Heat recovery via heat integration is one of the most effective strategies implemented in many industries for increasing the energy efficiency of processes through simultaneous optimization of the investment cost and the energy consumption. One of the most used tools for heat integration in refineries and petrochemical plants is the pinch analysis. In the last years, due to the complexity of the upstream facilities, pinch analysis starts to be key for their techno-economic evaluation in the designing phase. The scope of this thesis is to develop a practical methodology for heat integration via pinch analysis, which can be integrated in the advanced design process of any complex upstream plant. For that purpose, pinch analysis was used on a real case study represented by an existing plant for gas and stabilized condensate production. After analyzing the thermal data of all the gas processing facilities, the gas-sweetening unit and the gas-dehydration unit were identified as the main ‘heat sources’ while the condensate stabilization unit as a ‘heat sink’ of the plant. The calculations have been done using Pinch Spreadsheet developed by Gabriel Norwood from the Institute of Chemical Engineers. The results show that the pinch analysis can offer step-forward optimization even for high-level engineered plants. The retrofit design solutions include the use of the heat available from the amine and the glycol regeneration units in order to reduce the hot oil duty in the condensate stabilization unit. The integration was realized by designing and optimization of a heat exchangers‘ network without changing the already existing process. A validation of the proposed methodology and a feasible integration as a trade-off between the operational independence of the units and the thermo-economic improvements of the whole plant is a subject for future consideration.