Outcrop analogue study to determine reservoir properties of the Los Humeros and Acoculco geothermal fields, Mexico

Abstract

Abstract. The Los Humeros geothermal system is steam dominated and currently under exploration with 65 wells (23 producing). Having temperatures above 380 ∘C, the system is characterized as a super hot geothermal system (SHGS). The development of such systems is still challenging due to the high temperatures and aggressive reservoir fluids which lead to corrosion and scaling problems. The geothermal system in Acoculco (Puebla, Mexico; so far only explored via two exploration wells) is characterized by temperatures of approximately 300 ∘C at a depth of about 2 km. In both wells no geothermal fluids were found, even though a well-developed fracture network exists. Therefore, it is planned to develop an enhanced geothermal system (EGS). For better reservoir understanding and prospective modeling, extensive geological, geochemical, geophysical and technical investigations are performed within the scope of the GEMex project. Outcrop analogue studies have been carried out in order to identify the main fracture pattern, geometry and distribution of geological units in the area and to characterize all key units from the basement to the cap rock regarding petro- and thermo-physical rock properties and mineralogy. Ongoing investigations aim to identify geological and structural heterogeneities on different scales to enable a more reliable prediction of reservoir properties. Beside geological investigations, physical properties of the reservoir fluids are determined to improve the understanding of the hydrochemical processes in the reservoir and the fluid-rock interactions, which affect the reservoir rock properties.

On the Thermal Stresses Due to Weathering in Natural Stones

“…Thermal action has been demonstrated to be an important factor that leads to accelerated degradation in many carbonate rocks, such as marbles [19][20][21][22][23]. For this reason, it is considered in European standards that are focused on the applicability of natural stones in external environments.…”

Thermophysical properties of surficial rocks: a tool to characterize geothermal resources of remote northern regions

“…An option for overcoming the subsurface data gap problem is to use outcrops as surface analogues. Although exposed to weathering and erosion processes, outcrops can be easily accessed at low cost and provide reliable data to build geothermal conceptual models (e.g., Bauer et al 2017;Blázquez et al 2017a, b;Cumming 2009;Homuth and Sass 2014;Weydt et al 2018). In the absence of any sign of geothermal activity (e.g., thermal springs) and in the presence of low-permeability crystalline rocks, conduction is the main heat transfer mechanism expected for petrothermal systems of the Canadian Shield.…”

New Developments for the Sustainable Exploitation of Ornamental Stone in Carrara Basin

“…The effect of high temperatures as a degrading factor of rock materials has been investigated by [19,66]; marble samples were subjected to thermal cycles (ranging from 105 to 600 °C) and to In this field, studies are underway to improve the performance of the tools: the complexity of the cutting unit, which includes dozens of devices mounted at different angles, means that the inspection and replacement times are hours instead of minutes, and the environment in which research necessarily develops is a site much less equipped and comfortable than a mechanical workshop.…”

“…The effect of high temperatures as a degrading factor of rock materials has been investigated by [19,66]; marble samples were subjected to thermal cycles (ranging from 105 to 600 • C) and to subsequent non-destructive and destructive laboratory tests to evaluate the variation in the physical and mechanical properties as a function of thermal history after excavation ( Figure 10). The study showed that the increase in crack density with temperature and the consequent porosity increases were the leading causes of degradation of physical and mechanical properties.…”