System Design Alternatives and their Influence on Geothermal Heat Recovery from Co-Produced Oil and Gas Wells

Abstract

The conventional binary exchange approach for co-production of geothermal energy from oil and gas wells is investigated in the context of thermal energy recovery and thermodynamic assurance. It is compared to alternative choices in wellbore design and thermal recovery points for the system. The implications of well bore design, pressure management, oil and gas delivery systems, and surface system flexibility to handle changing production parameters and fluid properties are examined. Results are obtained using a thermal-hydraulic model that can handle several wellbore and surface system designs, working fluid types, and flow path alternatives. Thermal recovery results are presented and compared for the most promising alternatives, for different types of base hydrocarbon resources. The advantages and disadvantages of the different alternatives are discussed. Finally, it is argued that by suitable design of the system, thermal energy can be recovered optimally from any given hydrocarbon resource that also possesses thermal energy potential, through the resource life. It is hoped that this work will help operators make appropriate design and operational choices for geothermal co-production systems, depending upon the type of resource being considered.