Abstract：In W area,the relation between velocity(νp)and porosity(φ)can beexpressed using the empirical formula(φ=0.226/νp-41.37)which wasdeveloped by analysing drilling data in this area.In the area wherethere is no drilling data,seismic porosity φs can be calculated by put-ting into the formula the velocity that was obtained from seismic in-version and corrected then.Seismic porosity φs may indicate areal po-rosity variation in a formation.In the area where there are drillingdata,logging porosity φ1 which shows local porosity variation can becalculated by putting logging velocity into the formula.The porosityφ that is obtained by weighting φs and φ1 with the use of P.M.Do-yen's correlation model indicates porosity variation in this area morereasonably than φs and φ1 do.
