Stratum Framework And Distribution Characteristics Of Cenozoic In Qingdong Sag

Qingdong Area is located in the combining site of east part of Jiyang Depression and Tanlu Fault Zone and it is one of the area which has the lowest exploration degree in Shengli Oilfield.The scholars has no clear understanding of development Characteristics of Cenozoic in this area which has influenced the oil and gas resourse assessment and exploration of Qingdong Area.Therefore, the paper studied the vertical variation, distribution characteristics and controlling factors deeply started with stratigraphic division and correlation of Cenozoic and predicted favorable hydrocarbon zones preliminarily.First, the paper made multiple stratigraphic division of tectonic layer and lithostratigraphy to Cenozoic starting with materials of seism, well logging and regional geological background. And then the paper summarized the characteristics of every stratigraphic unit in parts of lithology, well logging, seism, palaeobiology and established stratum framework of Cenozoic in Qingdong Area. Cenozoic can be divided into Paleogene and Neogene to Quaternary these two tectonic layers. And Paleogene in Qingdong Sag develops Kongdian Formation, Sha-4 Member, Sha-3 Member, Sha-2 Member from bottom to top with Sha-1 Member and Dongying Formation loss. The development characteristics of strata in Qingdong Sag are kind of similar to those which in Dongying Sag except the incompleteness in vertical stratigraphic succession. Paleogene in Qingdongdong Sag develops Kongdian Formation and Sha-4 Member which are similar to Weibei Sag.Combining with drilling calibration and interpretation of seismic cross sections, the paper drew remnant strata thickness isograms of four tectonic sub-layers in Paleogene, analyzed the distribution characteristics of strata and contrasted the distribution characteristics of Paleogene with surrouding area. The research showed that the direction of distribution changed from NW to EW to NEE to NE and the area with the thickest remnant strata changed from south to north from Kongdian Formation to Sha-4 Member to Sha-3 Member to Sha-2 Member. The variation of Paleogene distribution in Qingdong Sag are similar to those in Dongying Sag ang the variation of Paleogene distribution in Qingdongdong Sag are between those in Weibei Sag and Laizhouwan Sag.In order to study how the tectonic movment influence the Cenozoic development in Qingdong Area, the paper analyzed the activity of major faults. The trends of those faults which actived strongly in Kongdian period are almost NW or EW. The trends of those faults which actived strongly in Sha-4 period are all direction. The trends of those faults which actived strongly in Sha-3 to Sha-2 period are almost NEE or NE. The paper also found that the plate motion, variation of strike-slip nature of Tanlu Fault Zone and the movement of the mantle plume influenced Cenozoic development significantly combining with the regional geological background.On the basis of understanding the Cenozoic development and controlling factors, the paper analyzed the favorable hydrocarbon source rocks in Qingdong Sag, drew thickness and Ro isograms of Sha-4 upper subinterval and Sha-3 lower subinterval and then predicted favorable hydrocarbon zones preliminarily. The results shows that the distribution range and maturity of Sha-4 upper subinterval are better than those of Sha-3 lower subinterval and it's the main hydrocarbon strata in Qingdong Sag.