Geomechanics studies deal mainly with coupled problems requiring simultaneous consideration of changes in temperature, pressure, stress, and chemical potential (THMC). Major current challenges in this domain include: accurate delineation of in situ physical properties and conditions (T, [σ ], p), especially for naturally fractured reservoirs; wellbore wall stability predictions in swelling and fractured shale strata; modeling and monitoring of multiple-stage hydraulic fracturing used for development of resources in low-permeability rocks; controlling or exploiting sand ingress into producing wellbores; predicting subsidence accurately enough so that rational design decisions can be made; mitigating or reducing the incidence of casing shear arising from subsidence or thermal reservoir stimulation; understanding and analyzing thermal production processes in viscous oil reservoirs; monitoring of deformations in and around reservoirs being subjected to complex processes; and, a newer development, using the deep sedimentary basin environment for the permanent and secure heat recovery, and disposal of fluid and granular wastes.