US 6,056,057 AGranted

Heater well method and apparatus

AssigneeShell Oil Company

InventorsHarold J. Vinegar, Thomas Mikus, John Michael Karanikas, Scott Lee Wellington

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Abstract

A method and apparatus is disclosed for heating of formations using fired heaters. Each fired heater may consist of two concentric tubulars emplaced in the formation, connected via a wellhead to a burner at the surface. Combustion gases from the burner go down to the bottom of the inner tubular and return to the surface in the annular space between the two tubulars. The two tubulars may be insulated in an overburden zone where heating is not desired. A plurality of fired heaters can be connected together such that the combustion gases from a first fired heater well are piped through insulated interconnect piping to become the air inlet for a second fired heater well, which also has a burner at its wellhead. This can be repeated for other heater wells, until the oxygen content of the combustion gas is reduced near zero. The combustion gas from the last fired heater well may be routed through a heat exchanger in which the fresh inlet air for the first heater well is preheated. A substantially uniform temperature is maintained in each heater well by using a high mass flow into the heater well.

Claims12

Dependent claims

A method to heat a formation, the method comprising the steps of:

providing a plurality of wellbores within the formation to be heated, each of the wellbores comprising a combustion gas flowpath through which a fluid can be routed, the combustion gas flowpath having an inlet and an outlet;
supplying to an inlet of a first wellbore combustion gas flowpath a flow of air;
burning an amount of fuel in the flow of air, thereby forming a stream of combustion products, the amount of fuel resulting in the stream of combustion products being at a first initial temperature;
passing the stream of combustion products through the first wellbore combustion gas flowpath, thereby transferring heat from the stream of combustion products to the formation, and decreasing the temperature of the stream of combustion products from the first initial temperature to a first final temperature;
routing the stream of combustion products to a second wellbore combustion gas flowpath inlet;
burning a second amount of fuel in the stream of combustion products, thereby forming a second stream of combustion products, the second amount of fuel resulting in the second stream of combustion products being at a second initial temperature;
and
passing the second stream of combustion products through the second wellbore combustion gas flowpath, thereby transferring heat from the second stream of combustion products to the formation, and decreasing the temperature of the second stream of combustion products from the second initial temperature to a second final temperature.

5 more elements

An apparatus to heat a formation comprising:

a plurality of wellbores extending from grade level above the formation to the formation, each of the wellbores comprising a combustion gas flowpath from an inlet at grade level, through a substantial portion of the wellbore, and back to an outlet at grade level;
a burner at the inlet of at least one combustion gas flowpath, the burner capable of producing a first combustion gas stream the burner having a combustion gas outlet in communication with the wellbore combustion gas flowpath inlet;
a combustion gas conduit in communication with the wellbore combustion gas flowpath outlet;
and
a second burner, the combustion conduit providing communication to the second burner, and the second burner capable of producing a second combustion gas stream, by combustion of a fuel with the first combustion gas stream, and the second burner having a combustion gas outlet in communication with a second wellbore combustion gas flowpath inlet.

2 more elements

Dependencies are inferred from the claim text.