Abstract: Comprehensive analysis for principal target strata in piedmont of northern Tianshan Mountain is conducted, including the studies of fundamental characteristics of reservoir, diagenesis, and other important factors affecting the petrophysical properties of reservoir. It is recognized that the evolution of various reservoir is strictly constrained by regional and local tectonic movements, deposits distribution and diagenesis. The unfavorable factors affecting reservoirs are the unsuitable sedimentary facies belt where they situated, carbonate cementation and the separate out of auto-genetic clay minerals etc.,while the favorable conditions are denudation,peripheral mud film and carbonate cements supporting in earlier stage. The paper indicated that the relatively good reservoirs are Taxihe formation(N₁t) of Anjihai, Shawan formation (N₁s) of Dushanzi, Ziniquanzi formation (E_1-2z) of Hutubi, and Anjihaihe formation (E_2-3a) of Manasi.

Key words: Junggar basin, clastic rock, reservoir rock, diagenesis, evaluation