Reservoir spaces of the Tertiary volcanic rocks in Oulituozi region

Liaohe Basin are generally developed in trachyte

tufflava

lava

trachydacite

brecciated trachyte

proclastic rocks

brecciated lava and can be divided into two main types. Primary pores include vesicles

inter-crystal pores

inter-breccia pores

cooling joint; the secondary porosity includes solution fissures

voids and structureal fissures. Vesicles and solution pores are the most important pore types in this area which occupy 65%～70% of the total amount of the porosity. Based on the statistics of mercury method and image plane scanning associated with the ratio curves of porosity and permeability

the reservoirs could be divided into four types. Type-Ⅰ and types-Ⅱ are favorable reservoirs. Four evolution stages of the reservoir spaces have been identified in Oulituozi region. Favorable reservoir spaces were mainly formed in the first and second stages.