Title:
REGENERATING METHOD FOR OLD WELL AND DOUGHNUT DRILL BIT USED FOR THE METHOD AND CUTTER FOR EXISTING CASING PIPE
Document Type and Number:
Japanese Patent JP2707193
Kind Code:
B2
Abstract:
PURPOSE: To regenerate an old well by a method wherein the periphery of the casing pipe of the old well is dug down by a pressure muddy-water circula tion type doughnut drill bit, the casing pipe is cut in proper length and extracted, and a casing pipe is constructed in the same method as a new well.
CONSTITUTION: A filled gravel layer 21 in the periphery of the casing pipe 6 of an old well and a part of a bedrock are dug down by a doughnut drill bit 1 conducting excavation by infecting pressure muddy water. The dug-up casing pipe 6 is cut in proper length by a cutter, and extracted. The operation is repeated successively, and the casing pipes 6 are extracted in succession. Excavation is performed by a diameter expander, and a casing pipe is constructed in the same method as a new well, thus regenerating the old well. Accordingly, a groundwater intake right need not be gained anew, thus reducing the cost of construction.
Inventors:
Kenjiro Hongo
Application Number:
JP34510592A
Publication Date:
January 28, 1998
Filing Date:
December 02, 1992
Export Citation:
Assignee:
Hongo Limited Co., Ltd.
International Classes:
E03B3/15; E21B7/18; E21B10/60; E21B29/00; (IPC1-7): E21B29/00; E03B3/15
Domestic Patent References:
| JP313622A | ||||
| JP5841395B2 |
Attorney, Agent or Firm:
Nakamura
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