This work demonstrates the development and the application of a set of integrated artificial expert systems in the area of forecasting, reservoir evaluation and multilateral well design. The applied method has gradually progressed in degrees of complexity from addressing a preliminary case of volumetric single phase gas reservoirs completed with only dual-laterals towards an expanded form of the same system with varying multi-laterals and reservoir properties to eventually and successfully implementing it to multiphase reservoirs with bottom water drive systems completed with multi-laterals...