Chemical Features Of Formation Water And The Relationships With Oil/Gas Pool In Xu Jiaweizi Fault Depression

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 geochemical features 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 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 issuggested that study of hydrogeology of field water from different areas and different horizons is also a method for exploring oil-gasreservoirs,which can provide essential basis for the oil and gas prospect evaluation in this basin.Detailed vertical and horizontal exposition of the geochemical features in Xu jiaweizi was expounded in this paper,which were organic and inorganic contents and other trace elements.Some fingerprint coefficients were chose,such as aliphatic acid,phenol,aromatic hydrocarbon index,desulfidation coefficient,(rCl-/rMg2+)coefficient,(rNa+/rCl-)coefficient and so on.The preservation conditions of the gas,the closing degree of reservoirs and the gas migration was researched by making use of these fingerprint coefficients.By comprehensive study of many chemical characteristics,favorable place for prospecting were predicted.