Seismic Structure Interpretation And Study On Structural Feather In The Northwestern Beier Depression

This paper is based on theories of structural geology and sequence stratigraphy and seismic data and logging data about northwestern Beier Depression, from the point of view tectonic evolution, deforming and distribution of the major unconformity as a main line, the seismic structure interpretation is carried out. First, based on horizon calibration and associated wells seismic geology interpretation, interface characteristics of main reflective layer are summarized, and three dimensional velocity field is established and structural features are made by making use of stacking velocity spectrum. Second, based on structural diagram and seismic section, structural feature and fracture feature are analyzed and summarized, including the tectonic pattern division, the main structural styles, and distribution characteristics of the fracture plane. Third, use tectonic development history sections, formation thickness and structural diagram to divide tectonic evolution stage. Last, discuss the relationship of structure and hydrocarbon.Based on the unconformity represented by three important seismic reflection interface T5, T22and T04, strata can be divided into3structure zones:rift structure, fault sag structure and depression structure. Mainly based on the T5reflector layer structural configuration, the rift tectonic unit in the area is divided into one negative secondary structural unit (depression belt in northwestern Beier) and three positive secondary structural unit (monoclinal tectonic belt in western Beier, Huoduomoer tectonic belt and Sudeerte tectonic belt). According to the fault structure geometry on the seismic profiles, structure style mainly includes3types, they are extensive structure, shear structure and inversion structure. The extensive structure can be divided into warped fault block and fault slope break belt. The inversion structure can be divide into folded inversion and fault inversion. Main extension direction of fault in early is NEE or NE, and the number of faults those extension direction is nearly SN in middle advanced is increasing. The seismotectonic development history analysis showed that the area exists5tectonic evolution stages:initial tension stage in faulted period, rapid subsidence stage in faulted period, stable tension stage in fault sag period, atrophy stage in fault sag period, inversion stage in depression period. Two aspects of relationship between fracture and hydrocarbons, tectonic belt and oil and gas show that growth faults in Huoduomoer region controls the distribution of hydrocarbon source rocks and also is oil source fault, and control the formation and distribution of trap. Tectonic belt in Huoduomoer and Sudeerte is beneficial to fracture oil and gas accumulation zone.