Surface Structure Interpretation And Hydrocarbon Microseepage Alteration Information Extraction Based On Satellite Images

The western kuqa Depression is located in the north of Tarim Basin.Cenozoic thick-crust extrusion salt structures are widely developed in the area,and various salt structures are developed in the salt overlying layers.The deformation of the subsalt basement is strong,and many oil and gas traps and large oil and gas fields are formed and discovered.At the same time,the multi-stage tectonic movement in the study area led to the development of abundant fault structures in different stratigraphic sequences such as salt overburden,intersalt and subsalt strata,which provided good migration channels for oil and gas reservoirs in the area.Due to the close relationship between the location of fault structures and the location of oil and gas reservoirs,the interpretation of fault structures in the study area is of great significance.With the development of aerospace technology,remote sensing technology is gradually being applied to geological research.Compared with traditional technology,remote sensing has the characteristics of low cost,wide coverage,high efficiency and high security.In this paper,landsat-8 image data were selected as the data source,combined with regional geological data,to understand the geological information of the study area,such as stratigraphic lithology,fold and fault structure and salt dome.Using Sentinel-2A image data as data source,the hydrocarbon microseepage alteration information in the study area was successfully extracted,and the close relationship between the alteration information and fault structure was analyzed.Based on the extraction results of hydrocarbon microseepage alteration information,supplementary interpretation of concealed fault structure in the study area was carried out,and the interpreted fault structure was also verified.The specific research results are as follows:(1)The remote sensing images of the study area were pre-processed,including radiometric correction,atmospheric correction,image fusion,image Mosaic and clipping.The geological interpretation of the study area was carried out with landsat-8 remote sensing image data as the main data and Sentinel-2A remote sensing image data as the auxiliary data.The lithology,structure and salt domes of the study area are defined and interpreted,and the image characteristics of geological interpretation are also described.Finally,8 sets of stratigraphic units,31 fault structures,2 types of fold structures and 4large exposed salt domes were interpreted.(2)After fully understanding the spectral characteristics of altered minerals and the characteristics of each band of Sentinel-2A data,the band ratio method was used to mask the interference factors in the study area,and then the principal component analysis of feature vector was used to select four characteristic bands for principal component analysis.Finally,the anomaly information of carbonate mineralization,clay mineralization and red layer fading alteration is successfully extracted.(3)By superposing the extracted alteration information with the existing geological data,geological interpretation information and known drilling positions in the study area,a high correlation between alteration information and fault structure distribution is found,which verifies the interpreted fault structure on the surface and confirms the accuracy of alteration information extraction.The hidden fault structures in the study area were interpreted by using the mineralized alteration information of hydrocarbon microseepage.Finally,6 hidden fault structures were interpreted and 19 fault structures were verified.The1:50,000 fault structure interpretation map of the western section of Kuqa Depression was drawn.