Abstract: A flowbore fluid temperature control system comprising a valve mechanism that adjusts the flow of a fluid through a flowbore. The flowbore fluid temperature control system also comprises an actuator that adjusts the valve mechanism. The flowbore fluid temperature control system also comprises an operating system that operates the actuator and controls the flowbore fluid pressure. The flowbore fluid temperature control system selectively controls the temperature of the flowbore fluid by adjusting the flow of the fluid through the flowbore. The control system controls the actuator and also controls the flowbore fluid pressure to affect the temperature of the flowbore fluid.

Abstract: A method for drilling a wellbore in a formation using a drilling fluid, wherein the drilling fluid has a first temperature, and wherein the wellbore has a first wellbore depth. In one embodiment, the method comprises determining at least one fracture gradient, wherein the fracture gradient is determined at about the first wellbore depth; increasing the temperature of the drilling fluid from the first temperature to a desired temperature at about the first wellbore depth; drilling into the formation at increasing wellbore depths below the first wellbore depth, wherein at least one equivalent circulating density of the drilling fluid is determined at about the first wellbore depth; and setting a casing string at a depth at which the equivalent circulating density is about equal to or within a desired range of the fracture gradient. In other embodiments, an automated system is used to maintain the temperature of the drilling fluid at about first wellbore depth.