Abstract: Volcanics in Dawa oilfield. mainly distributed in Cenozoic Fangshengpao formation and Mesozoic, ure of layered distribution. com-posed of such lithologies as basalt, andesite, volcanic breccia aurd tuffs, of which volcanic breccia is a key reservoir of Mesozoic. The analysis of volcanic petrology indicates that he volcanie lithofacies can be divided into volcanic breccia, lava, ash and sedimentary oncs. The epidiagenesis types of volcanics and their effects on petrophysical properlies of the volcanic reservoir ure revcaled. On the basis of analyses of valcanic lith(-facics, epidiagenetic variation and petrophysical property. the evaluation of volcanic reservoir is rmade. dividing il into I. I and III types. predict-ing the plane distribution of il, and providing basic information and data for studying the volcanic reservoir in Dawa oilfield in this paper.

Key words: Dawa oilfield, volcanic rock, reservoir, lithofacies, Mesozoic