Abstract:

The Beier depression in the Hailaer basin is an extensional faulted depression of the Early Cretaceous epoch.Based on seismic data and well logs, the evolution of Beier depression is discussed in this paper.It is concluded that alternation of extension and shortening is occurred through the evolution of this depression.Development of three sedimentary cycles，superimposition of extensional and inversion structures, and formation of oil reservoirs were controlled by three activities of tension and compression in the Early Cretaceous epoch.In general, the processes of extension and shortening control the structural styles and sedimentary cycles, and also are responsible for the distribution of source-reservoir-cap rock assemblages, and the migration, accumulation and preservation of oil and gas.

Key words:  Beier depression, extensional faulted depression, compression, inversion structure, reservoir