Petroleum geomechanics is the branch of engineering dealing with the mechanical properties and behavior of geological formations which influence the exploration, development, and production of oil and gas. This includes reservoir scale phenomena, such as faulting and fracture development over geological time, compaction and subsidence caused by production, and induced faulting and seismicity. It also includes wellbore scale phenomena, such as wellbore stability during drilling, hydraulic fracturing, formation/casing interaction during production, sand production, and waste injection.