Aims of a Basic EGS Model for the Cooper Basin, Australia

Abstract

Geodynamics Limited is currently undertaking field development activities to support a proposal for Engineered Geothermal Systems (EGS) in the Cooper Basin, Australia. For feasibility assessment it is essential that the relationship between EGS design variables and both net electrical power and return on investment are understood. This paper presents key aims and concepts of a spreadsheet model that will help provide this information. The model, which is currently in development, is called the Basic EGS Model. Incorporated into the Basic EGS Model are submodels that quantify fluid pressures and temperatures at key locations in the system, including within the geothermal reservoir, within the wells, across the heat-exchanger (of the power plant) and across the circulation pump. The model will link the geothermal power result to a generalist sub-model for a range of power plant designs to estimate the net electrical power deliverable to market. The model will then link the net electrical power results to an economic submodel for calculating financial performance. The EGS design variables of major interest include (i) well spacing, (ii) well diameter, (iii) well layout, (iv) well depth, (v) well trajectory, and (vi) number and location of stimulated fracture zones. These design variables are discussed in context of their potential impact on geothermal power and economic performance.