Method for blocking gas flow in a coal seam
AssigneeContinental Oil Company
InventorJ. Gilbert Davis, II
Life of this patent
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Abstract
Gas flow from a coal seam to a mine face in the seam is blocked by drilling a hole from the face into the seam in a direction generally parallel to the direction of the flow of the gas to be blocked; forming a notch at the interior end of the hole; injecting a fluid into the hole and notch under a pressure sufficient to hydraulically fracture the seam along a plane extending substantially perpendicular to the hole and to the direction of gas flow; and filling such fracture with a barrier-forming fluid. The hole is then plugged to prevent retrograde flow of the fluid to the mine face.
Claims14
In the mining of coal from a seam in which methane gas flow to a mining or rib face is blocked by positioning of a barrier fluid in the seam in the path of gas flow, the improvement comprising:
- drilling a plurality of substantially parallel holes into the seam from said face in a direction substantially parallel to the direction of the flow of gas from the interior of said seam;
- forming a notch in the coal seam at the interior end of each of the holes;
- introducing a hydraulic fracturing fluid under pressure into said notches via said holes;
- hydraulically fracturing the coal seam along one or more planes of fracture propagated from each of said notches and extending substantially normal to the direction of gas flow through the coal seam to said face;
- and
- stationarily positioning a barrier fluid in said fracture to effectively block the gas flow to said face.
A method for preventing dangerous emission of methane gas into a coal mine entry from a face of a coal seam comprising:
- drilling a hole into a coal seam from said face in a direction substantially parallel to the planes of cleavage in the seam which intersect the face;
- forming a lens-shaped notch at the inner end of said hole and projecting radially from said hole generally in a plane extending substantially normal to the longitudinal axis of said hole;
- placing a hydraulic fracturing fluid in the hole and notch;
- hydraulically fracturing the coal seam along an artificial fracture propagated outwardly from the notch substantially in a plane extending normal to the longitudinal axis of the hole and cutting across a plurality of planes of cleavage;
- and
- placing a blocking fluid in the artificial fracture to obstruct the migration of gas to said face through the passageways along said planes of cleavage.
Dependencies are inferred from the claim text.