Fluorescent dyes are frequently used for tracing the flow of groundwater. The quantitative determination (QD) of dyes is affected by some factors during measurement and storage of the samples and that could be a cause of error in measurement. In this research, factors affect to the QD are considered and the effects of each factor are investigated. In addition, the methods to control such effects are proposed. In the measurement and pre-treatment, pH of solutions, temperature of solutions, co-existence of natural organic matter and filtration were found to affect QD significantly. However they could be controlled by buffering the pH with buffer solution, adjustment sample temperature, investigation of the fluorescent/quenching characteristics of natural organic matter and using rinsed PTFE filter, respectively. In the storage of the samples, most important point is light shielding. However sometimes dyes might be changed by microbial activity.

In order to set the stage for commercial scale Carbon Capture and Storage (CCS), consistent, reliable technology is crucial. One serious problem is that during injection of supercritical CO₂ into the deep underground, the pore pressure in the geologic formation increases. The increase of pressure in the reservoir may cause several problems, including fault reactivation, changes in the neighbouring pressure regimes as well as maintaining a continuous injection rate. We investigated how effective pressure build-up can be reduced by applying pre-injection formation water (brine) production (dual-mode wells), or production of brine in parallel with CO₂ injection. A case study using numerical simulations was conducted, employing a reservoir model based on available data of a large-scale CCS demonstration project. The efficiency and influence of two reservoir volumes, and a hypothetically placed production well, on pressure build-up in the storage formation were tested. The results have shown that the dual-mode well efficiency is dependent on the reservoir volume. Furthermore, water production in parallel with injection was very effective in order to maintain the reservoir pressure and to avoid harmful effects on the overlying seal layers and other hydrogeological conditions.