<p>The propagation of fractures in rock is driven and characterized by fracture energy, defined as the energy required to create a unit area of new surface. Estimating this energy demand is difficult, as experimental methods face significant scaling issues and analytical models cannot fully capture complex in situ conditions. Numerical modeling, when integrated with actual treatment pressures and microseismicity-derived fracture dimensions, offers a robust alternative for estimating field-scale energy dissipation. This study validates such a framework using the Marcellus Shale Energy and Environment Laboratory (MSEEL) dataset, employing the finite element method (FEM) to history-match field records and rigorously quantify the total in situ fracture energy. The primary methodological contribution involves introducing a novel nonlinearity coefficient, φ, to quantify the degree of nonlinear deformation and govern total energy dissipation. A fully coupled 3D geomechanical model was developed using the Abaqus software to simulate stage-wise hydraulic fracturing at the MIP 3H well in the Marcellus shale. Through an iterative history-matching procedure, the model was optimized to a φ value of 10, which successfully aligned the simulation results with field pressure records, microseismic-derived fracture geometries, and established numerical and experimental benchmarks. With its fidelity confirmed, this robust framework offers a transferable methodology for predicting the more realistic energy demand of stimulation treatments. Although this study focuses on unconventional shale, the proposed approach can be extended to other formations subjected to hydraulic fracturing. Consequently, it provides a critical means to design stimulation treatments in diverse settings, including enhanced geothermal systems (EGS) and carbon capture and storage (CCS) initiatives.</p>