Seismic imaging in complex foothill belts remains a classic and persistent challenge due to intense near-surface lateral velocity variations and steeply dipping, fractured subsurface structures. These conditions collectively induce severe wavefield distortion, drastically low signal-to-noise ratio (SNR), and significant difficulties in velocity model building. To address the pervasive problems of low SNR and poor image registration in such highly heterogeneous areas, this paper proposes an integrated methodological framework. First, a quasi-three-dimensional (3D) static correction technique based on wave equation continuation is introduced, which fundamentally eliminates time shifts and phase distortions by back-propagating the seismic wavefield to a unified datum plane. Second, an anti-aliasing, fidelity-preserving denoising technique is developed, leveraging the synchrosqueezed curvelet transform to achieve precise signal–noise separation within a super-resolution time–frequency domain, thereby effectively preserving low-frequency components and steep-dip reflections. Finally, a multi-line traveltime-constrained tomographic velocity modeling technique is established. This method constructs a quasi-3D velocity volume and performs an inversion constrained by traveltime closure errors at line intersections, yielding a spatially consistent, high-precision velocity model. Applications in the western Liaoning Jinyang Basin (China) and a salt dome region in Kazakhstan demonstrate that this integrated approach significantly enhances the SNR, event continuity, and structural positioning accuracy of seismic sections, confirming its effectiveness and general applicability for high-precision imaging in “dually complex” geological settings.