大民屯凹陷西陡坡古近系岩性地层油气藏勘探

Exploration of Paleogene lithostratigraphic reservoir in western steep slope of Damintun Sag,Liaohe Oilfield

大民屯凹陷西陡坡在古近纪早期由边界断层控制形成,发育凸起—陡坡边缘、陡坡—洼陷边缘两个断裂坡折带。西陡坡的物源供给是形成岩性地层油气藏的重要条件。应用层序地层学原理,大民屯凹陷古近系可划分为1个二级层序、3个三级层序。三级层序可进一步划分为深断陷和浅断陷两种类型,深断陷型层序油气成藏条件好。断裂坡折带控制形成的低位域砂砾岩体及湖侵域的砂体是岩性地层油气藏勘探的重点目标。运用地震储集层预测技术预测的砂砾岩体的空间分布经钻探证实。

The margin fault controlled the formation of the western steep slope in the Damintun Sag during the early Paleogene, and two fracture slope break zones including salient-steep slope margin and steep slope-subsag margin were developed. The source supply of western steep slope was the important condition for forming the lithostratigraphic reservoir. In terms of sequence stratigraphical principles, the Paleogene can be divided into one 2-order sequence and 3- order sequences. The 3-order sequence can be further divided into deep-faulted sequence and shallow-faulted sequence, with the former one having excellent reservoir conditions. The sandstone body of low-stand system and the sandbody of lake transgression under the control of the fracture slope break zones are important targets for the lithostratigraphic reservoir exploration. Drilling proves the predicted spacial distribution characteristics of sandstone body.