 4: Use Surfer software to draw maps of various ore-controlling factors of the target horizons, and screen the most favorable metallogenic intervals for each factor; Step 5: Overlay and stack various types of maps to accurately locate favorable uranium metallogenic sand bodies; The above Step 4: Use Surfer software to draw maps of various ore-controlling factors of the target horizons, and screen the most favorable metallogenic intervals for each factor; Step 4.1: Use Surfer software to import the data in Step 3.3 into the software and draw contour maps of various factors of the target horizons; Step 4.2: Use borehole data to identify the facies markers of the target horizons and revise the sedimentary facies distribution map of the target horizons; Step 4.3: According to the existing research data in the early stage, summarize the threshold values of the favorable metallogenic factor intervals of typical sandstone-type uranium deposits, and delimit the most favorable metallogenic intervals of the favorable ore-controlling factors; Step 4.4: According to the criteria in Step 4.2, screen the most favorable metallogenic intervals for each factor, where the formation thickness > 80m, the bottom plate burial depth < 1000m, the sand body thickness ≥ 60m, the sand-to-ground ratio ≥ 0.5, the best reduction sand body is 10 - 50m, followed by 50 - 70m, and the oxidation sand body thickness is 10 - 40m.

2. The precise positioning method of a favorable uranium metallogenic sand body in the coverage area according to claim 1, characterized in that: The above Step 1.1: Preliminarily delineate key basin segments, including: collecting regional geological and tectonic evolution graphic and text data of the studied basin, clarifying basin types, sedimentary covers, basement lithologies, and source area condition factors, and delineating key prospecting basin segments with great potential according to the first-level tectonic units: For the first-level tectonic units of the compression basin type, the piedmont slope zone is the first choice, and for the first-level tectonic units of the rift basin type, the uplift area is the first choice; The sedimentary cover is favorable when it develops an interlayer oxidation zone and the thickness < 1000m; For the lithology of the source area, granite is the first choice, followed by volcanic clastic rocks and acidic volcanic rocks, and the uranium content ≥ 5ppm.

3. The precise positioning method of a favorable uranium ore-forming sand body in the coverage area according to claim 2, wherein: The above Step 1.2: On the basis of the key prospecting basin segments delineated in Step 1.1, delineate key regions, including: focusing on collecting and sorting out geological, tectonic, and seismic data of this basin segment, studying and analyzing the sedimentary system, paleoclimate evolution, and source - uranium source supply condition factors of this basin segment, dividing the second-level tectonic units and further delineating favorable metallogenic key regions accordingly: defining the favorable metallogenic geological age range vertically according to the thickness of the favorable sedimentary cover in Step 1.1; integrating the existing research data in the early stage, analyzing the paleoclimate and sedimentary evolution characteristics of this basin segment, and determining that the semi-arid - semi-humid climate condition and the river - delta system of the sedimentary system are favorable vertically; comprehensively considering the favorable factors in Step 1.1 above, taking the second-level tectonic units as units, ensuring sufficient source - uranium source supply horizontally, and being favorable to be close to the source area, the source area or the tectonic denudation area, and then comprehensively judging and delineating favorable metallogenic key regions.

4. A precise positioning method for a favorable uranium ore-forming sand body in a coverage area according to claim 3, characterized in that: Step 2: Defining favorable ore-prospecting target horizons includes: Step 2.1: Within the key areas demarcated in Step 1, collect borehole data, and the collected borehole data cover the seismic profile data of the whole area. Step 2.2: Vertically, establish multiple typical single-well columnar diagrams using the borehole data, clarify the formation thickness in combination with the regional seismic profile data, and establish the comprehensive columnar diagram of this key area. On this basis, analyze the lithologic structure between different formations and within formation groups, and select the favorable vertical lithologic combinations in combination with the previous existing research results, mainly the formations with stable mud-sand-mud structures. Step 2.3: Horizontally, draw cross-well profiles, further divide sedimentary facies belts, sand body development, and interlayer oxidation zone elements in units of formation groups, and determine braided river facies, meandering river channel sub-facies, and braided river delta plain sub-facies. Multiple layers of sand bodies are developed, with the thickness of a single sand body being 5 - 15 m and good continuity; the horizons with large-scale development of interlayer oxidation zones are the favorable target horizons.

5. The precise positioning method of a favorable uranium ore-forming sand body in the coverage area according to claim 4, characterized in that: In Step 3, supplement and collect borehole data of the boreholes that penetrate the favorable ore-prospecting target horizons defined in Step 2, and statistically analyze the data of various ore-controlling elements of the target horizons. Step 3.1: Determine the boundaries of the key areas demarcated in Step 1.2, revise the geological map of the key areas using Mapgis software based on previous research results, and make a table of the inflection point coordinates of the key area boundaries. Step 3.2: Based on a large amount of borehole data, statistically analyze the data of ore-controlling elements such as formation thickness, bottom plate burial depth, sand body thickness, sand-to-ground ratio, oxidized sand body thickness, and reduced sand body thickness of the favorable ore-forming target horizons defined in Step 2, as well as their borehole coordinates, and statistically organize them in tabular form. Based on the above steps, merge the boundary coordinates of the key areas with the statistical data of each ore-controlling element in Step 3.2 respectively, and assign the boundary coordinates of the key areas as 0, and organize them into independent tables for standby according to the ore-controlling elements.

6. A precise positioning method for a favorable uranium - mineralized sand body in the coverage area according to claim 5, characterized in that: Step 5: Overlay various map sets to accurately locate the favorable uranium ore-forming sand bodies. Step 5.1: Use Mapgis or CorelDRAW software to overlay the element maps of the most favorable ore-forming intervals selected in Step 4.3 on the sedimentary facies base map. Based on Step 5.1, according to the coincidence probability of each favorable element, demarcate the areas with a coincidence rate of more than 80% as the most favorable ore-forming sand bodies, and the areas with a coincidence rate of 65 - 80% are the next.

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