logOGW is designed to evaluate hydrocarbon layers from well logs. The knowledge-based Support Vector Machine will be used to build the bridge between the training samples and the prediction wells for the recognition and classification of hydrocarbon layers. A fuzzy membership converts oil/gas/water layers into a vector of three elements to describe the hydrocarbon layers. For example, (1,0,0) represents a water layer, (0,1,0) a gas layer, (0,0,1) a oil layer, and (0,0,0) dry layer