Characterization of a Fracture-Controlled Enhanced Geothermal System (EGS) in the Trans-Mexican-Volcanic-Belt (TMVB): Predictive Mechanical Model for Fracture Stimulation in an Enhanced Geothermal System Context (EGS)

Abstract

In 2020, as the world Energy demand keeps on rising (International Energy Agency (IEA), 2019), and with the global climate warming a reality (The Organisation for Economic Co-operation and Development (OECD), 2020), reducing our societal impact on Earth is of utmost importance. Energy and Climate have always been intrinsically related. Therefore, solving the Energy-Climate problem is a challenge where not one but several solutions should come together. Part of this global solution is the potential of geothermal resources. Geothermal energy is a renewable energy resource which has large potential to reduce the dependency on fossil fuels. Within the several uses of geothermal resources, a promising technique is titled Enhanced Geothermal Systems. More than renewable, this method has the potential to be sustainable. EGS consists of an originally low permeability reservoir rock that is artificially enhanced. The enhancement can be achieved by different stimulation techniques, such as mechanical, chemical, thermal or a combination of all. This thesis focuses on the mechanical EGS stimulation, where opening of existing fractures and creation of new ones is achieved by injecting a pressurized fluid in the reservoir rock formation. Such a process results in propagating a hydraulic fracture. The complexity of the EGS technique stands in predicting the hydraulic fracture propagation phenomena. EGS research and development is part of the GEMex goals. The GEMex project is a collaboration between Mexican institutions and the European Commission, dedicated to the development of non-conventional geothermal techniques. The Acoculco geothermal field, located in Puebla, is foreseen as a potential EGS. Because this field has been explored with two geothermal wells, and because an analogue exhumed system is available nearby, in the LasMinas area, this systemconstitutes a great research site for developing knowledge on EGS.