Geothermal Heat Sources From Oil Wells Using Binary Cycles

Abstract

The growing demand for energy challenges the development and utilization of renewable sources. Among them, the geothermal energy represents the natural and internal heat of the earth that is stored within the rock and its fluids. In the special case of hydrocarbon bearing basins the heat is conductively transferred to the surface trough its fluids giving the possibility to provide energy for the field itself and even to power generation. This latter is known as coproduced fluids since oil/gas is pumped from wells along with hot water. The energy required for operations in oil fields is obtained from the produced hydrocarbons representing an important high cost for companies. It is suggested here that the energy consumed in these procedures could be supplied from the hot waters produced during hydrocarbon extraction considerable reducing the present high expenses and extending the oilfield’s life. Additionally, direct uses can also be achieved for cooling or heating of individual buildings of the field or heating for pipe tubes in cold regions. Spent fluids can also be collected and used again for other industrial applications in a “cascading” process. A geothermal power generation project is expensive specially if it is necessary to drill wells but in the case of oil fields, the existing infrastructures, mature production technologies and rich reservoir data assure lowering the inversion cost. The Golfo San Jorge Basin located in Argentina exhibits normal geothermal gradients that go from 2 to 5 C each 100 meters. Considering that wells reaches up to 6 km deep, it is possible to ensure a low to medium enthalpy reservoir. In all cases, and given the diversity of depths to which the wells are drilled (from 300 to 4500 mah), fluids (280 bbl/d water) produced are at temperatures close to 100 -150 C, such as the South Flank of the Basin. This hot brine is not usable for the direct generation of electricity in classical steam power plants instead it is proposed here that this thermal energy could be transferred to a “binary cycle”, the Organic Rankine Cycle (ORC), and converted into electrical energy to be delivered in the field. This paper analyzes the technical feasibility of generating electricity from those wells using this technology and the new test facility Monika

AAPG Datapages/Search and Discovery Article #90323 ©2018 AAPG Annual Convention and Exhibition, Salt Lake City, Utah, May 20-23, 2018