Title:
METHOD AND APPARATUS FOR THROUGH ROTARY SUB-SEA PILE-DRIVING
Kind Code:
A1


Abstract:
The A pile-driving apparatus includes a pile, a shoe tip coupled to a toe of the pile, and a drill string disposed within the pile. The drill string includes a gripping device coupling the drill string to the pile and a hammer deployed into the pile such that the hammer is capable of transmitting a force to the shoe tip. A method, includes positioning a hammer in a pile such that the hammer is capable of transmitting a force to a shoe tip; positioning, in the pile, a portion of drill pipe having a gripping device to engage the pile; and deploying the pile beneath the surface of a body of water.



Inventors:
Bell, Douglas B. (Dabai, AE)
Mueller, Dan T. (Cypress, TX, US)
Gray-stephens, Malcolm G. S. (Aberdeen, GB)
Application Number:
11/380827
Publication Date:
08/24/2006
Filing Date:
04/28/2006
Assignee:
BJ Services Company
Primary Class:
International Classes:
E02D13/00
View Patent Images:
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Primary Examiner:
MAYO-PINNOCK, TARA LEIGH
Attorney, Agent or Firm:
Jeffrey A. Pyle (Houston, TX, US)
Claims:
1. (canceled)

2. The apparatus of claim 15, wherein the pile comprises a casing string, a deep water pile, a shallow water pile, a pipe line end manifold (“PLEM”) pile, a sub-sea template, a manifold pile, a tension leg platform anchor pile and a drill rig mooring pile.

3. The apparatus of claim 15, wherein the shoe tip includes a membrane covering.

4. The apparatus of claim 15, wherein the shoe tip is coupled to the pile interior.

5. The apparatus of claim 15, wherein the shoe tip is coupled to the pile exterior.

6. The apparatus of claim 15, wherein the hammer is coupled to the pile at the top thereof.

7. The apparatus of claim 15, wherein the hammer is coupled to the pile at the toe thereof.

8. The apparatus of claim 15, wherein the hammer is a percussive hammer or a rotation powered hammer.

9. (canceled)

10. The apparatus of claim 15, wherein the drill string further includes a gripping device by which the drill string is coupled to the pile.

11. (canceled)

12. (canceled)

13. (canceled)

14. (canceled)

15. An apparatus, comprising: a pile; a shoe tip deployed at a tip of the pile; and a hammer coupled to the pile such that the hammer is capable of transmitting a force to the shoe tip.

16. The apparatus of claim 15, further comprising a portion of drill pipe having a lockable telescoping section deployed in the pile.

17. The apparatus of claim 15, wherein the pile includes a shoe joint capable of receiving the force from the hammer and transmitting said force to the shoe tip.

18. (canceled)

19. The apparatus of claim 15, further comprising a valve system to direct a fluid to at least one of the shoe tip and the pile.

20. The apparatus of claim 15, further comprising a gripping device coupled to the hammer and coupled to the pile.

21. The apparatus of claim 15, further comprising a sling by which the hammer is coupled to the pile.

22. (canceled)

23. A method, comprising: positioning a hammer relative to a pile such that the hammer is capable of transmitting a force to a shoe tip; positioning a portion of drill pipe to engage the pile; and deploying the pile beneath the surface of a body of water.

24. The method of claim 23, wherein deploying the pile comprises deploying pile such that the shoe tip is in contact with a first selected location on a floor of the body of water.

25. The method of claim 23, wherein positioning the hammer includes positioning the hammer such that the hammer is capable of transmitting a force directly to the shoe tip.

26. The method of claim 23, wherein positioning the hammer includes positioning the hammer such that the hammer is capable of transmitting a force indirectly to the shoe tip.

27. An apparatus, comprising: means for positioning a hammer relative to a pile such that the hammer is capable of transmitting a force to a shoe tip; means engaging the hammer to the pile; and means for deploying the pile beneath the surface of a body of water.

28. The apparatus of claim 27, further comprising means for transmitting a force from the hammer to the shoe tip such that the shoe tip penetrates the floor at the first selected location.

29. The apparatus of claim 27, further comprising means for providing a lubricating fluid proximate the shoe tip.

30. (canceled)

31. (canceled)

32. (canceled)

33. (canceled)

34. A method for deploying a pile-driving apparatus, the method comprising: deploying the pile-driving apparatus; and single tripping the rigged-up pile-driving apparatus to the seabed.

35. The method of claim 34, wherein rigging up the pile-driving apparatus includes: positioning a percussive hammer relative to a pile such that the percussive hammer is capable of transmitting a force to a shoe tip; and positioning, in the pile, a portion of drill pipe having a gripping device to engage the pile.

36. The method of claim 34, wherein deploying the rigged-up pile-driving apparatus through the rotary of the drilling rig includes deploying the rigged-up pile-driving apparatus through a rotary of a mobile offshore drilling unit.

37. The method of claim 34, further deploying the rigged-up pile-driving apparatus through the rotary of a drilling rig.

38. (canceled)

39. (canceled)

40. (canceled)

41. (canceled)

42. (canceled)

43. (canceled)

44. (canceled)

45. (canceled)

46. (canceled)

47. (canceled)

48. (canceled)

49. (canceled)

50. (canceled)

51. (canceled)

52. (canceled)

53. (canceled)

54. A method, comprising: driving a pile into a floor under a body of water; and liquefying the soil into which the pile is being driven.

55. The method of claim 54, wherein liquefying the soil includes injecting a fluid from within the pile into the soil.

56. The method of claim 55, wherein injecting the fluid includes injecting ambient seawater.

57. The method of claim 56, wherein injecting the fluid further includes injecting a lubricant.

58. The method of claim 57, wherein injecting the lubricant includes injecting at least one of soapy water, coco fatty ketaine, various ethoxylated compounds such as alkyl phenols, fatty alcohols, amines, amides, diamines, quaternary ammonium chlorides, as well as sulphonated naphthalene formaldehyde condensate, sulfonated styreiemaleic anhydrides, and various polyacrylamides.

59. The method of claim 55, wherein injecting the fluid includes injecting a lubricant.

60. The method of claim 59, wherein injecting the lubricant includes injecting at least one of soapy water, coco fatty ketaine, various ethoxylated compounds such as alkyl phenols, fatty alcohols, amines, amides, diamines, quaternary ammonium chlorides, as well as sulphonated naphthalene formaldehyde condensate, sulfonated styreiemaleic anhydrides, and various polyacrylamides.

61. The method of claim 55, wherein injecting the fluid includes injecting spent prime mover fluid.

62. The method of claim 23, wherein gripping the pile includes gripping the pile at the top thereof.

63. The method of claim 23, wherein gripping the pile includes gripping the interior of the pile.

64. The method of claim 23, wherein gripping the pile includes gripping the exterior thereof via a sling.

65. A pile-driving apparatus, comprising: a pile; a valve system to direct a fluid to the toe of the pile; and a plurality of fluid injection ports defined at the toe of the pile.

66. The apparatus of claim 65, wherein the pile includes a shoe joint capable of receiving a driving force and transmitting the force to the shoe tip.

67. The apparatus of claim 65, further comprising a shoe tip deployed at the toe of the pile, and wherein the shoe tip defines the fluid injection ports and the valve system further directs the fluid to the shoe tip.

68. The apparatus of claim 67, wherein the shoe tip is coupled to the toe of the pile on the interior thereof.

69. A method, comprising: positioning a hammer relative to a pile such that the hammer is capable of transmitting a force to a shoe tip; and gripping the pile to engage the hammer to the pile.

70. The method of claim 69, wherein positioning the hammer includes positioning the hammer such that the hammer is capable of transmitting a force directly to the shoe tip.

71. The method of claim 69, wherein positioning the hammer includes positioning the hammer such that the hammer is capable of transmitting a force indirectly to the shoe tip.

72. The apparatus of claim 15, wherein the hammer comprises a portion of a drill string.

Description:

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates generally to underwater pile-driving, and, more particularly, to through rotary sub-sea pile-driving.

2. Description of the Related Art

Sub-sea, sometimes called “subsurface” in the sense of being under the surface of the water, pile-driving may be used to drill into the sediment at the bottom of a variety of underwater environments. For example, sub-sea pile-driving may be used to facilitate the installation of offshore production structures such as sub-sea platform skirt piles, sub-sea templates, drilling conductors, sub-sea manifolds, and the like. Sub-sea pile-driving may be performed in shallow water, typically less than 150 meters in depth, or in deep water.

The pile-driving apparatus typically includes a hammer, which drives a guide shoe tip into the sediment. The hammer and guide shoe tip are typically suspended from a platform by a crane or some cables, or, alternatively, a drill string and an umbilical. In various embodiments, the umbilical provides air, electricity, and hydraulic oil to the hammer, as well as retrieving the used hydraulic oil from the hammer. Examples of rigs used in sub-sea pile-driving include jack-up rigs, derrick barges, submersible rigs, semi-submersible rigs, drill ships, and the like. These types of rigs are sometimes referred to as mobile offshore drilling units (“MODUs”).

Conventional sub-sea pile-driving methods suffer from a number of disadvantages. For example, friction from the sediment beneath the mud line may reduce the penetration depth of the guide shoe tip. For yet another example, sub-sea pile-driving typically uses hydraulic oil, which may leak or spill into the undersea environment. Reels used to store and deploy the umbilical used to provide and retrieve the hydraulic oil may also consume valuable deck space on the platform. Furthermore, conventional pile-driving techniques may be limited to shallow water applications, at least in part because of the large hydraulic pressure that must be supplied to the hammer.

SUMMARY OF THE INVENTION

The invention comprises, in its various aspects and embodiments, an method and apparatus for driving a pile. The pile-driving apparatus comprises a pile, a shoe tip coupled to a toe of the pile, and a drill string disposed within the pile. The drill string comprises a gripping device coupling the drill string to the pile and a hammer deployed into the pile such that the hammer is capable of transmitting a force to the shoe tip. The method, comprises positioning a hammer in a pile such that the hammer is capable of transmitting a force to a shoe tip; positioning, in the pile, a portion of drill pipe having a gripping device to engage the pile; and deploying the pile beneath the surface of a body of water.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention may be understood by reference to the following description taken in conjunction with the accompanying drawings, in which like reference numerals identify like elements, and in which:

FIG. 1 conceptually illustrates, in an assembled, partially-sectioned, plan view of one embodiment of an apparatus in accordance with the present invention;

FIG. 2 conceptually illustrates a portion of the deployment of the pile-driving apparatus of FIG. 1 in one particular embodiment;

FIG. 3 illustrates a shoe joint for the apparatus of FIG. 1, including an optional membrane covering the end thereof;

FIG. 4 depicts a clamp for clamping an umbilical of the apparatus of FIG. 1 to the drill string thereof;

FIG. 5 illustrates a first percussive hammer as may be used in the apparatus of FIG. 1, the percussive hammer being a nitrogen cap hydraulic percussive hammer, with control umbilical;

FIG. 6 illustrates a second percussive hammer as may be used in alternative embodiments of the present invention, the percussive hammer being an automatic reciprocating hydraulic percussive hammer;

FIG. 7 illustrates a port collar;

FIG. 8 depicts a telescoping pipe joint as may be employed in the embodiment of FIG. 1;

FIG. 9 depicts a filtration for a filter sub as may be used in some alternative embodiments of the present invention;

FIG. 10 depicts a gripping device that may be used to couple the drill pipe of the apparatus in FIG. 1 to the pile thereof;

FIG. 11A-FIG. 11D illustrates one particular embodiment of the pile-driving apparatus in FIG. 1; and

FIG. 12A-FIG. 12D illustrate a second particular embodiment of the pile-driving apparatus in FIG. 1 alternative to the embodiment in FIG. 11A - FIG. 11D.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

Illustrative embodiments of the invention are described below. In the interest of clarity, not all features of an actual implementation are described in this specification. It will of course be appreciated that in the development of any such actual embodiment, numerous implementation-specific decisions must be made to achieve the developers' specific goals, such as compliance with system-related and business-related constraints, which will vary from one implementation to another. Moreover, it will be appreciated that such a development effort might be complex and time-consuming, but would nevertheless be a routine undertaking for those of ordinary skill in the art having the benefit of this disclosure.

The present invention relates to a method and apparatus for single journey conveyance of a sub-sea pile-driving device from the surface of a body of water to the sea floor, and the subsequent concussive installation of sub-sea caissons, tubular piles, and/or surface sections of well casing using the sub-sea pile driving device. The sub-sea pile driving device may, in various embodiments, be used in either shallow water or deep water environments. The caissons or tubular piles may, in one embodiment, be used to attach various structures to the sea floor. Examples of the various structures include sub-sea platform skirt piles, sub-sea templates, drilling conductors, sub-sea manifolds, and the like. The well casing is generally used for providing a stable foundation for drilling oil wells at depths in excess of 600′.

FIG. 1 conceptually illustrates, in an assembled, partially-sectioned plan view, one embodiment of a pile-driving apparatus 100 in accordance with the present invention. The pile-driving apparatus 100 comprises a pile 103, a shoe tip 106 coupled to a toe 109 of the pile 103, and a drill string 112 disposed within the pile 103. The drill string 112 includes a gripping device 115 and a percussive hammer 118. The gripping device couples the drill string 112 to the pile 106.

The percussive hammer 118 is deployed into the pile 106 such that the percussive hammer 118 is capable of transmitting a force to the shoe tip 106 directly or indirectly. Some embodiments are “toe-driven.” In these embodiments, the shoe tip 106 is coupled to the pile 103 at the toe 109 thereof, such that the percussive hammer 118 delivers the force directly to the shoe tip 106 at the toe 109. Some embodiments are “top-driven.” In these embodiments, the shoe tip 106 is coupled to the top 121 of the pile 103 such that the percussive hammer 118 delivers the force indirectly to the shoe tip 106 at the top 121. The embodiment in FIG. 1 is toe-driven.

FIG. 2 conceptually illustrates a portion of the deployment of the pile-driving apparatus 100 in one particular embodiment. In FIG. 2, the pile-driving apparatus 100 is deployed from a semi-submersible rig 200 after rig-up. However, the rig 200 may be any of a variety of MODUs, including, but are not limited to, jack-up rigs, semi-submersible rigs, and drill ships. The drill string (also known as a drill pipe column) is generally used to suspend the pile 103 from the rig 200 and deploy the pile 103 beneath the surface 206 of a body of water 209. In one embodiment, the casing is suspended from the rig by the drill string and descends through the rotary table as additional stands of drill pipe are added. Suitable rigs may include, but are not limited to, jack-up rigs, semi-submersible rigs, and drill ships. The pile-driving apparatus 100 is suspended from the rig 200 by the drill string 112 and lowered to the sea floor 215. On contact with the sea floor 215, the operation of the percussive hammer 118 delivers the force, directly or indirectly, to the shoe tip 106. Because the shoe tip 106 is coupled to the pile 103, the force of the impact is transferred through the shoe tip 106 to the pile 103 to drive the pile 106 into the sea floor 215. Note that, in this description, the labels “toe” and “top” are defined relative to the orientation of the pile-driving apparatus 100 during deployment, as shown in FIG. 2.

Returning to FIG. 1, as previously noted, the pile-driving apparatus 100 shown therein is but one embodiment and the invention admits variation in the implementation of the apparatus of the invention. One such variation was previously mentioned, i e., the apparatus may be toe-driven or top-driven. Another such variation is the nature of the pile 103. In the embodiment of FIG. 1, the pile 103 comprises a surface casing installation or a deep water conductor. In the interest of clarity, the term “casing” will hereinafter be understood to refer to either a surface casing installation or a deep water conductor. In this particular embodiment, the casing includes a plurality of casing joints.

Also in the embodiment of FIG. 1, the shoe tip 106 is deployed in the pile 103 and the percussive hammer 118 is deployed in the pile 103 such that the percussive hammer 111 is capable of transmitting a force to the shoe tip 106. For example, in one embodiment, the shoe tip 106 may be deployed in one casing joint. A vocationally designed, or implementation specific, shoe joint 300, shown in FIG. 3, is provided in the casing to accept energy transfer, i.e., the aforementioned force, from the percussive hammer 118 and transmit the force to the guide shoe tip 106. In one embodiment, the shoe joint 300 may include a membrane 303, also shown in FIG. 3, to prevent ingress of material from the sea floor 215 during self-penetration. In one embodiment, the shoe joint 300 may allow subsequent piles 103 to pass through by hammering or drilling while closing the pile 103.

The percussive hammer 118 in the embodiment of FIG. 1 is a hydraulic hammer. The percussive hammer 118 may receive hydraulic oil provided by an umbilical 127 to generate the force that is used to drive the shoe tip 106 into the sea floor 215, shown in FIG. 2. The umbilical 127 may be coupled to the drill string 112 by quick attach and release clamps, such as the clamp 400 in FIG. 4. Alternatively, the percussive hammer 118 may employ ambient water, or other fluids such as soapy water as described further below, to generate the force that is used to drive the shoe tip 106 into the sea floor 215. The percussive hammer 118 in this embodiment is generally controlled by signals transmitted via the umbilical 127.

The percussive hammer 118 of FIG. 1, shown in greater detail in FIG. 5, is an accelerated fluid driven hammer controlled by signals conveyed by umbilical 127 from the surface. The hydraulic fluid is, in this particular embodiment, derived from the ambient seawater. The tip 503 of the percussive hammer 118 displaces soil and the pile 103 is pulled down by the engagement ring, thus following the percussive hammer 118 into the sea floor 215, shown in FIG. 2, and through the formation in question. The percussive hammer 118, in one implementation of this particular embodiment, is an IHC S-90 hydraulic hammer, commercially available from BJ Services, Inc. at:

Hareness Circle

Altens, Aberdeen AB1 4YL

United Kingdom

Phone: 44-1224-249-678

Fax: 44-1224-249-106

Email enquiries.tubular@bjservices.co.uk

Other suitable hydraulic percussive hammers known to the art may be employed.

However, the percussive hammer 118 need not be hydraulic in all embodiments. For instance, the percussive hammer 118 may also be rotated from the rig 200, in FIG. 2, by the drill string 112. The rotational percussive hammer may engage the pile 103 through a landing ring (not shown) in a shoe joint (also not shown) of the pile 103. The hole would be bailed by return of fluids (e.g., seawater derived) discharged thru the top 121 of the pile 103 to open ocean or via a port collar, such as the port collar 130, first shown in FIG. 1 and best shown in FIG. 7, to sea floor 215 that can be closed after drive is completed. The automatic reciprocating percussion hammer may be implemented using, for instance, the automatic reciprocating percussion hammer sold as the Fluid Hammer 185 mud hammer, available from

SDS Digger Tools, Pty., Ltd.

49 Vulcan Road

Canning Vale, Western Australia 6155.

Note this hammer is relatively small and is primarily suitable driving relatively small piles, e.g. 30′ piles in soft conditions with the feeble existing item. Rotational percussive hammers used as drilling tools for pulling casing in by drilling with drill bits, as opposed to piling, may also be adapted to toe drive.

In several instances above, reference is made to the use of ambient seawater in various embodiments of the invention. In those embodiments, the seawater is filtered by, for example, a filtration unit 900, shown in FIG. 9, of a filter sub (not otherwise shown) assembled into the drill string 112. The seawater ingresses the filtration unit 900 from the top 903 thereof, is filtered by the filter screen 906 within the filter housing 909, and egresses through the bottom 912. The filtration unit 900 also includes a plug 915. Some embodiments may employ multiple filtration units 900. The position of the filtration unit(s) 900 within the drill string 112 will be implementation specific, but will generally be above the hammer 118. The seawater would also be filtered prior to entry into the drill string. Thus, in some alternative embodiments, pressurized ambient seawater is conveyed via the drill string 112 and provided to the percussive hammer 118.

Various other fluids may be provided to the percussive hammer 118 in assorted alternative embodiments. In one embodiment, the umbilical 127 provides hydraulic oil to the percussive hammer 118. The umbilical may also retrieve the hydraulic oil. In one embodiment, lubricating fluids may be provided to the percussive hammer 118 via the umbilical or, alternatively, via the drill string 112. The lubricating fluids may include, but are not limited to, soapy water, coco fatty ketaine, various ethoxylated compounds such as alkyl phenols, fatty alcohols, amines, amides, diamines, quaternary ammonium chlorides, as well as sulphonated naphthalene formaldehyde condensate, sulfonated styreiemaleic anhydrides, and various polyacrylamides. The lubricating fluids may be used to reduce friction between the formation and the pile/casing. Additional fluids that may be provided to the percussive hammer are described in U.S. Pat. No. 5,748,665, U.S. Pat. No. 5,020,598, U.S. Pat. No. 5,016,711, and U.S. Pat. No. 5,284,513, which are incorporated herein by reference.

A diverter valve system (not shown) may, in various embodiments, be used to direct the flow of the fluids. For example, the diverter valve system may redirect hydraulic fluid, such as the ambient seawater, to the toe of the shoe joint. Alternatively, the diverter valve system may be used to direct the hydraulic fluid, such as the ambient seawater, back into the pile 103 for eventual return to the surface of the sea floor 215 or tile surrounding body of water. Filter systems may also be included in the drill string for filtering the various fluids. For example, sea water may be filtered as it passes into and/or out of the drill string 112.

Thus, any given embodiment may use one or more of the following fluid conveyance techniques:

    • for deep-water applications it is considered feasible to utilize the drill pipe column to carry the fluid to the Percussion device in question;
    • in certain instances it may practical to use coil tubing in either concentric or single tube configuration;
    • filtration media can be introduced by virtue of filter subs at strategic and readily accessible points in the conveyance system; and
    • for shallow water jack-up installations, any of the above or standard hydraulic hoses can be considered.
      Still other fluid conveyance techniques known to the art may be employed in alternative embodiments.

Vocationally designed, or implementation specific, adaptor sub and/or crossover components (not shown) may also be included in the casing to merge individual items into the operational system. As is well known in the art, the assembly of drill strings frequently utilize adaptors, crossovers, etc. to line up connections and to provide interfaces between tools and pieces of pipe. Also, the use of these types of components is implementation specific, as the design for any given drill string will be unique for the given goals and conditions. The drill string 112 of the present invention, shown in FIG. 1, employs these types of components in accordance with conventional practice.

Returning to FIG. 1, in the illustrated embodiment, the surface casing installation may also include one or more telescopic drill pipe sections 124, shown in greater detail in FIG. 8 The telescopic drill pipe sections 124 may be used to position the percussive hammer 118 within the pile 103. In one embodiment, the telescopic drill pipe sections 124 are capable of being locked and unlocked. In one embodiment, the telescopic drill pipe sections 124 may be locked and/or unlocked by rotating the drill string 112 coupled to the pile 103. However, it will be appreciated that the telescopic drill pipe sections 124 are not necessary for the practice of the present invention. In alternative embodiments, a variety of hammer suspension systems, such as slings and the like, may also be used to position the percussive hammer 118 within the pile 103.

As previously mentioned a drill pipe section having a gripping device 115, shown best in FIG. 10, is also deployed in the pile 103. The gripping device 115 is set and/or unset by the rotation of the drill string 112. The gripping device 115 is substantially coupled to the pile 103 and holds the pile 103 substantially fixed with respect to the drill string 112. In the present context, the term “substantially” is used to indicate that, in the practice of the present invention, the gripping device 115 may not hold the pile 103 perfectly fixed with respect to the drill string 112. Those of ordinary skill in the art having the benefit of this disclosure will appreciate that the gripping device 115 may allow some movement of the pile 103 with respect to the drill string 112 during operation of the present invention. The amount of movement is a matter of design choice and not material to the present invention. The gripping device 115 will typically engage the hammer 118 to the pile 103 at the top of the pile 103, but this is not necessary to the practice of the invention. The gripping device 115 may engage the hammer 118 to the pile 103 at the bottom of the pile 103, but additional support devices, such as slings, etc. may be desirable to support the weight of the pile 103 and drill string 112.

FIG. 11A-FIG. 11D and FIG. 12A-FIG. 12D illustrate a two particular, alternative embodiments of the embodiment of the pile-driving apparatus in FIG. 1 alternative to the embodiment in FIG. 11A-FIG. 11D. FIG. 11A illustrates a toe-drive embodiment 1100, with enlarged views of the sections 1103, 1106, and 1109 in FIG. 11B-FIG. 11D. Similarly, FIG. 12A illustrates a top-drive embodiment 1200, with enlarged views of the sections 1203, 1206 in FIG. 12B and FIG. 12C-FIG. 12D, respectively. Note that both FIG. 12C and FIG. 12D are enlarged views of the section 1206, one a plan view and the other a partially sectioned view, respectively.

Turning now to FIG. 11A-FIG. 11D, the section 1103, best shown in FIG. 11B, contains the gripping device 1112, a part of the drill string 115, disposed within the pile 1118, which is a casing string in this particular embodiment. The umbilical 1121 is also shown running through the interior 1124 of the pile 1118 and, in FIG. 11C, to the hammer 1127. FIG. 11B also shows a telescopic drill pipe section 1130 intermediate the gripping device 112 and the hammer 1127, and interfacing with the hammer 1127 through an interface sub 1133. The pile 1118 terminates in a shoe collar 1136 and the embodiment 1100 terminates in a ported shoe 1139 defining several ports 1142 (only one indicated) through which fluids (not shown) may pass as described elsewhere.

Referring now to FIG. 12A-FIG. 12D, the top-drive embodiment 1200 includes a sling 1205 fastened to the wings 1207 of a drill plate 1206, shown in FIG. 12B, as part of the drill string 1209. The sling 1205 is also fastened to the pile 1212, which is also a casing string, to support the weight of the pile 1212, as is shown in FIG. 12C-FIG. 12D. (To release the pile, the fasteners 1213 can be explosive bolts that are set off or can be released through the use,of a remotely operated vehicle, not shown.) Note that, in some alternative embodiments, the hammer 1218 may be coupled to the drill string 1209 in some other manner, for example, through an external gripper known as an “elevator” in combination with a sling. A telescopic drill pipe section 1215 is positioned intermediate the drill plate 1206 and the hammer 1218, as best shown in FIG. 12B. The hammer 1218 receives power and control signals, etc. over the umbilical 1221. The hammer 1218 in top-drive embodiment 1200 interfaces with the pile 1212 through a chaser sub 1224 and an interface 1227.

To “rig-up” the pile-driving apparatus 100 in a toe-drive embodiment, percussive hammer 118 is deployed into the pile 103. In various alternative embodiments, the rig-up process may also include positioning one or more transfer subs, filter subs, flexible hoses, diverter valve assemblies, and at least one joint of drill pipe. The pile-driving apparatus 100 is racked back into a derrick 218, shown in FIG. 2. In this particular embodiment, the pile is a casing string and the casing string is made up, in a manner well known to those of ordinary skill in the art, starting with the shoe joint and extending to the desired length. The pile 103 to be driven is then set in a rotary table/drill floor.

A false rotary table (not shown) is positioned over the pile 103, having been set in the rotary table/drill floor (also not shown), to support the running of the percussive hammer 118 and any other desired components down inside of the pile 103. In one embodiment, the percussive hammer 118 is positioned inside the pile 103. A first stand of drill pipe is added. Although not necessary for the practice of the present invention, in one embodiment, the first stand of drill pipe may include a lockable telescoping section 124 of drill pipe 112. Additional stands of drill pipe may then be added.

When the percussive hammer 118 is approximately at the tip of the shoe joint, a further stand of drill pipe, which includes an internal gripping device, is added. If so desired, the internal gripping device may be set by, for example, rotating the drill string 112. The hammer 118 is landed on the shoe driving ring and half the stroke of the telescopic section 124 of drill pipe is compressed. The internal gripping device 115 is then engages and the pile 103, hammer 118, and drill string 112 is lifted as one assembly by the drill string 112.

The pile-driving apparatus 100 is then tripped down to the sea floor 215, shown in FIG. 2, by adding further stands of drill pipe. In one embodiment, a grooved bowl and slips may be used as each stand of drill pipe is added. In one alternative embodiment, power slips may be used as each stand of drill pipe is added. The umbilical (not shown) is fed onto the drill string 112 and, in one embodiment, supported by the quick attach and release clamps 400, shown in FIG. 4. Once the sea floor 215 has been tagged, and the pile 103 is substantially in contact with a selected location on the sea floor 215, self-penetration is logged until the combined weight of the drill string 112, the pile 103, and the percussive hammer 1118 is supported by the sea floor 215 except for weight required to keep pile from buckling. The operation of the percussive hammer 118 then commences to drive the pile 103.

During the pile-driving process, the percussive hammer 118 uses a prime mover fluid to generate the force, which is transmitted to the guide shoe tip to excavate a hole. In one embodiment, the prime mover fluid is hydraulic fluid provided by the umbilical. The hydraulic fluid may also be retrieved by the umbilical. In alternative embodiments, pressurized ambient sea water may be used as the prime mover fluid in the percussive hammer 118. For example, ambient sea water may be provided to the percussive hammer, which may use the sea water as the prime mover fluid when operating the percussive hammer in deep water. When ambient sea water is used as the prime mover fluid, the size of the umbilical may be reduced. In alternative embodiments, rotation of the drill string 112 may be used as the prime mover in the percussive hammer 118.

Material from the hole created by the pile-driving process is bailed by returning fluids, such as ambient sea water. In one embodiment, the returning fluids are discharged through the top of the casing to the open ocean. In an alternative embodiment, the material is discharged through a port collar to the sea floor 215. If the pile tip encounters stiff resistance or sandy layers, fluid may be dispensed from the tip to reduce external skin friction. In one embodiment, spent hydraulic fluid, such as the ambient sea water, may be dispensed. In alternative embodiments, other fluids, such as the aforementioned lubricants, may be dispensed.

Upon completion of driving, e.g. when the pile 103 has been driven to the desired depth, the drill string is rotated to unlock the internal gripping device 115. In one embodiment, the drill string 112 may also be rotated to relock the telescoping drill pipe section 124. The percussive hammer 118 is then withdrawn from the casing find tripped back to the rotary. Once in the rotary, the percussive hammer 118 is rigged-down. In one embodiment, rig-down is the reverse of rig-up.

In some embodiments, the pile 103 may be driven in stages. A second pile 103 may, for instance, be run into the rotary and made up to a desired length. The second pile 103 may have a reduced diameter and may be internally driven or top-driven. If the second pile is top-driven, a sacrificial centralizing ring may, in one embodiment, be included to allow a sleeve to pass the top of a second stage pile and establish contact with an anvil face.

More particularly, when the first pile 103 is driven to a desired depth, the gripping device 115 unset to release the hammer 118, and equipment the drill string 112 tripped back to the rotary, the hammer 118 is racked back into the derrick 218. A second, reduced diameter pile 103 is run into the rotary and made up to required length. Dependent on length and diameter of this second stage, this pile-driving apparatus 100 may be internally driven or top-driven. The equipment and procedure for internal driving follow closely the procedure for the first stage. In the instance of top driving for the second stage, the pile-driving apparatus 100 is set up with a sacrificial centralizing ring to allow the sleeve to pass over the top of the second stage pile and establish contact with the anvil face. The hammer is then activated and driving proceeds to desired depth. For internal drives the same procedure for first stage is followed. Choice of top drive versus internal “toe of pile” energy application is determined by the prevalent soil conditions on the location in question. The second stage is landed on the internal energy transfer ring in the toe joint of the previously driven section

By using the present invention, in its various embodiments and implementations, one or more of a number of advantages may be realized. For example:

    • the hydraulic pressure supplied to the percussive hammer may be reduced such that the present invention may be used in deep water pile-driving applications; by driving casing through shallow water flow sand(s), the underbalanced condition found after cementing, which may initiate shallow water flow, may be reduced or prevented;
    • friction from the sediment beneath the mud line may be reduced and the penetration depth of the guide shoe tip increased;
    • in deep water pile-driving, the use of hydraulic oil may be reduced, or eliminated, which may reduce, or eliminate, the potential for hydraulic oil to leak or spill into the undersea environment;
    • the size of the umbilical may be reduced, which may reduce the number of reels used to store and deploy the umbilical, which may also increase the amount of available deck space on the platform;
    • cutting disposal from drilling may be negated for environmental and economic advantage; and consolidation of the formation may lead to higher pile foundation capacity and seal flows of gas an fluid that may otherwise he initiated.

Still other advantages arising from one or more of the embodiments and implementations may become apparent to those in the art having the benefit of this disclosure.

Moreover, the present invention is expected to enhance prime equipment utilization by reducing the time required to carry out installations of caissons or tubular piles into the sea floor 215. By carrying out some or all of the above described functions “off the critical path,” the invention may accelerate the program of batch conductor installations in deep water. The invention may also help overcome certain hostile environments found below the sea floor 215 in the early stages of the construction of oil wells in deep water conditions.

This concludes the detailed description. The particular embodiments disclosed above are illustrative only, as the invention may be modified and practiced in different but equivalent manners apparent to those skilled in the art having the benefit of the teachings herein. Furthermore, no limitations are intended to the details of construction or design herein shown, other than as described in the claims below. It is therefore evident that the particular embodiments disclosed above may be altered or modified and all such variations are considered within the scope and spirit of the invention. Accordingly, the protection sought herein is as set forth in the claims below.