Claims
- 1. A riser assembly for connecting a marine well operating facility with a well site which is submerged in water comprising:
- (a) riser tube means having a first end flexibly joined to said operating facility and a second end flexibly joined to said submerged site;
- (b) liner means, positioned generally within said riser tube means, having a first end and a second end generally toward said first end and said second end of said riser tube means, respectively;
- (c) lower anchoring means for anchoring said liner means to said riser tube means for preventing upward movement of said second end of said liner means relative to said riser tube means;
- (d) upper anchoring means for anchoring said liner means to said riser tube means for preventing downward movement of said first end of said liner means relative to said riser tube means such that said upper and lower anchoring means may cooperate for maintaining said liner means under tension;
- (e) seal means for fluid sealing said liner means to said riser tube means generally toward said second end of said liner means, thereby defining a lower end of a generally annular region defined between the radially inner surface of said riser tube means and the radially outer surface of said liner means so positioned within said riser tube means; and
- (f) gas input means for selectively introducing gas into said generally annular region for generally increasing the buoyancy of said riser assembly by decreasing the density or the amount, or both, of liuqid in said generally annular region.
- 2. A riser assembly as defined in claim 1 wherein said lower anchoring means and said seal means comprise packer means equipped with anchoring means.
- 3. A riser assembly as defined in claim 1 wherein said upper anchoring means comprises liner hanger means.
- 4. A riser assembly as defined in claim 1 wherein at least one of said upper and lower anchoring means is constructed to prevent longitudinal motion of said liner means relative to said riser tube means in both relative longitudinal directions.
- 5. A riser assembly as defined in claim 1 further comprising well drilling equipment for drilling a well bore at said submerged site by extending said well drilling equipment through said liner means to said submerged site.
- 6. A riser assembly as defined in claim 5 wherein said well drilling equipment includes:
- (a) drill string means for extending from said operating facility through said liner means to said submerged site, and into said well bore being drilled; and
- (b) drill bit means, driven by said drill string means, for drilling said well bore.
- 7. A riser assembly as defined in claim 6 wherein said well drilling eqiupment further includes well casing means for lining said well bore.
- 8. A riser assembly as defined in claim 1 wherein said gas input means includes:
- (a) jet line means for extending into said generally annular region for providing means of egress of fluid from within said region; and
- (b) gas inlet line means for extending into said generally annular region for introducing gas into said jet line means for decreasing the density of liquid within said jet line means.
- 9. A riser assembly as defined in claim 8 wherein said jet line means includes a flared end, and said gas inlet line means includes an end having a check valve for preventing liquid from entering said gas inlet line means at said end, such that gas flow may be directed from said gas inlet line means end through fluid in said generally annular region and into said jet line means flared end.
- 10. A riser assembly as defined in claim 9 further comprising gas lift valve means, included in said gas input means, for connecting said gas inlet line means with said jet line means at at least one position within said generally annular region for selectively transmitting gas from said gas inlet line means to said jet line means.
- 11. A riser assembly as defined in claim 10 or, in the alternative, as defined in claim 1 further comprising liquid input means for selectively introducing liquid into said generally annular region for generally decreasing the buoyancy of said riser assembly.
- 12. An assembly for communicating a first location with a second location, wherein said assembly extends through a body of fluid, comprising:
- (a) first tube means extending continuously generally between said first location and said second location;
- (b) second tube means positioned generally within said first tube means;
- (c) first anchor means and second anchor means for anchoring said second tube means to said first tube means at two positions and for thereby maintaining said second tube means under tension;
- (d) seal means for at least partially closing off an area generally defined between the inner surface of said first tube means and the outer surface of said second tube means;
- (e) fluid means; and
- (f) pump means for selectively adjusting and maintaining said fluid means in said area in quantity and density to selectively control the buoyancy of said assembly relative to said fluid body.
- 13. A method of providing a connection between a first location and a second location, between which locations a body of fluid is located, comprising the steps of:
- (a) extending a first tube means between said first location and said second location, through said body of fluid;
- (b) positioning a second tube means generally within said first tube means, and anchoring said second tube means to said first tube means at two separated positions with said second tube means under tension greater than that of said first tube means;
- (c) at least partially fluid sealing said second tube means to said first tube means; and
- (d) selectively controlling the density and amount of liquid in the area generally between the inner surface of said first tube means and the outer surface of said second tube means to one side of said sealing by pumping liquid into or out of said area.
- 14. A method as defined in claim 13 further comprising the step of selectively pumping liquid out of said area by pumping gas into said area to aerate at least a portion of said liquid, thereby decreasing its density to permit larger density liquid in said area to force the resulting lower density liquid out of said area.
- 15. A method of operating on an underwater well from a marine drilling facility comprising the steps of:
- (a) flexibly joining a riser tube at the drilling facility and at the well site;
- (b) positioning a liner generally within the riser tube and anchoring the liner, near its lower end, to the riser tube;
- (c) pulling up on the liner and, while the liner is thus stressed, anchoring the liner, near its upper end, to the riser tube against downward movement relative to the riser tube, leaving the liner under tension;
- (d) fluid sealing the liner to the inner surface of the riser tube generally at the lower end of the liner, thereby defining a generally annular region between the outer surface of the liner and the inner surface of the riser tube, extending generally upwardly from the fluid seal; and
- (e) selectively controlling the buoyancy of the riser tube and its contents by adjusting the density or amount, or both, of liquid within the generally annular region.
- 16. A method as defined in claim 15 wherein the step of pulling up on the liner to place the liner under tension is carried out by pulling up on cable means joined to the liner.
- 17. A method as defined in claim 15 wherein the step of pulling up on the liner to place the liner under tension is carried out by pulling up on cable means, joined to the liner, by operation of tensioners and winch means.
- 18. A method as defined in claim 15 wherein the step of pulling up on the liner to place the liner under tension is carried out by pulling up on the liner by fluid-pressure jack means while said jack means apply downward force to the riser tube.
- 19. A method as defined in claim 15 further comprising the additional step, carried out before the liner is positioned within the riser tube, of drilling a segment of the well bore by means of a drill bit operated at the end of a drill string passing through the riser tube.
- 20. A method as defined in claim 19 further comprising the following additional steps, carried out after the liner is positioned within the riser tube and anchored therein under tension:
- (a) further drilling the well bore by means of a drill bit operated at the end of a drill string passing through the liner; and
- (b) lining the well bore with casing.
- 21. A method as defined in claim 15 further comprising selectively introducing gas into the generally annular region to gas lift liquid from that region to selectively increase the buoyancy of the riser tube and its contents.
- 22. A method as defined in claim 21 and, in the alternative, as defined in claim 18 further comprising selectively adding liquid to the generally annular region to selectively decrease the buoyancy of the riser tube and its contents.
- 23. A method as defined in claim 15 further comprising the steps of:
- (a) providing at least one jet line and a gas inlet line for each such jet line, extending down into the generally annular region such that gas may flow out of each gas inlet line and into a corresponding jet line within the generally annular region; and
- (b) selectively communicating gas down at least one gas inlet line to flow into such corresponding jet line to aerate liquid contained therein to lower the density of said liquid.
- 24. A method as defined in claim 23 further comprising the step of selectively continuing to communicate gas down at least one gas inlet line to flow into such corresponding jet line to aerate liquid contained therein to lower the denisty of said liquid so that higher density liquid entering such jet line propels liquid of lower density up the jet line and out of the generally annular region.
- 25. A method as defined in claim 24 and, in the alternative, as defined in claim 23 further comprising the steps of:
- (a) providing selective gas flow means between at least one gas inlet line and corresponding jet line within the generally annular region; and
- (b) selectively communicating gas from at least one gas inlet line through said selective gas flow means to such corresponding jet line for selectively reducing the density of liquid in said jet line.
- 26. A method as defined in claim 15 further comprising the additional steps of:
- (a) drilling the well bore by means of a drill bit operated at the end of a drill string passing through the liner; and
- (b) lining the well bore with casing.
- 27. A method as defined in claim 26 further comprising the additional steps of:
- (a) replacing the liner, anchored under tension within the riser tube, by a liner with smaller diameter after a well bore segment is lined with casing; and
- (b) drilling subsequent well bore segments with a drill bit of narrower cross section after the replacement of the liner.
- 28. A method of drilling an underwater well from a marine drilling facility comprising the steps of:
- (a) connecting the drilling facility with the well site by a riser tube, flexibly joined to the drilling facility at the top of the riser tube, and flexibly joined to the well site at the bottom of the riser tube;
- (b) positioning a liner generally within the riser tube and anchoring the bottom of said liner against upward movement relative to the riser tube;
- (c) applying generally upwardly directed force to said liner to place said liner under tension;
- (d) anchoring the top of said liner against downward movement relative to said riser tube while said liner is so under tension;
- (e) drilling the well bore by a drill bit directed by a drill string extending from the drilling facility down through the liner to the well site; and
- (f) circulating drilling fluid from the drilling facility down through the drill string, out into the well bore, up through the riser tube and liner surrounding the drill string, and back to the drilling facility.
- 29. A method as defined in claim 28 further comprising the steps of:
- (a) lining the well bore with casing after a segment of the well bore has been drilled;
- (b) replacing the liner with a subsequent liner of smaller diameter, set, under tension, within the riser tube as the original liner; and
- (c) drilling a subsequent segment of the well bore with a subsequent drill bit of smaller lateral cross section operated at the end of a drill string passing through the subsequent liner.
- 30. A method as defined in claim 29 further comprising the steps of repeating the steps of lining the well bore with casing, replacing the liner with one of smaller diameter set, under tension, within the riser tube, and further drilling the well bore with a drill bit of reduced cross section operated at the end of a drill string passing through the liner of smaller diameter.
- 31. A method of drilling an underwater well from a marine drilling facility comprising the steps of:
- (a) connecting the drilling facility with the well site by a riser tube, flexibly joined to the drilling facility at the top of the riser tube, and flexibly joined to the well site at the bottom of the riser tube;
- (b) positioning a liner generally within the riser tube, anchoring the bottom of said liner against upward movement relative to the riser tube, and fluid sealing the liner to the riser tube at the bottom of the liner to define a generally annular region between the inner surface of the riser tube and the outer surface of the liner and extending generally upwardly from the fluid sealing;
- (c) applying generally upwardly directed force to said liner to place said liner under tension;
- (d) anchoring the top of said liner against downward movement relative to said riser tube while said liner is so under tension;
- (e) providing at least one jet line extending downwardly into the generally annular region;
- (f) providing a gas inlet line, for each jet line, also extending downwardly into the generally annular region and positioned so that gas may communicate out of the one or more gas inlet lines into the corresponding one or more jet lines;
- (g) controlling the buoyancy of the riser tube and its contents by selectively communicating gas down the one or more gas inlet lines and into the corresponding one or more jet lines to aerate liquid within the one or more jet lines to permit said aerated liquid to be propelled upwardly by liquid of larger density;
- (h) drilling the well bore by a drill bit directed by a drill string extending from the drilling facility down through the liner to the well site; and
- (i) circulating drilling fluid from the drilling facility down through the drill string, out into the well bore, up through the liner surrounding the drill string, and back to the drilling facility.
- 32. A method as defined in claim 31 further comprising the step of further controlling the buoyancy of the riser tube and its contents by selectively adding liquid to the generally annular region.
- 33. A method as defined in claim 31 further comprising the steps of:
- (a) providing at least one gas lift valve connecting the one or more gas inlet lines with the corresponding one or more jet lines; and
- (b) further controlling the buoyancy of the riser tube and its contents by selectively communicating gas from the one or more gas inlet lines to the corresponding one or more jet lines by the one or more gas lift valves at at least one point along said one or more gas inlet and jet lines.
- 34. A method as defined in claim 31 further comprising the steps of:
- (a) lining the well bore with casing after a segment of the well bore has been drilled;
- (b) replacing the liner with a subsequent liner of smaller diameter, set, under tension, within the riser tube as the original liner; and
- (c) drilling a subsequent segment of the well bore with a subsequent drill bit of smaller lateral cross section operated at the end of a drill string passing through the subsequent liner.
- 35. A method as defined in claim 34 further comprising the steps of repeating the steps of lining the well bore with casing, replacing the liner with one of smaller diameter set, under tension, within the riser tube, and further drilling the well bore with a drill bit of reduced cross section operated at the end of a drill string passing through the liner of smaller diameter.
Parent Case Info
This is a continuation-in-part of application Ser. No. 736,396, filed Oct. 28, 1976, now issued as U.S. Pat. No. 4,081,039, issued Mar. 28, 1979.
US Referenced Citations (9)
Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
736396 |
Oct 1976 |
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