What are the critical factors that influence the 'long-term injectivity' of injection wells in enhanced geothermal systems (EGS)?

Long-term injectivity, the ability of an injection well to accept fluid over an extended period, is critical for the sustainable operation of Enhanced Geothermal Systems (EGS). Several factors influence this injectivity. Formation damage is a primary concern. This includes scaling, where minerals precipitate out of the injected fluid and plug the fractures, and swelling of clay minerals, which reduces permeability. Water quality is crucial. The injected water should be compatible with the reservoir rock and fluids to minimize scaling and clay swelling. Pre-treatment of the water, such as filtration and chemical treatment, is often necessary. In....