A Study On Oil And Gas Accumulating Conditions And Models Of Buried Hill In Sudeerte Area Of Beier Depression

The buried hill is the most important reservoir in Sudeerte area.But because of weathering-crust-type reservoir rock and high buried depth,It has seriously affected the further study of oil and gas exploration.So that it is of great significance to study the oil and gas accumulation conditions and patterns in the buried hill in Sudeerte area for correctly understanding the oil and gas distribution rules and guiding oil and gas exploration.This paper is based on the regional structure and stratigraphic research,using drilling,logging and seismic data,find out the accumulating conditions in oil supply condition of source rock,storage condition and shielding condition.And get them together with the vertical and horizontal distribution characteristics of oil and gas,summarize the hydrocarbon accumulation.Finally,the favorable target of hydrocarbon accumulation is predicted.The research results and understanding of this paper are as follows:1)The oil and gas in Sudeerte area are mainly from the source rock of the K₁n_1,which is in rich organic matter,well type and moderate evolution,and can provide oil and gas for Sudeerte buried hill.The hydrocarbon supply focus on the south section of source rock is mainly distributed in the north,and the hydrocarbon supply window is mainly formed by connecting the fault with the buried hill side,and there are 5 main hydrocarbon supply Windows in Sudeerte area.2)The oil and gas reservoirs in the buried hill in Sudeerte area are mainly weathering crust reservoirs,distributed within 300m from the top of the buried hill,and the physical properties of the reservoirs gradually deteriorate from top to bottom.On the plane,the weathering crust reservoirs at the high position of the structure are more developed.3)The vertical sealing ability of the fault cover configuration in the buried hill fault activity period in Sudeerte area is poor,but the lateral sealing ability of the fault is relatively good after the fault activity stops,which is conducive to oil and gas accumulation and preservation.4)Oil and gas in the buried hill in Sudeerte area are mainly distributed within 300m from the top of the buried hill,and mainly distributed in the high part of the structure on the plane.The type of oil and gas reservoir is fault block oil and gas reservoir.5)The hydrocarbon accumulation model of the buried hill in Sudeerte area is that the source rock in the south part of the Bessie trough is connected with the buried hill to form a hydrocarbon supply window,and the hydrocarbon mainly moves and accumulates in the weathering crust reservoir through fracture and unconformity trap in the buried hill.6)There are three favorable targets for the buried hill in the Sudeerte area.The first one is located in No.6 trap,near well Bei 40-B63-60.The second is located in No.7 trap,near well Bei 14-5.The third is located in No.10 trap,near well De 112-227.The research results can be used in guiding significance for oil and gas exploration in the buried hill of Sudeerte area.