High resolution sequence stratigraphic analysis of Qingyi section in Hei-258 area

School of Earth Science, North East Petroleum University, Daqing, China

^* Corresponding author: 541444920@stu.nepu.edu.cn

Abstract

In order to solve the problems of unclear division of the delta front pre delta facies belt of the first member of Qing Dynasty in Hei-258 area of Daqingzijing in the south of Songliao Basin and the lack of a unified fine isochronous stratigraphic framework in the whole region, the types and genesis of the cycle interface of the first member of Qing Dynasty are summarized by using the core data of a coring well and the logging data of more than 70 wells, combined with the theory of high-resolution sequence stratigraphy and sedimentology, Establish a high-resolution sequence stratigraphic framework and summarize the control of base level cycle on sedimentary evolution. The results show that the delta front subfacies are the main subfacies in the first member of Qinghe formation in Hei-258 area, and a small amount of pre delta deposits are developed in the northeast of the study area in some periods. The types of cycle interfaces are mainly Lake flooding surface of different levels, conversion interface from progradation to retrogradation or retrogradation to progradation, lithologic catastrophe interface, etc., and the short-term cycles are classified into three categories according to the structural style. The above understanding can provide a theoretical basis for the distribution range of sedimentary facies belt and the establishment of high-resolution sequence stratigraphic framework in Daqingzijing area.