Argillization mechanics of rock from the Xing'anling Group in the Beier depression of the Hailar basin

The reservoir of the Xing'anling Group in the Beier depression of the Hailar basin is loosely cemented with many tuffaceous grains. This causes argillization and collapse of the grain framework of the reservoir sandstones. A detailed study on the characteristics of rocks and minerals was carried out through polarized microscope, X-ray diffraction, X-ray fluorescence, SEM and energy spectrum analysis. The results indicate that the reason for argillization is the abundant pyroclastic, and especially tuffaceous, grains in the reservoir. The alkaline component is relatively high in some strata. These are easily altered to montmorillonite in diagenesis. Na⁺ montmorillonite swells strongly when exposed to water. This is the fundamental reason for the reservoir's argillization and plugging.