|dc.description.abstracteng||In a tracer test, applied tracers are introduced and transported with a working fluid so that the tracer response signals can be used to determine the target parameters of the aquatic system, such as temperatures, flow paths and residence times. Implementing a tracer test requires adherence to a series of specified steps, and a failure in one step can attribute to an unreliable tracer response. The presented work focuses on ameliorating tracer test results with regard to selecting a proper tracer compound, preserving the tracer test samples, and expanding the number of thermo-sensitive tracers.
The application of reactive tracers can provide specific information about a system, such as temperature distribution. Reactive tracers have become important as they have been extensively developed during the past decades for a wide spectrum of field applications. Amongst numerous reactive tracer compounds, selecting suitable tracers for a specific system is challenging due to the lack of knowledge of their physicochemical properties while satisfying the large number of requirements each tracer must fulfill. In this thesis, a complete overview of the current state of reactive tracers is provided. Thorough understanding of tracer properties assists not only the selection of proper reactive traces, but also the synthesis of a future tailor-made tracer. Furthermore, the potential research directions of reactive tracers are suggested.
Sample preservation is prerequisite to achieve reliable results, especially for complex water samples like geothermal fluids. However, there is a lack of proper sample preservation methods in tracer testing. In this thesis, a preservation method for the most commonly applied conservative tracers, namely uranine, eosin, 1-naphthalene sulfonate, 1,5-naphthalene disulfonate, 2,6-naphthalene disulfonate, 4-amino-1-naphthalene sulfonate, 6-hydroxy-2-naphthalene sulfonate, 1,3,6-naphthalenetrisulfonate, and 1,3,6,8-pyrene tetrasulfonate, is provided. A simple but effective preservation method is proposed to ensure the quality of the analytical results for conservative tracers.
In addition, a new class of thermo-sensitive tracers is investigated that brings more options for researchers involved with characterizing geothermal reservoir performance. Carbamates are hydrolysable compounds susceptible to a well-defined thermo-sensitive hydrolysis reaction. In this study, the kinetic parameters of structurally different carbamates (eight primary and one secondary carbamate(s)) are investigated by isothermal batch experiments. The influences of compound structure, temperature, and pH/pOH on hydrolysis kinetics are estimated. The results demonstrate the possible application of carbamates within a broad range of temperatures (up to 200 °C).||de