Redesigning the EFCOSS framework toward finding optimally located boreholes in geothermal engineering.

Abstract

Since drilling for deep resources is extremely expensive, one of the most important questions in industrial geothermal engineering is how to determine a suitable location for a borehole to extract thermal energy. We argue that this question can be tackled by a set of advanced numerical techniques known as optimal experimental design. More precisely, we formulate the problem of finding a borehole for a given geological reservoir in terms of a mathematical optimization problem. We demonstrate that today numerical solutions of such practically relevant geothermal engineering problems are manageable by bringing together complementary skills from geophysics, mathematics, and computer science. The EFCOSS framework is designed for the solution of optimization problems with an emphasis on optimal experimental design and distributed computing. In this work, we redesign EFCOSS to improve its usability for engineering problems. The overall methodology is applied to a two-dimensional reservoir engineering problem of practical interest. We determine the position of boreholes in a reservoir in western Australia such that the uncertainty of estimating the hydraulic permeability from temperature measurements is minimized. Our findings show that the solution of this challenging optimization problem is feasible. However, there is still room for further research including studying different optimality criteria and extension to three space dimensions.