Structural-Sequence Stratigraphy And Depositional System Research Of Paleogenein Baxian Depression

Depart from the whole Baxian depression, the structure controlling the depositional system, and the applications of the principle and theory of sequence stratigraphy, the article analyses the function of the basin-controlled fault to the sequence architecture, the function of the transverse transfer zone to the provenance orientation and the function of the paleostructure and the paleotopograhy to the sandstone bodies distribution ,discusses the vertical and plane distribution of the depositional systems and sedimentary facies. Based on the integrated analysis of cores, well logging, seismic data and other basic data, the sequence stratigraphy and the depositional systems of Paleogene of Baxian Depression are studied. The sequence of Paleogene is one 1st order sequence, and which can be divided ulteriorly into three long-term base-level cycles (2st order sequence) and 10 intermediate-term base-level cycles (3st order sequence). The Baxian depression can be subdivided into three subsections in north-south and west-east orientation by Niudong fault, every paleostructure-paleotopograhy unit has evidently difference of sequence strata architectures and the types of sedimentary facies.There are over ten types of depositional systems and sedimentary facies of Paleogene in Baxian depression. Every paleostructure-paleotopograhy unit has different architectures of sequence stratigraphy, types, modes, and characteristics of depositional systems. Different orders of the transverse transfer faults control the provenance systems'development and the distribution of the depositional systems and the sand. The first and the second order of the transverse transfer faults dominate the provenance system in the south and north depression, the third order of the transverse transfer faults mainly restrict the development of the depositional systems and the sand distribution in part area. The slope zone sediment the different types of delta. Based on the architecture of the structure-sequence stratitgraphy and the distribution of depositional systems, the article analyses the four basic conditions of subtle trap in Baxian depression. The different paleostructure-paleotopograhy unit has different exploration orientations, the middle Wen'an slope is the best advantageous zone for the subtle traps.