| Abstract |
The Serdán-Oriental Basin is located at the eastern margin of the TransMexican Volcanique Belt, central Mexico. The main feature of the Serdán-Oriental Basin is the Los Humeros Volcanic Complex (LHVC), a complex caldera system continuously active for the past 3 Myr. The main volcanic event of the LHVC being the two caldera forming Xaltipan and Zaragoza ignimbrites, that occurred respectively 164 and 69 Ma years ago. All this volcanic activity, as well as the plinian activity between the ignimbrites and the numerous monogenic volcanism, is to be related to magmatic storage that creates a significant heat source bellow the LHVC. This heat source, combined with an active hydrological system, has created a dynamic geothermal system that is in exploitation in the central part of the Los Humeros Caldera with and installed capacity for electricity generation of 93 MW produced from 20 wells. With the aim to better understand the thermal structure of the geothermal system, we used a basin modelling tool, TemisFlow®, to build a 2D model across the Serdán-Oriental Basin for the last 10 Ma. The geometry considered is a thick limestone layer covering the crystalline basement and overlayed by the complex LHVC that has been separated in 3 phases (pre-caldera, caldera, and post-caldera). Bellow, the magmatic system corresponding to these phases has been considered with the emplacement at shallow level (5-7 km depth) of large magmatic chambers during the caldera phases and more limited in extension otherwise. Creating a composite heat source. In addition to these shallow systems, deeper storage have been considered, creating a high background temperature. The modelling of the Serdán-Oriental Basin’s thermal structure concentrates on two aspects, the heat source generated by the storage of the magma in the crust and hydrological system that increase the temperature in certain areas at shallower depth through a convective transport of the heat. Results show still a significant impact of the remnant heat from the ignimbrite related magmatic chambers and a variability increased by the hydrological convection. Through this work, we can clearly see the interest of using powerful O&G modelling tool such as TemisFlow® and adjusted for geothermal energy, helping the exploration of green field or guiding further development in existing geothermal energy systems. |