Abstract：The tectonic background of the east area of the Wushi Sag in Beibuwan Basin is complex and there are few previous studies of the types, characteristics, quantitative descriptions, and formation mechanisms of the structural transfer zones in this area. In response, drawing on previous studies and seismic data and starting from the development of faults, this paper identified and classified the structural transfer zones in the study area via quantitative statistical methods such as the distance-displacement curve and the vertical buried depth-displacement curve. The identification marks and their characteristics were summarized. In terms of the structural transfer zones, their distribution laws, formation mechanisms, and relationships with oil and gas reservoirs were expounded. The following understandings were obtained: ① The structural transfer zones in this area are divided into 5 types, namely the collateral type, the overlapping type, the approaching type, the hinge zone type, and the collinear type. ② As for the collateral type of structural transfer zones, the main controlling faults have high levels of sequence and displacement and deformation are mostly adjusted and transferred by "hard connections", with a complex "Y" shape on the section. The overlapping structural transfer zones are parallel to each other on the plane and their fault sequences are low. Their control over the tectonic zones is weak and the section is in an anticline "soft connection". The approaching type connects the main faults by relay ramps. The middle sections of the main faults of the single-line structural transfer zones are open in finger shapes. The east and west sections are in opposite directions and the faults on the section are staggered, forming an "X" shape. The hinge zone type is in a horsetail shape on the plane, adjusting the faults to converge to the bending parts of the main controlling faults. It has the function of a-djusting the bending degrees and displacements of the main faults. ③ Different types of structural transfer zones, controlled by the tectonic background and boundary control conditions, have different distribution locations. The collateral type is widely distributed throughout the region. The overlapping type and the approaching type are in the northeast. The collinear type is in the central and northern region and the hinge zone type is close to fault No. 7. ④ The NE basement faults lay the foundation for the formation of the structural transfer zones. Under the combined action of the slip of the Ailaoshan-Honghe fault zone, the expansion of the South China Sea, and the tensile stress generated by mantle upwelling, segmented fault growth became the immediate cause of the structural transfer zones. This study enriches the structural system of transfer zones, fills the gaps in the study of the structural transfer zones in the Wushi Sag, and provides a reference for the identification of transfer zones and the selection of favorable zones in a complex geological environment.
董方, 吴孔友, 崔立杰, 李彦颖, 周培兴, 董文馨. 北部湾盆地乌石凹陷东区构造转换带识别及其特征[J]. 石油地球物理勘探, 2021, 56(5): 1180-1189.
DONG Fang, WU Kongyou, CUI Lijie, LI Yanying, ZHOU Peixing, DONG Wenxin. Identification and characteristics of structural transfer zones in the east area of Wushi Sag, Beibuwan Basin. Oil Geophysical Prospecting, 2021, 56(5): 1180-1189.
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