Provenance, Sedimentary System and Beach Bar Distribution of the Upper Es⁴ in Qingnan Area, Dongying Depression

Key words: 
• Qingnan Area /
• Upper Es⁴ /
• Provenance Characteristics /
• Sedimentary Evolution /
• Beach Bar Distribution

Abstract: The provenance and sedimentary facies of the upper Es⁴ of Qingnan area, Dongying Depression lack systematic research, especially the distribution and scale of lacustrine beach-bar sediment, which restrict the precise exploration and reserves promotion in this area. This paper determines the types of sedimentary facies through petrological study, clarifies the sedimentary evolution by using logging methods, cleares the provenance direction and influence range using heavy mineral assemblage and the distribution of characteristic element ratio, and thus restricts the distribution of different sedimentary facies controlled by different provenance, especially the precise distribution of each sand-body, which can provide references for precise exploration of the oilfield. According to the research, there are four sedimentary systems(alluvial fan, delta, lake and gravity flow)and five sedimentary facies(coastal subsea apron, delta, fan delta, lake and deep water turbidity fan)in the study area; The boundary of southern and northern provenances lies along the line X7-Wx583-W58-W126-L74-Wx119-L108-L2-L64-Lx63, the southern Guangrao Heave provides a massive provenance to the north and northwest, nevertheless, the northern Qingtuozi Heave provides a limited provenance to the southwest; Delta sand-body exists through the whole Es⁴ and widely spreads from Guangrao Heave to northwest, deep water turbidity fan sand-body exists at the middle period of Es⁴ and distributes contiguously at the semi-deep and deep lake evironment in the northwest, fan delta sand-body exists at the late period of Es⁴ and has a limited distribution from Qingtuozi Heave to the southwest, beach bar sand-body exsits at the whole time of Es⁴ and has a wide range at the shore-shallow lake evironment, which has a range only smaller than delta sand-body and provides abundant potential reservoirs for lacustrine tight oil and gas.