High-power laser systems are increasingly investigated as a potential alternative for well perforation and stimulation in subsurface energy applications. This study presents a coupled optical–thermal–mechanical simulation of laser perforation in a two-layer system designed to mimic actual well perforation conditions. The model consists of a steel layer representing the casing and an underlying sandstone layer representing the formation rock. Laser irradiation is modeled using a Gaussian intensity distribution, while optical absorption at the surface is incorporated through an effective absorptivity parameter that accounts for reflection and scattering losses. The absorbed laser energy serves as the heat source in the transient heat equation, enabling simulation of the temperature evolution in both casing and rock layers.

The results show that the laser beam generates highly localized heating near the beam center, producing steep temperature gradients across the laser-treated surface. These gradients induce significant thermoelastic stresses due to constrained thermal expansion of the heated materials. Compressive stresses develop near the irradiated surface, while tensile stresses arise in the surrounding region. This tensile stress field governs fracture initiation and contribute to the formation of microcracks and spallation.

The simulation also demonstrates that thermoelastic stresses redistribute much faster than heat diffuses into the rock, allowing fracture initiation to occur in regions that have not yet reached the highest temperatures. Overall, the coupled optical–thermal–mechanical model provides insight into the mechanisms controlling laser perforation through casing and into sandstone rock formations, and it offers a useful framework for evaluating laser parameters and optimizing perforation performance.