Abstract
One significant source of geothermal energy is the co-produced hot water from oil/gas field production. There is potential to utilize oilfield infrastructure to produce geothermal electricity profitably, in a process called co-production. Due to the increasing demands of energy now days, this paper presents an investigation of geothermal energy production and utilization for electricity generation on the petroleum fields via organic Rankine cycle (ORC) technology, which is a reliable way to convert heat into electricity. The current research focuses on the use of an ORC unit to generate electricity from co-produced water from ten oil wells in two oilfields, Jalo and Sarir. These wells refer to GX1, GX2, Gx3, GX4, GX5, SX1, SX2, SX3, SX4, and SX5, and they are combined in gathering centers (GC1) and (SC2) to utilize an existing medium-temperature geothermal source. The estimated total flow rates of co-produced water from the two gathering centers after separation are 5,728.34 BWPD and 14,618.65 BWPD respectively. Whereas, the geofluid mass flow rates from both oilfields are 12.25 kg/s and 34.05 kg/s, respectively, with an inlet geofluid (brine) temperature (T1) of 60°C and an outlet geofluid temperature (T2) of 35°C. The thermal efficiency (ηth) values for the Jalo and Sarir oilfields are 3.28% and 4.22%, respectively. According to the power output analysis, which indicates that the specific power outputs are 5.17 kW/kg/s and 9.85 kW/kg/s, and the gross power outputs are 63.33 kW and 338.80 kW, respectively, with a required hot water flow rate of 12.25 kg/s and 34.05 kg/s. This study revealed that the temperature and water flow rate are crucial factors affecting power output. By using an ORC plant, the generated electric power can be used in the field, supplied to the local grid, or utilized to offset on-field electricity consumption. Also, this study recommended by focusing efforts to extract the energy through electric power generation via production oil wells in oilfields.

Key words: Geothermal energy, oilfields, co-production, temperature, power generation, power plant.