Abstract: Geochemical-seismic trap evaluation is a comprehensive method of applying 2D and 3D seismic observation systems to get geophysi-cal infornation, through seismic dala processing to properly describe in-situ structural trap 's spatial morphology and related faulting distribution in order to define the reliability of structural traps. It can directly detect hydrocarbons within traps, pick-up oil gas leakage informalion near sur-face soil from traps under process of stress field, delineating the location of oil-gas accumulation in traps, help recognition of fhuid attribute in traps and conduct classification, evaluation and selection of explorative targets. Applying this method to Songnan oil-gas field, several structural traps have been evaluated and selected, which also passed an verification from drilling. achieving good results.

Key words: geochemical exploration, seismic prospecting, trap evaluation