In the competitive and growing oil and gas industry, efficiency plays a crucial role. Activities and its associated resources must be efficiently scheduled in order to maintain satisfactory production, reducing operational costs. This is, however, a still manual and difficult task currently faced. This work presents thus a decision support system including a multiperiod mixed-integer linear programming (MILP) model, which was structured with a base model and seven phases. Each phase adds complexity to the model and improves the final solution. The model estimates the optimal scheduling for a heterogeneous fleet of drilling rigs with a long term time horizon and several operational and technical restrictions. To assist the scheduling process a system was developed. This system creates a structured database and allows the user to plan the activities, providing input data for the model. Furthermore, the system allows the creation of scenarios and provides an interactive interface to visualize and handle the final schedule.