Millions of wells will need to be abandoned in the coming decades, at a phenomenal expense to the oil & gas industry with zero return on investment (ROI). A sizeable portion of these wells is already leaking primarily methane, a powerful greenhouse gas, into the atmosphere, and more wells are expected to do so at some point in the future. In this presentation, Dr. van Oort will discuss the main risk factors associated with well leakage as a result of compromised well integrity. In addition, he will present his own R&D work on using shale and salt formations to create and remedy annular barriers to prevent and eliminate gas migration, surface vent flows and sustained casing pressures. Given the many drawbacks associated with the long-term reliance globally on Portland cement as a preferred barrier and P&A material, it will be shown that low-permeability shale and salt formations can generate highly competent barriers through the creep deformation mechanism. Such barriers can significantly reduce the likelihood and risks of well leakage and methane venting in the future, while at the same time reducing well abandonment complexity and costs by allowing rigless well abandonments. Results from creep barrier formation, induced by artificial temperature/pressure/chemical activation, in the North Sea offshore environment will be shared.