Rushing out firstly the oil flow off the wellhead from the delta-front sandbodies of Qingshankou Group

give rise to a new ground for exploration activties in Qijia depression

Songliao basin.Qijia depression measures about 2

000 km

2

situated between Daqing anteclise and Taikong uplift.Its structures are quite simple

in addition to some faults

the positive structures are mainly anticlinal noses and mid-depression ridges

with 8 small anticlines found during detailed seismic examination.In this region

the lithofacies of Qingshankou and Yaojia Fms are complex.Deposition occurred mainly in transitional fluvio-lacustrine zone

therefore

a great many of sand-bodies were formed with different size and morphology.Under the control of above conditions

the main trap-types are supposed to be stratigraphic and composite stratigraphic-structural ones which may hold the larger part of poten-tial reserves.Now

the oil-gas exploration are well underway on a large scale.