Deep volcanic reservoirs of Songliao basin have mainly been found in Huoshiling and Yingcheng Fms..The eruptive and overflow facies have better reservoir capacity

commonly with the porosity of 6.3%～10.8% and permeability of about 0.55×10

-3

～122.0×10

-3

μm

2

.The reservoir capacity of volcanic rocks has largely been affected by tectonism

solution and fluid activity.There are lots of fractures in volcanic rock due to tectonic activity during the volcanic-fault-depression period in Songliao basin

which would enhance the reservoir capacity.The eruptive tuffaceous volcanic has been mainly changed by leaching

and become loose and porous

with the porosity to be increased to over 15%.Fluid flow has double effects on reservoir capacity of volcanic rock

reservoir capacity would be reduced by cementation and filling of new minerals

but on the other hand

porosity would be increased by alteration and solution.These should

therefore

be studied separately by stages and periods.