METHOD AND APPARATUS FOR UNIFORMLY HEATING LONG SUBTERRANEAN INTERVALS AT HIGH TEMPERATURE

摘要

METHOD AND APPARATUS FOR UNIFORMLY HEATING LONG SUBTERRANEAN INTERVALS AT HIGH TEMPERATURE Long intervals of subterranean earth formations are heated at high temperatures for long times with an electrical heater containing spoolable, steel-sheathed, mineral-insulated cables which have high electrical conductivities, enabling them to heat the earth formations at a substantially uniform rate of more than about 300 watts per metre at temperatures between about 600 and 1000 .degree.C, with a pattern of localized electrical resistances which are correlated with the heat conductivities of the earth formations and the heat stabilities of materials providing power and support for the heater.