Abstract:The former seismic velocity generally is divided into two separately independent parts:the first part mainly is static corrections,coherent processing and velocity analysis,which all takes improving imaging as a goal;the second part is to interpret the velocity analysis and mapping,which takes obtaining the geologic results as a goal.The velocity-field model-building method introduced by the paper is to combine the above-mentioned two parts together to carry out integrative analysis,using spatial field,ray tracing and model iteration of 3-D static corrections and combination with 3-D velocity field to finish structural map,greatly improved the velocity precision.The method has been used in P5 well zone,Junggar basin,and discovered structure with amplitude 40m and area 42km2,which is oil-bearing structure proved by P5 well.On 2-D seismic structural map,the structure did not exist;and on 3-D t isogram,only the trap with about amplitude 5ms is discovered.