Abstract: Generation, migration, accumulation, preservation and dispersion of hydrocarbon are always associated with or accompanied by formation water. The moving formation water acts as the driving force and the carrier for oil-gas migration, accumulation and dispersion, and its chemical compositions can directly or indirectly reflect the environments and conditions of hydrocarbon occurrence. The movements of formation water and hydrocarbon are of interdependent and inter-restricted relationship. This paper studies the evolution of oil, gas and water in hinterland of Junggar basin from point of view of hydrogeology, analyzes the mutual action among them and the effect of formation water on the formation and distribution of oil-gas reservoirs, including applying some ions and characteristic factors of formation water to reflect the closed relations among the preservation conditions of the oil and gas, the closing degree of reservoirs and the oil-gas migration for the purpose of searching for favorable oil-gas accumulation zones by the varied features of formation water. It is suggested that study of hydrogeology of field water from different areas and different horizons is also a method for exploring oil-gas reservoirs, which can provide essential basis for the oil and/or gas prospect evaluation in this basin.

Key words: Junggar basin, formation water, oil-gas generation, migration, accumulation, preservation, petroliferous evaluation