Abstract:

Achievements in determination of hydrogen and oxygen isotopic composition from stratum and oil field waters of various ages are used in discussing the origen of reginal ground waters and their regim of motion.Variation of these isotopes in Jizhong depression have their regularity both in horizontal and vertical directions.Three aquifers in this paper are discussed.Most of δD and δO¹⁸ values of Q-N aquifer system are plotted on δD-δO¹⁸ correlation curve of standard meteoric waters,with only few points shift not far to the right side.In samples,the ion contents,total solids,temperature and δD values are clearly correlated to each other.It is suggested by the author that this system is an admixture of meteoric waters with stratum ones.In E aquifer system,δD and δO¹⁸ values fall between curves of meteoric waters and SMOW.All values are concentrated in a highly restricted area and are higher than that of Q-N aquifer system.It proves that this kind of stratum waters is an admixture of ancient atmospheric waters with syngenetic depositional water.The Pz-Za aquifer system in "buried hill"traps has relatively stagnant hydrodynamic condition and is in dynamic equilibrium state with lower Tertiary stratum waters,differing from openly circulating ground waters in underlying"buried hill"system.Every water system is characterized by its own isotopic composition and hydrochemical index.This study provides some evidences for oil formation,migration,accumulation and preservation in region under consideration.