Abstract：By using the formula Gaik=(ρaik-ρaikk)/ρaikk after analysing various noises in DC resistivity trielectrode gradient measurement,we can easy highlight high-resistivity hydrocarbon reservoir in the strong noise background that results from structural undulation,landform undulation and shal-low nonuniform body.In the formula,Ga means effective anomaly due to a finite high-resistivity geologic body(reservoir)in low-resistivity formations,ρaik and ρaikk are respectively the apparent resistivities at k points of the anomaly curve for which Ga curve needs to be plotted and of reference curve.This method is feasible.It canbe applied to both reservoir development monitoring and reservoir prediction (determination of boundary,top depth and bottom depth of a reservoir)in plain andmountainous district where seismic exploration is difficult.
