Systems and methods for an in situ heat treatment process that utilizes a circulation system to heat one or more treatment areas are described herein. The circulation system may use a heated liquid heat transfer fluid that passes through piping in the formation to transfer heat to the formation. In some...http://www.google.co.uk/patents/US20080135254?utm_source=gb-gplus-sharePatent US20080135254 - In situ heat treatment process utilizing a closed loop heating system
