高分辨率层序地层学在北部湾盆地重点层系选段中的应用OA北大核心CSTPCD

Beibu Gulf Basin is one of the five major oil-bearing basins in the north of the South China Sea,with great potential for oil and gas resources and good exploration prospects.However,little research has been done on the thick Weizhou Formation in the Haizhong Depression,the third-level structural unit of the Beibu Gulf Basin.This significantlyhinders the hydrocarbon exploration in the Haizhong Depression.High resolution sequence stratigraphy is an effective method for stratigraphic division in geographic explora-tion frontiers.Using 3D seismic,well logs and core data,and on the basis of identification of second-order and third-order sequence boundaries on seismic profiles and wells,this paper uses maximum entropy spec-tral analysis,wavelet transform analysis and core analysis methods to identify and subdivide the high-reso-lution sequences of the Weizhou Formation.The results show that the maximum entropy spectral analysis has high resolution for third-order and fourth-order sequence boundaries;wavelet transform can analyze fourth to sixth order cycles and higher order cycles;Core data can be used for short-term and ultra-short-term cycle analysis.Based on 3D seismic,well logging,maximum entropy spectral analysis,wavelet trans-form technology and core data,the Weizhou Formation can be divided into 1 second-order sequence that includes 6 third-order sequences,which are in turn composed of 13 fourth-order sequences.According to the comparison of 13 fourth-order sequences,the highest sand ratio occurs in SQ6 LST,which is followed by SQ6 HST,suggesting great exploration potential.This study indicates that high resolution sequence stra-tigraphy of multi-scale and multi-method has certain guiding significance for screening key intervals in de-pression with low degree of exploration.