Abstract:

Underground waters were involved in the entire proeesses of betroleum generation,migration,concentration and deterioration,An important approach for recognizing regularities of oil and gas distribution,therefore,is to study the evolution and motion of underground waters in oil- and gas-bearing basins. As for the case of Taizhou,Jiangsu proyince,hydrological phases and subphases are divided according to paleotectonic and sedimentary settigns. It is suggested that the form ation and preservation of oil and gas are related to hydrological subphases of deposition waters,while remigration,evolution and deterioration ofoil and gas to hydrological subphases of percolation waters. Based on paleogeo-logic characteristics and paleohydrodynamics,promising zones for oil and gas migration and concentration,i.e. the fault-step zones,and complicated hydrological patterns of deposition or/and percolation waters are described. Paleonydrological environments and tectonic traps which may produce negative influence to reservoirs are also discussed in terms of indensity index of water interechange,hydrochemistry,physical and chemical properties of petroleum and content end distribution of superficial minerals. Finally,a principle for evaluation of oil potentiality is given from the hydrological point of view.