Different types of volcanic rocks are developed in Songliao Basin.Exploration activities revealed that oil/gas shows occur in all the volcanic rocks.In order to further understand the characteristics of favorable volcanic reservoirs

a comparative study for reservoir space

pore structure and physical property is conducted by using core

thin section and test data.The distribution of primary voids are extremely uneven in different types of volcanic reservoirs

that of secondary pores and fractures is better

and that of primary micropores and fractures is relatively even.Five throat types are identified

including coarse throat

medium-coarse throat

fine throat on the high side

fine throat and very fine throat.There are 6 types of porosity distribution

including high porosity with single peak

high porosity with double peak

medium porosity

medium-low porosity

lower porosity and low porosi-ty.Permeability distribution can be grouped into five types

namely high permeability

medium-high permeability

medium permeability

medium-low permeability and low permeability.Based on the four parameters mentioned above

it is believed that vesicular rhyolite

rhyotaxitic rhyolite

spherulitive rhyolite

ignimbrite

brecciated lava and breccia reservoir have good poroperm characteristics

while tuff

massive basalt

tuffaceous breccia and sedimentary tuff are poor in reservoir quality.