A Drilling Engineer's Explanation

摘要

Geothermal wells differ greatly from oil and gas wells. Due to temperature increases in the well bore, geothermal wells are cemented from the bottom of all casing strings back to the surface. Oil and gas wells are usually only cemented around the casing bottom leaving the upper zones uncemented. Therefore, in areas where geothermal well fracking is proposed-and, as Steve says, this is rare-the frack interval will be deep. It must take place in the portion of the well where a reservoir can exist at high temperatures because we want to inject water into the fractures to be heated in order to produce a commercial geothermal fluid.