Reliable geological models of the North Sea are essential for a robust assessment of subsurface potentials in this vital European economic region. While commercial and scientific surveys have effectively explored the upper 2 to 4 km, there is currently no well data reaching the base of the locally more than 10 km deep rift structures such as the Central and Horn Graben. This leads to considerable uncertainties in the regional seismic velocity model and thus in the depth-conversion of reflection seismic profiles. Our objective is to reduce these uncertainties in the German North Sea by integrating the abundant gravity data, offering additional constraints on both the geometry and petrophysical properties of deep basins. We present the results of 2D gravity forward modelling, which combines existing regional and global crustal models with the most recent structural model of the Paleozoic to Cenozoic sedimentary sequences. Density information is thereby derived from well logs, seismic tomography studies, and further literature implications. The calculated free-air gravity anomalies are then compared with the measured gravity field to assess the quality of the used crustal and sedimentary models. The insights gained will subsequently inform a more intricate inverse 3D modeling, resulting in a quantitative description of the geological uncertainties.