Energy efficiency and conservation measures are considered key solutions to foster energy transition and to reduce both energy consumption and greenhouse gas emissions, especially for the intense carbon footprint activities like in the petroleum industry. In this industry, gas flaring is considered a waste of heat and a principal source of pollution due to volatile organic compounds and greenhouse gas emissions. Gas turbine units are largely used for upstream facilities in the petroleum industry. These units are known to have low thermal efficiency and thus a high amount of the supplied fuel is not utilized and is rejected as high-temperature waste heat through exhaust hot gases. In this context, the present paper aims to assess the energy-saving potential of an organic Rankine cycle (ORC) activated by a combined gas turbine and flare waste heat recovery. The mass and energy balances as well as realistic technical specifications of the main components of the hybrid power plants form the core of the theoretical model. The simulations are performed using Aspen Hysys and typical case studies corresponding to an Algerian upstream petroleum facility are investigated. The conducted analysis highlights that the hybrid Gas Turbine-Flare gas-ORC configuration leads to a power output of 5.8 MW and a thermal efficiency of 7.41%.