US3851719A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Stabilized under-drilling apparatus
Assignee: American Coldset Corp
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Filing: 1973-03-22
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Granted: 1974-12-03
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Expires: 1993-03-22
Abstract
Abstract Improved rotary under-drilling apparatus, of the type used for extending and enlarging the bore hole of a well from some point below the surface, includes a pilot drill bit for drilling a small hole in the desired direction of the well, an under-reamer of the offset or assymmetric type, axially spaced from the drill bit, for enlarging the pilot hole to the desired final diameter, and at least one stabilizing means positioned between the reamer and the pilot drill bit. The stabilizing means has an effective diameter of substantially the same size as the hole drilled by the pilot bit but has no cutting surfaces, so that it acts as a journal bearing against the wall of the pilot hole, both to isolate the drill bit from the radial and moment forces generated by the reamer and also to cause the reamer to rotate concentrically with the axis of the pilot hole. Preferably, two stabilizing means are provided, one adjacent to the lower end of the under-reamer and the other spaced between the first guide means and the upper end of the drill bit.
Inventors
- 👤 C Thompson
- 👤 B Thompson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 23:03
CPC Classifications
E; E21; E21B; E21B17/00; E21B17/10; E21B17/1078; E21B10/00; E21B10/26
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
179 words
A rotary under-reaming device for enlarging a pilot hole of predetermined radius drilled in the earth, the device comprising: an elongated cylindrical body having a radius no greater than the predetermined radius of the pilot hole and a threaded upper end for attachment to a drill pipe; an asymmetrical reaming section extending outwardly from the upper part of the body about only an arcuate portion of the circumference thereof to a radius greater than the radius of the pilot hole, the arcuate portion subtending an angle of less than 180* and the remainder of said circumference having a non-reaming face, and a first non-reaming stabilizing section located on the body below the reaming section, the stabilizing section having a smooth, non-cutting, bearing surface defined by a first cylinder concentric with the longitudinal axis of the cylindrical body and having a radius approximately equal to the predetermined radius of the pilot hole but having sufficient clearance to rotate in the pilot hole without binding, whereby the reaming section is caused to rotate concentrically with the axis of the pilot hole.
Claim 2
Dependent Claim
179 words
A rotary under-reaming device for enlarging a pilot hole of predetermined radius drilled in the earth, the device comprising: an elongated cylindrical body having a radius no greater than the predetermined radius of the pilot hole and a threaded upper end for attachment to a drill pipe; an asymmetrical reaming section extending outwardly from the upper part of the body about only an arcuate portion of the circumference thereof to a radius greater than the radius of the pilot hole, the arcuate portion subtending an angle of less than 180* and the remainder of said circumference having a non-reaming face, and a first non-reaming stabilizing section located on the body below the reaming section, the stabilizing section having a smooth, non-cutting, bearing surface defined by a first cylinder concentric with the longitudinal axis of the cylindrical body and having a radius approximately equal to the predetermined radius of the pilot hole but having sufficient clearance to rotate in the pilot hole without binding, whereby the reaming section is caused to rotate concentrically with the axis of the pilot hole.
Claim 3
Dependent Claim
48 words
The under-reaming device of claim 1 further comprising: a drill bit attached to the lower end of the reamer body and having a cutting head axially spaced from the lower end of the first stabilizing section for simultaneously drilling the pilot hole as the reaming section enlarges it.
Claim 4
Dependent Claim
48 words
The under-reaming device of claim 1 further comprising: a second non-reaming stabilizing section located below and axially spaced from the first stabilizing section, the second stabilizing section having smooth, non-cutting bearing surfaces defined by a second cylinder coaxial with and having the same diameter as the first cylinder.
Claim 5
Dependent Claim
48 words
The under-reaming device of claim 3 further comprising: a drill bit located below the second stabilizing section and having a cutting head axially spaced from the lower end of the second stabilizing section for drilling the bottom of the pilot hole as the reaming section enlarges its sides.
Claim 6
Dependent Claim
114 words
The under-reaming device of claim 3 wherein: the first stabilizing section comprises a plurality of axially extending first lands circumferentially spaced about the cylindrical body in the region complementary to the circumferential region subtended by the reaming section, the outer surfaces of the first lands comprising wear-resistant, non-cutting, bearing surfaces defined by the first cylinder; and the second stabilizing section comprises a plurality of axially extending second lands symmetrically spaced about the cylindrical body, the outer surfaces of the second lands comprising wear-resistant, non-cutting, bearing surfaces defined by the second cylinder, whereby the bearing surfaces of the first and second lands cooperate to subtend a major portion of the circumference of the pilot hole.
Claim 7
Dependent Claim
74 words
The under-reaming device of claim 5 further comprising a centraL passageway through the cylindrical body for conducting drilling fluid under pressure downward through the bottom of the body and then upward through the spaces between the lands of the second and first stabilizing sections, and wherein the reaming surface contains circumferentially spaced grooves to permit a portion of the fluid flowing upward from the first stabilizing section to lubricate and cool the reaming surface.
Claim 8
Dependent Claim
43 words
The under-reaming device of claim 1 wherein the reaming section comprises a cutting surface defined by a circumferential portion of a cylinder concentric with the axis of the reamer body and having a radius larger than the predetermined radius of the pilot hole.
Claim 9
Dependent Claim
37 words
The under-reaming device of claim 7 wherein the first stabilizing section comprises a plurality of axially extending lands circumferentially spaced about the cylindrical body in the region complementary to the circumferential region subtended by the reaming section.
Claim 10
Dependent Claim
173 words
A rotary under-reaming device for increasing the radius of a pilot hole of predetermined radius drilled in the earth, the device comprising: an elongated cylindrical body having a threaded upper end adapted for attachment to a drill stem and a threaded lower end adapted for attachment to a stabilizing element and an asymmetrical reaming section extending outwardly from a first arcuate circumferential portion of the cylindrical body, the reaming section subtending an angle of less than 180* and the remaining circumference of the cylindrical body having a non-reaming surface, the reaming section including a lower cutting surface extending outwardly from the first portion of the circumference of the cylindrical body to a radius greater than the radius of the pilot hole and an upper surface defined by a portion of a cylinder having a radius substantially equal to the maximum radius of the cutting surface, the lower cutting and upper reaming surfaces having rows of embedded cutting elements separated by upwardly directed passages for drilling fluid to cool and lubricate the cutting elements.
Claim 11
Dependent Claim
173 words
A rotary under-reaming device for increasing the radius of a pilot hole of predetermined radius drilled in the earth, the device comprising: an elongated cylindrical body having a threaded upper end adapted for attachment to a drill stem and a threaded lower end adapted for attachment to a stabilizing element and an asymmetrical reaming section extending outwardly from a first arcuate circumferential portion of the cylindrical body, the reaming section subtending an angle of less than 180* and the remaining circumference of the cylindrical body having a non-reaming surface, the reaming section including a lower cutting surface extending outwardly from the first portion of the circumference of the cylindrical body to a radius greater than the radius of the pilot hole and an upper surface defined by a portion of a cylinder having a radius substantially equal to the maximum radius of the cutting surface, the lower cutting and upper reaming surfaces having rows of embedded cutting elements separated by upwardly directed passages for drilling fluid to cool and lubricate the cutting elements.
Claim 12
Dependent Claim
45 words
The under-reaming device of claim 9 wherein a second circumferential portion of the reamer body above the lowest extent of the reamer cutting surface in the region not subtended by the reaming section has a radius approximately equal to the radius of the pilot hole.
Claim 13
Dependent Claim
29 words
The under-drilling device of claim 10 wherein the second circumferential portion comprises the outer surfaces of a plurality of spaced lands separated by upwardly directed passageways for drilling fluid.
References Cited (Backward Citations)
US1721004A
Cited
US2084421A
Cited
US2589534A
Cited
US2587231A
Cited
US2738167A
Cited
US3231029A
Cited
US3367430A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-12-02 | 1978-06-03 | 1978-12-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-12-02 | 1982-06-03 | 1982-12-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-12-02 | 1986-06-03 | 1986-12-03 | $7700.00 | Window Closed / Lapsed |