Geothermal Resource Conceptual Models Using Surface Exploration Data

The most important element of an analysis to target a geothermal well or assess resource capacity is a resource conceptual model consistent with the available information. A common alternative approach to both targeting and assessment is to focus on a data anomaly or, in some cases, several stacked anomalies. However, even stacked anomalies are commonly misleading without support from a conceptual model. The most important element of a geothermal conceptual model is a predicted natural state isotherm pattern, especially in section view. Although inferring such an isotherm pattern at an exploration stage can be challenging, many case histories show how this can be done based on surface geochemistry, resistivity, hydrothermal alteration, geology, hydrology and structure. This highlights a few basic rules of thumb for building and characterizing the uncertainty of geothermal resource conceptual models based on information from typical geothermal exploration data sets. A conceptual model approach is particularly effective when exploring blind prospects because it makes fuller use of more limited data and helps identify strategies to address the lack of information, as well as identifying targets.