Flat surface versus present-day topography for cylindrical and spherical sources in temperature field simulation models: The Cerritos Colorados geothermal field, Jalisco, Mexico

Abstract

Most thermal simulation studies assume a flat upper surface, which is not strictly valid for geothermal areas and volcanic centers. Further, even those thermal simulations that have taken into account the actual topography did not objectively evaluate the simulated temperature differences between the flat surface and topography models. We provide the first 3-D simulations of the Cerritos Colorados geothermal field of Mexico for the flat surface and actual topography models as well as for cylindrical and spherical primary heat sources whose upper surface was assumed to be located at the same subsurface depths. The simulated subsurface temperatures were reported at 9 different subsurface depths from +1275m a.s.l. to −1725m a.s.l. The flat surface models always overestimated the subsurface temperatures as compared to the respective topography models by about 27% near the surface (at +1275m a.s.l.) to only about 1% near the heat source (at −1725m a.s.l.) in the central part of the modelled region, and about 18–70% near the surface to 2–16% near the heat source at eight other selected locations within the area. The percent temperature differences between the flat surface and topography models showed a statistically significant linear dependence for both cylindrical and spherical heat sources on the topographic contrast.