Large scale en echelon faults on the west uplift in Bohai Gulf,China
Peng Wen-xu1,2, Zhang Ru-cai2, Fan Jian-hua2, Mao Li2, Chen Lei2
1. Institute of Ocean and Earth Science, Tongji University, Shanghai 200092, China;
2. Bohai Oil field Exploration and Development Research Institute, CNOOC, Tianjin 300452, China
Abstract：Three groups of echelon faults(A,B,C) are founded in Neogene strata of Shaleitian uplift in Bohai Sea.Dimensional features show that the faults are arranged in left-hand step-over,en echelon faults distribute diagonally in Shaleitian uplift.From southwest to north,the faulting plane of group A of echelon faults becomes northing and NNW from north east,the faulting plane of groups B and C towards the north-east.Each group of echelon faults are composed by two pairs of echelon faults with different dip direction,which form partial barrier blocks,showing that there is a north-west broken zone or fault in the basement.According to seismic sections,the maximum vertical slip of en echelon fault is relatively small;most en echelon faults extend alone to the surface of buried hill.Few shallow regulation faults are found in local and they often combine main faults into various "Y" shape,which show that en echelon faults are alone and do not intersect in deep stratum.On sections en echelon faults form three groups of flower structures.Each group of flower structures in shallow stratum eventually converges in a main fault in the interior buried hill.Our research shows that en echelon faults are extensional and,at a certain stage of their history,may act as excellent conduits for vertical fluid flow.
彭文绪, 张如才, 樊建华, 茆利, 陈磊. 渤海海域西部凸起区大型雁列断层特征[J]. 石油地球物理勘探, 2011, 46(5): 795-801.
Peng Wen-xu, Zhang Ru-cai, Fan Jian-hua, Mao Li, Chen Lei. Large scale en echelon faults on the west uplift in Bohai Gulf,China. OGP, 2011, 46(5): 795-801.
