Abstract: In conventional interpretation of seismic data in northerm area of Tarim basin, the interfacial average velocity was extracted with poor regularity, big mean square deviation between closures, and big artificial factors during the adjustment of seismic interfacial average velocity, leading to low accuracy of extracted interfacial average velocity and structural depth after time-to-depth conversion. For this reason, this paper presented an another method for extraction of interfacial average velocity, in which a fitting function was selected to match stacking velocity vs time, statistically analyze systematic part from coefficient closure of fitting function and correct it, fulfill correction of stacking velocity closure, and offer interfacial average velocity and interfacial depth as function of interfacial reflected time by transform according to intergral formula DIX and fitting function subjected to closure corrections.

Key words: Stacking velocity, Average velocity, Interval velocity, Fitting, Function