EP1362159B1

EP1362159B1 - Shoe with earth formation disiplacing structure

Info

Publication number: EP1362159B1
Application number: EP01911022A
Authority: EP
Inventors: Donald E. Mosing; David L. Sipos
Original assignee: Mosing Donald; Franks International LLC
Current assignee: Mosing Donald; Franks International LLC
Priority date: 2001-02-21
Filing date: 2001-02-21
Publication date: 2007-04-25
Anticipated expiration: 2021-02-21
Also published as: WO2002068790A1; DK1362159T3; EP1362159A1; EP1362159A4

Description

TECHNICAL FIELD

The present invention relates to an apparatus used in helping penetrate earthen formations, especially subsea soils as encountered in offshore wells, when used in combination with conductor pipe section as such are known in the drilling of wells for hydrocarbons and other fluids.

BACKGROUND ART

It is known, in the drilling of wells for hydrocarbons and other fluids, to drive conductor pipe or tubulars, comprising a string of segments of large diameter tubulars such as conductor pipe, into an earthen formation, especially offshore into the seabed.
As is known in the art, a well bore into an earthen formation provides a cylindrical, continuous casing for drilling of the well. In current practice, conductor pipe is driven from a point below a drilling rig floor to form a continuous string to a point in the earthen formation anywhere to a desired depth. This string of conductor pipe is normally driven by a pile driving apparatus such as a pile driving hammer. The conductor pipe string should be driven in as straight a line as possible since typically the centre line of the conductor pipe should be the centre line of the well bore for guiding and directing subsequent casing and drilling operations.
A procedure used for driving conductor pipe depends upon numerous factors such as hardness of the earthen formations and the friction on the inner and outer circumference of the pipe which cause increasing resistance to penetration as a conductor pipe is driven into the soil.
U.S. Patent No. 1,552,755, U.S. Patent No 4,715,455 and U.S. Patent No 3,467,204 all relate to coring tools for producing cores. They do not relate to pile driving and in fact would not function if used in this respect.
U.S. Patent No. 4,657,441 teaches that soil is compressed and that such compression of the soil is unacceptable when using a drive shoe. The soil is compressed because, as the pipe is driven, both the soil at the inner diameter (ID) of the drive shoe and the soil at the outer (OD) of the shoe are compressed. U.S. Patent No. 4,657,441 teaches breaking up of the soil by having a series of ribs and a series of spiral inner bar sections on the OD to torsionally disassociate the soil, intermittently de-cohering the soil causing it to break up and become loose. The important feature of this invention is to make the earth or soil less compact for the drilling process.
There is no teaching of a system or method which specifically compresses the earth around the formation displacing structures to enable enhanced penetration of a tubule into the earth formation.

SUMMARY OF THE INVENTION

A new and improved drive shoe for penetrating the soil is disclosed. The drive shoe, typically fastened below a conductor pipe section, has been found to increase the driveability of a string of conductor pipe by causing soil to be compressed and moved away from the ID and OD of the drive shoe.

BRIEF DESCRIPTION OF DRAWINGS

For a further understanding of the nature and objects of the present invention, reference should be had to the following detailed description, taken in conjunction with the accompanying drawings, in which like elements are given the same or analogous reference numbers and wherein:

Fig. 1 is a representational view of a typical offshore rig showing a conductor pipe being driven into a subsea earthen formation. Fig. 1A is a close up representational view of the drive shoe attached to conductor pipe.
Fig. 2 is a partial cross-sectional view of the drive shoe mounted with conductor pipe.
Fig. 3 is a cross section of Fig. 2 showing the interior of the drive shoe with the interval beveled bottom teeth.
Fig. 4 is a perspective view of exemplary embodiments of drive shoe teeth configurations.

GENERAL DESCRIPTION AND PREFERRED MODE FOR CARRYING OUT THE INVENTION

As illustrated in Fig. 1, a representational view of a typical offshore rig showing a conductor pipe being driven into a subsea, earthen formation, the drive shoe of the present invention, generally illustrated at 10, is connected to conductor pipe 11 being driven into earthen formation12. Conductor pipe 11 forms a continuous string 15 driven by a suitable pile driving and/or hammer apparatus 16 mounted on a suitable offshore drilling structure generally illustrated at 17, which is mounted on offshore drilling rig 18 with supporting legs or structure as at 19 for drilling into earth formation 12 beneath the surface of water 13.
Conductor pipe string 15 forms an outer casing and must be driven deeply enough in earthen formation 12 for eliminating erosion, blow outs, or other pressures that may later be encountered within the well bore. Such conductor pipe 15 is typically driven to a satisfactory point which may be one hundred feet or more through earthen formation 12. It should be evident to those skilled in the well drilling art that significant forces are exerted by the resistence of earth formation 12. Accordingly, the purpose of drive shoe 10 is to enhance penetration of conductor pipe 11 as it is driven.
Fig. 1A is a close up view of drive shoe 10 embedded in earth formation 12.
Referring now to Fig. 2, a partial cross-sectional view of an embodiment of drive shoe 10 mounted with conductor pipe 11, and Fig. 3, a cross section of Fig. 2 showing the interior of an embodiment of drive shoe 10 with interval beveled teeth 28, drive shoe 10 may have a larger inner and/or outer diameter than conductor pipe 11 to which drive shoe 10 is attached.
In a preferred embodiment, drive shoe 10 is fixedly attached to lower end 20 of conductor pipe 11 such that inner diameter (ID) 22 and outer diameter (OD) 24 of drive shoe 10 are less than the interior diameter (not numbered in the figures) of conductor pipe 11 and greater than the exterior diameter (not numbered in the figures) respectively.
Drive shoe 10 is thicker than the bottom end of conductor pipe 11 and thus is substantially stronger and more deformation resistant. Drive shoe 10 is fixedly attached to conductor pipe 11 by any suitable means such as welding or other type means.
In a preferred embodiment, lower end 26 of drive shoe 10 includes a series of saw teeth, generally indicated at 28, having exterior surface 46 with the same outer diameter as OD 24 of drive shoe 10. The lowest portion of saw teeth 28, illustrated at 30, ends at intersection 32 formed by edges 31 and 33 to form the "saw tooth" configuration. Lower end 26 is beveled on ID 24, the beveling, generally indicated at 34, preferably having a forty five degree angle although the angle may vary from twenty to eighty degrees. Typically, lower end 26 is first beveled and then saw teeth 28 cut into lower end 26 of drive shoe 10 such that lower end 26 has projecting, formed teeth 28 on OD 24 but an interior beveled surface such as 34 such that teeth 28 are slanted from point 36 forty five degrees outwardly to the tip of lowest portion 30. In this manner, the thickness of teeth 28 at point 36 is the wall thickness 38 of drive shoe 10 and the thickness of drive shoe 10 decreases from point 36 to lowest portion 30 of teeth 28.
As shown in Fig. 4, teeth 28 may have numerous patterns as will be familiar to those skilled in the drive shoe arts, including by way of example and not limitation pointed 28A, round 28B, truncated 28C, castellated 28D, or the like, or any combination thereof.
As also illustrated, exterior band 40 for increasing at least a portion of OD 24 may be mounted on OD 24 of the drive shoe 10 by any suitable manner, such as welding to the external surface of drive shoe 10, forming exterior band 40 into OD 24, or other manners known to those skilled in the tubular arts. In addition, it should be understood that interior band 41 may be similarly formed or attached to ID 22 of drive shoe 10 to decrease ID 22 at the location of interior band 41. It also should be understood that more than one interior band 40 or other structure for increasing OD 24 may be formed in or on or attached to the outer surface of drive shoe 10, and that more than one interior band 41 or other structure for decreasing ID 22 may be formed or attached ID 22.
Further, it is within the contemplation of the present invention that OD 24 alone may be larger than the outer diameter of conductor pipe 11 to which drive shoe 10 is attached. It is further within the contemplation of the present invention that ID 22 alone may be larger than the inner diameter of conductor pipe 11 to which drive shoe 10 is attached. It is further still within the contemplation of the present invention that interval beveled teeth 28 may be omitted when OD 24 is larger than the outer diameter of conductor pipe 11 or ID 22 is less than the interior diameter of conductor pipe 11, or a combination thereof. In these embodiments, soil may be compressed externally and/or internally by the disparity in diameter, especially in the presence of exterior band 40 and/or interior band 41.
In the operation of the preferred embodiment, drive shoe 10 is attached, by way of example and not limitation, such as by welding to lower end 20 of conductor pipe 11. In a typical mode of operation, conductor string 15 is continually hammered by pile driving apparatus 16 to drive conductor pipe I into earth formation 12. As conductor string 15 is so driven, saw teeth 28, because of their structure, penetrate through earth formation 12 and force soil inwardly while at the same time compressing soil to reduce the resistence away from interior surface 44 of drive shoe 10.
In an alternative embodiment, an inner band 41 or series of inner bands 41 or any other similar structure that would further compress soil interiorly into drive shoe 10 further compresses the soil to move it away from interior surface 44 of drive shoe 10. In a further alternative embodiment, an exterior band 40 or series of exterior bands 40 or any other structure that would further compresses soil exteriorly away from drive shoe 10 further compress the soil to move it away from exterior surface 46 of drive shoe 10.
As drive shoe 10 is being driven and penetrating earth formation 12, exterior band 40 compresses soil away from exterior surface 46 of drive shoe 10 such that earth formation 12 may be compressed away from exterior surface 46. In the embodiment where ID 22 is larger than the inner diameter of conductor pipe 11, earth formation 12 may be compressed away from interior surface 46 by inner band 41. In either of these manners or in combination, enhanced penetration of drive shoe 10 and, along with drive shoe 10, conductor string 15 into earth formation 12 is achieved.
It will be appreciated that very specific combination examples have been described and disclosed, the invention of the instant application is considered to comprise and is intended to comprise any equivalent or alternative structure or elements.

Claims

A new and improved drive shoe (10) for enabling enhanced penetration by pile driving of surface conductor tubulars (11) into an earthen formation, comprising:
a drive shoe (10) having an inner surface, an outer surface, a first end suitable for attachment to a tubular (11), and a second end; and

an earth formation displacing structure (40, 41) for compressing said earthen formation (12), said earth formation displacing structure disposed proximate said outer surface and/or inner surface;
characterised in that:
said outer surface is larger in diameter than an exterior surface diameter of said tubular (11) to which said drive shoe (10) is attached; and

said earth formation displacing structure (40, 41) compresses said earthen formation exteriorly away from said outer and/or inner surface for enabling enhanced penetration of said tubular into said earthen formation.
The structure as set forth in claim 1,
characterised in that:
said inner surface is larger in diameter than an inner surface diameter of said tubular (11) to which said drive shoe (10) is attached; and

said earth formation displacing structure (41) compresses said earthen formation interiorly away from said inner surface for enabling enhanced penetration of said tubular (11) into said earthen formation (12).
The structure as set forth in Claim 1 or claim 2 wherein said earth formation displacing structure (40, 41) disposed proximate said outer and/or inner surface for compressing said earthen formation is integral with said outer and/or inner surface.
The structure as set forth in any of Claims 1 or 3 wherein said earth formation displacing structure (40, 41) includes at least one circumferential band (40).
The structure as set forth in Claim 4 wherein said at least one circumferential band (40) is fixedly attached to said inner and/or outer surface of said drive shoe (10).
The structure as set forth in Claim 5 wherein said at least one circumferential band (40) is welded to said outer and/or inner surface of said drive shoe.
The structure of any preceding Claim wherein said tubular (11) to which said drive shoe (10) is attached is a conductor pipe.
The structure as set forth in any preceding claim further characterised in that the structure comprises a plurality of teeth disposed about said second end.
The structure of claim 8, further characterised in that:
said second end is bevelled to a bevel having an angle projecting inwardly from said outer surface to said inner surface; and

said plurality of teeth form a sawtooth pattern along an outer perimeter of said second end such that said plurality of teeth are further slanted from said outer surface to said inner surface along said bevel; whereby

a thickness of said teeth on at least one point on said teeth is the same as a thickness of said drive shoe at a point proximate to said teeth;

said thickness of said teeth decreases from said at least one point to a furthest extension of said teeth; and

an outer diameter of said drive shoe is not diminished at said second end.
The structure of Claim 8 or Claim 9 wherein said plurality of teeth are integral with said second end.
The structure as set forth in any of Claims 8 to 10 wherein said angle is between twenty degrees and eighty degrees.
The structure as set forth in Claims 11 wherein said angle is forty five degrees.
The structure of any of Claims 8 to 12 wherein an outer diameter of said first end is larger than an outer diameter of said tubular at which said drive shoe is attached at said first end.
The new and improved drive shoe of any of Claims 8 to 13 wherein an inner diameter of said first end is larger than an inner diameter of said tubular at which said drive shoe is attached at said first end.
The structure set forth in any preceding claim further comprising:
a first earth formation displacing structure for compressing said earthen formation, said first earth formation displacing structure disposed proximate said outer surface; and

a second earth formation displacing structure for compressing said earthen formation, said second earth formation displacing structure disposed proximate said second end;

wherein said first earth formation displacing structure and said second earth formation displacing structure compress said earthen formation, exteriorly and interiorly respectively, away from said outer surface and said inner surface for enabling enhanced penetration of said tubular into said earthen formation.