Well logging is an important tool used in the oil and gas industry to measure properties of the geological environment. The information obtained from well logs contribute to depositional system and reservoirs characterization. In this paper, we used the interpretation of well logs to identify lithologies and to estimate the clay volume, porosity and saturation in two offshore wells of the New Zealand's Taranaki Basin. From these properties, we analyzed and concluded that the reservoirs of the Tui and Maui fields in this basin have many different characteristics with respect to the depositional system and the type of hydrocarbons, although they are close.