Characteristics Of Strike-slip Structure And It's Relationship To Hydrocarbon Distribution In The Subei Basin

This paper focuses on the strike-slip structures in the North Jiangsu Basin and is based on the theoretical guidance of structural geology,petroleum geology and seismic exploration principles,combining with previous achievement,fully utilizing the regional geological data,logging data and three-dimensional seismic data of the Su Bei Basin,the typical strike-slip structures in the study area are analyzed in detail,and the plane and section geometric characteristics of the strike-slip structures in the Su Bei Basin are defined.Using ANSYS software numerical simulation method and combining regional dynamics background,the genesis of strike-slip structure in Subei Basin is clarified,and the influence of strike-slip structure on oil and gas distribution is analyzed.By means of three-dimensional seismic data interpretation technology,the main faults in Subei Basin are interpreted,the results showed that the Yangcun,Zhenwu,Wubao,Shigang,Hanliu and Tongcheng fault zones have obvious strike-slip structural characteristics.Laterally,there are oblique structure,en echelon structure,feather structure,?-type structure and broom-like structure,vertically,flower structure,flower-like structure and broom-like structure are developed.Since the Late Eocene,the interaction between the near-NS extension and the right-slip interaction of the Tanlu fault zone have provided better dynamic conditions for the development of the strike-slip structure in the study area,through the tectonic evolution profile and activity analysis of the Shigang and Wubao fault zones shows that the Sanduo period is the strike-slip active period of the fault zone.Using ANSYS software to simulate the tectonic stress field in the North Jiangsu Basin,Jinhu Sag and Gaoyou Sag,the results show that the high value area of differential stress is the main fault development area in Subei basin,and the right-lateral shear property is the main factor for the formation of strike-slip structure in Subei basin,NE and NW trending faults are easy to form in high shear stress area,and near EW trending faults are easier to form in relatively low shear stress area.Further analysis of the stress field in the Shigang and Wubao fault zones shows that the high shear stress values are characterized by banded distribution along the trend of the fault zones.The NE-trending faults are developed in the high-value areas,which are derived from the right strike-slip process of the main faults.The faults near EW-trending are developed in the relatively low-value areas and T-trending faults are associated with the activities of the main faults..Strike-slip structures in the Subei Basin control the formation of hydrocarbon traps,according to different genesis,they can be divided into four types: fault block traps arranged in pinnate,fault nose and fault block traps arranged in echelon,fault nose and fault block traps located in broom-like faults,which control the formation of pinnate fault block reservoirs,echelon fault nose and fault block reservoirs,broom-like fault nose and fault block reservoirs.