Sand Sources and Origin of Gaoqing Sandbody from Shahejie Formation in Boxing Basin of Shandong Province

Gaoqing sandbody in the third member of the Paleocene Shahejie formation in Boxing Basin is one of the important oil reservoirs in Dongying Sag.Analysis on the sandbody's isopach map and the sediment source of the Gaoqing sandbody has suggested that it is not originating from the Qingcheng Arch itself,but probably from the area northwest to the Qingcheng Arch.The Gaoqing sandbody mainly developed in the two periods of Es2 and Es1.At the early period,the Gaoqing sandbody expanded gradually from northwest to southeast,and the source of sands was relatively simple.During the late period,however,as the syndepositional faulting became more active in the area,the sandbody increased in thickness around the faults,and is characterized by massive to thick beds,intercalated with more mudstones.Based on the analysis of Gaoqing sandbody's macroscopic and microscopic sedimentary features,and compiling the sandbody's isopach map of each parasequence set,Gaoqing sandbody has been confirmed to be of fan delta sedimentation.