This study highlights how the recovery and reuse of existing hydrocarbon infrastructure can contribute to the diffusion of district-heating (DH) projects that implement principles of circular economy. The complete paper presents two examples of reusing hydrocarbon wells to satisfy the energy demand for heating residential buildings through locally available geothermal renewable energy sources.
Background
The mature phase of oil and gas reservoirs usually is characterized by the production of formation waters together with hydrocarbons. The volume of the produced water generally increases as fields mature until hydrocarbon production becomes uneconomical and wells are cemented and closed.
Reservoir fluids could have temperatures high enough to support geothermal exploitation depending on the geothermal gradient. Therefore, when hydrocarbon wells are approaching the end of their productive life, and where geothermal potential exists, conversion to geothermal wells could be a reasonable alternative to closure.
The authors’ results show how the repurposing of hydrocarbon wells into geothermal wells constitutes an excellent opportunity to access geothermal resources, reducing investment and mining risks and improving project economics.
Considering that the temperature of reservoir fluids accessible through existing active wells generally is lower than 100–110°C, one of the more suitable applications for the harvested heat is to power new-generation DH systems that can operate with delivery temperatures even lower than 60°C.
Data and Results
Geothermal Potential of Using Hydrocarbon Wells in Italy. Data regarding hydrocarbon production concessions and active hydrocarbon wells are made available by the Italian Ministry of Environment and Energy Security.
