Temperature Dependence of Electrical Resistivity - Part I: Experimental Investigations of Hydrothermal Fluids

The temperature dependence of electrical properties of single-component brines was extensively studied up to supercritical condi- tions. However, only very few data are available for multicomponent brines, representing natural geothermal fluid compositions. We present a new measuring cell, designed to investigate electrical resistivities of mixed salt solutions at conditions simulating su-percritical hydrothermal reservoirs. The cell was tested at 23 MPa and 23 – 380 °C on a diluted aqueous solution of NaCl, CaCl2, and K2SO4, simulating the Icelandic Krafla hydrothermal system. The measured data are used to calibrate resistivity measurementson fluid saturated rock samples, which are presented in an associated paper.