03952802 is referenced by 234 patents and cites 11 patents.

The process of the invention includes the concept of igniting a coal formation in situ with hot granular material and subsequently allowing the material to flow into the burning coal formation to serve as a propping agent in the event of a cave-in. Gasifying agents are injected into the formation in an alternating pattern to alternately oxidize and reduce the coal environment to optimize the BTU content of the recovered gas. Further, a heat receptive liquid is circulated through the casing in the well connecting the coal formation to the surface to strip the sensible heat from the produced gases so that the heat can be used for useful purposes apart from the produced gas.

The apparatus of the invention includes a casing in the well bore which has a plurality of vertically spaced dividers each having a passage therethrough so that a heat receptive fluid can be passed between dividers in a vertical descent through the casing and during such descent strip sensible heat from the produced gas before being brought back to the surface. Hot granular material is placed in the well in contact with the coal formation to ignite the formation and to flow into cavities formed in the formation during the burning thereof to serve as a propping agent.

Title
Method and apparatus for in situ gasification of coal and the commercial products derived therefrom
Application Number
5/531453
Publication Number
3952802
Application Date
December 11, 1974
Publication Date
April 27, 1976
Inventor
Ruel C Terry
Denver
CO, US
Agent
Burton Crandell & Polumbus
Assignee
In Situ Technology
CO, US
IPC
E21B 43/24
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