Study On The Hydrocarbon Accumulation Characteristics Of Fu3Member In Zhangjiaduo Area,Subei Basin

In Zhangjiaduo area of Subei Basin, the type of Fu-3interval`s facies, reservoircharacteristics, abnormal pressure distribution, and the mechanism of hydrocarbon formationare not clear, which are directly Affect the efficient of oil development. This paper is based onthe observation of core, casting body slice, hydrocarbon fluid inclusions, use the knowledgeof reservoir geology, logging geology, reservoir geochemistry, combined with dates ofseismic, logging, and oil testing.We have distinguished the facies type of Fu-3interval inZhangjiaduo area types of sedimentary facies, recognized characteristics of reservoir,abnormal pressure and oil accumulation, identified reservoirs of Fu-3interval were beach andbar sands in the shallow lake, with medium porosity and low permeability, high clay contentand intragranular dissolution porosity make pores structure be complex, porosity distributionrange is from13%to17%, porosity and permeability are closely related. By undercompaction,many parts of Fu-3interval in Zhangjiaduo area have abnormally high pressure, reservoirscompaction are not strong and very different in different places, that lead to the reservoir,which was buried very deep, still has good reservoir properties. There are two belts ofAbnormally high pressure, Pressure coefficient in Eastern is higher than it in western.Hydrocarbon in Fu-3interval of Zhangjiaduo area was from source rocks in Fu-2formationwith two processes hydrocarbon generation. Eastern formation pressure coefficient isgenerally higher than the Western. the process occurred at43Ma to38Ma,15Ma to now, mostof hydrocarbon is generated in the late process.By study of reservoir, abnormal high pressure, and hydrocarbon formation, we haveclearly recognized the mechanism of oil accumulation in the pressure compartment and out ofthem, The reservoir type has been decided by the pressure compartment in good condition ornot. Hydrocarbon accumulation in Fu-3interval of Zhangjiaduo area is controlled bycharacteristics of reservoir and abnormal high pressure. The oil production is related to thequality of reservoir, the dominant migration direction of oil is determined by abnormalpressure distribution. For qualitys of reservoir have been significantly changed by the, oilaccumulation in the reservoir which has high pressure coefficient. Relief District reservoirdeveloped in Dainan formation or above them.