Heat injection process
AssigneeShell Oil Company
InventorThomas Mikus
Life of this patent
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Abstract
A method for heat injection into a subterranean formation is provided. The method utilizes flameless combustion. The absence of a flame eliminates the flame as a radiant heat source and results in a more even temperature distribution throughout the length of the burner. Flameless combustion is accomplished by preheating the fuel and the combustion air to a temperature above the autoignition temperature of the mixture. Preheating hydrocarbon fuel requires the inclusion of a carbon formation suppressant such as carbon dioxide or steam to prevent carbon formation.
Claims8
A method of heating a subterranean formation comprising at least one borehole providing communication from the surface to the subterranean formation to be heated, the method comprising:
- combining a hydrocarbon fuel gas with a carbon formation suppressant;
- passing the fuel gas and carbon formation suppressant mixture through a fuel gas conduit to a mixing point within the borehole juxtapose to the formation to be heated;
- passing a combustion air stream though an air conduit to the mixing point;
- preheating either the fuel gas and carbon formation suppressant mixture, the combustion air stream or both such that the temperature of a mixture of the streams exceeds an autoignition temperature of the mixture of the streams;
- combining the preheated combustion air and fuel gas and carbon formation suppressant at the mixing point resulting in autoignition forming combustion products;
- passing the combustion products through the borehole from the mixing point to the surface,
- wherein the amount of the carbon formation suppressant combined with the fuel gas exceeds that which prevents carbon formation at the temperature of the preheated fuel gas and carbon suppressant mixture.
Dependencies are inferred from the claim text.