胜利探区埕岛地区前古近系断层发育特征及其油气地质意义OA

Based on detailed interpretation of 3D seismic data and drilling data,we systematically explored the developmental characteristics of pre-Paleogene faults in the Chengdao area using refined geometric structural ana-lysis and balanced cross-section techniques,and deeply analyzed their controlling effects on buried hill reservoirs,traps,and the hydrocarbon accumulation process.Results show that the dominant faults in the Chengdao area in-clude the Chengbei Fault,Chengbei 20 Fault,and Chengbei 30 Fault.As the main controlling faults of buried hills,we divided the Chengdao buried hills into three rows:the western,the middle,and the eastern ones.Moreover,during the Yanshanian period,the middle row and the eastern row of Hills were influenced by the sinis-tral strike-slip of the Tan-Lu Fault Zone,resulting in the development of a series of NNE-trending strike-slip faults,by which further divided the buried hills into several north-south trending strips.The nearly EW-trending reverse extension faults exacerbated the structural complexity,forming a complex east-west fault-block structural pattern in the buried hills.In structural styles and stress field characteristics,the Chengdao buried hill area was di-vided into an extensional tectonic zone,a transtensional tectonic zone,a transpressional tectonic zone,and a strike-slip tectonic zone.The main faults in the Chengdao area controlled the overall evolution of the buried hill struc-ture,while the subordinate faults determined the formation and distribution patterns of traps.In addition,differ-ences in fault activity were the main controlling factors on the differential enrichment of hydrocarbon reservoirs in the buried hills.The range of fracture activity controlled by large-scale active faults is between 270 m and 350 m.The intensity and duration of fault activity are positively correlated with the development degree of weathered crust and fractured reservoirs.Overall,the buried hills in the Chengdao district exhibit characteristics of multiple hydrocarbon sources and segmentation by major faults.