A method for thermal fluid injection into a plurality of strata wherein a well is packed off to establish a first and a second zone. A first tubing string is introduced and is terminated in the first zone. The first tubing string is paralleled by a second tubing string. The first and second tubing strings are physically separated. A first fluid at a first temperature is injected into the first tubing string while a second fluid at a second temperature is simultaneously injected into the second tubing string. The first fluid at the first temperature is applied to the first zone while the second fluid at the second temperature is applied to the second zone.