Fracture and rock alteration characterization from geophysical well logs and core: Ngatamariki geothermal field

Abstract

In this thesis I study ways to identify permeable zones and fractures from elastic wave signatures at two scales. The first scale corresponds to the borehole logging scale which is in the decimetre to meter range (macro-fractures and lithofacies); the second scale is in the sub-centimetre range of cores (pores and micro-fractures). I identify such rock physical properties from elastic wave quality factors and from effective media inversion of density and shape of micro-fractures. By integrating the response from other logs, mineralogy and pore space from XRD and CT analyses, I quantify these parameters which will help interpret, define and calibrate production and injection models at the Ngatamariki geothermal field.