Novel Workflows Using Multiple Realizations in Fracture Characterization for Permeability in Geothermal Reservoirs

Abstract

Summary This project defines a workflow to generate fracture models across a hydrothermal field with an associated permeability distribution based on the fracture intensity, orientations, lengths, and aperture and include uncertainties by incorporating multiple realizations of the process. In the Darajat geothermal field near the southern coast of Java, Indonesia, fracture sets are imaged from borehole image data and fracture types labelled by their orientation. To model the distribution of fractures through the reservoir away from the wells, a methodology was applied to characterize fractures based on four main drivers: two drivers associated with faults and two drivers with the intrusion. Assigning lengths and apertures to the fractures generates permeability distributions across the geothermal reservoir and “sweet spot” maps that improve future infill well locations. An automated sensitivity analysis investigates the impact of varying parameters on objective measures, e.g., the mismatch between modeled and measured permeability in selected areas of interest.