原型盆地演化及其对沉积体系和成藏条件的控制作用OA

This study investigates the Jiufengshan Formation in the southern sag of the Dayangshu Ba-sin.Using fine-scale seismic interpretation and tectonic evolution restoration techniques,we reconstruc-ted the prototype basin of the Jiufengshan Formation and analyzed its controlling effects on sedimentary evolution and hydrocarbon accumulation.The results indicate that the prototype basin of the Jiufengs-han Formation was controlled by segmented boundary faults in the east,exhibiting a paleo-tectonic framework characterized by"deep in the east and shallow in the west,east-west zonation,and north-south block division".The Taipingchuan Sag in the north and Yulintun Sag in the center formed early and underwent long-term sustained development,whereas the Baoshan Sag in the south formed later.Tectonic evolution constrained the distribution of sedimentary systems:the eastern boundary faults con-trolled the subsidence-depocenter and facilitated the development of coarse-grained fans,while volcanic fans developed in the west.The subsidence center migrated from east to west,controlling the distribu-tion and thermal maturation of source rocks.The paleo-tectonic framework governed the development of favorable reservoir facies such as fan delta fronts.Late-stage tectonic activities formed faulted anticlines and faulted noses,creating a reservoir assemblage characterized by"source rocks in the third member of the Jiufengshan Formation,reservoirs in the fifth member,and caprocks in the Ganhe Formation".The Jiufengshan Formation in the southern depression possesses a petroleum resource potential of 8.19× 107 t.The Taipingchuan Sag and Yulintun Sag characterized by thick source rocks,high thermal matu-rity,and stacked multi-stage fan reservoirs,are identified as favorable zones for future hydrocarbon ex-ploration.These findings provide a scientific basis for understanding hydrocarbon accumulation patterns and guiding exploration deployment in the Dayangshu Basin.