We have developed a geomechanically based restoration method to model reservoir deformation. The approach, founded on the finite-element method, simulates the physical behavior of the rock mass and considers heterogeneous material properties, bedding slip, and the mechanical interaction of faults. To demonstrate the method's potential, we analyze the deformation and fault growth in the hanging wall of a synsedimentary listric normal fault from a sand-box model, which provides an analog for evaluating complex faulted reservoirs. The numerical model results are then analyzed to investigate the chronology of faulting. The numerical model corresponds well to the physical model and provides additional insights about reservoir evolution and deformation. The approach is also tested on a natural example of folding using outcrop data to study contractional deformation. These examples illustrate how undetected faults and fractures, reservoir compartmentalization, hydrocarbon-migration pathways, and hydrocarbon traps can be understood in the context of tectonic processes and how this understanding can be exploited in decision making and reducing risk. We conclude that the geomechanically based restoration of faulted and fractured reservoirs has significant potential for industry applications compared to common geometric restoration techniques, which lack a mechanical bases.