## 5 Discussion  
Porosity reduction and compaction have been investigated in the 1980s in the Pannonian Basin; that study focused on only some lithofacies, namely sandstones, marls, and shales [91]. Moreover, only core-based measured data have been incorporated into the previously published compaction trends. The proposed compaction trends have considered the measured and the calculated porosity values that were created for every Late Miocene and younger lithost stratigraphic units, so [PERSON]'s and the proposed compaction trends are just partly comparable. [PERSON]'s marls trend could fit well with the Late Miocene prodelta mary sediments (Endrod Fm. ), the [PERSON]'s sandstone trend could be equal with the Late Miocene-Pliocene turbidite sandstones (Szolnok Fm.-silty sandstones), and the [PERSON]'s siltstone trend correlates well with the delta slope shale-rich sediments (Algyo Fm.). [PERSON]'s and the proposed compaction trends have generally less than 5% absolute porosity differences, which is just a slight deviation (Figure 14). [PERSON]'s sandstone and the proposed Szolnok silty sandstone trend have a good correlation; both show very similar shapes with just minor porosity differences. [PERSON]'s marls and siltstones trends start from the same initial porosity; then, there are the proposed Algyo and Endrod Formation trends, but [PERSON]'s trends consider slower compaction that resulted in higher porosity values on the 500-3000 m depth interval. The different trends reach the maximal absolute differences  
Figure 13: Predicted stochastic pore pressure-depth plots at the middle of the deepest point of Section_01: (**a**) predicted minimum, maximum, and average pore pressure; (**b**) minimum, maximum, and the most frequent pore pressure. around 1000 m that are not higher than 10%, but the deviation between the [PERSON]'s and the proposed trends vanished below 3000 m. This study emphasized that the pore pressure models are mainly sensitive to the permeability, so the porosity has a minor impact on the pressure condition. Only the initial porosity controls the pore fluid volumes at the sediment deposition, so the higher fluid volume could result in higher overpressure during the under-compaction mechanism. The initial porosities are almost the same in case of [PERSON]'s trends, and the proposed ones that result in only slight differences from the pore pressure prediction point of view. The initial and reduction of the permeability are more important from the pore pressure point of view. Poroperm trends have not been published previously from the Pannonian Basin; only permeability-depth relationships were identified that were controlled by the lower limit of the laboratory tools [10]. Average permeability intervals have been collected by [PERSON] and [PERSON] [12] for the main Late Miocene and younger formations, the permeability intervals rely on measured core and calculated data from drill stem tests (DST). The permeability of the aquifer units is represented by a similar interval that the evaluated core-based permeability covers; the biggest differences have been identified in the case of the shale-rich sediments, but the difference could be explained with the data sources. The shale-rich sediments contain a sand lens, and if the perforation covered a sandstone body during a DST, the calculated k*h value results in information about the matrix permeability of the sandstone. It is supported by several well tests from the clear shale and marls layer, which resulted in no inflows. The highest difference between the published and the currently measured permeability values have been identified in case of the pelagic marl and calcareous marks, because the published data mentioned a \(-1\) to \(0\) log mD interval, but the lowest measured permeability values fall into the \(-6\) to \(-8\) log (K) interval. The lower measuring limit of the standard laboratory permeability meter was \(-1\) log mD in the 1980s-1990s [10].