THE APPLICATION OF TRACE ELEMENT TO THE STUDY ON PALEOSALINITIES IN SHAHEJIE FORMATION OF DONGYING BASIN SHENGLI OILFIELD,

In this paper,the authors measure the trace elements, such as B, Ga, Sr and Ba, from a total of 131 samples in 4 wells of Shahejie Formation of Lower Tertiary in the northern Dongying Basin with atomic absoption spectrophometer. Salinities of water as deposited in Shahejie Formation was specified qualitati-velybased on the content of boron with equivalent boron,the ratio of B/Ga as well as Sr/Ba.Paleosalinites have been calculated with the formulas Adans, T.D.and Walker,C.T. in accordance with the data of clay mineral analysis and the measure boron content.The results shows that salinity in some strata of the fourth member of Shahejie Formation in the northern Dongying Basin gets as high as 31‰, 24.3‰ in the lower part of the third member of Shahejie Formation, and 7‰ and 8.2‰ in the middle and npper part in the thirt member and in the second member respectively, whereas it run up to 15‰ in the first member, particularly in the lower part of the first member of Shahejie Formation.The study is of quite significance both to the determination of sedimentary enviroment and the evalu tion of the source rocks and reservoir in Lower Tertiary.