Method for controlling the downhole temperature during fluid injection into oilfield wells

Methods and apparatus for using a fluid within a subterranean formation comprising forming a fluid comprising a fluid additive, introducing the fluid to a formation, observing a temperature, and controlling a rate of fluid introduction using the observed temperature, wherein the observed temperature is lower than if no observing and controlling occurred. A method and apparatus to deliver fluid to a subterranean formation comprising a pump configured to deliver fluid to a wellbore, a flow path configured to receive fluid from the pump, a bottom hole assembly comprising a fluid outlet and a temperature sensor and configured to receive fluid from the flow path, and a controller configured to accept information from the temperature sensor and to send a signal.