开鲁盆地奈曼凹陷北部地区下白垩统地层剥蚀量恢复及其对油气藏的影响OA北大核心CSTPCD

Restoring the thickness of stratigraphic erosion is a crucial foundational task in studying basin evolutionary history and evaluating oil and gas resources.In the Kailu Basin,the Naiman Sag is an important sedimentary depression with relatively low exploration.This study employed the seismic stratigraphic thickness trend method,complemented by structural and sedimentary synthesis,to restore the ancient stratigraphic thickness and delineate the range of stratigraphic erosion in the upper and lower sections of the Jiufotang Formation from the Lower Cretaceous in the northern area of the Naiman Sag.By integrating the structural evolution and sedimentary facies characteristics of the Naiman area,the study pinpointed the subsidence center in the northern part of the Naiman Sag near the Nai 10 well area.It also clarified the original sedimentary facies distribution characteristics during the Jiufotang Formation period.Regarding material source supply,it was determined that the northern material source,hindered by long transport distances and challenges in erosion preservation,failed to deposit significantly.The primary sources were identified as fan delta facies deposits from the western steep slope zone and braided river delta facies deposits from the eastern gentle slope zone.Additionally,the study revealed that the geological model of the ancient stratigraphic thickness in the Lower Cretaceous of the northern area of the Naiman Sag is characterized by intense uplift and erosion,particularly in the northeast direction,with a broad erosion range and significant erosion thickness.This study provides valuable insights into the structural evolution history and the oil and gas accumulation process of the region.The methodologies applied in this study are also of referential significance for erosion recovery studies in similar sedimentary basins.