US Patent 7625845 Method of using thermal insulation fluid containing hollow microspheres

A thermal insulating fluid contains microspheres of hollow spherical particulates. The presence of the hollow spherical particles improves the thermal insulating properties of the fluid by imparting to the thermal insulating fluid a low heat transfer coefficient. The hollow particulates may be inorganic or organic in nature and include hollow spheres of glass, ceramics and plastics. The thermal insulating fluid is capable of controlling the heat transfer from a production tubing or transfer pipe to one or more surrounding annuli and the environment. In addition to reducing heat transfer in the producing well, heat transfer in the fluid produced from the well is also minimized.