Enlarged bore hole drilling method

Patent · Tue Aug 26 04:00:00 EDT 1980

OSTI ID:7020229

Johnson, G R

The method is 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 milited 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.

• Assignee: Tri State Oil Tool Ind Inc
• Patent Number(s): US 4219087
• OSTI ID: 7020229
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020300* -- Petroleum-- Drilling & Production
03 NATURAL GAS
030300 -- Natural Gas-- Drilling
Production
& Processing
42 ENGINEERING
422000 -- Engineering-- Mining & Underground Engineering-- (1980-)
AIR
BOREHOLES
CAVITIES
DRILL BITS
DRILLING
DRILLING EQUIPMENT
EQUIPMENT
FLUIDS
GASES
GEOLOGIC FORMATIONS
NATURAL GAS WELLS
OIL WELLS
PIPES
VENTURI TUBES
WELL DRILLING
WELLS