Method of underground conversion of coal

• US 4,662,439 A
• Filed: 05/14/1985
• Issued: 05/05/1987
• Est. Priority Date: 01/20/1984
• Status: Expired due to Fees

• Current Assignee: Amoco Corporation (BP PLC)
• Original Assignee: Amoco Corporation (BP PLC)
• Inventors: Puri, Rajen
• Primary Examiner(s): Suchfield, George A.
• Application Number:
  US06/734,501
• Time in Patent Office: 721 Days
• Field of Search: 166/245, 166/256, 166/258, 166/259, 166/261, 166/263, 166/266, 166/272, 166/303, 48/DIG. 6
• US Class Current: 166/245
• CPC Class Codes: E21B 43/247 in association with fracturing processes or crevice forming processes
• CPC Class Codes: E21B 43/30 Specific pattern of wells, e.g. optimising the spacing of wells

Abstract

A method of converting coal and other solid carbonaceous material to gaseous and liquid products by heating the coal in the presence of the gaseous effluent to a sufficient temperature for pyrolyzing the coal to produce liquid and gaseous products. Thereafter, further gasifying the coal to produce a gaseous effluent to be used in subsequent steps to produce liquid and gaseous products.

Claims

1. A method of converting to gaseous and liquid products, coal and other carbonaceous material contained in a coal seam wherein the seam contains a plurality of groupings of pairs of wells, the wells in each pair being linked, comprising:

(a) affecting pyrolysis in the seam between two pairs of linked wells in a grouping by injecting a mixture of steam and syngas to one of said pairs and removing pyrolysis products from the other of said pairs;

(b) thereafter injecting an oxidant into the seam between said two pairs of linked wells to gasify remaining carbonaceous material for producing syngas; and

(c) using at least a portion of the syngas recovered from step (b) as the syngas injected in step (a) into a second pair of linked wells in said plurality of groupings.

2. The method of claim 1 wherein said wells are linked by a reverse combustion process.

3. A method of claim 1 wherein said step (b) is accomplished by forward combustion.

4. The method of claim 1 wherein said seam is inclined.

5. The method of claim 1 wherein the sequence of said steps (a), (b), and (c) is repeated across said seam in subsequent groupings of wells.