Smart Nanosensors for In-Situ Temperature Measurement in Fractured Geothermal Reservoirs

Abstract

Temperature measurements are important for the optimum development and energy extraction of enhanced and conventional geothermal resources. Currently, temperature is only measured in the wellbore, as no technology exists to provide information far into the formation. The development of temperature-sensitive nanotracers could allow for such measurements virtually anywhere in the formation. This paper describes the synthesis and characterization of two types of temperature-sensitive particles: tin-bismuth alloy nanoparticles and silica nanoparticles with covalently linked dye. Three experiments were performed with the tin-bismuth nanoparticles: a heating test, a slim-tube injection, and a Berea sandstone core injection. Both the heated sample and the effluent samples were characterized using Scanning Electron Microscopy (SEM) and Dynamic Light Scattering (DLS). A heating experiment was also performed with the dye-linked silica particles, and the heated sample was characterized using SEM imaging and fluorimetry. The feasibility of using nanomaterials as tracers to measure reservoir temperature in-situ and estimate the geolocation of these measurements is addressed.