“Earth Research” 3-Dimensional Geological Modelling of Geothermal Systems in New Zealand – a New Visualisation Tool

Abstract

Diagrammatic 2D representation (i.e., cross-sections and maps) of drillhole data (e.g. stratigraphy, permeable zones, secondary mineral occurrence) and inferences (e.g. hydrology, structural relations) have historically been used for visualisation. Advances have been made using newly developed 3D computer modeling software where we are able to render detailed geological information (e.g., stratigraphy, structure, hydrothermal alteration mineralogy) and overlay it with hydrological data (e.g., temperature, flow data). This provides greater insights into active fluid flow behaviour in the geothermal reservoir, and the thermal and chemical evolution of the geothermal system, leading to greater efficiency in the decision-making processes at all stages of field exploration, reservoir development and production.

“Earth Research” is 3D modelling software that has been developed by ARANZ (a New Zealand-based software development company), with scientific input from GNS Science and Contact Energy Ltd., to image geology and structure of high-temperature geothermal systems of the Taupo Volcanic Zone (TVZ), New Zealand. This visualisation software incorporates user-defined geothermal well information such as geology (e.g., stratigraphy, inferred faulting), hydrothermal alteration mineralogy (e.g., intensity, rank, occurrence), temperatures, pressures, and feed zone locations. 3D visualisation field models that have been utilised for planning exploration drilling strategies and reservoir management of fields already developed for electricity generation.