Drill string and drill collar therefor |
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| 申请号 | US41423973 | 申请日 | 1973-11-09 | 公开(公告)号 | US3856096A | 公开(公告)日 | 1974-12-24 |
| 申请人 | WILLIAMS E; | 发明人 | WILLIAMS E; | ||||
| 摘要 | A drill string and drill collar therefor used in rotary drilling of a borehole through earth formations to substantial depths wherein the drill string includes an elongated tubular drill stem having a longitudinal axis and opposite ends thereof adapted for connection between a drill bit and a column of drill pipe to provide a drill stem for the drill bit. The drill stem has an upper end portion having a pad or pads secured thereon and extending around a minor portion of the peripheral surface thereof and the pad or pads each have a face for wiping contact with a wall of the borehole to provide lateral support for the upper end portion of the drill stem which also has a lower end portion which may have a pad secured thereon and extending around a minor portion of the peripheral surface thereof and the pad on the lower end portion when used is in longitudinal alignment with the pad on the upper end portion. The drill stem has an intermediate portion having a smaller cross section than the cross section of the upper end portion and the lower end portion. A plurality of longitudinally spaced and aligned pads are secured to the intermediate portion and each pad on the intermediate portion extends around a minor portion of the peripheral surface thereof and the plurality of pads are positioned in diametrically opposed relation with the pads or pad on the upper end portion and the pad on the lower end portion of the drill stem. | ||||||
| 权利要求 | 1. A drill collar comprising: a. an elongated tubular drill stem having a longitudinal axis and opposite ends adapted for connection into a drilling string between a drill bit and a column of drill pipe to provide the stem for the drill bit, said drill stem having an upper end portion and a lower end portion and an intermediate portion therebetween, said intermediate portion of said drill stem having a cross section smaller than said upper end portion and said lower end portion, said intermediate portion having the center of gravity thereof positioned laterally of the longitudinal axis of said drill stem; b. at least one pad secured to said upper end portion and extending around a minor portion of a peripheral surface thereof, said pad on said upper end portion having a face for wiping contact with a wall of a borehole to provide lateral support for said drill stem; and c. at least one pad secured to said intermediate portion of said drill stem and extending around a minor portion of a peripheral surface of said intermediate portion and positioned in diametrically opposed relation with said pad on said upper end portion. 2. A drill collar as set forth in claim 1 wherein: a. said intermediate portion of said drill stem has a Plurality of longitudinally spaced and aligned pads secured thereon; and b. each of said plurality of pads on said intermediate portion of said drill stem has a face spaced from the longitudinal axis of said drill stem a distance less than the spacing between the longitudinal axis of the drill stem and the face of said pad on said upper end portion whereby the face of each of said pads on said intermediate portion of said drill stem is spaced from the wall of the borehole when the drill bit is spaced from a bottom of the borehole and in wiping contact with the wall of the borehole when the weight of the drilling string is on the drill bit and said drill stem is being rotated. 3. A drill collar as set forth in claim 1 wherein: a. said lower end portion has at least one pad secured thereto and extending around a minor portion of a peripheral surface thereof; b. the pad on said lower end portion is in longitudinal alignment with said pad on said upper end portion; and c. said pad on said lower end portion has a face spaced from the longitudinal axis of said drill stem a distance less than the spacing between the longitudinal axis of the drill stem and the face of said pad on upper end portion whereby the face of said pad on said lower end portion is spaced from the wall of the borehole both when the drill bit is spaced from the bottom of the borehole and when the weight of the drilling string is on the drill bit and said drill stem is being rotated. 4. A drill collar as set forth in claim 1 wherein: a. said intermediate portion of said drill stem has a plurality of longitudinally spaced and aligned pads secured thereon; b. said drill stem includes a first tapered portion extending between said upper end portion and said intermediate portion of said drill stem; c. said drill stem includes a second tapered portion extending between said lower end portion and said intermediate portion of said drill stem; d. a major portion of the peripheral surface of said intermediate portion of said drill stem is arcuate; e. a minor portion of the peripheral surface of said intermediate portion of said drill stem is flat; and f. said plurality of pads on said intermediate portion of said drill stem are mounted on said arcuate surface with each of said plurality of pads being positioned in diametrically opposed relation with said flat surface. 5. A drill collar as set forth in claim 1 wherein: a. a major portion of the peripheral surface of said intermediate portion of said drill stem is arcuate b. a minor portion of the peripheral surface of said intermediate portion of said drill stem is flat; c. said intermediate portion of said drill stem has a plurality of longitudinally spaced and aligned pads secured thereon; and d. said plurality of pads on said intermediate portion of said drill stem are mounted on said arcuate surface with each of said plurality of pads being positioned in diametrically opposed relation with said flat surface. 6. A drilling string as set forth in claim 5 wherein each of said plurality of pads on said intermediate portion of said drill stem has a face spaced from the longitudinal axis of said drill stem a distance less than the spacing between the longitudinal axis of the drill stem and the face of said pad on said upper end portion whereby the face of each of said pads on said intermediate portion of said drill stem is spaced from the wall of the borehole when the drill bit is spaced from a bottom of the borehole and in wiping contact with the wall of the borehole when the weight of the drilling string is on the drill bit and said drill stem is being rotated. 7. A drilling string comprising: a. a column of drill pipe; b. a drill bit having a plurality of cutting cones, one of said cutting cones being adapted to cuttingly engage a wall and a bottom of a borehole to thereby define the gauge of the borehole, the other of said cutting cones being adapted to engage the bottom of thE borehole; c. an elongated tubular drill stem having a longitudinal axis and opposite end adapted for connection into said column of drill pipe and to said drill bit, said drill stem having an upper end portion and a lower end portion and an intermediate portion therebetween, said intermediate portion of said drill stem having a cross section smaller than said upper end portion and said lower end portion, said intermediate portion having the center of gravity thereof positioned laterally of the longitudinal axis of said drill stem; d. at least one pad secured to said upper end portion and extending around a minor portion of a peripheral surface thereof, said pad on said upper end portion having a face for wiping contact with a wall of a borehole to provide lateral support for said drill stem; and e. a plurality of longitudinally spaced and aligned pads secured to said intermediate portion of said drill stem with each of said plurality of pads extending around a minor portion of a peripheral surface of said intermediate portion, said plurality of pads being positioned in diametrically opposed relation with said pad on said upper end portion. 8. A drilling string as set forth in claim 7 including means on said lower end portion of said drill stem for effecting longitudinal alignment of said one cutting cone and said pad on said upper end portion of said drill stem. 9. A drilling string as set forth in claim 7 wherein each of said plurality of pads on said intermediate portion of said drill stem has a face spaced from the longitudinal axis of said drill stem a distance less than the spacing between the longitudinal axis of the drill stem and the face of said pad on said upper end portion whereby the face of each of said pads on said intermediate portion of said drill stem is spaced from the wall of the borehole when the drill bit is spaced from a bottom of the borehole and in wiping contact with the wall of the borehole when the weight of the drilling string is on the drill bit and said drill stem is being rotated. 10. A drilling string as set forth in claim 7 including: a. a second drill stem having a longitudinal axis and opposite ends adapted for connection into said column of drill pipe and to said first named drill stem, said second drill stem having an upper end portion and a lower end portion and an intermediate portion therebetween, said intermediate portion of said second drill stem having a cross section smaller than said upper end portion and said lower end portion of said second drill stem, said intermediate portion having the center of gravity thereof positioned laterally of the longitudinal axis of said drill stem; b. at least one pad secured to said upper end portion of said second drill stem and extending around a minor portion of a peripheral surface thereof, said pad on said upper end portion of said second drill stem having a face for wiping contact with a wall of borehole to provide lateral support for said second drill stem; c. at least one pad secured to said lower end portion of said second drill stem and extending around a minor portion of a peripheral surface thereof, said pad on said lower end portion of said second drill stem being in longitudinal alignment with said pad on said upper end portion of said second drill stem and in longitudinally aligned relation with said pads on said upper end portion of said first named drill stem and in longitudinally opposed relation with said plurality of pads on said intermediate portion of said first named drill stem; and d. a plurality of longitudinally spaced and aligned pads secured to said intermediate portion of said second drill stem each extending around a minor portion of a peripheral surface of said intermediate portion of said second drill stem, said plurality of pads on said intermediate portion of said second drill stem being positioned in diametrically opposed relation with said pad on said upper end portion and said pad on said lower end portion of said sEcond drill stem and in diametrically opposed relation with said pad on said upper end portion of said first named drill stem. 11. A drilling string as set forth in claim 10 wherein: a. a major portion of the peripheral surface of said intermediate portion of said second drill stem is arcuate; b. a minor portion of the peripheral surface of said intermediate portion of said second drill stem is flat; and c. said plurality of pads on said intermediate portion of said second drill stem are mounted on said arcuate surface with each of said plurality of pads being positioned in diametrically opposed relation with said flat surface. 12. A drilling string as set forth in claim 10 wherein: a. said second drill stem includes a first tapered portion extending between said upper end portion and said intermediate portion of said second drill stem; b. said second drill stem includes a second tapered portion extending between said lower end portion and said intermediate portion of said second drill stem; c. a major portion of the peripheral surface of said intermediate portion of said second drill stem is arcuate; d. a minor portion of the peripheral surface of said intermediate portion of said second drill stem is flat; and e. said plurality of pads on said intermediate portion of said second drill stem are mounted on said arcuate surface with each of said plurality of pads being positioned in diametrically opposed relation with said flat surface of said intermediate portion of said second drill stem. |
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