Sedimentary evolution of the upper member of the Guantao Formation in northern Xinbei Oil Field, Shandong

The stratigraphic redivision and sedimentary facies analysis are made for the upper member of the Guantao Formation in northern Xinbei Oil Field, Shandong according to the core logging and well logs in combination with the previous data. The first three sand sets are redivided into 12 layers. The upper member of the Guantao Formation is composed of the delta plain subfacies which may be subdivided into distributary channel, interdistributary bay and natural levee microfacies, occasionally with crevasse splay microfacies, and the distribution patterns of the sedimentary facies were less variable. During the deposition of the upper member of the Guantao Formation, the sedimentary environments were relatively stable, and the sediments mainly derived from the northeastern part of the basin.