Abstract: The lower Siegenian sand reservoir is the main target in D block of Algeria. The reservoir characteristics and control
factors on the exploration potential evaluation and development has important implications. After the analysis，we find out that
the lower Siegenian sandstones are quartzarenite，litharenite and lithic quartz. Secondary pores with a few microfissure are the
main types of pores in the studied region，such as intergranular，intragranular dissolved pore. The pore structure is mainly in
fine throat with middle-small pore. Reservoir property is poor，belonging to low-medium porosity and low-poor permeability.
Reservoir quality is mainly controlled by depositional environment and diagenesis. The main impacts on reservoir property in
diagenes are compaction and dissolution，cementation and replacement are secondary.

Key words: Algeria, deposition feature, pore structure, impact factors, diagenesis