INVERSION STRUCTRURE AND ITS IMPLICATION TO HYDROCARBON ACCUMULATION IN WEIXI EXPLORATION REGION OF THE BEIBUWAN BASIN

It was indicated that there were two different inversion structures formed in two period based on analysis of seismic profiles in Weixi exploration region of the Beibuwan Basin.The first inversion structure was developed during the end of the Oligocene and the second during the end of the Miocene.These two periods of inversion structures can be divided into two types which were fault type and fold type.Formation of these inversion structures was resulted from the directional and qualitative adjustment of regional stress.On the one hand these inversion structures formed favourable traps,and on the other hand these inversion structures caused the early faults reactivation and made for oil migration.In addition,the formation periods of these inversion structures were matchable with the peak stages of hydrocarbon generation and expulsion.These inversion structures are preferred targets for finding giant-medium size of oil-gas fields.