Modeling of Hydrothermal Flow in a Geothermal System Based on Resistivity Structure Revealed from Magnetotelluric Data
Wahyu Srigutomo (a*), Siti R. Auliyani (a), Prihandhanu M. Pratomo (a), Anggie Susilawati (a,b)
a) Physics of Earth and Complex Systems, Physics Dept., Fac. of Mathematics and Natural Sciences, Institut Teknologi Bandung
*wahyu[at]fi.itb.ac.id
b) Geophysics Dept., Fac. of Mathematics and Natural Sciences, Universitas Padjadjaran
Abstract
Comprehension of hydrothermal flow in geothermal systems is very important in designing geothermal power plant development. As an alternative to qualitative approaches of inferring hydrothermal flow based on geochemistry analyses, a quantitative modeling scheme is discussed in this study. The modeling scheme was carried out by utilizing the Brinkman-s equation as a form of modified Darcy-s law. The equation compensates the effects of buoyancy force exerted on a fluid owing to temperature change known as the Boussinesq buoyancy term. The heat equilibrium equation for a convection-conduction condition was simultaneously incorporated to reconstruct the fluid flow in the associated geothermal system coupled with the temperature distribution in the subsurface. The geometrical constrains of the subsurface geothermal system can be provided from the resistivity structure obtained from the inversion of magnetotelluric (MT) data. Other physical parameters required by the modeling were determined from the results of geological and geochemical studies at the particular geothermal area. The modeling scheme was able to infer numerically the pattern hydrothermal flow pattern as well as its velocity magnitude. The modeling scheme was applied to real geothermal systems in Central Java and East Nusatenggara, Indonesia to test its applicability.
Keywords: hydrothermal flow; geothermal system; Darcy-s law; Brinkman-s equation; heat equilibrium equation; magnetotelluric (MT) data
Topic: Computation and Other Related Field