Binnan Oilfield is located in the north of Shandong Province. It is one of the Shengli Oilfields. Commercial oil was discovered in Late Eocene basalts in 1982. The effective thickness of the basalt reservoir rocks is about 13.5m. The maximum porosity is up to 25%. The main pores are vugs resulted from lea-ching of augite and basic volcanic glass in the vadose zone. A part of the pore space is filled by vadose silts

vadose ooids and vadose pisolites. Favourable conditions for the formation of the basalt reservoir are:the basalts spreaded over high paleogeomorphic and paleotectonic position

and had a great deal of tec-tonic fractures which could provide lots of passages for meteoric water to flow

it was very favourable for the formation of basalt reservoir with bigger thick-ness and higher porosity.