The Precise Correlation Study On The Oil Groups Of Nantun Formation In Beizhong Zone Beier Depression

Wuerxun and Beier Depression are two of the most potential depressions in Hailaer Basin which are characterized by complex tectonic interpretation and fast facies changes. The study area Beizhong Zone is situated in the middle of Beier Depression which includes Beizhong sub-depression and Huhenuoren Faulted nose structural zone. The study formation is Nantun Group.This thesis is based on a large number of drilling,logging and 3-D interpreted seismic data,incorprating drilling core data, using the tectonic and depositional evolution history as settings,appling the terrigenous sequence stratigraphic theory to build up the sequence stratigraphic framework of the Nantun formations. Through well-seismic calibration, the correlation of the 3-rd order sequence is accomplished in Beizhong Zone.After completing the high-frequency sequence stratigraphic division and correlation of the oil groups of the two main oil fields,analying the development character of the oil groups,several research results are achieved restrained by the 3rd order sequence stratigraphic framework.The research results are much as follows:1.The achitecture character of the depositional systems and temporal-spacial relationships of Beizhong Zone which are the main structural units are analyzed based on the past research results.Through the core observation of different structural position, identification of character of the logs assemblage and the precise interpretation of the seismic data,using classic theory of sequence stratigraphy as guidance, Nantun Formation are classified into 2 third-order sequence.2.By means of the control of the 3rd-order sequence,seismic restraint,transition surface and the stacking patterns of the drilling/logging,the division and correlation of the high-frequency cycles are completed. The formation and the distribution area are controled by the factors of their provenance systems,variation in tectonic subsidence and paleo-topography, taking advantage of the precise analysis of the system tracts of the 3rd-order sequences,the relationships of the high-frequency cycles which are corresponding to oil groups are made clear.3.Guided by the principles and analysis methods of the high-resolution sequence stratigraphy,confined by oil groups,the high-frequency time surfaces are identified by the analysis of response of stratigraphy and sedimentology which are controled by the ratio of accomodation and sediment surpply,and standard profiles of the layer correlation of oil field of Beizhong Zone are built up.4.By means of core observation, identification of the eletro-facies and the seismic facies of the study area,the research found that four depositional systems mainly developed in the study area during Nan-one Member and Nan-two Member period. They are alluvial fan, fan delta,braided delta and lake...