DISTRIBUTION CHARACTERISTICS OF UPPER PALEOZOIC DEEP STRATA SERIES IN SONGLIAO BASIN: Evidence from Comprehensive Geophysical Data

As the Carboniferous-Permian strata in Songliao Basin and its periphery are widely distributed with large thickness, the prospect of oil-gas resources is of great concern, yet the residual characteristics of the Upper Paleozoic strata cannot be clearly described by the relevant information of deep strata series obtained currently, thus the Carboniferous-Permian strata in the deep part of Songliao Basin remains to be studied systematically and carefully. Based on 2D deep reflection seismic section and gravity data of the basin, the distribution and occurrence characteristics of target strata series and preservation status of Carboniferous-Permian strata superposed by multi-stage structures are obtained by means of strong constrain stripping method, fine interpretation of seismic data and multi-information fusion inversion of logging data. The results indicate that the Upper Paleozoic strata can be roughly divided into north, middle and south zones. The present Carboniferous-Permian strata still retains the E-W uplift and depression fold structure formed under the influence of Paleo-Asian Ocean plate. The influence of Pacific plate is different in the north and south of basin during the Mesozoic. The Carboniferous-Permian in the fault depression of basin is characterized by deep burial, thick strata, thick cap rock and good preservation.