The Potential of Utilizing Geothermal Energy Coupled with Geomechanics: A Case Study for Trinidad and Tobago

Trinidad and Tobago (TT), a small island developing state (SIDS), has been experiencing the impact of global warming and climate change. TT has been heavily dependent on fossil fuels and has been lagging behind the rest of the Caribbean in transitioning to utilizing green energy. This paper focused on the evaluation of the potential for harnessing geothermal energy from a conceptual reservoir using field data and utilizing the commercial software CMG. The Upper Cruse sand in the Parrylands area was selected since there was geothermal potential due to its proximity to mud volcanoes and high geothermal gradients. The impact of rock geomechanics was also investigated. The results for the single porosity models which were developed showed that an optimum cumulative enthalpy of 5.507E+12 Btu was achieved at a constant water reinjection pressure of 1000 psi with a well spacing of 1300 ft. Using two-way coupling and the same parameters of this optimum case, a geomechanical analysis of the Natural Fracture (3D Linear Elastic) Geomechanical Model gave an enthalpy of 4.187E+12 Btu. These results coincided with a reduction in CO2 emissions of 1043.07 MM lbs when compared to using natural gas for the generation of electricity. In addition, when the unsubsidized electricity price of US$ 0.35 was used in the economic evaluation, the associated IRR was 39.2%. This study demonstrated the significant potential of geothermal energy as a sustainable substitute for natural gas for the generation of electricity in TT.