Hydrocarbon Sourced From The Kongdian Formation And Its Accumulation In The Jiyang Super-depression

The Ek₂ source rock was first founded from the Well Wang-46 in the Dongyin depression in 2004. Oil accumulations discovered in the Wangjiagang, Well Fengshen-1, Gaoqing, Linfanjia, Linshang and Gubei-Bonan areas were believed as a genetic relation with the Ek₂ source rock. This paper conducts an oil-source correlation and hydrocarbon accumulation model over those areas, and finds an excellent hydrocarbon potential of the Ek₂ source rock for oil accumulations in the studied areas. Therefore, this investigation gives new ideas to oil exploration in the Jiyang Super-depression.Having investigated on oil accumulation process, four accumulating models are established in the Wangjiagang area.(1) oil is generated and accumulated in the Kongdian Formation; (2) oil is generated from Ek₂ but accumulated in the Ordovician buried-hill; (3) oil is sourced from Es4 and stored in the same and upper strata; (4)oils in some reservoirs are generated either from Ek₂ or Es₄ source rocks, i.e. the mixed oil. According to geochemical features of the mixed oil, the oil from the Ek2 source rock is about 50～80%. The Ek₂ and the Es₄ oil kitchens, the trap efficiency and the migration pathway control the hydrocarbon accumulations in the Wangjiagang area.On oil-source correlation, it recognizes that the oil from Ek₂ source rock is common in the studied areas, and always mixes with the oil from Es4 source rock. The lithologic and"salt base"structural traps are the most advantageous locations for condensate and cracking gas in Es4 and Ek1 in the steep slope zone and central anticline zone in the Dongying depression. Linshang fault zone, north of Linfanjia structural belt and Fanjia anticline are advantageous places for exploring structural reservoirs in the Kongdian Formation, buried hill traps in the hanging walls of the boundary faults and the"salt base"traps are also have perfect prospect in Gubei -Bonan sag.