An oil recovery method employing amphoteric surfactants with the steps of: a) Injecting into one or more injection wells an aqueous solution containing a mixture of amphoteric surfactants containing mixture of amphoteric surfactants having a hydrocarbyl chain length between 8 and 26 and certain degree of unsaturation, and b) recovering the oil from one or more producing wells. The semiconductor body is provided with a thermal-insulation device including a dissipator element arranged between the high-temperature operating portion and the low-temperature operating portion. The housing includes an inlet and an outlet and a cavity extending between the inlet and the outlet.