Building on the previous chapter, this chapter proposes an improved spatial branch-and-cut (B&C) method for the rapid resilience assessment of integrated energy systems (IES). To accelerate fault recovery solutions, the proposed method introduces two key improvements to the traditional B&C algorithm. First, to address the non-convex characteristics of the integrated electricity-gas flow (OEGF), a novel cone-specific spatial branching strategy is proposed. Compared to existing strategies that can only handle bilinear equality constraints, the proposed method reduces the scale of branching variables by two-thirds without compromising solution accuracy. Second, a combined cut generation strategy is introduced, transforming fault scenario enumeration into a guided generation process within a single search tree. The core idea is to formulate the solution process for each fault scenario as a subset of the search tree, thereby reducing the load restoration problem to a single optimization process. The proposed algorithm is tested on systems of three different scales. Comparative analysis with seven existing algorithms further validates its superiority in both solution accuracy and computational efficiency.