The volcanic rocks of the Lower Es3 in Oulituozi region are mainly volcaniclastic rock

basalt and trachyte.The volcanic rock diagenesis and reservoir space evelution are studied.It is considered that

different deposition stages have different paleo geothermal gradients

and different diagenetic stages correspond to different depths.Thick volcanic rocks from Sha-1 mumber to present are in the early diagenetic B-stage;the reservoir spaces are generally fissure-primary porosity and fissure compound porosity

and are poorly preserved;the volcanic rocks in the lower part are mainly well-developed fissure-secondarfy porosity.