WO2003033952A1

WO2003033952A1 - Method and apparatus for installing a pipe

Info

Publication number: WO2003033952A1
Application number: PCT/AU2002/001387
Authority: WO
Inventors: William Dee Cherrington
Original assignee: William Dee Cherrington
Priority date: 2001-10-15
Filing date: 2002-10-15
Publication date: 2003-04-24

Abstract

A pipe (10) is shown extending from a land-based location (12) to a location on the floor (14) an adjacent body of water (16). The process of installing the pipe (10) firstly involves rotatably drilling an elongate hole (20) that extends from the land-based location (12) to the floor (14) of the water body (16). The hole (20) is advanced along a pre-determined profile path until the drill bit approaches the floor (14) of the water body (16). Following completion of the hole drilling, the process further involves the use of a pipe installation device (22) for installing the pipe (10) in the hole (20) by slidable insertion of the pipe (10) or a plurality of joinable sections of pipe into the hole (20). The land-based device (22) pushes (forward thrusts) the pipe (10) into a pre-formed hole (20) by gripping the peripheral surface of the pipe or pipe sections so as to enable insertion into the hole (20).

Description

METHOD AND APPARATUS FOR INSTALLING A PIPE

Field of the Invention

The present invention relates to a method and apparatus for installing a pipe. In one form the invention relates to a method and apparatus for installing a pipe suitable as a fluid or fluid-solid mixture carrier pipe extending between a land-based location and an underwater location and will primarily be described with reference to this context. It is also to be understood that the invention has broad use in pipeline installation applications for all manner of pipeline types, in order to provide linkage between a land-based facility and an underwater facility, such as a communication cable pipeline.

Background Art

Pipeline apparatus and methods of installing pipelines for conveying fluid or fluid-solid mixtures and for retaining communication cables (eg optic fibre cabling) and the like are known in the art. Pipelines are sometimes required to pass under a body of water such as a river, canal or lake,' rather than merely being placed along the floor of such a body of water. A method known as horizontal directional drilling (HDD) has been developed to achieve this .

In HDD a small diameter pilot hole is drilled under the body of water using a steering tool. The entry point for the drilling tool is on land on one side of the body of water. At the exit side, on the land on the other side of the body of water, once the steering and drilling device has penetrated the surface it can be replaced by a reaming head. As the reaming head is drawn back through the hole to the entry side, the reamer rotates, thus enlarging the hole. The reamer is then returned to the hole exit position and a pipeline end is then attached to it. The pipeline (with or without the reamer) is then pulled back through the hole from the exit position to the entry position thereby slidably installing the pipeline in the drilled and reamed hole . In some instances the reaming step is not required and it is the steering and drilling device which is pulled back through the hole from the exit position to the entry position dragging the pipeline with it in order to slidably install that pipeline in the hole. Pipeline installation machines are also known, for example shown in US 5,375,945.

Summary of the Invention

In a first aspect the present invention provides a method for installing a pipe including the steps of: - forming an elongate hole that extends from a land- based location to a location in an adjacent body of water; and subsequently installing the pipe in the hole by slidably inserting thereinto the pipe or a plurality of joinable sections of pipe, wherein the pipe is inserted in the hole from the land- based location.

The present invention provides a method for pipeline installation where the exit position is not on land, but on a river, lake or ocean floor. For example, a submarine cable conduit may be required to be installed from a land- based location to an undersea communication cable conduit, or a submarine oil or gas product pipeline may be required to be installed from a land-based storage or transportation facility to a pipeline joined to an offshore rig. In such situations it is unwise to run the conduit or pipeline off the land, down a beach or cliff face and directly onto the ocean floor because the ocean entry portion of such a pipeline would be subject to damage from tidal movements and waves, and great wear from the action of rocks and sand etc .

When the location of the hole is said to be "in a body of water" , this can include the situation where the opening is in fact achieved in two stages by firstly forming a hole to a position very near to breaking through into the body of water followed by the step of finally breaking through so as to form the opening, where this second step is actually done either from the body of water side of the hole, or from the land side by the use of a further cutting tool inserted into the hole or even attached to the end of the inserted pipe .

In use the invention can provide a simpler, safer and more convenient method of installing a subterranean pipe of a specific standard to extend from land to water and involving minimal marine construction activity. The present invention provides a method for installing such conduits or pipes from a land-based location to an undersea location, for example, to a location some 500-1500m offshore and to a depth of 10-50m below the sea floor. The difficulty with the known prior art method is that divers and barges loaded with heavy machinery are required to enable the exchange of equipment for the reaming step and to float or tow the pipeline into position at the marine (exit) end of the drill hole. There is considerable risk of damage to a lengthy pipe which has been specially welded, tested and assembled prior to its use in the open sea or other wide body of water, because the pipe is subjected to wind, currents and tidal action. Such marine operations are also subject to extremes of weather and are often highly dangerous from an occupational health standpoint, as diving can be hazardous to human health (eg the bends) along with the other typical dangers of using open bodies of water such as strong currents and rips which may drown divers as well as the activities of ocean predators such as sharks.

In contrast in the present invention the installation of the pipe into the hole is conducted from the land, thus minimising the need for river, lake or ocean drilling barges or other water-based componentry used in the prior art method. The invention allows for the installation of a single carrier pipe for the conveying of fluids (such as liquid or gas) or fluid-solid mixtures whether the pipe be in one piece or made from a plurality of joined pipe sections . In the latter case the land-based nature of the installation of the pipe allows more convenient joining of the pipe sections prior to installation into the hole.

Preferably the hole is formed by drilling from the land-based location.

Preferably the hole is reamed to increase its diameter prior to installation of the pipe . The hole can be reamed (or widened) from the land-based opening to the water body opening by using known forward-reaming techniques. Alternatively the hole may be only partially reamed from the land-based opening, terminating before exiting the water body opening. In some cases the hole may not require reaming at all before the pipe is slidably installed thereinto .

Preferably the pipe or pipe section is inserted by a pipe pushing apparatus, which has a land-based location. Most preferably the pipe (or joined sections of pipe) is pushed through the hole until it exits the hole into the body of water. Preferably upon exiting of the pipe (or joined pipe sections) into the body of water the pipe is pulled further into the body of water so that it can eventually be joined to a further underwater pipeline located on the river, lake or ocean floor. However in some installations the pipe may not be pushed through the water body opening, and in fact may be pulled through this opening and out into the body of water.

Preferably when the pipe is made up of joined sections of pipe, joints between adjacent sections are formed prior to insertion of the resulting pipe into the land-based opening of the hole. Most preferably the joint formation includes welding. In some instances when the pipe is used to carry fluids and fluid-solid mixtures, the pipeline welding will need to be of a pipeline standard which requires X-radiation integrity checks as well as leakage checks, fatigue assessment etc. Such checking can be done conveniently at the land-based location prior to slidable insertion of the pipe into the land-based opening.

In a second aspect the present invention provides an apparatus for installing a pipe including: a device for forming an elongate hole that extends from a land-based location to a location in an adjacent body of water; and a pipe installation device for installing the pipe in the hole by slidable insertion thereinto of the pipe or a plurality of joinable sections of pipe from the land-based location.

Preferably the device for forming the hole is a drilling tool. Preferably the pipe installation device is a pipe pushing means having a land-based location. Preferably the pipe pushing means includes a grip for attaching to the peripheral surface of the pipe or pipe sections so as to enable insertion of said pipe or pipe sections into the hole.

Preferably a pipe pulling means is used to pull the pipe (or joined pipe sections) into the body of water once the said pipe has exited or is adjacent the exit of the hole. Preferably when the pipe is made up of joined sections of pipe, a joint-forming device is used to form joints between adjacent sections prior to insertion of the resulting pipe into the land-based opening of the hole. Preferably the joint-forming device is a welding tool. Preferably the installed pipe is of a pipeline standard suitable for the in use transmission of fluid and solid-fluid mixtures therethrough, and will cope with the passage of pressurised fluids etc without leaking. Alternatively the installed pipe can be a carrier pipe suitable for encasing a further pipeline of a standard suitable for the in use transmission of fluid and solid- fluid mixtures therethrough, and the carrier pipe is of a less rigorous materials specification.

In a third aspect the present invention provides an apparatus for mounting to an end of a pipe and adapted for releasing fluid from the interior of the pipe into a pre- drilled hole into which the pipe is being inserted, the apparatus being removeable for replacement with a plug so that the pipe is then able to be pressurised.

Preferably the apparatus is a nozzle incorporating a one-way valve so that solid, liquid or gaseous material located outside the pipe is prevented from entering the interior of the pipe in use .

Preferably the nozzle is detachable from an outlet in a mounting plate mountable at the end of the pipe. Preferably the nozzle is positioned in a housing mountable to the mounting plate to define a chamber around the nozzle at the end of the pipe, the housing having at least one fluid exit nozzle therein for releasing fluid from the chamber in use . Preferably the housing has an opening closable with a closure, the removal of which enables the nozzle to be removed from the housing and the plug to be inserted therein and attached to the outlet in place of the nozzle.

Such an apparatus has a dual advantage. During installation of the pipe in the hole, a fluid is passed through the pipe and out of the fluid release adaptation to facilitate the movement of the pipe in the hole. Such a fluid can be a jet of water or other liquid or a high viscosity fluid-like material such as a bentonite slurry suspension which can suspend drilling debris in the hole (such as small rocks or other particulates) in order that such material does not deposit in the bottom of the hole under the influence of gravity and block the ready sliding movement of the pipe. Once the pipe is installed in position in the hole, a diver can simply remove the fluid release adaptation and replace it with a plug so that the pipe is then sealed and can be pressure tested for weld integrity, fluid leakage and the like before commencement of use of the pipe for its designated purpose.

In a fourth aspect the present invention provides a method for facilitating the introduction of a pipe into a pre-formed hole that extends from a first land-based location to either a second land-based location or a location in or adjacent to a body of water, including the step of passing a fluid through the pipe to exit from a leading end thereof whilst the pipe is being inserted into the hole.

Preferably the hole is pre-formed by drilling such that drilling debris remains in the hole, and the fluid is a high viscosity solid-liquid mixture capable of suspending the drilling debris therein when ejected from the pipe.

In a fifth aspect the present invention provides an apparatus for facilitating the introduction of a pipe into a pre-formed hole that extends from a first land-based location to either a second land-based location or a location in or adjacent to a body of water, including a fluid ejection device for releasing a fluid from a leading end of the pipe whilst the pipe is being inserted into the hole, the fluid ejection device arranged to prevent solid, liquid or optionally gaseous material located outside the pipe from entering the interior of the pipe in use.

During installation of the pipe in the hole, a fluid is passed through the pipe and out of the fluid ejection device to facilitate the movement of the pipe in the hole. Again, such a fluid can be a jet of water or other liquid or a high viscosity fluid-like material such as a bentonite slurry suspension which can suspend drilling debris in the hole in order that such material does not deposit in the bottom of the hole under the influence of gravity and block the ready sliding movement of the pipe. The fluid injection device only allows the flow of fluid out of the p p whilst in the hole so that the drilling debris does not enter and block the pipe itself during its insertion.

Preferably the fluid ejection device is a nozzle as defined in the third aspect.

Brief Description of the Drawings

Notwithstanding any other forms which may fall within the scope of the present invention, preferred forms of the invention will now be described, by way of example only, with reference to the accompanying drawings in which: Figure 1 shows a side schematic view of one embodiment of an elongate hole formed from a land-based location to an opening in or at a body of water when a pipe is slidably inserted into the hole in accordance with the invention.

Figure 2 shows a side view of one embodiment of an apparatus used for injecting fluid into a hole from a pipe located in the hole in accordance with the invention.

Figure 3 shows a side view of the embodiment shown in Figure 2 when the fluid injection nozzle is replaced by a plug.

Modes for Carrying out the Invention Referring to the drawings, and in particular to Figure 1, a pipe 10 is shown extending from a land-based location 12 to a location on the floor 14 an adjacent body of water 16. The process of installing the pipe 10 firstly involves rotatably drilling an elongate hole 20 that extends from the land-based location 12 to the floor 14 of the water body 16. Typically a drilling tool is utilised to bore through rock strata and earth at an angle, where the entry angle A and the set-back B of the drill hole is of sufficient distance to ensure that the hole 20 bored out will have a typical 10 metre clearance below the floor 14 of the water body 16, and perhaps as much as 50 metres. The hole 20 is advanced along a pre-determined profile path until the drill bit approaches the floor 14 of the water body 16. This may occur anywhere from 500-1500m offshore in an ocean-drilling situation. Typically a fine clay substance such as bentonite is used as a high viscosity drilling mud to capture and suspend cuttings from the borehole (to prevent settling) . This drilling mud is extracted up the borehole and the cuttings are separated. The drilling mud may then be recycled via pipeline 19 into the drilling process.

Following completion of the hole drilling, the process further involves the use of a pipe installation device 22 for installing the pipe 10 in the hole 20 by slidable insertion of the pipe 10 or a plurality of joinable sections of pipe into the hole 20. The land-based device 22 pushes (forward thrusts) the pipe 10 into a pre-formed hole 20 by gripping the peripheral surface of the pipe or pipe sections so as to enable insertion into the hole 20.

When the pipe is made up of joined sections of pipe, a joint-forming device typically in the form of a welding station is used to form joins between adjacent sections. The welds can be examined so that the pipe is of a standard suitable for the in use transmission of fluid and solid- fluid mixtures therethrough, and will cope with the passage of pressurised fluids etc without leaking. The land-based nature of the installation of the pipe allows both more convenient joining and checking of the joins between pipe sections prior to installation of the assembled pipe into the hole.

In alternative embodiments the installed pipe can merely be a carrier pipe suitable for encasing a further pipeline of a welded standard suitable for the in use transmission of fluid and solid-fluid mixtures therethrough. Such a carrier pipe can be of a less rigorous materials specification such as softer plastics, and does not require pressure rating.

Once the pipe 10 is positioned in the hole 20 it can be pulled into the body of water 16 if the pipe 10 has exited or is adjacent the exit 25 of the hole 20. If the hole 20 has been made to penetrate the floor 14 of the body of water 16, typically compressed air is pumped through the drill hole to locate and verify the exit location of the hole for divers in attendance. In some situations it may be preferable for the drill hole to be extended very near to breaking through into the floor of the body of water followed by the step of finally breaking through the floor so as to form the opening. In such a situation this second breakthrough ₍step can be done by divers operating at the body of water side of the hole, or from the land side by the use of a further cutting tool inserted into the hole or even attached to the end of the inserted pipe.

In some situations the hole can be reamed (widened) to increase its diameter prior to installation of the pipe. The hole can be reamed from the land-based opening to the water body opening by using known forward-reaming techniques. Alternatively the hole may be only partially reamed from the land-based opening, terminating before exiting the water body opening. In some cases the hole may not require reaming at all before the pipe is slidably installed thereinto.

Once the pipe has exited the floor 14 of the body of water 16, typically a cable is attached to the pipe and to a floating vessel such as a tug to facilitate pulling of the pipe 10 into the body of water 16 so that the pipe may be joined to further underwater conduit or submarine pipeline 27 etc. The attachment for this cable at the end of the pipe is shown in more detail in Figures 2 and 3 in the form of pull eye 122 and will now be described in more detail.

Referring to Figures 2 and 3, the present invention provides an apparatus 100 for mounting to an end of a pipe 10 and adapted for releasing fluid such as drilling mud from the interior 102 of the pipe 10. In one preferred form the end of the pipe 104 has a mounting plate in the form of a high pressure cap 106 which has a central orifice 108 with a detachable high pressure fitting seated thereat. The high pressure fitting is in the form of a threaded female socket portion 110 for receiving a threadably mated male nozzle portion 112, the nozzle 112 incorporating a one-way valve so that solid or liquid material located outside the pipe 10 is prevented from entering the interior 102 of the pipe 10 in use. In use the one way valve provides a net flow of drilling mud from the interior 102 of the pipe through the nozzle 112. The nozzle 112 is positioned in a housing in the form of a jet head assembly 114 mounted to the high pressure cap 106 to define a chamber 116 around the nozzle at the end of the pipe. The jet head assembly 114 has four high pressure fluid exit nozzles 118 directed upstream from a face 120 of the jet head assembly 114 and pipe 10, the four nozzles 118 for releasing fluid from the chamber 116 in use.

The jet head assembly 114 has an opening with a closure in the form of a pull eye 122 which is welded to a lateral flange 124, the flange 124 being held in position by a number of circumferential bolts 126 which are received into the jet head assembly 114. The unbolting of the flange 124 and pull eye 122 from the jet head assembly 114 enables a diver to reach into the jet head assembly 114 and unscrew the nozzle 110/112 from the high pressure test cap 106 and to insert a plug 128 to into the central orifice

108 in place of the nozzle 110/112.

During installation of the pipe 10 in the hole 20, a fluid is passed through the pipe 10 and out of the high pressure cap 106 at the leading end of the pipe 10 to facilitate the movement of the pipe 10 in the hole 20.

Such a fluid can be a jet of water or other liquid or a high viscosity fluid-like material such as a bentonite slurry suspension which can suspend drilling debris in the hole 20 in order that such material does not deposit in the bottom of the hole 20 under the influence of gravity and block the ready sliding movement of the pipe 10. Once the pipe 10 is installed in position in the hole 20, a diver can simply remove the high pressure fitting nozzle 110/112 and replace it with the plug 128 so that the pipe 10 is then sealed and can be pressure tested underwater for weld integrity, fluid leakage and the like before commencement of use of the pipe 10 for its designated purpose. Such a step is used to detect any damage that may have occurred to the pipe 10 during installation.

Previously, the only way that an open-ended pipeline has been pressure tested has involved drawing the installed pipeline to the surface and sealing the end by welding etc, before a pressure test could commence. If a pipe with a ^λblind' end (already welded over) is installed in the preformed hole, the only way of introducing fluid lubricant to assist its path into the hole has been via the annular space around the pipe when it is in the hole, which has been an inefficient method of facilitating pipe insertion past drilling debris. The present technique can be applied to facilitate the introduction of a pipe into a pre-formed hole that extends from a first land-based location to either a second land-based location or to a location in or adjacent to a body of water. In further embodiments the hole, orifice or other fluid ejection device located at the leading end of the pipe can be of any shape or orientation provided that the device is arranged to prevent solid or liquid material located outside the pipe from entering the interior of the pipe in use either under hydrostatic pressure or by being directed therein by movement of the pipe. In use the invention can provide a simpler, safer and more convenient method of installing a subterranean pipe of a specific standard to extend from land to water and involving minimal marine construction activity at the marine (exit) end of the drill hole.

The materials of construction of the pipe can comprise any suitable materials which can be shaped, formed and fitted in the manner so described, such as appropriate metal or metal alloys for strength and even metal pipes with protective exterior coatings for corrosion resistance .

It is to be understood that, if any prior art information is referred to herein, such reference does not constitute an admission that the information forms a part of the common general knowledge in the art, in Australia or any other country.

Whilst the invention has been described with reference to preferred embodiments it should be appreciated that the invention can be embodied in many other forms .

Claims

1. A method for installing a pipe including the steps of: - forming an elongate hole that extends from a land- based location to a location in an adjacent body of water; and subsequently installing the pipe in the hole by slidably inserting thereinto the pipe or a plurality of joinable sections of pipe wherein the pipe is inserted into the hole from the land- based location.

2. A method as claimed in claim 1 wherein the hole is formed by drilling from the land-based location.

3. A method as claimed in claim 1 or claim 2 wherein the hole is reamed to increase its diameter prior to installation of the pipe.

4. A method as claimed in any one of the preceding claims wherein the pipe or pipe section is inserted by a pipe pushing apparatus which has a land-based location.

5. A method as claimed in claim 4 wherein the pipe (or joined sections of pipe) is pushed through the hole until it exits the hole into the body of water.

6. A method as claimed in claim 5 wherein upon exiting of the pipe (or joined sections of pipe) into the body of water the pipe is pulled further into the body of water.

7. A method as claimed in any one of the preceding claims wherein when the pipe is made up of joined sections of pip , joints between adjacent sections are formed prior to insertion of the resulting pipe into the hole.

8. A method as claimed in claim 7 wherein the joint formation includes welding.

9. A method as claimed in any one of the preceding claims wherein the installed pipe is of a pipeline standard suitable for the in use transmission of fluid and solid- fluid mixtures therethrough.

10. A method as claimed in any one of claims 1 to 8 wherein the installed pipe is a carrier pipe suitable for encasing a further pipeline of a standard suitable for the in use transmission of fluid and solid-fluid mixtures therethrough.

11. Apparatus for installing a pipe including: a device for forming an elongate hole that extends from a land-based location to a location in an adjacent body of water; and a pipe installation device for installing the pipe in the hole by slidable insertion thereinto of the pipe or a plurality of joinable sections of pipe from the land-based location.

12. Apparatus as claimed in claim 11 wherein the device for forming the hole is a drilling tool.

13. Apparatus as claimed in claim 11 or claim 12 wherein the pipe installation device is a pipe pushing means having a land-based location.

14. Apparatus as claimed in claim 13 wherein the pipe pushing means includes a grip for attaching to the peripheral -surface of the pipe or pipe sections so as to enable insertion of said pipe or pipe sections into the hole .

15. Apparatus as claimed in any one of claims 11 to 14 wherein a pipe pulling means is used to pull the pipe (or joined pipe sections) into the body of water once the pipe has exited or is adjacent the exit of the hole.

16. Apparatus as claimed in any one of claims 11 to 15 wherein when the pipe is made up of joined sections of pipe, a joint-forming device is used to form joints between adjacent sections prior to insertion of the resulting pipe into the hole .

17. Apparatus as claimed in claim 16 wherein the joint- forming device is a welding tool .

18. Apparatus for installing a pipe as claimed in any one of claims 11 to 17 wherein the installed pipe is of a pipeline standard suitable for the in use transmission of fluid and solid-fluid mixtures therethrough.

19. Apparatus for installing a pipe as claimed in any one of claims 11 to 17 wherein the installed pipe is a carrier pipe suitable for encasing a further pipeline of a standard suitable for the in use transmission of fluid and solid-fluid mixtures therethrough.

20. Apparatus for mounting to an end of a pipe and adapted for releasing fluid from the interior of the pipe into a pre-drilled hole into which the pipe is being inserted, the apparatus being removeable for replacement with a plug so that the pipe is then able to be pressurised.

21. Apparatus as claimed in claim 20 wherein the apparatus is a nozzle incorporating a one-way valve so that solid, liquid or gaseous material located outside the pipe is prevented from entering the interior of the pipe in use .

22. Apparatus as claimed in claim 21 wherein the nozzle is detachable from an outlet in a mounting plate mountable at the end of the pipe .

23. Apparatus as claimed in claim 22 wherein the nozzle is positioned in a housing mountable to the mounting plate to define a chamber around the nozzle at the end of the pipe, the housing having at least one fluid exit nozzle therein for releasing fluid from the chamber in use .

24. Apparatus as claimed in claim 23 wherein the housing has an opening closable with a closure, the removal of which enables the nozzle to be removed from the housing and the plug to be inserted therein and attached to the outlet in place of the nozzle.

25. A method for facilitating the introduction of a pipe into a pre-formed hole that extends from a first land- based location to either a second land-based location or a location in or adjacent to a body of water, including the step of passing a fluid through the pipe to exit from a leading end thereof whilst the pipe is being inserted into the hole.

26. A method as claimed in claim 25 wherein the hole is pre-formed by drilling such that drilling debris remains in the hole, and the fluid is a high viscosity solid- liquid mixture capable of suspending the drilling debris therein when ejected from the pipe.

27. Apparatus for facilitating the introduction of a pipe into a pre-formed hole that extends from a first land- based location to either a second land-based location or a location in or adjacent to a body of water, including a fluid ejection device for releasing a fluid from a leading end of the pipe whilst the pipe is being inserted into the hole, the fluid ejection device arranged to prevent solid or liquid material located outside the pipe from entering the interior of the pipe in use .

28. Apparatus for facilitating the introduction of a pipe into a pre-formed hole as claimed in claim 27 wherein the fluid ejection device is a nozzle as defined in any one of claims 22 to 25.

29. A method for installing a pipe as herein described with reference to the accompanying drawings .

30. Apparatus for installing a pipe as herein described with reference to the accompanying drawings .

31. Apparatus for mounting to an end of a pipe as herein described with reference to the accompanying drawings .

32. A method for facilitating the introduction of a pipe into a pre-formed hole as herein described with reference to the accompanying drawings .

33. Apparatus for facilitating the introduction of a pipe into a pre-formed hole as herein described with reference to the accompanying drawings .