Figure 3. V_P/V_S map for a 2.75 km by 2.75 km area of the Plover Lake field. Low V_P/V_S values in the middle of the map correspond to thicker Bakken and Lodgepole, while higher V_P/V_S values on the southeastern side of the map correspond to a zone where the Bakken sand and Lodgepole Formation have both been eroded – suggesting that V_P/V_S is a good lithology discriminator.