Patent ID: 8122955

Claim:
A method for in situ heating of a selected portion of an organic-rich rock formation, comprising: providing casing in a wellbore located at least partially within the organic-rich rock formation, the casing extending to a depth within or below the selected portion of the organic-rich rock formation; providing a tubing within the casing, the tubing defining a first annulus between the tubing and the surrounding casing; injecting an oxidant and a combustible fuel into the wellbore, with either the oxidant or the combustible fuel being injected at an excess mass flow rate greater than about 2.0 times a stoichiometric combustion flow rate, wherein the excess mass flow rate is selected to provide a more uniform temperature profile in the first annulus along the selected portion of the organic rich rock formation; providing hardware in the wellbore so as to cause the oxidant and the combustible fuel to mix and to combust into flue gas at a first combustion depth located substantially within the selected portion of the organic-rich rock formation; moving the flue gas up the first annulus; and providing insulation along at least a portion of the tubing located below the first combustion depth, thereby reducing the heat transfer coefficient between the flue gas in the first annulus and the flue gas within the tubing.