A Comparative Study Between The Deep Hydrothermal Fluid In Sinian Of Sichuan Basin,Silurian Of Tarim Basin And The Surface Hydrothermal Fluid In Jurassic Of Yili Basin

In this paper,the Sinian dolomite in the southeastern part of the Sichuan Basin and the Silurian clastic rocks in the Tarim Basin which is affected by deep hydrothermal fluids,and the Jurassic clastic rocks in Yili basin affected by surface hydrothermal fluids are studied.Based on the lithological characteristics of dolomite in Dengying Formation of Well Lin-1 in the southeastern Sichuan area,analysis of influence of deep hydrothermal fluid on dolomite,characteristics of clastic clay in Kepingtage Formation in Tarim basin,generation and migration of surface hydrothermal fluids in Jurassic of Yili basin.After a comparative study,we summarize the characteristics of deep hydrothermal dolomite and clastic rock,and the migration and production of surface hydrothermal fluids.The following main achievements were obtained:The dolomite of Dengying Formation in southeastern Sichuan is dominated by native grain dolomite,subject to strong hydrothermal effects.Hydrothermal dolomite petrographic characteristics significantly.After the analysis of the electron probe,the changes of the elements in the formation of hydrothermal dolomite were studied.The changes of the elements in the formation of hydrothermal dolomite were preliminarily understood,and it was found that several deep hydrothermal fluids invaded during the formation of hydrothermal dolomite.A variety of high temperature and low temperature hydrothermal mineral combinations are found in the clastic rocks of the Kepingtage Formation cement in the Tarim Basin.It is concluded that the carbonate minerals in the clastic Stratum of the Kepingtag Formation are controlled by hydrothermal fluids.Based on the geological data,the summary of previous studies and the macroscopic characteristics of the core,it is found that there is a trace of high temperature baking in the Well Zhong-1,and it is inferred that the hydrothermal dissolution should occur during the Permian volcanic activity,which can form a favorable reservoir.The Jurassic surface hydrothermal fluid in the Yili Basin is a new concept that has just been put forward.In the dry climate,the spontaneous combustion coal seam can form surface hydrothermal fluid when the climate is changed to humid climate.The surface hydrothermal fluid flow path is mainly by permeable sandstone.The red sandstone under the coal seam show the impact of high temperature hydrothermal fluid,and the white sandstone show the impact of low temperature hydrothermal fluid.The relationship between surface hydrothermal fluid and sandstone type uranium deposit is proposed.The surface hydrothermal fluid is different from the deep hydrothermal formation,so the nature is different,for the transformation of the surrounding rock is also different.Deep hydrothermal formation in the deep high-temperature fluid activity,the main heat source of its hydrothermal fluid is provided for deep tectonic thermal events,the flow is mainly controlled by deep faults and other crack.The surface hydrothermal fluid heat from the coal seam spontaneous combustion,with is closed to the surface,the flow is limited by the permeability of the sandstone roof and floor.