Drilling unit for rotary drilling of wells |
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| 申请号 | US3661218D | 申请日 | 1970-05-21 | 公开(公告)号 | US3661218A | 公开(公告)日 | 1972-05-09 |
| 申请人 | CICERO C BROWN; | 发明人 | BROWN CICERO C; | ||||
| 摘要 | A drilling unit for rotary drilling of wells using casing as the drill string. The drilling unit is a self-contained assembly designed to be bodily inserted and withdrawn through the bore of a well casing string and comprises releasable latch means for non-rotatively locking the structure to the casing; a rotary power unit supported by the latch means and rotatively connected to a bit assembly. The latter comprises a main or pilot bit and a plurality of radially extendible and retractable underreamers actuated by fluid pressure which may first be employed for driving the power unit. | ||||||
| 权利要求 | 1. In the rotary drilling of wells, the combination of: a. a string of well casing; b. a drilling assembly constructed and arranged to be bodily inserted and removed through the bore of said well casing; said assembly comprising: i. anchor means for releasably securing said drilling assembly to the lower end portion of said casing and against rotation relative thereto, including; i1. a landing shoe carried by the lower end of the casing and having an annular recess circumferentially about the inner wall thereof; i2. a tubular cage slidably receivable in saId shoe; i3. anchor dogs mounted in the wall of said cage for radial movement into and out of said recess; i4. a setting sleeve slidably mounted in the bore of said cage for movement between position actuating and releasing said anchor dogs; and i5. means initially securing said setting sleeve in the dogreleasing position and releasable for movement to the dogactuating position by application of downward jarring force to said sleeve; ii. a rotary drive member secured to said anchor means; and iii. a pilot bit and underreamer assembly secured to said drive member for rotation thereby. 2. The combination of claim 1 wherein said anchor means includes: a. landing pins projecting inwardly from the inner wall of said shoe below said recess; and b. landing slots in the exterior of said cage positioned to receive said landing pins to limit relative downward movement of said cage and to hold said cage against rotation relative to said shoe. 3. The combination of claim 1 wherein said rotary drive member is fluid pressure-operated. 4. The combination of claim 1 wherein said pilot bit and underreamer assembly comprises: a. a tubular body connectible to the lower end of said drive member; b. a pilot bit carried by the lower end of said body; c. a plurality of angularly spaced underreamers pivotally mounted to the body above the pilot bit for radial extension and retraction; d. actuating means mounted in said body normally biasing said underreamers to extended position; and e. releasable means initially securing said underreamers in retracted positions. 5. The combination of claim 4 wherein: a. said rotary drive member is operated by fluid pressure applied through said casing; and b. release of said releasable means is effected by said fluid pressure. 6. The combination of claim 4 wherein said actuating means includes: a. plunger means slidably mounted in said body; b. crank means operably connecting said plunger means to said underreamers; and c. coil spring means mounted in downwardly biasing relation to said plunger means. |
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