A method for searching for oil sand enrichment areas in the Tibetan region

Abstract

The application provides a method for searching oil sand enrichment area in Tibetan area, comprising the following steps: S1, remote sensing interpretation idea; S2, remote sensing interpretation method; S3, stratum unit remote sensing geological feature; S4, ASTER and ALOS remote sensing data source and interpretation. The information provided by the remote sensing data can effectively and accurately delineate the regional geological body, and can control the overall framework of the regional geological structure from the macro aspect, and has a very important role in improving the quality of regional geological survey. In the high-altitude semi-desert area with difficult traffic, bad climate, large geographical span and dangerous working environment, fully utilizing the remote sensing data can improve the map quality with half the effort and double the effect, can save manpower, financial resources and time, reduce the field work amount, has remarkable economic benefit and safety benefit, and the remote sensing image can reveal the space trend of the ore body, and has a special important guiding significance in searching new oil sand ore body.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of oil and gas exploration in Tibet region, and particularly relates to a method for searching oil sand enrichment area in Tibet region. BACKGROUND

[0002] Firstly, the stratum unit of the research area is interpreted based on remote sensing image, the spatial distribution characteristics of the suspected oil-bearing stratum are analyzed and researched, and the range of the suspected oil-bearing stratum is circled. Then, the geological interpretation result of the 1:50000 or 1:100000 satellite remote sensing image is verified in the field and the image geological mapping is adjusted, the interpretation signs are supplemented, and the remote sensing geological interpretation map is modified and enriched. The large-scale image is carried to the field to compare and analyze various geological elements one by one, to seek similarities and differences, to find the reasons for the differences, and to accumulate experience to better complete the subsequent interpretation work. The remote sensing image interpretation data are comprehensively and systematically sorted out by using the existing geological and geochemical data combined with the field data, and the final matching interpretation and comprehensive research are carried out. That is, the detailed interpretation, comparative interpretation and comprehensive interpretation stages. Finally, the oil-bearing stratum distribution map in the research area is obtained.

[0003] The Tibet region has a large geographical span, a complex geological environment, a high-altitude semi-desert landform, and a harsh climate, and it is difficult to travel, which seriously affects the oil and gas resource exploration. Therefore, in the process of oil and gas resource exploration, it is a key problem to be solved to efficiently and reliably circulate the oil and gas stratum distribution area.

[0004] In the past oil and gas exploration methods, the field carpet search is mostly used, the oil-bearing stratum is circled according to the past exploration experience, the work amount is huge, the searching efficiency of the oil-bearing stratum is low, and it is difficult to meet the current efficient and rapid exploration requirements. Therefore, the traditional searching method has the disadvantages of low efficiency and high consumption, the remote sensing technical method can accurately circulate the regional geological body, control the overall framework of the regional geological structure from the macro aspect, reveal the spatial trend of the ore body, find new oil sand ore body, and improve the searching efficiency of the oil mine stratum. Therefore, a method for searching oil sand enrichment area in Tibet region is provided. SUMMARY

[0005] Therefore, the present application provides a method for searching oil sand enrichment area in Tibet region to solve or alleviate the technical problems in the prior art, and at least provides a beneficial choice.

[0006] The technical scheme of the embodiment of the present application is implemented as follows: a method for searching oil sand enrichment area in Tibet region, comprising the following steps:

[0007] S1, remote sensing interpretation idea;

[0008] S2, remote sensing interpretation method;

[0009] S3, stratum unit remote sensing geological characteristics;

[0010] S4, ASTER and ALOS remote sensing data sources and interpretation.

[0011] Further preferably, in the S1, remote sensing interpretation can be roughly divided into three stages of data collection, image interpretation and field verification, according to different research purposes, remote sensing interpretation work is carried out in three aspects, including the following steps,

[0012] S1-1, interpreting Landsat 7 satellite data, the remote sensing image is geometrically corrected, inlaid and image enhanced, ETM color composite satellite photos are obtained, and the stratigraphic unit in the survey area is interpreted;

[0013] S1-2, ASTER remote sensing data interpretation, according to the characteristics of oil-bearing strata having characteristic absorption in ASTER 1, 8 bands and characteristic reflection in ASTER 4, 9 bands, the carbonate information in the survey area is extracted, and the spatial distribution characteristics of Jurassic carbonate strata are analyzed and studied;

[0014] S1-3, ALOS remote sensing data interpretation, remote sensing images with a spatial resolution of 10 meters are made, and the range of oil-bearing strata is circled;

[0015] S1-4, field verification, field survey in the circled oil-bearing strata range to verify whether the oil-bearing strata in the circled range are real oil-bearing strata, and analyze the unique characteristics of the error area, which provides important guidance for error correction in the following remote sensing interpretation.

[0016] Further preferably, in the S2, it is composed of the following steps,

[0017] S2-1, remote sensing interpretation work platform;

[0018] S2-2, data processing and image production;

[0019] S2-3, remote sensing interpretation work procedure;

[0020] S2-4, remote sensing interpretation work content.

[0021] Further preferably, in the S2-1, the geographic information source adopts the geographic base map generated by the spatial database as the background information layer for the whole area interpretation, image mosaic registration and three-dimensional model construction, adopts the 1:100,000 paper medium topographic map as the geographic basis for the key section thematic map production, 1:100,000 scale TM image production, interpretation result field verification and local section DEM data generation, and the image processing and information extraction operation platform is configured with PIV type desktop microcomputer, Windows XP environment, ENVI 3.4, MAPGIS 6.1 and PHOTOSHOP 6.1, CD-ROM and 600 dpi line density scanner support input, and A0 format 600 dpi line density color jet plotter support output.

[0022] Further preferably, in the S2-2, the spectral characteristics of the TM original wave band data include high correlation between the visible light wave bands 1, 2 and 3, high correlation between the infrared wave bands 5 and 7, and the lowest correlation between the near infrared 4 and them, therefore, the 4 wave band is selected as one of the synthesized wave bands for the interpretation base image production, the 7 wave band is sensitive to clay and carbonate rocks and is the best wave band for rock mapping, after comparison and identification, the TM 741 is selected as the regional interpretation base image for RGB synthesis, the image geographic registration adopts polynomial operation, 13 or more control points are selected for the single scene TM, the histogram matching method is used for smooth transition between scenes, the contrast is expanded by stretching the histogram between the upper and lower frequency ends, finally, 300 dpi 1:250,000 one sheet and 1:100,000 9 sheets of false color paper medium images of two scales are output, the TM 741 regional interpretation base image has rich color and clear level, the rock structure framework and surface landscape are clearly reflected, and the performance for various geological elements is strong, the cooperation precision with the topographic map is not greater than 1 pixel after calibration, the ground resolution of the large scale image is still maintained at 30 m, there is no cloud and cloud shadow influence, and the detailed interpretation of various geological elements in the whole area can be satisfied. The 1:100,000 scale images are applied to the field interpretation.

[0023] Further preferably, in the S2-3, on the basis of collecting the prepared remote sensing information source and familiarizing the regional geological data, the interpretation workflow is performed according to the procedure of image processing→rough interpretation + initial establishment of interpretation marks→field verification and supplementary modification of the interpretation marks→comprehensive detailed interpretation→key interpretation + thematic information extraction, the principle of transition from macro to local and from qualitative information to quantitative information is implemented, the process is gradual and deepening, the early stage interpretation starts from dividing the image zones, establishes the overall geological framework, and then divides the image tectonic belts (blocks) and image geographic belts (blocks), and the steps for the interpretation work are as follows:

[0024] First, a systematic preliminary interpretation of remote sensing data is carried out in the whole range of the map sheet before reconnaissance and design writing. According to the image characteristics of remote sensing data, remote sensing image units and remote sensing morphological units (linear, ring) are divided, and remote sensing image interpretation sketches are prepared; based on the existing geological data, the lithology and tectonic geological interpretation marks of the whole area are prepared;

[0025] According to the interpretation marks, the remote sensing data is interpreted and the remote sensing geological interpretation map is drawn, which provides reference for field reconnaissance, so as to arrange geological observation routes in a targeted manner, and the interpretation content is checked and verified in the field, and the interpretation marks are continuously modified, supplemented and improved to improve the interpretation quality; at the same time, the relevant contents of the original remote sensing geological interpretation map are modified and supplemented, so that the interpretation content is more consistent with the objective situation. This modified and supplemented remote sensing geological interpretation map should be an important part of the design book writing and provided to the field work stage for comprehensive checking and verification along with the geological route survey;

[0026] The reliable geological bodies and geological boundaries checked and verified in the field can be treated as measured geological bodies and boundaries. When the image does not match the actual situation, the actual observation should be used to draw the geological boundaries and geological bodies. However, the reasons caused by the inaccurate image should be summarized and explained, and the subsequent interpretation basis is modified based on the difference between the image and the actual situation, so as to continuously improve the interpretation effect. Finally, according to the results of the comprehensive geological checking and verification in the field, the lithology and tectonic geological remote sensing image interpretation marks of the working area are modified, and the remote sensing data is interpreted in detail according to the new interpretation marks, and the relevant contents of the remote sensing geological interpretation map are further modified, supplemented and improved, and the remote sensing geological map of the working area is made.

[0027] Further preferably, in the S2-4, the interpretation of remote sensing images is carried out in the order of whole to part, through comparison and reasoning, single-band or color composite satellite images of different scales are interpreted, and then multi-temporal, multi-band, multi-plate type and aerial and satellite mosaic maps are compared to determine the image characteristics of various geological bodies, lines and rings, as well as their distribution and changes, etc. The remote sensing interpretation process can be roughly divided into four steps: preliminary interpretation, detailed interpretation, comparative interpretation and comprehensive interpretation. The interpretation results are filled in the interpretation cards and interpretation maps. Comparative interpretation is mainly carried out between different time phases, different scales and different plate types; comprehensive interpretation is to make the final judgment by comparing with the existing geological data, comprehensive analysis and exploring the internal relationship between the causes and rock types and geological structures, etc. The specific operation procedures are as follows:

[0028] I. Indoor design stage

[0029] ①, collect various remote sensing image data of the working area, mainly satellite remote sensing images, including multi-plate type, multi-temporal, multi-band satellite images, black and white and color aerial images and remote sensing geological work data in this area by predecessors;

[0030] 2. Production of satellite remote sensing regional mosaic, standard geographic frame 1:100000 remote sensing image map and single scene satellite remote sensing image, the regional mosaic is mainly used for regional structure analysis, the remote sensing image map can be used as the base map for remote sensing geological interpretation, and the single scene satellite remote sensing image (single band black and white or color composite sheet) is used for geological interpretation;

[0031] 3. The scale of remote sensing image data should meet the following requirements: the scale of satellite remote sensing regional mosaic and standard geographic frame remote sensing image map is the same as that of geological map, and the scale of other satellite remote sensing images should be the same as that of field work hand map, and 1:100000 or 1:50000 black and white single band images, color composite images or other enhanced processed different satellite images and corresponding data tapes and optical discs can be selected, in order to enable field investigation first-line technical personnel to fully, quickly and high-quality complete the investigation task, it is best to equip with microcomputer remote sensing image processing software, and strive to carry out image interpretation on the computer;

[0032] 4. Preliminary interpretation is carried out on the remote sensing image of the working area, and after reconnaissance, preliminary interpretation marks are established, remote sensing geological interpretation map is prepared, and is used as design drawing, and the scale of the interpretation result map should be the same as that of conventional geological map;

[0033] 5. On the preliminary interpretation geological sketch, the position of profile and the deployment of field verification observation route are reasonably selected, according to the image characteristics of remote sensing image, combined with geological interpretation data, the observation points are arranged in the places which are possible to be rock mass, rock facies change, phase change boundary, contact zone, oil sand mine belt, linear structure and circular structure, and image processing work is carried out in the above key sections to enhance and extract relevant geological information;

[0034] 6. The interpretation and extraction of spatial and temporal distribution information of different rocks in the area are carried out, according to the geographical location and coverage degree of the survey area, the degree of bedrock exposure and other characteristics, the distribution and lithology of various formal and informal stratigraphic units are divided and determined, and the image structure characteristics are analyzed in detail, the contact relationship of different geological bodies is studied, and the range and boundary of ore body are circled.

[0035] 7. After the interpretation and confirmation of the structural characteristics such as extension, branching, compounding, insertion and intersection of linear image and the mutual relationship with linear image of adjacent area, the classification, naming and grading of the linear image are carried out according to its geological properties, and the interpretation of circular structure image should be carried out in detail, the color difference and structure inside and outside the circular structure, the spatial distribution relationship such as mutual inclusion, superposition and cutting between different circular images and the relationship such as intersection and derivation between linear image and circular image are studied, and then the classification, naming and grading are carried out according to its geological origin.

[0036] ⑧ For image units that are reflected in different blocky forms on the image, interpretation should utilize multi-band data processing to extract image information and analyze the distribution characteristics of strata and rocks shown in the images. Intrusive bodies, especially intermediate-acidic intrusive bodies, generally appear as clusters on the image. The interpretation of fault structures is characterized by: prominent or faintly discernible linear extension features, often forming tonal interfaces and textured geometric interfaces. Sometimes, it manifests as the boundary lines of geomorphic units, geological bodies, and hydrogeological units (such as straight lines, arc-shaped piedmont zones, ridge lines, and groundwater outflow zones) as well as color bands and dense microtexture zones. Negative topography, steep rock walls, and other structural landforms are clearly shown on large-scale images. The interpretation of fold structures is characterized by parallel and dense smooth curves as the framework, with different tones and textures appearing symmetrically and repeatedly. The turning points of the lines are clearly shown, often appearing as rounded or sharp edges, forming closed or semi-closed arc-shaped image bodies.

[0037] II. Field Verification Phase

[0038] ① For the geological interpretation results of 1:50,000 or 1:100,000 satellite remote sensing images, conduct geological verification and image geological mapping in the field, supplement interpretation markers, and modify and enrich the remote sensing geological interpretation map. This work is generally carried out simultaneously with ground route and profile geological surveys. When conducting route surveys and profile studies, interpretation sketches can be made in advance, and large-scale images can be taken to the field work site to conduct one-to-one comparison and analysis of various geological elements, seek similarities and differences, and find the causes of differences, so as to accumulate experience to better complete subsequent interpretation work. The original remote sensing image data should be backed up and taken to the field for timely thematic information extraction, machine-aided interpretation, and other work, so as to integrate remote sensing technology into the regional geological survey to the greatest extent possible. The two complement each other and jointly promote the geological survey research work.

[0039] ② Field route surveys should proceed from areas to lines, and from lines to points. By utilizing the spatial structure of satellite imagery—points-lines-areas-volumes—the geological problems of the route should be interpreted and analyzed holistically to identify potential and resolving fundamental geological issues, ensuring a clear objective and a thorough understanding of the situation.

[0040] ③ Based on the landform, topographic map and geological information of satellite imagery, and with reference to the working sketch, interpret and compile remote sensing geological profile maps along the route to be traversed, so as to be used when filling in the route map and sketching the random route profile, and to cross-verify them during geological route observation.

[0041] ④ On the remote sensing geological profile, based on the information and geological structure of the remote sensing geological interpretation map, delineate the rock stratigraphic units, special rock units, image marker layers, typical structural features and image anomalies, establish a remote sensing structural model, and improve the predictability of oil sand body mapping.

[0042] III. Comprehensive Research Phase

[0043] ①, using existing geological, geochemical, and other data, combined with field data, to comprehensively and systematically process remote sensing image interpretation data, and to conduct final matching interpretation and comprehensive research. That is, detailed interpretation, comparative interpretation, and comprehensive interpretation stages. At the same time, remote sensing image interpretation maps, remote sensing geological interpretation maps, and remote sensing geological maps, as well as typical satellite image atlases of the working area, are prepared;

[0044] ②, the remote sensing geological mapping is based on the principle of fully reflecting the distinguishable remote sensing information in the survey area, and the mapping content includes regional geological structure, magmatic activity, Cenozoic plateau uplift geological structure and landform, mineral geological characteristics, water resources, land resources, and ecological environment variation, etc., which are expressed in the form of series maps;

[0045] ③, the basic unit and precision of the mapping are consistent with those of the 1:100,000 regional geological map. All image bodies with a diameter or length greater than 500 m should be accurately circled and drawn, and image bodies with a diameter greater than 100 m in key sections and linear bodies with a length greater than 250 m should be interpreted, and special small image bodies should be labeled. For special image bodies such as rings and halos, their main characteristics should be accurately represented in the map, and important small feature images such as marker layers, layer lines, and spring points should be reflected, and if necessary, exaggerated representation should be made.

[0046] ④, the interpretation point density can be appropriately reduced compared to the route observation point density, and the principle is that all main geological boundaries and various mapping entities are controlled by a certain number of interpretation points, and the key points are laid out in sections where the interpretation marks are representative or route observation is difficult to implement, and the key sections are correspondingly densified with interpretation points for fine interpretation.

[0047] Further preferably, in the S3, the following steps are further included:

[0048] S3-1, Triassic stratigraphic unit remote sensing geological features;

[0049] S3-2, Jurassic stratigraphic unit remote sensing geological features;

[0050] S3-3, Cretaceous stratigraphic unit remote sensing geological features;

[0051] S3-4, Paleogene stratigraphic unit remote sensing geological features;

[0052] S3-5, Neogene stratigraphic unit remote sensing geological features.

[0053] Further preferably, in the S4, the following steps are further included:

[0054] S4-1, carbonate rock remote sensing image features and interpretation;

[0055] S4-2, dolomite remote sensing image features and interpretation.

[0056] The embodiment of the present application has the following advantages due to the adoption of the above technical solutions.

[0057] The information provided by the remote sensing data can effectively and accurately delineate regional geological bodies, and can control the overall framework of regional geological structure from a macro perspective, and has a very important role in improving the quality of regional geological survey.

[0058] The above summary is only for the purpose of the description and is not intended to be limiting in any way. In addition to the illustrative aspects, embodiments and features described above, further aspects, embodiments and features will be readily apparent to those skilled in the art by reference to the drawings and the following detailed description. BRIEF DESCRIPTION OF DRAWINGS

[0059] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed in the embodiments or the prior art description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor on the basis of these drawings.

[0060] Figure 1 Flowchart of the present application;

[0061] Figure 2 Spectral curve of the main carbonate rock of the present application;

[0062] Figure 3 ASTER remote sensing image of the Angdala Lake area of the present application;

[0063] Figure 4 Distribution area of carbonate rock indicated by ASTER mid-infrared image of the Angdala Lake area of the present application;

[0064] Figure 5 ALOS remote sensing image of the working area of the present application;

[0065] Figure 6 Dolomite image feature schematic diagram near Balzainai of the present application;

[0066] Figure 7 Dolomite image feature schematic diagram near Banaimargou of the present application;

[0067] Figure 8Fig. 1 is a schematic diagram of the image features of the dolomite in the vicinity of the tooth plug and the dongla according to the present application;

[0068] Figure 9 Fig. 4 is a dolomite oil sand distribution map in the Biluocuo-Angdaluo area according to the present application;

[0069] Figure 10 Fig. 5 is a remote sensing geological interpretation map in the Biluocuo-Angdaluo area according to the present application. DETAILED DESCRIPTION

[0070] In the following, only certain exemplary embodiments are simply described. As those skilled in the art can recognize, the described embodiments can be modified in various different ways without departing from the spirit or scope of the present application. Therefore, the drawings and the description are considered to be exemplary in nature rather than limiting.

[0071] The embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0072] As shown in Figures 1-10 , the present application provides a method for searching the oil sand enrichment area in the Tibetan area, which comprises the following steps:

[0073] S1, remote sensing interpretation idea;

[0074] S2, remote sensing interpretation method;

[0075] S3, remote sensing geological features of the stratum unit;

[0076] S4, ASTER and ALOS remote sensing data source and interpretation.

[0077] In one embodiment, in S1, the remote sensing interpretation can be roughly divided into three stages of data collection, image interpretation and field verification. According to the different research purposes, the remote sensing interpretation work is carried out in three aspects, which comprises the following steps,

[0078] S1-1, interpreting Landsat7 image data satellite data, performing geometric correction, inlaying and image enhancement processing on the remote sensing image, obtaining ETM color composite satellite photos, and focusing on interpreting the stratum unit in the survey area;

[0079] S1-2, ASTER remote sensing data interpretation, according to the characteristics that the oil-bearing rock layer has characteristic absorption in ASTER1, 8 bands and characteristic reflection in ASTER4, 9 bands, extracting the carbonation information of the survey area, and analyzing and researching the spatial distribution characteristics of the Jurassic carbonate stratum;

[0080] S1-3, ALOS remote sensing data interpretation, respectively making remote sensing images with a spatial resolution of 10 meters, and delineating the range of the oil-bearing stratum;

[0081] S1-4, field verification, going to the delineated oil-bearing formation range to conduct field investigation, verifying whether the delineated oil-bearing formation is a real oil-bearing formation, and analyzing the unique characteristics of the error area to provide important guidance for error correction in the following remote sensing interpretation.

[0082] In one embodiment, in S2, consisting of the following steps,

[0083] S2-1, remote sensing interpretation work platform;

[0084] S2-2, data processing and image production;

[0085] S2-3, remote sensing interpretation work procedure;

[0086] S2-4, remote sensing interpretation work content.

[0087] In one embodiment, in S2-1, the geographic information source adopts the geographic base map generated by the spatial database as the background information layer for full-area interpretation, image mosaicking and registration, and three-dimensional model construction, adopts 1:100,000 paper medium topographic map as the geographic basis for key section thematic map production, 1:100,000 TM image production, interpretation result field verification, and local section DEM data generation, and the image processing and information extraction operation platform is configured with PIV type desktop microcomputer, Windows XP environment running ENVI3.4, MAPGIS6.1, PHOTOSHOP6.1, CD-ROM and 600dpi line density scanner supporting input, and A0 format 600dpi line density color inkjet plotter supporting output.

[0088] In one embodiment, in S2-2, the spectral characteristics of TM original waveband data include high correlation between visible light wavebands 1, 2 and 3, high correlation between infrared wavebands 5 and 7, and lowest correlation between near-infrared 4 and them, therefore, 4 waveband is preferred as one of the synthesized wavebands for the production of interpretation base images, 7 waveband is sensitive to clay and carbonate rocks, which is the best waveband for rock mapping, after comparison and identification, TM741 is selected as the regional interpretation base image for RGB synthesis, the image geographic registration adopts polynomial operation, 13 or more control points are selected for single TM scene, histogram matching method is used for smooth transition between scenes, and the enhancement mode is histogram stretching contrast expansion between upper and lower frequency ends, finally, 300dpi 1:250,000 one sheet and 1:100,000 9 sheets of false color paper medium images of two scales are output, the TM741 regional interpretation base image has rich color and clear level, the rock structure framework and surface landscape are clearly reflected, and the performance of various geological elements is strong, the cooperation accuracy with the topographic map is not greater than 1 pixel after calibration, the ground resolution of large scale image remains at 30m, there is no cloud and cloud shadow influence, and it can meet the detailed interpretation of various geological elements in the whole area. The 1:100,000 sheet image is applied to field interpretation.

[0089] In one embodiment, in S2-3, based on the collection of remote sensing information sources and familiar regional geological data, the interpretation workflow is carried out according to the procedure of image processing → preliminary interpretation + initial interpretation marks → field verification + supplementary modification of interpretation marks → comprehensive detailed interpretation → key interpretation + thematic information extraction, the principle of transition from macro to local and from qualitative information to quantitative information is implemented, and the interpretation is gradually deepened, the early interpretation starts from dividing image zones, establishes the overall geological framework, and then divides image structural belts (blocks) and image geographic belts (blocks), the steps of the interpretation work are as follows:

[0090] First, a preliminary interpretation of remote sensing data is carried out in the pre-investigation and design preparation stage, according to the image features of remote sensing data, remote sensing image units and remote sensing morphological units (linear, ring) are divided, and a remote sensing image interpretation sketch is prepared; according to the existing geological data, the lithology and tectonic geological interpretation marks of the whole area are prepared;

[0091] According to the interpretation marks, the remote sensing data is interpreted and the remote sensing geological interpretation map is prepared, which is used as a reference for field investigation to arrange geological observation routes, and the interpretation content is checked and verified in the field, the interpretation marks are continuously modified, supplemented and improved to improve the interpretation quality; at the same time, the relevant contents of the original remote sensing geological interpretation map are modified and supplemented to make the interpretation content more consistent with the objective situation, such modified and supplemented remote sensing geological interpretation map should be provided as an important part of the design book for the field work stage to check and verify the geological route investigation;

[0092] The reliable geological bodies and boundaries checked and verified in the field can be used as the measured geological bodies and boundaries, when the image does not match the actual situation, the actual observation should be used to draw the geological boundaries and geological bodies, but the reasons caused by the inaccurate image should be summarized and explained, based on the difference between the image and the actual situation, the subsequent interpretation basis is corrected to continuously improve the interpretation effect; finally, according to the results of the field comprehensive geological check and verification, the lithology and tectonic geological remote sensing image interpretation marks of the working area are modified, and according to the new interpretation marks, the remote sensing data is interpreted in detail, the relevant contents of the remote sensing geological interpretation map are further modified, supplemented and improved, and the remote sensing geological map of the working area is prepared.

[0093] In one embodiment, in S2-4, the interpretation of remote sensing images is carried out in the order of whole to part, through comparison and inference, single-band or color-composite satellite images of different scales are interpreted, and then multi-temporal, multi-band, multi-type and aerial-satellite mosaic images are compared to determine various types of geological bodies, lines and ring-shaped image features, their distribution and changes, etc. The remote sensing interpretation process can be roughly divided into four steps: preliminary interpretation, detailed interpretation, comparative interpretation and comprehensive interpretation. The interpretation results are filled into the interpretation cards and interpretation maps. Comparative interpretation is mainly carried out between different time phases, different scales and different types of images; comprehensive interpretation is compared with existing geological data, and the final judgment is made through comprehensive analysis, and the internal relationship between the causes and rock types and geological structures, etc. is explored. The specific operation procedures are as follows:

[0094] I. Indoor design stage

[0095] ① Collect various remote sensing image data in the work area, mainly satellite remote sensing images, including multi-type, multi-temporal, multi-band satellite images, black and white and color aerial images, and previous remote sensing geological work data in the area;

[0096] ② Make satellite remote sensing regional mosaic images, standard geographic division 1:100000 remote sensing image maps and single scene satellite remote sensing images. Regional mosaic images are mainly used for regional structure analysis. Remote sensing image maps can be used as the bottom map for remote sensing geological interpretation. Single scene satellite remote sensing images (single band black and white or color composite images) are used for geological interpretation;

[0097] ③ The scale of remote sensing image data should meet the following requirements: the scale of satellite remote sensing regional mosaic images and standard geographic division remote sensing image maps should be the same as that of geological maps. The scale of other satellite remote sensing images should be the same as that of field work sketch maps. 1:100000 or 1:50000 black and white single band images, color composite images or other enhanced processed different satellite images and corresponding data tapes and optical discs can be selected. In order to enable field investigation first-line technical personnel to fully, quickly and high-quality complete the investigation task, it is best to equip with microcomputer remote sensing image processing software to carry out image interpretation on the computer;

[0098] ④ Preliminary interpretation of remote sensing images in the work area is carried out. After reconnaissance, preliminary interpretation marks are established, remote sensing geological interpretation maps are prepared, and they are used as design drawings. The scale of interpretation result maps should be the same as that of conventional geological maps;

[0099] ⑤ On the preliminary interpretation geological sketch, the position of cross section and the layout of field verification observation route are reasonably selected. According to the image features of remote sensing images, combined with geological interpretation data, observation points are arranged in places that may be rock mass, rock facies change, phase change boundary, contact zone, oil sand mine zone, linear structure and ring-shaped structure. Image processing work is carried out in the above key sections to enhance and extract relevant geological information;

[0100] ⑥ Interpretation and extraction of the spatiotemporal distribution information of different rock types in the area. Based on the geographical location and coverage of the survey area, the degree of bedrock exposure, and other characteristics, the distribution and lithology of various formal and informal stratigraphic units are divided and determined. The structural characteristics of the images are analyzed in detail, the contact relationships of different geological bodies are studied, and the scope and boundaries of ore bodies are delineated.

[0101] ⑦ After interpreting and confirming the structural features of linear images, such as extension, bifurcation, compounding, interpenetration, and intersection, as well as their relationship with adjacent linear images, classify, name, and grade them according to their geological attributes. For the interpretation of ring-shaped structural images, a detailed study should be conducted on the tonal differences and structure inside and outside the ring, the spatial distribution relationships such as mutual inclusion, superposition, and cutting between different ring images, and the relationships such as intersection and derivation with linear images. Then, classify, name, and grade them according to their geological origin.

[0102] ⑧ For image units that are reflected in different blocky forms on the image, interpretation should utilize multi-band data processing to extract image information and analyze the distribution characteristics of strata and rocks shown in the images. Intrusive bodies, especially intermediate-acidic intrusive bodies, generally appear as clusters on the image. The interpretation of fault structures is characterized by: prominent or faintly discernible linear extension features, often forming tonal interfaces and textured geometric interfaces. Sometimes, it manifests as the boundary lines of geomorphic units, geological bodies, and hydrogeological units (such as straight lines, arc-shaped piedmont zones, ridge lines, and groundwater outflow zones) as well as color bands and dense microtexture zones. Negative topography, steep rock walls, and other structural landforms are clearly shown on large-scale images. The interpretation of fold structures is characterized by parallel and dense smooth curves as the framework, with different tones and textures appearing symmetrically and repeatedly. The turning points of the lines are clearly shown, often appearing as rounded or sharp edges, forming closed or semi-closed arc-shaped image bodies.

[0103] II. Field Verification Phase

[0104] ① For the geological interpretation results of 1:50,000 or 1:100,000 satellite remote sensing images, conduct geological verification and image geological mapping in the field, supplement interpretation markers, and modify and enrich the remote sensing geological interpretation map. This work is generally carried out simultaneously with ground route and profile geological surveys. When conducting route surveys and profile studies, interpretation sketches can be made in advance, and large-scale images can be taken to the field work site to conduct one-to-one comparison and analysis of various geological elements, seek similarities and differences, and find the causes of differences, so as to accumulate experience to better complete subsequent interpretation work. The original remote sensing image data should be backed up and taken to the field for timely thematic information extraction, machine-aided interpretation, and other work, so as to integrate remote sensing technology into the regional geological survey to the greatest extent possible. The two complement each other and jointly promote the geological survey research work.

[0105] 2. Field route survey should be from area to line, from line to point, using the space structure of satellite image point-line-area-body to make overall interpretation and analysis of geological problems of the route, and clean up the possible and basic geological problems to be solved, so as to achieve clear purpose and have a clear idea in mind;

[0106] 3. Based on the landform pattern of satellite image, topographic map and geological information, referring to the working map, along the route to be crossed, the remote sensing geological profile is interpreted and drawn, so as to be used when drawing the profile of the route and to be verified in the geological route observation;

[0107] 4. On the remote sensing geological profile, according to the information and geological structure of the remote sensing geological interpretation map, the rock stratum unit, special rock unit, image marker layer, typical structure trace and image abnormal point are drawn, the remote sensing structure model is established, and the predictability of oil sand body mapping is improved.

[0108] Three, comprehensive research stage

[0109] 1. Using the existing geological, geochemical and other data, combined with field data, the remote sensing image interpretation data is comprehensively and systematically arranged, and the final matching interpretation and comprehensive research are carried out. That is, the detailed interpretation, comparative interpretation and comprehensive interpretation stage. At the same time, the remote sensing image interpretation map, remote sensing geological interpretation map and remote sensing geological map and the typical satellite image atlas of the working area are prepared;

[0110] 2. The remote sensing geological mapping takes fully reflecting the distinguishable remote sensing information in the survey area as the principle, and the mapping content includes regional geological structure, magmatic activity, Cenozoic plateau uplift geological structure and landform, mineral geological characteristics, water resources, land resources and ecological environment variation, etc., which are expressed in series of maps;

[0111] 3. The basic unit and precision of mapping are consistent with 1:100,000 regional geological map. The image bodies with a diameter or length greater than 500m should be accurately circled and drawn, the image bodies with a diameter greater than 100m in key sections and the linear bodies with a length greater than 250m should be interpreted, and special small image bodies should be marked. The main characteristics of the ring and halo special images should be accurately represented in the map, and the small characteristic images with important indication significance such as marker layer, layer line and spring point should be reflected, and if necessary, exaggerated representation should be made.

[0112] 4. The interpretation point density can be appropriately reduced compared with the route observation point density, and the principle is that all the main geological boundaries and various mapping entities are controlled by a certain number of interpretation points, and the key sections are correspondingly densified with interpretation points for fine interpretation.

[0113] In one embodiment, in S3, the following step is further included:

[0114] S3-1, Triassic strata unit remote sensing geological features (reference Figure 10 )

[0115] 1) Jiangzhong group strata image unit remote sensing geological features

[0116] Exposure area: Eya Lake west and Yagen Lake south near the area;

[0117] Color features: light purple red, light pink as the main, light and dark degree slightly dark;

[0118] Landform features: 200-500m mountainous area, the overall continuity of the ridge in the strike, local discontinuous; main ridge slightly round, side ridge short slightly round;

[0119] Morphological features: banded, patchy;

[0120] Water system features: development of moderate, dendritic;

[0121] Gully features: relatively developed, "V" type valley;

[0122] Lithological composition: quartz sandstone, feldspar quartz sandstone, mudstone, mudstone as the main.

[0123] 2) Jiaomurichaoye group strata image unit remote sensing geological features (T3j)

[0124] Exposure area: Sangmona and other places, relatively scattered;

[0125] Color features: light gray pink, light gray brown, light and dark degree slightly dark;

[0126] Landform features: 100-200m mountainous area, the overall continuity of the ridge in the strike, local discontinuous; discontinuous ridge in the form of isolated hills, isolated peaks, side ridge not developed;

[0127] Morphological features: irregular broken banded, patchy;

[0128] Water system features: development of moderate, parallel.

[0129] 3) Zha group strata image unit remote sensing geological features

[0130] Exposure area: Naijiang Lake-Pusaili Lake area, sporadic exposure;

[0131] Color features: light gray brown, gray brown, light and dark degree dark;

[0132] Landform features: 100-700m mountainous area, ridge discontinuous, no obvious main ridge; discontinuous ridge in the form of isolated hills, isolated peaks, side ridge not developed, local in the form of steamed bun hill;

[0133] Morphological feature: Irregular shape

[0134] Water system feature: Developed moderately, parallel, dendritic

[0135] Gully feature: Gully development, mostly "V" shaped valley

[0136] Lithological composition: Mainly clastic rock, with a small amount of limestone.

[0137] 4) Remote sensing geological features of the Suobuza Formation stratigraphic image unit (T3s)

[0138] Outcrop area: Lhunxun Co - Qixiang Co area

[0139] Color feature: Light pink, pink, light beige, etc., with general light and dark degree

[0140] Landform feature: Mountainous area with height difference of tens of meters to 500m, mostly in the shape of dumpling-shaped hills, with inconspicuous ridges, isolated hills, isolated peaks, and broken mountains

[0141] Morphological feature: Irregular band shape, trending nearly east-west

[0142] Water system feature: Developed generally, mainly parallel

[0143] Gully feature: Gully development, mostly "V" shaped valley

[0144] Lithological composition: Mainly limestone.

[0145] S3-2, remote sensing geological features of the Jurassic stratigraphic unit

[0146] 1) Remote sensing geological features of the Quse Formation stratigraphic image unit (J1q)

[0147] Outcrop area: Found in Qena - Quru - Dingren area

[0148] Color feature: Light pink, pink, light beige, light gray brown, gray brown

[0149] Landform feature: Mountainous area with height difference of tens of meters to 500m, with discontinuous ridges and no obvious main ridge; intermittent ridges trending randomly, isolated hills, isolated peaks, with no side ridge development, and locally in the shape of dumpling-shaped hills

[0150] Morphological feature: Irregular shape

[0151] Water system feature: Developed moderately, parallel, dendritic

[0152] Gully feature: Gully development, mostly "V" shaped valley

[0153] Lithological composition: Mainly clastic rock, with limestone.

[0154] 2) J2s remote sensing geological features of the color group strata unit

[0155] Exposure area: north of Xiangcuo and color area;

[0156] Color features: gray black, gray brown, slightly dark;

[0157] Landform features: mountainous topography, ridge overall continuous, locally intermittent, ridge slightly sharp, steep slope;

[0158] Morphological features: striped banded, obvious folding;

[0159] Drainage features: relatively developed, dendritic;

[0160] Gully features: developed, "V" shaped valley;

[0161] Lithological combination: mainly clastic rock, with thin layer of limestone, locally interbedded with limestone and clastic rock, from top to bottom, the number of lime mudstone gradually increases; clastic rock is mainly siltstone, argillaceous siltstone and mudstone, with dark gray color.

[0162] 3) Remote sensing features of the Saxiawu group strata unit

[0163] Exposure area: north of Saxiawu Mountain in color, image features similar to color, not easy to distinguish;

[0164] Color features: light gray pink, gray black, light gray, light gray green or light gray brown, medium light and dark, with light color at the boundary of color group, slightly bright;

[0165] Landform features: mostly mountain top, peak, ridge slightly sharp, steep slope;

[0166] Morphological features: relatively uniform color block or banded;

[0167] Drainage features: not developed;

[0168] Gully features: not developed, "V" shaped valley;

[0169] Lithological combination: light gray, gray fine sandstone, siltstone, dark gray argillaceous siltstone, top and bottom color light, relatively coarse grain size, middle fine grain size, dark color.

[0170] 4) Remote sensing geological features of the Buqu group strata unit (J2b)

[0171] Exposure area: Biluocuo area and west of Angdalucuo, near east-west;

[0172] Color features: light pink, light gray brown, pink white, light gray pink, medium light and dark;

[0173] Landform features: low mountain and hilly landform in Biluo Lake area, rounded ridges, isolated hills, isolated peaks, and faulted mountains developed, with height difference of tens of meters to 400m or so, ridge-like mountains in the west of Angdala Lake, continuous and straight ridges, slightly rounded, with no lateral ridges developed;

[0174] Morphological features: zonally banded in the west of Angdala Lake; banded and irregular in Biluo Lake area;

[0175] Water system features: dendritic branch stream system, parallel trunk stream, and obvious meandering;

[0176] Gully features: well developed, mostly vertical to the main ridge, and "V"-shaped valleys;

[0177] Lithological combination: limestone in the first member, sandstone in the second member, and limestone in the third member in Biluo Lake area. Folds are well developed, with axial direction near east-west. Limestone, polycrystalline limestone, and siltstone and mudstone are developed in the west of Angdala Lake.

[0178] 5) Remote sensing geological features of Xiali Formation stratigraphic unit (J2x)

[0179] Outcrop area: found in the Angdala Lake-Zhadai period Suma Mountain area, with near east-west strike;

[0180] Color tone features: light flesh red and light pink;

[0181] Landform features: low mountain landform, with ridge development and local doughnut-shaped hills;

[0182] Morphological features: striped banded and patchy. Local folds are developed;

[0183] Water system features: short and small branch stream and parallel trunk stream;

[0184] Gully features: well developed, with "V"-shaped valleys;

[0185] Lithological composition: mainly sandstone with limestone interbedded.

[0186] 6) Remote sensing geological features of Suowa Formation stratigraphic unit (J3s)

[0187] Outcrop area: found in the Angdala Lake-Zhadai period Suma Mountain, Wu'ar Kongma-Sarigazha area, with near east-west strike;

[0188] Color tone features: light flesh red and flesh red;

[0189] Landform features: low mountain landform, with ridge development and local doughnut-shaped hills;

[0190] Morphological features: striped banded and patchy. Local folds are developed;

[0191] Water system features: short and small branch stream and parallel trunk stream;

[0192] Gully feature: development, "V" type valley;

[0193] Lithologic composition: mainly limestone with sandstone.

[0194] S3-3, Cretaceous stratigraphic unit remote sensing geological features

[0195] The Cretaceous in the area only sees the Abushan Formation unit (K2a), which is exposed in the Jiangrimari foot-Zongmudong area in the northeast of Angdarcuo, and is distributed in the northwest;

[0196] Color feature: light pink, locally brown spots, darker. Partially due to later stratigraphic coverage and small scale, color tone is blurred;

[0197] Landform feature: low mountain and hilly landform, dumpling-shaped hills;

[0198] Morphological feature: irregular banded or patchy;

[0199] Drainage feature: not developed, dendritic;

[0200] Gully feature: short, "V" type valley;

[0201] Lithologic combination: a set of strata dominated by clastic rock with intermediate-basic volcanic rock.

[0202] S3-4, Paleogene stratigraphic unit remote sensing geological features

[0203] Paleogene in the area only found Nadingcuo Formation (E3n) stratigraphic unit, exposed in Xiaogaxiona, Tibogaomu, etc., small scale;

[0204] Color feature: gray-green, flesh red, slightly dark;

[0205] Landform feature: low mountain, or solitary hill;

[0206] Morphological feature: vein, patchy or banded, string of beads, etc.;

[0207] Drainage feature: dendritic drainage in large area of exposure, small area of exposure, not developed;

[0208] Gully feature: "V" type valley;

[0209] Lithologic composition: gabbro, basalt, andesite, basaltic andesite, alkaline andesite, etc.

[0210] S3-5, Neogene stratigraphic unit remote sensing geological features

[0211] Neogene stratigraphic unit in the area only found Kangto Formation, exposed in the whole southern region of Qiangtang Basin, widely distributed, such as piedmont, intermontane basin, mountain top, mountain waist concave, etc.

[0212] Color features: pink, light gray pink, light blue purple, meat red, light gray green, light blue, purple red, etc., slightly bright;

[0213] Landform features: with complex landforms such as high mountain landforms and low hilly landforms according to the base landform;

[0214] Morphological features: skirt, hat, strip, etc.;

[0215] Water system features: influenced by neotectonics and base characteristics, water system features are complex, mainly dendritic water system;

[0216] Gully features: relatively developed, "V" shaped valley;

[0217] Lithological combination: purple red, brick red, gray conglomerate, sandstone and miscellaneous color siltstone, mudstone, etc.

[0218] In one embodiment, in S4, the following steps are further included:

[0219] S4-1, carbonate rock remote sensing image features and interpretation

[0220] The extraction of carbonation information is based on ASTER remote sensing data. The adopted bands are 1, 2, 3N, 4, 5, 6, 7, 8 and 9, and the system parameters are shown in Table 1

[0221] Table 1 ASTER system parameter table

[0222]

[0223]

[0224] From the dolomite and calcite spectral curve ( Figure 2 ), it can be seen that dolomite and calcite have similar spectral characteristics, which are characterized by characteristic absorption in ASTER 1 and 8 bands and characteristic reflection in ASTER 4 and 9 bands. According to this characteristic, the carbonation information of the study area can be extracted. However, in the short-wave infrared region, the spectral characteristics of dolomite and calcite are most similar, and the reflectivity is high and low respectively, so it is impossible to distinguish limestone and dolomite;

[0225] The ASTER remote sensing image of the Onzhalcuo area purchased is shown in Figure 3 , and the carbonate strata in the area are extracted by remote sensing according to the above method, and the results are shown in Figure 4 , the information in the middle region of the image is good, and the carbonation is distributed in a narrow and long belt near the east-west direction, which is consistent with the spatial distribution of the regional carbonate rock strata

[0226] S4-2, dolomite remote sensing image features and interpretation

[0227] The ALOS (Advanced Land Observation Satellite) is a next-generation land observation satellite developed by the Japan Space Agency (NASDA). It carries the new AVNIR-2 (Advanced Visible and Near-Infrared Radiation Meter Type 2) with a spatial resolution of 10 meters. It operates in four bands within the visible-near-infrared spectrum: B1 (0.42–0.52 μm), B2 (0.52–0.60 μm), B3 (0.61–0.69 μm), and B4 (0.76–0.89 μm). The operational area encompasses three ALOS images. Figure 5 );

[0228] According to regional geological survey data, the dolomite in the Biluocuo-Angdarcuo area is mainly found in the Middle Jurassic Buqu Formation (J2b), and also in the Middle Jurassic Shaqiaomu Formation. It also appears sporadically in the distribution areas of the Middle Jurassic Xiali Formation (J2x);

[0229] The interpretation of dolomite is based on the fact that the images mainly show light gray or bright gray thin stripes, which are mainly developed in higher terrains, such as mountain ridges. The texture is relatively smooth, with dendritic drainage systems and clear boundaries with the surrounding strata. Figure 6 , Figure 7 and Figure 8 );

[0230] A total of 63 dolomite patches were interpreted in the study area, covering a total area of ​​219.08 km². Field surveys confirmed 34 dolomite outcrops, with the largest surface oil sand outcrop area reaching 13.57 km², and a total outcrop area of ​​approximately 132.69 km² (Table 2). The surface oil sand outcrops are mainly distributed between 88°30′–90°00′ E and 30°00′–31°30′ N, extending approximately 150 km east-west and 50 km north-south. The most concentrated area of ​​dolomite distribution is located in the central part of the study area, exhibiting a narrow, elongated, near-east-west trending distribution controlled by regional tectonic activity. Additionally, dolomite in the western part of the study area trends northwest-southwest, while a small amount of dolomite in the eastern part trends northeast-east. Figure 9 ).

[0231] Table 2. Distribution area of ​​dolomite in the Biloco-Angdarco region (unit: km²) 2 Statistical table

[0232]

[0233] In one embodiment, in Figure 2In the figure, red and green represent different granularity calcite spectral curves, and blue and sky blue represent different granularity dolomite spectral curves.

[0234] The above merely describes specific embodiments of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think of various changes or replacements within the technical range disclosed by the present application, which should be encompassed in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A method for searching for an oil sand enrichment area in the Tibet region, characterized in that, Comprise the following steps: S1, remote sensing interpretation idea; S2, remote sensing interpretation method; S3, stratum unit remote sensing geological features; S4, ASTER and ALOS remote sensing data sources and interpretation; In the S1, remote sensing interpretation is divided into three stages of data collection, image interpretation and field verification, according to the different purposes of the study, three aspects of remote sensing interpretation work, including the following steps, S1-1, interpretation of Landsat 7 satellite data, ETM image is carried out geometric correction, inlay and image enhancement processing, obtain ETM color composite satellite photos, focus on interpretation of stratum unit in the survey area; S1-2, ASTER remote sensing data interpretation, according to the characteristics of oil-bearing strata in ASTER 1, 8 band has characteristic absorption, ASTER 4, 9 band has characteristic reflection, the carbonate information of the survey area is extracted, the spatial distribution characteristics of Jurassic carbonate strata are analyzed and studied; S1-3, ALOS remote sensing data interpretation, respectively making the spatial resolution of 10 meters of remote sensing image, delineating the range of oil-bearing strata; S1-4, field verification, go to the delineated oil-bearing strata range to carry out field survey, verify whether the oil-bearing strata in the delineated range is real oil-bearing strata, and analyze the unique characteristics of the error area, provide important guidance for the error correction in the next remote sensing interpretation; In the S2, consists of the following steps, S2-1, remote sensing interpretation work platform; S2-2, data processing and image production; S2-3, remote sensing interpretation work procedure; S2-4, remote sensing interpretation work content; In the S2-1, geographic information source adopts the geographic base map generated by spatial database as the background information layer of the whole area interpretation, image inlay registration and three-dimensional model construction, adopts 1:100000 paper medium topographic map as the geographic basis for 1:100000 TM image production, interpretation result field verification and local section DEM data generation; In the S2-2, according to the spectral characteristics of TM original band data, select TM741 as the regional interpretation basis image of RGB synthesis, image geographic registration adopts polynomial operation, select 13 or more control points for single scene TM, use histogram matching method for smooth transition between scenes, enhance the contrast between the upper and lower frequency ends, finally output 300dpi 1:250000 one piece, 1:100000 nine pieces of two scales of false color paper medium image, the cooperation accuracy of TM741 regional interpretation basis image and topographic map is not more than 1 pixel, the ground resolution of large scale image is kept at 30m, without cloud and cloud shadow influence, among them, 1:100000 sectional image is applied to field interpretation; In the S2-3, on the basis of collecting remote sensing information sources and familiarizing with regional geological data, the interpretation workflow is as follows: image processing→rough interpretation + initial establishment of interpretation marks→field reconnaissance verification + supplementary modification of interpretation marks→comprehensive detailed interpretation→key interpretation + thematic information extraction, which implements the principle of transition from macro to local and from qualitative information to quantitative information, and gradually deepens, with the early interpretation starting from dividing image zones, establishing the overall geological framework, and then dividing image structural belts and image geographic belts, and the steps of interpretation work being: First, a preliminary interpretation of remote sensing data is carried out in the range of the whole image before reconnaissance and design, according to the image features of remote sensing data, remote sensing image units and remote sensing form units are divided, and remote sensing image interpretation sketches are prepared; the existing geological data are referred to, and the lithology and tectonic geological interpretation marks of the whole area are drafted; According to the interpretation marks, the remote sensing data are interpreted geologically, and the remote sensing geological interpretation map is prepared, which is provided for reference in field reconnaissance, so as to arrange the geological observation routes in a targeted manner, and the interpretation content is checked and verified in the field, the interpretation marks are continuously modified, supplemented and improved, and the interpretation quality is improved; at the same time, the related content of the original remote sensing geological interpretation map is modified and supplemented, so that the interpretation content is more consistent with the objective situation, and such modified and supplemented remote sensing geological interpretation map is provided for the field work stage as an important part of the design book, and is provided for the comprehensive check and verification along with the geological route investigation; The reliable geological bodies and geological boundaries checked and verified in the field can be treated as measured geological bodies and boundaries, when the image does not match the actual situation, the actual observation should be used to draw the geological boundaries and geological bodies, but the reasons caused by the inaccurate image should be summarized and explained, based on the difference between the image and the actual situation, the subsequent interpretation basis is modified, and the interpretation effect is continuously improved; finally, according to the results of the comprehensive geological check and verification in the field, the lithology and tectonic geological remote sensing image interpretation marks of the working area are modified, the remote sensing data are interpreted in detail according to the new interpretation marks, and the related content of the remote sensing geological interpretation map is further modified, supplemented and improved, and the remote sensing geological map of the working area is prepared; In the S2-4, the interpretation of remote sensing images is carried out in the order of whole to local, through comparison and reasoning, single-band or color composite single images of different scales are interpreted, then multi-temporal, multi-band, multi-image types and aerial and satellite image mosaic maps are compared, from which the image features of various geological bodies, lines and ring shapes, their distribution and changes are determined, the remote sensing interpretation process can be divided into four steps: preliminary interpretation, detailed interpretation, comparative interpretation and comprehensive interpretation, the interpretation results are filled in the interpretation cards and interpretation maps, the comparative interpretation is carried out between different time phases, different scales and different image types; the comprehensive interpretation is compared with the existing geological data, the final judgment is made through comprehensive analysis, and the internal relationship between the causes and rock types and geological structures is explored, the specific operation procedures are as follows: I. Indoor design stage ①, collect various remote sensing image data of the working area, mainly satellite remote sensing images, including multi-image types, multi-time phases, multi-band satellite images, black and white and color aerial images and remote sensing geological work data in the area by previous people; 2. The satellite remote sensing regional mosaic map, the standard geographic division 1:100000 remote sensing image map and the single scene satellite remote sensing image are made, the regional mosaic map is mainly used for regional structure analysis, the remote sensing image map can be used as the bottom map of remote sensing geological interpretation, and the single scene satellite remote sensing image is used for geological interpretation; 3. The scale of the remote sensing image data should meet the following requirements: the scale of the satellite remote sensing regional mosaic map and the standard geographic division remote sensing image map is the same as that of the geological map, and the scale of other satellite remote sensing images should be the same as that of the field work hand map, and 1:100000 or 1:50000 black and white single band images, color composite images or other enhanced processed different satellite images and corresponding data tapes and optical discs of different periods and different bands can be selected, in order to enable the first-line technical personnel to complete the investigation task fully, quickly and high-quality, the microcomputer remote sensing image processing software is provided, and the image interpretation on the computer is strived for; 4. The remote sensing image of the working area is preliminarily interpreted, the preliminary interpretation marks are established after the reconnaissance, the remote sensing geological interpretation map is prepared, and is used as the design drawing, and the scale of the interpretation result map should be the same as that of the conventional geological map; 5. On the preliminary interpretation geological sketch, the profile position is reasonably selected and the field verification observation route is arranged, according to the image features of the remote sensing image, the observation points are arranged in the possible rock mass, lithofacies change, phase change boundary, contact zone, oil sand mine belt, linear structure and circular structure with the purpose of combining the geological interpretation data, and the image processing work is carried out in the above key sections, and the relevant geological information is enhanced and extracted; 6. The interpretation and extraction of the spatial and temporal distribution information of different rocks in the area are carried out, according to the geographical location and coverage degree of the survey area and the characteristics of the bedrock exposure degree, the distribution and lithology of various formal and informal stratigraphic units are divided and determined, and the image structure characteristics are analyzed in detail, the contact relationship of different geological bodies is studied, and the range and boundary of the ore body are circled; 7. After the interpretation and confirmation of the structure characteristics of the linear image such as extension, branching, compounding, insertion and intersection and the mutual relationship with the linear image of the adjacent area, the linear image is classified, named and graded according to its geological properties, the interpretation of the circular structure image should be carried out in detail, the color difference and structure inside and outside the circular structure are studied, the spatial distribution relationship of the mutual inclusion, superposition and cutting of different circular images and the intersection and derivation relationship with the linear image are studied, and the circular image is classified, named and graded according to its geological origin; ⑧ For image units that are reflected in different blocky forms on the image, the interpretation should utilize multi-band data processing to extract image information and analyze the distribution characteristics of strata and rocks shown by the images. Intermediate-acidic intrusive bodies appear as clusters on the image. The interpretation of fault structures is characterized by: prominent or faintly discernible linear extension features, often forming tonal interfaces and textured geometric interfaces. Sometimes, it appears as the boundary lines and color bands of geomorphic units, geological bodies, and hydrogeological units, as well as dense microtexture bands. The structural landforms of negative topography and steep rock walls are clearly shown on large-scale images. The interpretation of fold structures is characterized by parallel and dense smooth curves as the framework, with different tones and textures appearing symmetrically and repeatedly. The turning points of the lines are clearly shown, often in rounded or sharp shapes, forming closed or semi-closed arc-shaped image bodies. II. Field Verification Phase ① For the geological interpretation results of 1:50,000 or 1:100,000 satellite remote sensing images, conduct geological verification and image geological mapping in the field, supplement interpretation markers, and modify and enrich the remote sensing geological interpretation map. This should be carried out simultaneously with ground route and profile geological surveys. When conducting route surveys and profile studies, interpretation sketches can be made in advance. Large-scale images can be taken to the field work site to conduct one-to-one comparison and analysis of various geological elements, seek similarities and differences, and find the causes of differences. The original remote sensing image data should be backed up and taken to the field. Thematic information extraction and machine-aided interpretation should be carried out in a timely manner, and remote sensing technology should be integrated into the regional survey. ② Field route surveys should proceed from areas to lines, and from lines to points, utilizing the spatial structure of satellite imagery—points—lines—areas—volumes to comprehensively interpret and analyze the geological issues of the route, identifying potential and resolving fundamental geological problems. ③ Based on the landform, topographic map and geological information of satellite imagery, and with reference to the working sketch, interpret and compile remote sensing geological profile maps along the route to be traversed, so as to be used when filling in the route map and sketching the random route profile, and to cross-verify them during geological route observation. ④ On the remote sensing geological profile, based on the information and geological structure of the remote sensing geological interpretation map, delineate the rock stratigraphic units, special rock units, image marker layers, typical structural features and image anomalies, establish a remote sensing structural model, and improve the predictability of oil sand body mapping. III. Comprehensive Research Phase ① Utilize existing geological, geochemical, and research data, combined with field data, to comprehensively and systematically organize remote sensing image interpretation data, and conduct final overlay interpretation and comprehensive research, namely, detailed interpretation, comparative interpretation, and comprehensive interpretation stages. At the same time, compile remote sensing image interpretation maps, remote sensing geological interpretation maps, and remote sensing geological maps, as well as typical satellite image atlases of the work area. ② The remote sensing geological mapping should fully reflect all kinds of identifiable remote sensing information in the survey area. The mapping content includes regional geological structure, magmatic activity, Cenozoic plateau uplift geological structure and landform, mineral geological characteristics, water resources, land resources and ecological environment variation, which are expressed in the form of a series of maps.

3. The basic unit of mapping, precision and 1: 100,000 regional geological map to keep consistent, diameter or length greater than 500m image body should be accurate circle, key section diameter greater than 100m image body and length greater than 250m linear body should be interpreted, special small image should be marked, for ring, halo special image on its main features accurately in the map, important small feature image, including the marker layer, layer lines, springs points are reflected, or exaggerated representation; 4. Interpretation point density than route observation point density can be appropriately reduced, the principle is that all major geological boundaries, various mapping entities have a certain number of interpretation points control, layout focus on interpretation of the significance of the mark or route observation difficult to implement in the section, the corresponding key section interpretation points, fine interpretation.

2. The method for searching the oil sand enrichment area in the Tibetan region according to claim 1, characterized in that: In the S3, further comprising the following steps: S3-1, Triassic stratigraphic unit remote sensing geological features; S3-2, Jurassic stratigraphic unit remote sensing geological features; S3-3, Cretaceous stratigraphic unit remote sensing geological features; S3-4, Paleogene stratigraphic unit remote sensing geological features; S3-5, Neogene stratigraphic unit remote sensing geological features.

3. The method for searching the oil sand rich area in the Tibetan region according to claim 1, characterized in that: In the S4, further comprising the following steps: S4-1, carbonate rock remote sensing image features and interpretation; S4-2, dolomite remote sensing image features and interpretation.

Images