Offshore drilling apparatus and method |
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| 申请号 | US3631932D | 申请日 | 1968-09-03 | 公开(公告)号 | US3631932A | 公开(公告)日 | 1972-01-04 |
| 申请人 | LONGYEAR CO E J; | 发明人 | LINDELOF LEONARD A; | ||||
| 摘要 | Method and apparatus for taking core from a submerged earth formation that including drilling a casing into an earth formation a number of feet. A flotation tank is provided on the upper end of the casing while a cushion drum assembly is mounted on the lower end of the casing to control the rate of descent of the rotating casing into the formation; and such an assembly or weight on the lower end of the casing is provided to maintain the major portion of the casing in tension. After the casing is extended into the earth formation, a drill unit is supportedly mounted on the casing, a drill stem extended down through the casing and the drill stem drilled into the formation for continuing the core-taking operation. | ||||||
| 权利要求 | 1. In apparatus for drilling into an underwater earth formation, an elongated casing having an upper end portion, a lower end portion and a terminal lower end, weight means mounted on the lower end portion of the casing a preselected distance from said terminal lower end, said weight means including a weight member in relative rotatable surrounding relationship to the casing and bearing means mounted on the casing for mounting the weight means on the casing and permitting rotation of the casing relative the weight member, float means mounted on the casing upper end portion a substantial distance beneath the surface of the water for supporting at least part of the weight of the casing and cooperating with the weight means to retain a major portion of the length of the casing in tension, a platform mounted on said casing at an elevation above the float means and supported by the casing, and a drill unit mounted on said platform. 2. In apparatus for drilling into an underwater earth formation, an elongated casing having an upper end portion, a lower end portion and a terminal lower end, weight means mounted on the lower end portion of the casing a preselected distance from said terminal lower end, said weight means including a weight member in relative rotatable surrounding relationship to the casing and bearing means mounted on the casing for mounting the weight means on the casing and permitting rotation of the casing relative the weight member, float means mounted on the casing upper end portion for supporting at least part of the weight of the casing and cooperating with the weight means to retain a major portion of the length of the casing in tension, said casing lower end portion including a core barrel outer tube having a latch seat, and a retractable wire line core barrel inner tube mounted in said core barrel outer tube. 3. The apparatus of claim 2, further characterized in that said core barrel outer tube includes a drill bit. 4. The apparatus of claim 2, further characterized in that there is provided a drum having an upper end portion and a lower end portion, said drum upper and lower end portions respectively having a top opening and a bottom opening that are of larger diameters than the casing, said drum upper end portion and weight means having cooperating means for suspendingly supporting the drum from the weight means to extend to a substantially lower elevation than the weight means while permitting the weight means to move downwardly in the drum, said weight means having means for forming a sliding fluid seal with the drum. 5. The apparatus of claim 4 further characterized in that valve means is attached to the lower end portion of the drum to open to the interior thereof for providing a liquid discharge passageway to permit the escape of liquid from the interior of the drum only after the liquid pressure in the drum exceeds a preselected level. 6. The apparatus of claim 5 further characterized in that a flow control valve is connected to the valve means to control the rate of discharge of liquid through the valve means and that the drum includes means for venting air prior to any substantial downward movement of the weight means in the drum. 7. The apparatus of claim 6 further characterized in that said vent means comprises a drum wall portion having a vent aperture that is at a slightly lower elevation than the seal means when the drum is suspendingly supported from the weight means. 8. The apparatus of claim 6 further characterized in that there is provided a shield that is attached to the drum lower end portion, said shield having an opening of a size for the casing to pass therethrough. 9. The apparatus of claim 8 further characterized in that said shield has an outer peripheral edge bounding a substantially larger area than the cross-sectional area of the drum transverse to the direction of elongation of the casing, and that the shield is of a shape to slope downwardly and inwardly from its outer peripheral edge in a direction toward said shield opening. 10. The apparatus of claim 8 further characterized in that a platform is mounted on said casing at an elevation above the float means and is supported by the casing and that a drill unit is mounted on the platform. 11. The apparatus of claim 8 further characterized in that there is provided means in the drum for forming a rotary fluid seal between the drum and the casing at an elevation between the shield and the opening of the valve means to the drum. 12. Apparatus for taking core samples from an underwater earth formation, comprising an elongated casing having an upper end portion and a lower end portion, said lower end portion including a drill bit, at least one weight, bearing means mounted on the lower end portion a preselected distance from the drill bit for mountingly retaining said weight on the casing substantially spaced from the drill bit, an elongated drum of a greater length than said preselected distance extending in surrounding relationship to said weight, said drum and weight having cooperating means for suspendingly supporting the drum from the weight while permitting the weight to move downwardly in the drum, means on the weight for forming a slidable fluid seal with the drum, and means opening to the interior of the drum for controlling the rate of exhaust of water from the drum as the weight moves downwardly in the drum. 13. The apparatus of claim 12 further characterized in that the last-mentioned means includes a valve set to open at a predetermined pressure of liquid in the drum, and that an annular shield is mounted on the lower end of the drum for engaging an earth formation, said shield having a central aperture for the casing to pass through, said aperture being at a lower elevation than the drill bit when the weight suspendingly supports the drum. 14. Apparatus for drilling into an underwater earth formation comprising a casing having an upper end portion, a lower end portion and a drill bit lower terminal end portion, float means attached to the casing upper end portion a substantial distance beneath the surface of the water for supporting a substantial part of the weight of the casing, means for rotating the casing and first means attached to the lower end portion of the casing for engaging the underwater earth formation and controlling the rate of descent of the casing as it is being rotated. 15. The apparatus of claim 14 further characterized in that said first means comprises an elongated drum having an upper end portion and a lower end portion, second means opening into the interior of the lower end portion of the drum for discharging liquid from the drum at a controlled rate, and a weight attached to the casing a preselected distance above the drill bit to move with the casing and being movable downwardly in the drum from a first position to a lower second position to force water out of the drum through the second means. 16. The apparatus of claim 15 further characterized in that said weight has means to form a slidable fluid seal with the drum, that said drum has vent means for exhausting air from the drum, said vent means being at a higher elevation than the above-mentioned sealing means between the drum and the weight after the weight has moved a short distance downwardly from its first position toward its second position, that the second means includes valve means opening into the drum that opens at a higher pressure than the pressure of the liquid in the drum when the drum is closely adjacent the earth formation, and that the first means includes means at a lower elevation than the opening of the valve means to the drum for forming a fluid seal between the drum and the casing while permitting the casing to move relative the drum. 17. A method of drilling an earth formation underwater wherein an elongated casing having an upper end portion, a loWer end portion and a lower terminal end is used, said method comprising the steps of attachably mounting a weight member on the lower end of the casing a preselected distance from the lower terminal end of the casing, lowering the casing in water until the lower end of the casing is adjacent the earth formation, attaching a flotation tank to the casing upper end portion to retain at least a major portion of the casing in tension, further lowering the casing until the lower end of the casing abuts against the earth formation, drilling the casing to a depth in the earth formation that the weight member is located substantially more closely adjacent the earth formation than when the casing lower end abutted against said formation, then mounting a drill unit platform on the casing for being supported thereby and then utilizing the drill unit to lower a drill stem through the casing and operate the drill stem to penetrate the earth formation to a greater depth than the casing. 18. The method of claim 17 further characterized in that the drilling with a casing is continued until the weight member abuts against the earth formation. 19. The method of claim 18 further characterized in that the step of attaching a weight member also includes mounting a drum to at least in part surround said weight member and form a cylinder to effectively provide a piston cylinder combination and presetting a flow control valve to open to permit water to exhaust out of said combination at a controlled rate of flow after the water pressure in the casing has exceeded a preselected level to control the rate of penetration of the casing into the earth formation. 20. In a method of drilling into an earth formation below the surface of a body of water wherein an elongated casing having a lower end and an upper end portion is used, the steps of attaching a cushion drum assembly to surround a substantial length of the lower end portion of the casing including mounting a weight on the casing a preselected distance above the lower end of the casing and suspendingly supporting a drum on the weight, setting a valve to exhaust water from the interior of the drum at a pressure higher than the pressure of water in the interior of the drum at the time the drum has been lowered to the earth formation, lowering the casing, applying a buoyant force to the upper end portion of the casing through a submerged float to retain a major portion of the length of the casing between the float and the weight in tension, and imparting a rotary motion to the casing when the drum device has engaged the earth formation. 21. The method of claim 20 further characterized in that the rate of exhaust of the water from the drum is controlled to thereby control the rate of descent of the casing as it drills into the earth formation. 22. The method of claim 21 further characterized in mounting a drill unit on the upper end of the casing to be supported thereby after the casing has been drilled a selected depth into the earth formation, and operating a drill stem through said casing to drill a deeper hole in the earth formation, and collecting core samples through the use of the drill stem. 23. The apparatus of claim 22 further characterized in that there is provided a drill steam extended through the casing and operated by the drill unit for penetrating the earth formation to a greater depth than the casing. 24. Apparatus for drilling into an underwater earth formation comprising a casing having an upper end portion, a lower end portion and a drill bit lower terminal end portion, float means attached to the casing upper end portion for supporting a substantial part of the weight of the casing, means for rotating the casing and first means attached to the lower end portion of the casing for engaging the underwater earth formation, said first means including weight means mounted on the lower end portion of the casing a preselected distance from said lower terminal end portion to cooperate with the float means to retain a major portion of the length of the casing in tension, and a drum having an upper end portion and a lower end portion engageable with the underwater earth formation, said drum upper and lower end portions respectively having a top opening and a bottom opening that are of larger diameters than the casing, said drum upper end portion and weight means having cooperating means for suspendingly supporting the drum from the weight means to extend to a substantially lower elevation than the weight means while permitting the weight means to move downwardly in the drum, said weight means having means for forming a close sliding fit with the drum. 25. Apparatus for drilling into an underwater earth formation comprising a casing having an upper end portion, a lower end portion and an earth-penetrating lower terminal end portion, first means attached to the casing upper end portion for supporting a substantial part of the weight of the casing, second means attached to the casing for moving the casing to penetrate the underwater earth formation and third means attached to the lower end portion of the casing for engaging the underwater earth formation to control the rate of penetration of the underwater earth formation by the casing as the casing is moved by the second means. 26. The apparatus of claim 25 further characterized in that the first means comprises float means attached to the casing, and that the second means is attached to the casing above the float means. |
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