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 (choice of 2-5 laterals). The developed method and tools cover a wide spectrum of rock and fluid properties spanning tight to conventional sands. The developed approach successfully delivers a total of five distinct artificial expert systems, three of which serve as proxies to the conventional numerical simulator and the other two as inverse-looking solutions, one that addresses the multi-lateral well design problem and the other that estimates critical reservoir properties that can be used at the very least as first estimators in assist history matching problems.