We present a parallel algorithm for computing the minimum s-t cut in structured 3-dimensional proper order graphs arising from image segmentation problems. Proper order graphs are multi-column structures where vertices are arranged in parallel columns, with each vertex connected to consecutive vertices in adjacent columns. This graph structure naturally arises in surface extraction problems for geological horizon segmentation in seismic imaging volumes. We develop two parallel approaches: a hierarchical merging variant of the Boykov-Kolmogorov algorithm, and a novel parallel push-relabel algorithm with level synchronized global relabeling. Our primary contribution is the push-relabel variant, which partitions the graph into segments along columns with processor affinity, eliminating the need for a global shared queue. We introduce level synchronized global relabeling that enables concurrent label updates while maintaining correctness through barriers at each frontier level.