Boring or penetrating the earth – Cutter element laterally shiftable below ground – Cutter element shifted by fluid pressure
Patent
1977-11-23
1980-02-12
Leppink, James A.
Boring or penetrating the earth
Cutter element laterally shiftable below ground
Cutter element shifted by fluid pressure
175215, 175340, 175337, E21B 926
Patent
active
041879201
ABSTRACT:
Method and apparatus are disclosed for drilling a pilot hole and subsequently enlarging the pilot hole in earth formation. A dual concentric pipe string is used for circulating air downwardly through the outer pipe, through a pilot bit and upwardly through the bore hole outside the pipe string to bail cuttings, during drilling of the pilot hole. The air pressure expands the cutters of an expansible bit while a limited portion of the air supplied cools the cutters. After the cutters are fully expanded, additional air is utilized to clean and cool the cutters. Air is returned through the inner pipe of the dual concentric pipe string. A venturi device is utilized to induce return flow through the inner pipe during enlargement of the hole and to vacuum residue when enlargement is completed. The dual concentric pipe string is made up of lengths of pipe providing threaded, sealed joints.
REFERENCES:
patent: 1302967 (1919-05-01), Pickin
patent: 2457628 (1948-12-01), Baker
patent: 2849213 (1958-08-01), Failing
patent: 3196960 (1965-07-01), Kammerer
patent: 3198267 (1965-08-01), Madson
patent: 3528516 (1970-09-01), Brown
patent: 3757877 (1973-09-01), Leathers
patent: 3885838 (1975-05-01), Childers et al.
patent: 3949820 (1976-04-01), Furse
Favreau Richard E.
Leppink James A.
Tri-State Oil Tool Industries, Inc.
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