Geothermal Potential to Meet Heat Demand in Magallanes, Chilean Patagonia

Abstract

Based on previously gathered data during oil and gas exploration by the hydrocarbon industry as well as the heat demand, the aim of this work is to assess the potential of developing deep geothermal energy in the Magallanes basin for district heating purposes. Two main options are evaluated for deep geothermal energy recovery: (1) Geothermal Doublet; and (2) Deep Borehole Heat Exchanger (DBHE). In both cases a district network is considered due to its wide range of long-lasting advantages. The good permeability (~250 mD) of a 15 m thick sandstone sequence in the Springhill Formation of the Magallanes basin shows promising economic feasibility for a geothermal doublet development from a hydrothermal system. The formation temperature ranges from 105 to 147 ˚C at depths of 2,420 to 2,900 m. The latter in conjunction with a favourable vertical thermal property distribution of rocks seem also economically reasonable for the development of DBHE. As the Chilean National Oil Company (ENAP) has been exploring and exploiting oil and gas for more than six decades, 40% of the wells are no longer hydrocarbon producers. Therefore, rehabilitation of no longer producing oil and gas wells as deep geothermal injection and/or production wells should reduce significatively the initial investment of the systems. Based on heat demand, for medium size urbanised areas geothermal doublets are preferred. However, for small villages and boundary crossing points the DBHE are preferred.