Abstract:

Through thin-section, casting thin-section and scanning electron microscope, the authors ascertain rock types, diagenesis patterns and pore types of Shangkuli Formation. It was considered that rock types consist of vocanic breccia, ignimbrite, crystal-debris tuff，vitric tuff，multi-clastic tuff and sendimentary tuff etc. And diagenesis includes compaction, alteration, devitrification, authigenesis, erosion-dissolution and cementation etc. While diagenetic phases of Shangkuli Formation in Labudalin basin are divided into B stage of early diagenetic phase and A stage of middle diagnetic phase. And pore types are mainly comprised by intergranular pore, filling inner pore and solution pore, and so on. Pyroclastic rocks belong to reservoir beds with medium-low porosity and extra low permeability. It was thought that mechanical compaction, authigenic ankerite and precipitation of authigenic kaolinite reduced physical properties of the reservoir, while authigenesis of chlorite and microcrystalline quartz coatings and erosiondissolution may improve them.

Key words: Labudalin basin, Shangkuli Formation, pyroclastic rock, diagenesis, reservoir, pore types