Abstract: Comprehensive analyses of various data including core, scanning electron microscope, energy spectrum, thin section, fluid inclusion mineral assemblages and authigenic mineral forming temperature reveal evidences that hydrothermal clastic reservoirs exist in the Tarim Basin. The petrological evidences were found in the Silurian Kepingtage Formation in Well Zhong-1 as interlayers of ultrabasic intrusive rock, hydrothermal breccias, thermal burning phenomena and hydrothermal corrosion caverns. Three hydrothermal mineral assemblages were identified in the clastic reservoirs of Kepingtage Formation in Tazhong and Shuntuoguole area in Central Tarim Basin. Thermal fluids invasion occurred mainly in the Permian, causing the ionic disturbance of pore fluid. The dissolution in the clastic reservoirs accelerated the development of secondary porosity and the precipitation of hydrothermal minerals, which improved the overall reservoir quality and was an ignorable factor for the the formation of the clatic reservoirs in the Kepingtage Formation. The infusion of hydrothermal fluid would destroy the paleo-oil reservoirs, thus might play a key role in the formation of the Silurian asphalt sandstones in the Tarim Basin.

Key words: hydrothermal solution, mineral assemblage, secondary pore, clastic reservoir, Silurian, Tarim Basin