Method for in-situ utilization of fuels by combustion

Claim 1

The method of burning subsurface combustible material in situ as claimed in claim 1 wherein a reduced pressure is mAintained at the upper end of said second passage to facilitate the removal of said products of combustion of said combustible material, from said combustion chamber, through said second passage.

Claim 2

The method of burning subsurface combustible material in situ that comprises: drilling a passage which extends downwardly from the surface to said combustible material and then extends a substantial distance through said combustible material in a generally horizontal direction; drilling a second passage which extends downwardly from said surface to said combustible material and then extends a substantial distance through said combustible material in a generally horizontal direction; said second passage being spaced from the first said passage but the generally horizontal portion of said second passage being generally at the same level as, and being generally parallel to, the generally horizontal portion of said first said passage; igniting the combustible material adjacent the inner ends of said passages to cause a portion of said combustible material to burn away and thereby form a combustion chamber within said combustible material which extends transversely of said first said and said second passages and which interconnects said inner ends of said first said and said second passages; supplying air, to the combustible material defining the walls of said combustion chamber, through said first said passage; removing products of combustion of said combustible material from said combustion chamber through said second passage; said generally horizontal portions of said first said and said second passages being overlain by an overburden; the portion of said overburden adjacent to the inner ends of said first said and said second passages providing a self-supporting overhang which enables air to enter said combustion chamber from said first said passage and which enables products of combustion to move to and outwardly through said second passage; said air supplied to said combustion chamber by said first said passage causing that wall of said combustion chamber which is adjacent to said inner ends of said first said and said second passages to burn away and cause said combustion chamber to progressively ''''move'''' along the lengths of said generally horizontal portions of said first said and said second passages while continuing to interconnect said inner ends of said first said and said second passages; portions of said overburden adjacent to the opposite wall of said combustion chamber slumping down into said combustion chamber, but said portion of said overburden adjacent to said inner ends of said first said and said second passages enabling air to continue to enter said combustion chamber from said first said passage and enabling products of combustion to move to and outwardly through said second passage; subsequently supplying air to said combustible material, which defines said walls of said combustion chamber, through said second passage; removing products of combustion of said combustible material, from said combustion chamber, through said first said passage; and the resulting flow of air and products of combustion through said combustion chamber, from said inner end of said second passage to said inner end of said first said passage, increasing the rate of burning of the portion of the first said wall of said combustion chamber which is adjacent to said inner end of said second passage.

Claim 3

The method of burning subsurface combustible material in situ that comprises: drilling a passage which extends downwardly from the surface to said combustible material and then extends a substantial distance through said combustible material in a generally horizontal direction; drilling a second passage which extends downwardly from said surface to said combustible material and then extends a substantial distance through said combustible material in a generally horizontal direction; said second passaGe being spaced from the first said passage; igniting the combustible material adjacent the inner ends of said passages; supplying air to said combustible material through the first said passage; removing products of combustion of said combustible material through said second passage; drilling a third passage so it extends downwardly from said surface to said combustible material and then extends a substantial distance through said combustible material in a generally horizontal direction; said third passage having the inner end thereof lapping part of said first said passage so the burned out area in said combustible material will merge with said third passage before it moves wholly away from said first said passage; drilling a fourth passage so it extends downwardly from said surface to said combustible material and then extends a substantial distance through said combustible material in a generally horizontal direction; and said fourth passage having the inner end thereof lapping part of said second passage so said burned out area will merge with said fourth passage before it moves wholly away from said second passage.

Claim 4

The method of burning subsurface combustible material in situ that comprises: drilling a passage which extends downwardly from the surface to said combustible material and then extends a substantial distance through said combustible material in a generally horizontal direction; drilling a second passage which extends downwardly from said surface to said combustible material and then extends a substantial distance through said combustible material in a generally horizontal direction; said second passage being spaced from the first said passage; igniting the combustible material adjacent the inner ends of said passages; supplying air to said combustible material through the first said passage; removing products of combustion of said combustible material through said second passage; drilling a third passage so it extends downwardly from said surface to said combustible material and then extends a substantial distance through said combustible material in a generally horizontal direction; said third passage having the inner end thereof lapping part of said first said passage so the burned out area in said combustible material will merge with said third passage before it moves wholly away from said first said passage; drilling a fourth passage so it extends downwardly from said surface to said combustible material and then extends a substantial distance through said combustible material in a generally horizontal direction; said fourth passage having the inner end thereof lapping part of said second passage so said burned out area will merge with said fourth passage before it moves wholly away from said second passage; said third passage being drilled so it coacts with said first said passage to define a row of passages; and said fourth passage being drilled so it coacts with said second passage to define a second row of passages which is spaced from, but generally parallel to, the first said row of passages.

Claim 5

The method of burning subsurface combustible material in situ which comprises: drilling a row of passages which extend downwardly from the surface to said combustible material and then extend substantial distances through said combustible material in a generally horizontal direction; drilling the passages of said row of passages so they overlap in part; drilling a second row of passages which extend downwardly from said surface to said combustible material and then extend substantial distances through said combustible material in a generally horizontal direction; drilling the passages of said second row of passages so they overlap in part; said second row of passages being formed so it is spaced from but generally parallel to the first said row of passages; drilling a further row of passages which extend downwardly from said surfaCe to said combustible material and then extend substantial distances through said combustible material in a generally horizontal direction; said further row of passages being drilled so it is close to, but is directed transversely of, said first said and said second row of passages; using said further row of passages to burn out the combustible material adjacent the inner ends of the passages of said first and second row of passages and thereby form an elongated combustion-supporting chamber in said combustible material which is close to, but is directed transversely of, said first said and said second row of passages; supplying air to at least one passage of said first said row of passages and applying a reduced pressure to the upper end of at least one passage of said second row of passages to promote burning of the combustible material forming one face of said elongated combustion-supporting chamber; and subsequently supplying air to a further passage of said first said row of passages and applying a reduced pressure to the upper end of a further passage of said second row of passages to continue to promote burning of the combustible material forming one face of said elongated combustion-supporting chamber.

Claim 9

The method of maintaining a reduced pressure throughout a substantial area within a subsurface seam which comprises drilling a small diameter passage that curVes downwardly from the surface to said seam, extending the inner end of said passage a substantial distance through said seam in a direction generally parallel to said seam, connecting the upper end of said passage to the inlet of a gas-moving device, and operating said gas-moving device to withdraw gas from said upper end of said passage and thereby maintain a reduced pressure within said passage, said passage performing the dual functions of collecting gases withdrawn from said subsurface seam by said reduced pressure within said passage and of then conducting said gases to said surface of said area.

Claim 11

The method of maintaining a reduced pressure throughout a substantial area within a subsurface seam which comprises drilling a small diameter passage that curves downwardly from the surface to said seam, extending the inner end of said passage a substantial distance through said seam in a direction generally parallel to said seam, connecting the upper end of said passage to the inlet of a gas-moving device, drilling a second small diameter passage that curves downwardly from said surface to said seam, extending the inner end of said passage a substantial distance through said seam in a direction generally parallel to said seam, drilling said second passage so said inner end thereof is spaced from but is generally parallel to and is generally coextensive with said inner end of said first said passage, a combustion-supporting chamber within said seam, supplying air to the upper end of said second passage to cause said air to pass to said combustion-supporting chamber, and operating said gas-moving device to cause products of combustion from said combustion-supporting chamber to pass upwardly through said first said passage to said gas-moving device.

Claim 12

The method of recovering subsurface material in situ that comprises: drilling a passage which extends downwardly from the surface to said material and then extends a substantial distance through said material in a generally horizontal direction; initiating and sustaining combustion adjacent the inner end of said passage to vaporize part of said material and to incompletely burn part of said material; the vaporizing of part of said material and incomplete burning of part of said material forming a combustion chamber within said material in communication with said inner end of said passage; the horizontally extending portion of said passage being overlain by an overburden; the portion of said overburden adjacent said inner end of said passage providing a self-supporting overhang which enables air to enter said combustion chamber and which enables said vaporized portion of said material and the products of incomplete combustion of said material to flow through and out of said combustion chamber; supplying pressurized air to said combustion chamber to cause that wall of said combustion chamber which is adjacent said inner end of said passage to volatilize and to incompletely burn and thereby cause said combustion chamber to ''''move'''' along the length of said horizontally extending portion of said passage; and withdrawing said vaporized portion of said material and the products of incomplete combustion of said material to the surface for utilization thereof; and portions or said overburden adjacent the opposite wall of said combustion chamber slumping down into said combustion chamber, but said portion of said overburden adjacent said inner end of said passage enabling air to continue to enter said combustion chamber and enabling said vaporized portion of said material and the prodUcts of incomplete combustion of said material to flow through and out of said combustion chamber.