## 5 Discussion
### Consequences for Migration Pathways  
In this study, FiCs analysis is applied to enhance the understanding of the migrated and accumulated fluids trapped within the investigated samples. Based on [PERSON] et al. [22], and [PERSON] et al. [18], a mixture of different fluid regimes (e.g., magmatic, metamorphic, meteoric, and hydrothermal) along with the corresponding volatile compositions can be assumed when interpreting the FiCs results. Comparing the sidewall rock and laumontite samples, both differences and similarities are evident in the pattern of individual mass spectra and chemostrigraphic logs based on the core. The responses of the selected non-hydrocarbon and hydrocarbon species are generally sufficient, making interpretation possible. The obtained scattering patterns of the H\({}_{2}\)O and CH\({}_{3}\)\({}^{+}\) compounds in the sidewall rock samples indicate the presence of multiple fluid inclusion assemblages and/or migrating fluids with different compositions. Laumontite, as the final vein-filling phase, is possibly less affected by fluid migration events, indicated by the fact that a smooth and even log with a substantial hydrocarbon signal is recorded (Figure 13). Despite the abovementioned distribution in the sidewall rock samples, the cogenetic behaviour of the immiscible fluids cannot be excluded due to the co-occurrence of water, methane and water-soluble hydrocarbons (e.g., benzene and toluene), as has already been discussed previously (e.g., [59; 60]). In both sample sets, whenever C\({}_{7}\) hydrocarbons are present, an exponentially decreasing pattern characterises the C\({}_{2+}\) hydrocarbon range (Figure 12b). Based on the characteristic fragmentation of the hydrocarbons (e.g., [61]), the obtained mass spectra indicate the contribution of higher-carbon-numbered hydrocarbons to the recorded spectra. The aromatic hydrocarbons benzene and toluene are also present in relatively great abundance (Figures 12c and 13). The contribution of benzene to the FiCs signal is almost constant, with some fluctuations in case of the laumontite samples. In contrast, three intervals in the sidewall rock samples are richer in benzene, and these zones overlap with the corresponding maximum loci detected in the laumontite (Figure 13). The assumed composition of hydrocarbons (C\({}_{7+}\) and aromatics) indicates the presence of gas condensate or liquid hydrocarbons (e.g., light oil; [62]) in the fluid remnants trapped in the samples. This presumption is consistent with the American Petroleum Institute (API) gravities of the oils produced in the research area [63], indicating that the explored zones were not only active during ancient fluid conduction but also part of a more recent hydrocarbon system. As petrological modelling has demonstrated, laumontite is an excellent indicator of a communicating fracture system. The FiCs analysis indicates that the fracture-filling laumontite preserves a unique stage of fluid migration when hydrocarbons are present throughout the connected fracture network. Laumontite, which encloses hydrocarbons of a composition similar to that produced recently in oil, probably crystallises coevally with hydrocarbon migration. The overlap between the enhanced benzene content of the fluid remnants in the sidewall rock and in the laumontite samples indicates that microcracks exist within the country rock, serving as conduits for hydrocarbon migration. The elevated abundance of the aromatics (e.g., benzene and toluene), liquid hydrocarbons (e.g., C\({}_{7}\)) and co-existing water suggests migrating hydrocarbons with various water saturations in the depth range between 2061 and 2067 m, as well as between 2072 and 2077 m. However, besides the inferred differences in water saturation of particular fluid migration events, the results might also have been affected by contributions of the remnants of earlier fluid regimes (e.g., magmatic or metamorphic). In the sidewall rock samples, the abundance of hydrocarbons is found to decrease to 2060 m and a generally water-dominated zone is detected.