Towards the Use of Geothermal Resources Available in Oil and Gas Sedimentary Basins in Colombia

Abstract

The electrical energy generation in oil and gas fields from co-production waters is possible by using binary or Organic Rankine Cycle (ORC) plants with the aim of converting heat into electricity. The better efficiencies of ORC plants facilitate the use of low-temperature water that has been determined unfeasible both technically and economically in a previous study carried out for petroleum-producing sedimentary basins in Colombia. From reports and studies, it was estimated that about 10-12 million barrels of water are co-produced daily from oil and gas wells with temperatures varying between 42-179 °C. We show that from the co-production waters with temperatures of 80 °C, in the sedimentary basins Eastern Llanos, Eastern Cordillera, Caguán-Putumayo, Catatumbo, Cesar Ranchería and Middle Magdalena Valley, about 170 MWe of electric power could be installed. The Eastern Llanos basin would contribute the largest amount with about 81%. It also presents the oil and gas fields with potential for geothermal development from co-production fluids. Additionally, we analyse two particular cases oil and gas fields located in the Eastern Llanos basin, with water temperatures of 82 °C and 88 °C, mass flows of 61 kg/s and 99 kg/s, and with a temperature differential of the water outlet of 10 °C for both cases. The electric power is modeled and calculated based on four working fluids: R123, R245fa, R134a and Isopentane. The outcomes show powers of 200 kWe for the first case and 320 kWe for the second. Isopentane is the working fluid that provides better results in terms of power, and by using the lowest possible values of evaporation pressure and mass flows. Finally, the financial feasibility assessment allows us to conclude that it is possible to implement the ORC binary plant technology for electrical energy generation using co-produced waters in Colombia from oil and gas sedimentary basins. This assessment is carried out having the local energy market as a constraint. The outcomes indicate that the ORC plants with generation capacity of 200 kWe and 320 kWe are profitable with project paybacks of 7 years and 9 years, respectively.