| Abstract Submission No. | ABS-4.1-0051 |
| Title of Abstract | Subsurface Resistivity Modeling of the San Emidio Geothermal Field. |
| Authors | Mr. Prajnananda Sahu*, Prof. Ujjal Kumar Borah |
| Organisation | Indian Institute of Technology (Indian School of Mines) Dhanbad |
| Address | IIT(ISM), Dhanbad Dhanbad, Jharkhand, India Pincode: 826004 E-mail: 23mc0058@iitism.ac.in |
| Country | India |
| Presentation | Poster |
| Abstract | Geothermal energy is an essential unconventional resource in the worldwide transition towards decarbonization, offering reliable, low-carbon baseload power. It demands advanced geophysical techniques to unlock its potential�especially in hidden systems within structurally complex geology regions like the Basin and Range province. Among all physical parameters, subsurface resistivity is especially important for geothermal characterization, as it is sensitive to hydrothermal alteration, fluid content, and temperature-dependent mineralogical changes directly associated with reservoir properties. Magnetotellurics (MT) is a powerful geophysical technique due to its high sensitivity to variations in the resistivity of the subsurface, allowing for the imaging of geothermal systems. MT facilitates the identification of conductive clay caps, conductive reservoir zones, and fluid pathways controlled by faults. Therefore, in the present study, an attempt has been made to characterize the San Emidio Geothermal System using open-source MT data. The dimensionality analysis of the MT data shows a predominant 1D structure in the frequency range 1-1000 Hz for several sites. Therefore, a 1D MT inversion is carried out for the frequency range of 1�10� Hz. The algorithm used for 1D inversion is based on the minimization of a Tikhonov-style objective function. A one-dimensional inversion framework, which incorporates smoothness-constrained regularization, is solved using an inexact Gauss�Newton optimization. Forward modeling is carried out at each step, allowing the model to be progressively updated so that the predicted responses align more closely with the observed data.The 1D resistivity models obtained after inversion highlight the clay cap, reservoir, and deeper resistive zones. This underscores the crucial role of resistivity imaging in promoting reliable and sustainable geothermal resource development. |
| Keywords | Keywords: Geothermal; Magnetotelluric; Unconventional energy; resistivity modelling; Inversion ; Forward Modelling; 1D inversion |