A method comprising: correlating a measured log of a wellbore to a predicted log of the wellbore, the correlating by: plotting values of the measured log with respect to an ordinate axis and an abscissa axis, and the plotting in a first pane on a display device of a computer system; and plotting values of the predicted log with respect to the ordinate axis and the abscissa axis, and the plotting on the display device of the computer system, the method being further characterised by: selecting an inflection point of the predicted log responsive to a pointing device coupled to the computer system; shifting horizontal position of the inflection point relative to the measured log responsive to the pointing device; changing dip of at least one modeled surface (120, 122) in a structural model based on the relative location of the inflection point; recalculating the predicted log based on the change in dip, the recalculating creates a modified predicted log; and then plotting the modified predicted log. correlating a measured log of a wellbore to a predicted log of the wellbore, the correlating by: plotting values of the measured log with respect to an ordinate axis and an abscissa axis, and the plotting in a first pane on a display device of a computer system; and plotting values of the predicted log with respect to the ordinate axis and the abscissa axis, and the plotting on the display device of the computer system, the method being further characterised by: selecting an inflection point of the predicted log responsive to a pointing device coupled to the computer system; shifting horizontal position of the inflection point relative to the measured log responsive to the pointing device; changing dip of at least one modeled surface (120, 122) in a structural model based on the relative location of the inflection point; recalculating the predicted log based on the change in dip, the recalculating creates a modified predicted log; and then plotting the modified predicted log. plotting values of the measured log with respect to an ordinate axis and an abscissa axis, and the plotting in a first pane on a display device of a computer system; and plotting values of the predicted log with respect to the ordinate axis and the abscissa axis, and the plotting on the display device of the computer system, the method being further characterised by: selecting an inflection point of the predicted log responsive to a pointing device coupled to the computer system; shifting horizontal position of the inflection point relative to the measured log responsive to the pointing device; changing dip of at least one modeled surface (120, 122) in a structural model based on the relative location of the inflection point; recalculating the predicted log based on the change in dip, the recalculating creates a modified predicted log; and then plotting the modified predicted log. selecting an inflection point of the predicted log responsive to a pointing device coupled to the computer system; shifting horizontal position of the inflection point relative to the measured log responsive to the pointing device; changing dip of at least one modeled surface (120, 122) in a structural model based on the relative location of the inflection point; recalculating the predicted log based on the change in dip, the recalculating creates a modified predicted log; and then plotting the modified predicted log.