CN117642547A

CN117642547A - Grouting-free expandable riser

Info

Publication number: CN117642547A
Application number: CN202280050097.XA
Authority: CN
Inventors: 乔尔·尤金·亚当斯; 伊万·安德烈·科索罗克
Original assignee: Inflatable Packaging International LLC
Current assignee: Inflatable Packaging International LLC
Priority date: 2021-05-24
Filing date: 2022-05-23
Publication date: 2024-03-01
Also published as: WO2022251098A1; CA3219972A1; AU2022283196A1

Abstract

A groutless expandable riser (10) and a method for anchoring into a formation (22) and injecting grout into the formation (22) are provided without the need to first grout the riser (10) into the formation (22). The expandable riser (10) has a swage seal (43) that can be expanded with a swage tool such as an inflatable swage packer (60) of unitary construction or the like for anchoring and sealing the riser (10) into a pilot hole (16) without the need for grouting. A grout hole (96) can then be drilled through the bore hole of the expandable riser (10) and into the formation. Grout can then be injected into the formation (22) via the grout holes (96) without waiting about 24 hours for the grout to cure and harden to anchor and seal the expandable riser (10) into the pilot hole (16).

Description

Grouting-free expandable riser

Technical Field

The present invention relates to a groutless expandable riser and a method for grouting a subterranean formation. The present invention also relates to a method of anchoring and sealing a riser into a formation using an expandable riser having a swaged seal set by an inflatable packer.

More particularly, the present invention relates to a riser having swaged seals for anchoring and sealing into a formation to avoid the need to grout the riser into the formation. The advantage of using a swage set expandable riser instead of a grouting riser is that the riser can be anchored and sealed in less than an hour (more typically less than 30 minutes), whereas prior art grouting risers require up to 24 hours to set the grout to effect sealing and anchoring of the riser. Conventional risers are not expandable.

More specifically, the groutless expandable risers of the present invention may be used to form grouting curtains to protect ongoing tunnel excavation from flooding with high pressure groundwater from the formation surrounding the tunnel. Expandable risers may also be used in underground mining processes. Preventing groundwater from flooding is particularly important during underground excavation. It is known to use curtains of grouted boreholes around an underground excavation to block groundwater flow. However, the time required for grout to cure and set greatly slows the excavation progress.

Terminology

The following specific terms are used in the context of the present invention:

in the context of the present invention, "curtain" refers to a curtain of grout that solidifies into the formation in front of and surrounding the tunnel for stabilizing the surface and inhibiting groundwater flow into the tunnel;

In the context of the present invention, "grouting" refers to a settable, flowable agent, typically made from a mixture of cement, water and sand, as is known for pressure grouting. Typically, grout is made from portland cement and provides a water barrier when set. In the prior art, riser grouting is used to seal the riser into a pilot hole in the ground. Such prior art risers are referred to herein as grout seal risers. In the context of the present invention, grout is not used to seal a riser into the ground, but is used only to stabilize the formation around a grout hole drilled through the riser;

in the context of the present invention, "groutless" means that the operations of setting and sealing the riser into the formation do not require the use of grouting, yet grouting is still required to create a grouting curtain in front of and around the tunnel;

in the context of the present invention, "grout hole" refers to a hole drilled through the end of a pilot hole once a riser has been sealed into the pilot hole. The grouting holes are typically 15 to 50 meters long and are substantially coaxial with the pilot holes;

in the context of the present invention, "grouting" refers to the process of injecting grout into the formation beforehand and through risers around the subterranean tunnel;

In the context of the present invention, an "inflatable packer" refers to a plug device capable of temporarily or permanently plugging a hole in the surface or inside a pipe (such as a riser). Inflatable packers of the type preferred in the context of the present invention incorporate the elastomer, reinforcement layer, and external anchoring surface finishes and covers within a single vulcanized composite element. Suitable inflatable packers are manufactured by inflatable packer International (Inflatable Packers International). Other forms of inflatable packer are made of three or more separate components stacked on top of each other and are less suitable for use in the riser of the invention;

in the context of the present invention, a "mechanical packer" refers to an elastic tubular member having a mandrel passing through its longitudinal axis, the expansion of the mechanical packer being achieved by compressing the ends of the tubular member towards each other. Mechanical packers generally cannot achieve high expansion ratios and cannot operate at as high pressures as inflatable packers. In the context of the present invention, a mechanical packer cannot swage a riser to seal against a pilot hole;

in the context of the present invention, "pilot hole" refers to a hole drilled in the formation for receiving a riser. The pilot holes are typically 2 to 4 meters long;

In the context of the present invention, "pressure" is a pressure difference between a pressure inside the reference riser or its setting tool and a pressure outside the riser or the setting tool;

in the context of the present invention, "high pressure" generally refers to a water pressure greater than about 10Mpa and up to about 100Mpa, and "low pressure" refers to a water pressure below about 500 kPa. With respect to swaging with the inflatable packer used in the present invention, the high pressure is about 70MPa;

in the context of the pilot hole of the present invention, "shallow" refers to a distance of less than about 5 meters;

in the context of the present invention, "riser" refers to a pipe that sits substantially horizontally in the formation during tunneling and underground mining. Risers are used to deliver grout into the formation, for example to stabilize the ground in front of and around a tunnel when it is excavated;

"riser" disambiguation: notably, the term riser is also used in connection with plumbing and water service in building operations or in delivering water into tunnels. The use of the term riser for the delivery of water is totally different and dissimilar to the use of the term riser in the present invention. The main reason for the difference is that in the context of the present invention the risers are sealed and anchored into pilot holes drilled in the ground and filled with solidified grout to prevent water flow through and thus not allow water to pass through. That is, the risers of the present invention are in contrast to risers known for use with pipelines;

In the context of the present invention, "substantially horizontal" means in a generally horizontal direction and may be at 10 to 20 degrees from horizontal. Typically, the pilot holes and grout holes referred to in the present invention are offset from the path of the tunnel with which they are used by 10 to 20 degrees. In the case where the tunnel is not horizontal, then "substantially horizontal" means radiating outwardly from the tunnel at an angle of 10 to 20 degrees from the longitudinal direction of the tunnel;

in the context of the present invention, "swaging" refers to using outwardly expanding forces to expand the diameter of a tubular member, such as a riser. In the context of the present invention, swaging does not involve swaging the connection or performing the swaging to make the diameter of the tubular member smaller;

in the context of the present invention, "swaged" refers to the action of increasing the diameter of a tubular (such as a riser) by using an expanding inflatable packer or by explosive forces. More specifically, in the context of the present invention, swaging involves sealing between the riser and the pilot hole in the ground by the action of swaging; and

in the context of inflatable packer elements of the invention, "unitary construction" means that the inner bladder, reinforcement and outer cover of the element are fused together into a single unit such that they expand and contract as a single unit, which tends to make it well suited for multiple inflation and deflation cycles.

It is important to note that expandable risers of the type of the present invention typically have a wall thickness of about 10mm and are made of ductile metallic material that is easily swaged to increase the diameter of the riser. Conventional risers for pressure grouting and the like are made of non-ductile metallic materials because of the desire to reduce costs, and cannot be increased in diameter by swaging.

It is also important to note that risers of the type of the present invention include an outer cover made of an elastomeric material for assisting in the compliance, sealing and anchoring of the riser to the interior of the pilot hole once swaging is complete.

Background

Pressure grouting

In excavation fields such as tunnelling and underground mining, when an unstable formation is encountered, a "grout curtain" is typically set around and in front of the tunnel. During tunnel construction, curtains are used to stabilize the formation and reduce the flow of groundwater into the tunnel. This technique is commonly referred to as formation consolidation. For a detailed understanding of this technique, please refer to Knut F. Garshol Pre-Excavation Grouting in Rock Tunneling [ grouting before rock tunnelling ]]Copyright 2003 is owned by MBT International underground construction group (MBT International Underground Construction Group), MBT (Switzerland) Division of MBT (Switzerland) Ltd) (available from https://www.academia.edu/ 8167266/Pre_Excavation_Grouting_in_Rock_Tunneling_Pre_E xcavation_Grouting_ in_Rock_Tunneling)。This technique is commonly referred to as pressure grouting.

Stabilization is achieved by pumping grout into the formation. In the simple lower pressure case, a pilot hole is drilled into the formation and a mechanical packer is inserted and expanded (typically using a turnbuckle) to seal against the formation and allow grout to be pumped into the formation. In the more difficult high pressure case where the groundwater pressure is 6MPa (60 bar) or higher, it is not efficient to expand the mechanical packer into the hole drilled in the formation, because the packer may slip out, or the high pressure water may pass around the packer. Typical lengths of such mechanical packers are 0.5 to 1.0 meters. At these high pressures, the use of risers is required to deliver grout into the formation.

The risers of the prior art are cylindrical and typically have a length of about 2 to 4 meters, an outer diameter of about 66mm and an inner diameter of about 55 mm. The riser is inserted into a substantially horizontal pilot hole of diameter about 76mm drilled into the formation. Such a pattern of holes is usually drilled at an angle or about 10 degrees for a horizontally arranged tunnel in front of the tunnel in an outward radiating manner. Because the formation is unstable, the pilot hole is prone to drift, and thus the diameter of the hole is typically 10mm or more larger than the riser.

In the prior art, the annulus between the riser and the pilot hole is filled with grout which is allowed to set to prevent water from flowing out of the formation through the annulus and into the tunnel being drilled. Grouting is typically high quality shrinkage-compensating cementing. Grouting of so-called risers is typically accomplished by positioning mechanical packers near and inside the downhole end of the riser. Typically, the mechanical packer is located a few meters from the outer end of the bore of the riser. Grouting fluid is then pumped through the riser to the end of the pilot hole. The grout then flows into the annular space between the riser and the pilot hole and returns along the riser until the grout begins to be pumped out of the annular space between the riser and the pilot hole into the tunnel.

Once set in place and coated with grout, the prior art risers must wait for the grout to cure. Grouting (typically in the form of portland cement) typically requires about 24 hours to set/cure to a hardness of 10 to 20MPa in order to provide adequate sealing between the riser and the pilot hole. If sufficient stiffness is not achieved, further drilling of the borehole to pump the cemented curtain into the formation is dangerous and impossible.

For this purpose, the post grouting risers are typically pressure tested after 24 hours of cure time. If the riser fails the pressure test, the riser is discarded and a new pilot hole, riser and grouting process is performed and retested after another 24 hours cure time. The water pressure test is typically performed at 1MPa, however, if high pressure water is present in the formation, the test needs to be performed at a higher pressure, in some cases up to 10MPa.

The purpose of the pressure test is to ensure that the riser will not be pushed out of the pilot hole by the weight of the grout being supported or by the water pressure that may be present in the formation around the grouted curtain. The pressure test is also to ensure that the riser does not leak water from the formation into the tunnel.

Once the riser passes the pressure test, a grout hole may be drilled through the riser and into the formation. The grout holes are typically about 25 meters long; much longer than the pilot hole that accommodates the riser. The pump is then attached to the riser and grout may be injected into the formation via the riser and grout holes to form a grout curtain in the formation forward of and surrounding the tunneling direction. A typical curtain may include several tons of grout, for example about 4 tons.

Grout around the risers is also needed to anchor the prior art risers into the formation to prevent the risers from being forced out of the shallow pilot holes as the grout is pumped into the grout holes and formation. The anchoring also prevents high groundwater pressure from forcing the riser out of the pilot hole.

Once the curtain has set, the tunnel may be excavated into the formation for a greater distance under the safety and stability of the grouting curtain. Typically, the tunnel is advanced a distance less than the distance of the grouting curtain in order to ensure that further operations are performed in a safe state of the grouting curtain that has been injected, solidified and tested. This avoids the formation not yet being stabilized or the high pressure water impermeable tunnel being submerged or collapsed.

In the prior art of forming tunnels, 4 to 16 risers are typically grouted in a ring-shaped structure around and in front of the tunnel path. The number of risers generally increases in proportion to the water pressure encountered when drilling the borehole in the direction of tunnel construction and the porosity of the formation. Typically, risers are grouted into 4 primary perimeter holes around the tunnel, and if too much water is encountered, 4 secondary risers are set and grouted, and if more water is encountered, a set of 4 tertiary risers are also set and grouted. Once the water encountered is below the trigger flow rate, the riser is no longer installed and the tunnel can be propelled by further excavation.

A major disadvantage of prior art risers and grouting techniques for tunnelling is that it takes a certain time for the grout to set around the riser before the grout holes can be drilled and additional grout pumped in to stabilize the formation. This is especially troublesome in formations that are prone to high pressure water. In addition, in the event that the riser fails its pressure test, another riser must be installed, which requires more time to cure the grout to seal and anchor the riser into the formation.

The present invention seeks to overcome the disadvantages of the prior art risers by using swaged seals to anchor and seal the riser into the formation. Thus, no grout is required to seal and anchor the riser of the present invention into the formation. This has the advantage of setting the expandable riser faster (typically less than 1 hour, more typically less than 30 minutes) and thus grouting of the formation can occur faster than prior art riser techniques and the excavation proceeds much faster (up to 24 hours per turn of riser), thereby reducing the overall cost of the excavation operation.

Swageable seal

It is known in downhole applications such as drilling oil or water to swage and expand a pipe using a mandrel that is pulled or driven from the distal end of the pipe to the proximal end to gradually expand the pipe as the mandrel moves through the pipe. Examples include US6457532 and US9702229. However, these types of swages are not suitable for short pipes, such as expandable risers.

In particular, the expandable risers of the present invention are used for very shallow substantially horizontal holes (typically less than 5 meters in length), whereas the swaged expansion tubes of the prior art are used for deep at least partially vertical holes (typically more than 100 meters in depth). The consequence of the much greater depth of the prior art bore is that the weight of the metal tube upstream of the portion of the pipe to be swaged limits the tendency of the pipe string to pull out of the bore as the mandrel is pulled through the pipe.

Integrated inflatable packer element

Most conventional prior art inflatable packer elements are made of three components, namely a separate inner bladder, a separate reinforcing layer and a separate outer cover layer, whereby the three layers expand and contract according to their own characteristics, which in the case of multiple inflation and deflation cycles, tend to cause the element to fail. The characteristics of the individual layers of such prior art inflatable packers tend to inhibit their ability to collapse to their original diameter, thus risking the inflatable packer being stuck in the pipe in which it is operating. In addition, these multi-layer inflatable packers tend to perform poorly at the high pressures (about 70 MPa) required to expand the malleable risers (wall thickness of about 10 mm).

In contrast, inflatable packers used in the setting tool of the present invention have a unitary structure that has been vulcanized to fuse the inner bladder, reinforcement, and outer cover together into a single unit. The result of this fusion is that the fused components expand and contract as a single unit, which tends to make an inflatable packer of unitary construction well suited for multiple inflation and deflation cycles, especially at high differential pressures.

Disclosure of Invention

It is therefore an object of the present invention to provide an apparatus and method for sealing and anchoring an expandable riser and grouting a formation using an expandable riser with swaged seals, thereby avoiding the need to grout the expandable riser prior to injecting the grout into the formation.

According to one aspect of the present invention, there is provided a method of anchoring and sealing an expandable riser into a formation, the method comprising the steps of:

forming shallow pilot holes in the formation;

inserting a majority of the expandable riser into the pilot hole; and

expanding the riser radially outwardly to anchor and seal into the pilot hole;

thereby expanding the riser so that it is anchored and sealed into the formation without grouting.

Typically, the expandable riser has a swaged seal that expands radially outward under internally applied pressure.

Typically, the swage seal is positioned near the blind end of the pilot hole.

Typically, an inflatable packer is used to expand the swage seal to anchor and seal into the pilot hole.

Typically, the diameter of the pilot hole is between 75mm and 150mm, for example about 90mm.

Typically, the grouting holes have a diameter of between 30mm and 60mm, for example about 45mm.

Typically, the grouting holes have a diameter about half the diameter of the pilot hole.

Typically, the inflatable packer has a unitary structure and is capable of multiple inflation and deflation cycles while returning substantially to its original diameter and without failure.

It is recommended to ensure that there are no chips in the pilot hole prior to insertion of the riser, which might otherwise get stuck in the riser and inhibit expansion of the swage seal.

According to another aspect of the present invention, there is provided a method of grouting a subterranean formation with an expandable riser, the method of grouting a subterranean formation comprising the steps of:

forming shallow pilot holes in the formation;

inserting a majority of the expandable riser into the pilot hole;

Expanding the riser radially outwardly to anchor and seal into the pilot hole;

forming a grout hole through the bore hole of the expandable riser into the formation ahead of the pilot hole; and injecting grout into the formation through the riser and through the grout hole;

Typically, the pilot hole is formed by drilling.

Typically, the pilot hole is about the same length as the riser.

Typically, the riser is inserted into the guide to a depth such that a space of between 150mm and 500mm, for example about 300mm, is left between the insertion end of the riser and the blind end of the guide bore.

Typically, the expandable riser has a swaged seal that expands under internally applied pressure.

Typically, the swage seal is positioned near the blind end of the pilot hole.

Typically, an inflatable packer is used to expand the swage seal radially outward to anchor and seal into the pilot bore.

According to another aspect of the present invention there is provided a groutless expandable riser for anchoring and sealing into a pilot hole in a formation without grouting, the expandable riser being usable for pumping grouting into a grout hole in a formation, the expandable riser comprising:

an elongate tube comprising a delivery tube end connected to a swaged tube, the elongate tube sized to be inserted into the pilot hole, the elongate tube further comprising a bore through the delivery tube and the swaged tube, the bore capable of receiving a setting tool for expanding the swaged tube and for receiving a drill rod for drilling a grout hole through the blind end of the pilot hole approximately half the diameter of the pilot hole;

the delivery tube is configured for insertion of the elongate tube into the guide aperture and the delivery tube is capable of protruding from the guide aperture in use; and, in addition, the processing unit,

the swage tube is positionable in the pilot hole to a position proximate a blind end of the pilot hole, the swage tube being radially expandable with an inflatable packer element to contact the pilot hole; and

a swage seal on an outer curved surface of the end of the elongated tube proximate the blind end of the pilot hole, the swage seal being expandable radially outwardly to anchor and seal the riser into the pilot hole;

Wherein anchoring and sealing the expandable riser into the formation does not require grouting; and is also provided with

Wherein grout can be pumped into the grout hole through the expandable riser to stabilize the formation surrounding the grout hole.

Typically, the swage seal is malleable to expand radially outward without cracking or splitting.

Typically, the swage seal is made of a ductile metallic material such as ductile stainless steel.

Typically, the swage seal has an elastomeric layer on its outer curved surface.

Typically, an expansion tool is removably inserted into the riser and expands radially outward to expand the swaged seal.

Typically, the expansion tool is a swaged packer. More specifically, the expansion tool includes an inflatable packer configured to form a swage packer.

According to another aspect of the present invention, there is provided a groutless expandable riser system for pumping grout into a grout hole formed in a subterranean formation, the expandable riser system comprising:

a setting tool comprising an inflatable packer element positionable within the riser for expanding the swage seal into contact with the pilot bore, the setting tool being removable from the riser once the swage seal is expanded; and

A high pressure pump connected to the setting tool for inflating and deflating the inflatable packer;

In one example, the expansion tool (also referred to as a setting tool) includes an inflatable swage packer.

In another example, the expansion tool includes a high energy device (HERD) capable of rapidly expanding the swaged seal into contact with the inner wall of the pilot hole. The HERD may be a high pressure liquid, such as water, that is explosively injected into the swage seal. Alternatively, the HERD may be an explosive charge that is located in the bore of the swage seal and detonated to cause the swage seal to expand.

Throughout this specification, unless the context requires otherwise, the word "comprise" or variations such as "comprises" or "comprising" will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers. Likewise, the word "preferably" or variations such as "preferred" will be understood to imply that a stated integer or group of integers is desired but not necessary to the practice of the invention.

Unless the context requires otherwise to mention a riser, a riser is equivalent to or is a groutless expandable riser.

Drawings

Exemplary embodiments of the present invention will now be described with reference to the accompanying drawings, in which: -

FIG. 1 is a side cross-sectional view, partially in section, of a grouting-free expandable riser shown in a pilot hole in a formation, the riser in an inserted operational state, according to the invention;

FIG. 2 is a side cross-sectional view, partially in section, of the riser of FIG. 1 shown with a setting tool in the form of an expanded swage packer expanded within the riser for swaging the swage seal of the riser;

FIG. 3 is a cross-sectional side view of the swage seal of the riser of FIG. 1, the swage seal being shown to a smaller scale and including an anchor coupling;

FIG. 4 is a cross-sectional side view of the inflatable swage packer (setting tool) of FIG. 2, taken along section line A-A of FIG. 5, shown in a compact mode of operation;

FIG. 5 is a side view of the inflatable swage packer of FIG. 4, shown to a smaller scale;

FIG. 6 is a partial cross-sectional view of the riser of FIG. 1 shown installed into a pilot hole in a formation and having a grout hole formed through the blind end of the pilot hole; and is also provided with

FIGS. 7-9 are schematic cross-sectional side views of the riser of FIG. 1, showing, respectively, insertion of the riser, expansion of the swage packer to expand the swage seal of the riser, and removal of the swage packer to expose the swaged riser anchored in the formation;

FIGS. 10-16 illustrate steps in the use of the groutless expandable riser of the present invention;

FIG. 10 is a side view, partially in section, of the riser of FIG. 1 shown inserted into a pilot hole in the formation;

FIG. 11 is a side view, partially in section, of the riser of FIG. 1 showing temporary insertion of a setting tool into the riser;

FIG. 12 is a side view, partially in section, of the riser of FIG. 1 showing the riser being expanded with a setting tool to seal into a pilot hole without the use of grout;

FIG. 13 is a side view, partially in section, of the riser of FIG. 1 showing the setting tool removed and pressure tested with a non-settable liquid to test the integrity of the seal of the riser against the pilot hole;

FIG. 14 is a side view, partially in section, of the riser of FIG. 1 showing a drill bit inserted through the riser to drill a grout hole in the formation ahead of the riser;

FIG. 15 is a side view, partially in section, of the riser of FIG. 1 showing the pumping of grout through the riser and through the grout holes into the formation surrounding the grout holes;

FIG. 16 is a side view, partially in section, of the riser of FIG. 1, showing the riser extension of the riser removed from the riser;

FIG. 17 is a perspective view from above of the groutless expandable riser system of the present invention, comprising the expandable riser of FIG. 1, the setting tool of FIGS. 4 and 5, and the high pressure pump, both of which are shown with their bore inner ends at the forefront;

FIG. 18 is a perspective view of the riser of FIG. 1 shown with its outer end of the bore furthest forward;

fig. 19 is a perspective view of the setting tool of fig. 4 and 5, shown with its hole outer end forward most;

FIG. 20 is a perspective view of the outer end of the bore of the setting tool of FIG. 18, the outer end of the bore being shown to a larger scale; and is also provided with

Fig. 21 is a cross-sectional perspective view of the setting tool of fig. 19.

In the drawings, like reference numerals are used to identify like parts.

Detailed Description

Other features of the invention are more fully described in the following detailed description of several non-limiting embodiments. The detailed description is included merely for the purpose of illustrating the invention to those skilled in the art. The detailed description is not to be taken in a limiting sense of the broad summary, disclosure, or description of the invention (as set forth above).

An exemplary embodiment of a groutless expandable riser 10 in accordance with the present invention is shown in the drawings.

As shown particularly in fig. 1, riser 10 includes a delivery tube 12 and a swaged tube 14. The riser 10 is shown inserted into a pilot hole 16 in a rock wall 18.

The pilot hole 16 is typically formed into the formation 22, such as the tunnel face of a tunnel being constructed, by drilling or boring. Typically, the pilot hole 16 has an inner diameter of about 89mm and is shallow with a blind end 20 located less than 5m within the formation 22 as measured from the rock wall 18. Typically, the pilot holes are 2 to 4 meters long. The pilot holes 16 are arranged substantially horizontally and diverge from the longitudinal axis of the tunnel such that the pattern of pilot holes 16 evenly distributed around the advancing tunnel forms a substantially frustoconical ring having the widest extent from the forefront of the tunnel face.

The delivery tube 12 is elongated and has two externally threaded pin ends 30 and 32. Typically, the delivery tube 12 is in the form of a well casing tubing. Typically, the threads of the pin ends 30 and 32 are an API threat. Typically, the delivery tube 12 is made of schedule40 or SCH 80 grade carbon steel having an outer diameter of about 73mm and a length of about 2m to 4m, although other lengths may be used. The delivery tube 12 typically has a wall thickness of about 10 mm. The delivery tube 12 is not easily deformed or expanded radially outward under the operating pressure of the expandable riser 10. That is, the delivery tube 12 need not be malleable.

Swage tube 14 includes a tube 40 around which is formed an elastomeric cap, typically in the form of a vulcanized rubber cap 42. The rubber boot 42 and the portion of the tube 40 covered by the rubber boot 42 together constitute a swage seal 43 of the present invention. Swage tube 14 also has bore 44, a subterranean end 46, and a centralizer 48 positioned opposite subterranean end 46. Centralizer 48 is in the form of a box and is internally threaded to receive pin end 32 of delivery tube 12. Centralizer 48 typically has an outer diameter of about 86mm.

Typically, the tube 40 is made of a ductile metallic material, such as stainless steel, and the tube 40 is conventionally manufactured using grade 304 or 316 schedule 10 stainless steel. The ductility of the tube 40 is important to allow the swage seal 43 to expand radially outward into contact with the inner surface of the pilot hole 16, as described below.

Typically, tube 40 has an outer diameter of about 62 mm. Typically, the tube 40 is a tube having a circular cross-section with a constant internal dimension along its length. However, when the tube 40 expands, the expanded portion of the tube 40 has a larger cross-sectional area than the rest of the tube 40.

Typically, the rubber boot 42 is vulcanized and has a toothed (castellated) longitudinal cross-section. The teeth include repeated pairs of peaks and valleys, each peak and valley being substantially square or rectangular in cross-section, as shown in fig. 3. The teeth allow the rubber boot 42 to better conform to the shape of the interior of the pilot hole 16, thereby achieving a better seal with the formation 22 surrounding the swage tube 14. The teeth also enable better anchoring of the swage seal 43 into the pilot hole 16 because they provide higher frictional engagement of the swage seal 43 with the pilot hole 16. If the teeth and/or rubber cap 42 were omitted, the standpipe would tend to slide out of the pilot hole 16 even after the swage seal 43 radially expands. Typically, the rubber boot 42 is about 1200mm in length and about 10 to 15mm in thickness. A rubber boot 42 extends around the outer surface of the tube 40 adjacent its underground end 46. The outer diameter of the rubber boot 42 is about 86mm.

Typically, swaged tube 14 has a length of about 2 m.

Typically, the total length of the expandable riser 10 is about 4m to 6m, although other lengths may be used.

As shown in particular in fig. 3, riser 10 conventionally also includes an anchor coupling 50 that is threadably attached to the free end of delivery tube 12. The anchor coupling 50 is conventionally made of a metallic material, such as carbon steel or stainless steel. The coupling 50 has two flanges 52 that are disposed in opposite directions and each has a hole 54 that is sized for attachment of a delivery machine or drill rig (not shown) for maneuvering the riser 10 into and/or out of the formation 22.

Swage tube 14 is intended for use with an expanding setting tool, as shown in fig. 2 and 8, conventionally in the form of a swaged packer tool 60. Typically, swage packer tool 60 is an inflatable swage packer capable of inflation by a high pressure fluid (typically in the form of water or oil delivered by high pressure pump 61). Swage packer tool 60 is capable of operating at inflation pressures up to about 70 MPa. More specifically, swage packer tool 60 is operated at a fluid pressure of greater than about 50MPa to swage tube 14.

Swage packer setting tool 60 includes a top connector 62, a push rod 64, and an inflatable packer 66. As shown in fig. 2, 4 and 5, the top connector 62 generally has an outer diameter that is greater than the inner diameter of the delivery tube 12. The push rod 64 is of sufficient length to enable the placement of the inflatable packer 66 within the bore 44 of the rubber boot 42 of the swage tube 14. Typically, pushrod 64 is approximately 2.5m to 4.5m long.

Specifically, as shown in fig. 3 and 4, the top connector 62 has a central flow path 70 for high pressure inflation fluid flow to inflate the packer 66. The top connector 62 also has two lifting rings 72 for maneuvering the riser 10 via a lift. Typically, the top connector 62 is threaded to one end of the pushrod 64.

The push rod 64 is cylindrical and elongated and has a bore 76 for communicating fluid from the top connector 62 to the inflatable packer 66. Typically, pushrod 64 has an outer diameter of about 43mm and a wall thickness of about 9 mm.

The inflatable packer 66 includes a packer mandrel 80, conveniently in the form of a solid rod having a ferrule 82 at its upstream end and a ferrule 84 at its downstream end. The inflatable packer 66 also includes a packer element 86 secured between the ferrules 82 and 84, and a top sub 87 for connecting the inflatable packer 66 to an end of the push rod 64 opposite the top connector 62. The inflatable packer 66 also has an annular cavity 88 between the inner curved surface of the packer element 86 and the outer curved surface of the packer mandrel 80. The cavity 88 is in fluid communication with the pushrod 64 via an expansion passageway 90 in the top sub 87. The swellable packer 66 also has a sliding end fitting 92 that is threadably engaged with the ferrule 84. The sliding end fitting 92 is capable of sliding along the packer mandrel 80 to accommodate expansion of the packer element 86. The inflatable packer 66 also has various O-ring seals, represented in fig. 2 as small square black elements. An O-ring seal is required to allow the inflatable packer 66 to operate at inflation pressures up to about 70MPa without leakage.

The packer element 86 is conventionally made of a wire reinforced rubber material and is capable of expanding under inflation pressure and contracting once the inflation pressure is removed. The packer element 86 typically has an outer diameter of about 55mm and a thickness of about 20 mm. The packer element 86 is capable of supplying sufficient outward radial force to plastically deform the swage tube 14 to cause the swage tube 14 to expand radially outward into engagement with the interior of the pilot bore 16 proximate the blind end 20.

Typically, the packer element 86 has an effective length of about 1m, a non-expanded diameter of about 55mm, and an expanded diameter of about 75mm to 80 mm. That is, the packer element 86 can expand to more than about 130% of its original diameter, and more specifically to about 150% of its original diameter. In addition, the packer element 86 must be reusable a number of times and must be capable of contracting from its expanded diameter to about 100% of its original diameter. To achieve these specifications, the packer element 86 needs to have a unitary construction. The one-piece construction primarily requires that the packer element 86 be vulcanized to fuse its inner bladder, reinforcement and outer housing together into a single unit. The result of such fusion is that the fused components expand and contract as a single unit, which tends to make the packer element of unitary construction well suited for multiple inflation and deflation cycles, particularly at high differential pressures.

It should be noted that swage tube 14 is hollow and its bore 44 is in fluid communication with pilot hole 16. Thus, a grout hole 96 may be formed, such as by drilling, through the bore 44 of the swage tube 14 and into the formation 22 at the blind end 20 of the pilot hole 16 for delivering grout into the formation 22. The grout hole 96 has a blind end 98 remote from the riser 10. Typically, the grouting holes 96 have a length of 15m to 50m, more specifically 20m to 30m, for example about 25m, although other lengths may be used. The grout holes 96 are generally coaxial with the pilot holes 16.

The high pressure pump 61 is conventionally of a conventional type, such as is used to inflate a high pressure inflatable packer element with a liquid to a pressure of between about 40MPa and 70 MPa.

Using

In use, the riser 10 of the present invention is used in the construction of underground tunnels or other underground excavations, including underground mining and the like.

More generally, the groutless riser 10 of the present invention may be used in a variety of applications, including, but not limited to:

groundwater control in tunnelling and mining;

grouting before excavation;

grouting a high-pressure curtain;

underground exploration drilling; and

tunnel construction using a tunnel boring machine.

The method of operation of the riser 10 of the present invention is shown generally in fig. 7-9, and more particularly in fig. 10-16.

The grouting-free riser 10 of the present invention comprises the following operative steps:

drilling pilot holes 16 in the formation 22 (fig. 10);

inserting the riser 10 into the pilot hole 16 until the riser 10 approaches the depth of the blind end 20 of the pilot hole (fig. 10);

inserting a setting tool 60 into the riser 10 (fig. 11);

connecting the high-pressure pump 61 to the setting tool 60 (fig. 17);

expanding the packer element 86 to expand the swage seal 43 to anchor and seal against the interior of the pilot bore 16 without the need for grouting (fig. 12);

removing the setting tool 60 from the riser 10 and connecting the pump 61 to the riser 10 and pressure testing the riser 10 to ensure that injected liquid does not leak into the tunnel from between the riser 10 and the pilot hole 16 (fig. 13);

inserting a drill bit 100 through the riser 10 and drilling a grout hole 96 (fig. 14) into the formation 22;

the drill bit 100 is removed from the riser 10, the riser is connected to a grout pump (not shown), and grout is pumped through the riser 10 into the grout holes 96 and into the formation 22 surrounding the grout holes 96.

Further details of the above-described operating steps of riser 10 are as follows.

Pilot holes 16 are drilled into the rock wall 18 in the advancing face of the tunnel or around the perimeter of the tunnel, where it is desirable to inject grout into the formation 22 near the tunnel in order to consolidate and stabilize the formation 22. Typically, the pilot hole 16 is drilled to a depth of about 4m, wherein the riser 10 has a length of about 4 m.

It is recommended to ensure that there are no chips in the pilot hole 16 prior to insertion of the riser 10 that might otherwise become lodged in the riser 10 and inhibit insertion of the riser 10 and expansion of the swage seal 43.

Next, the riser 10 is inserted into the pilot hole 16 leaving a gap of between 150mm and 500mm with the blind end 20 of the pilot hole 16. In this arrangement, riser 10 is oriented with its swaged tube 14 and swaged seal 43 adjacent blind end 20.

The inflatable packer setting tool 60 is then inserted into the riser 10, wherein its inflatable packer element 86 is disposed within the bore 44 of the rubber boot 42 of the swage seal 43.

The end of the expanded swage packer tool 60 protruding from the riser 10 is then connected to a high pressure pump 61 via a shut off valve (not shown). The pump 61 is then turned on and water or oil, or other unset inflation fluid, is injected into the inflatable packer 66 at high pressure to inflate the packer element 86. Inflation causes the packer element 86 to expand and meet the inner curved surface of the swage seal 43. The water (or oil) pressure continues to increase to between about 40MPa and 70MPa, which causes the swage seal 43 to plastically deform and expand radially outward to contact the inner curved surface of the pilot hole 16. This expansion causes the rubber boot 42 of the swage seal 43 to anchor and seal into the pilot hole 16, which prevents the riser pipe 10 from being removed from the pilot hole 16 and prevents liquids such as groundwater from flowing out of the pilot hole 16 via the annular space between the delivery tube 12 and the pilot hole 16.

The pressure in the pump 61 is then reduced to deflate the packer element 86. The inflatable swage packer tool 60 may then be withdrawn from the riser 10. Swage seal 43 has been fully swaged into engagement with pilot hole 16 and is ready and ready for grouting operations into formation 22.

Next, pump 61 is connected to riser 10 and water or oil is pumped in to test whether any liquid leaks through swage seal 43 and exits pilot hole 16 via the annular space existing between delivery tube 12 and pilot hole 16. Swage seal 43 leak testing is typically performed when the pump delivers liquid up to 10 MPa. If there is no or little leakage, the riser is considered to have been sufficiently anchored and sealed into the pilot hole 16. If the amount of water leaking from the pilot hole 16 is not acceptable, another pilot hole 16 must be drilled, another riser pipe 10 inserted into the new pilot hole 16, swaged into sealing connection with the new pilot hole 16, and then pressure tested.

The process of inserting, expanding and removing swage tool 60 from riser 10 and pressure testing the seal integrity of the swage seal with pilot hole 16 typically takes less than 30 minutes.

When the riser 10 passes the pressure test, a grout hole 96 may then be drilled by passing a drill bit 100 through the bore 44 of the swaged tube 14 to drill into the formation 22 a distance of typically about 25 m.

It should be noted that there is no delay between the swaging of the swaged tube 14 and the drilling of the grout holes 96. This is in marked contrast to prior art risers that require grout to seal the riser into the pilot hole.

Next, a grout pump is threaded to the connector 50 and a grout source is provided for delivery into the formation 22 through the riser 10 and grout holes 96. Typically, for a 25 meter grout hole 96, a grout amount equal to about 4 tons is injected into the formation 22 in a single grouting operation of each riser 10.

Once the grouting operation has ended, the shut-off valve is turned to a closed position, which prevents the grouting from flowing out of the formation 22 through the bore hole of the riser 10. The pump may then be disconnected from the riser 10 and moved to another riser 10 for further grouting operations.

This delivery of grout has the effect of forming a portion of the grout curtain into the formation 22 adjacent the advancing tunnel.

Typically, many such riser installations are performed at each stage of the tunneling operation. The number of riser installations used typically varies between 4 and 16, depending on the condition of the formation 22 and the amount and pressure of water contained within the formation 22.

Once the grout in the curtain has cured and hardened, the tunneling operation may resume. Such curing typically requires a period of up to about 24 hours. It should be noted that the grout curtain extends about 25m in front of the current tunneling. Once the grout cures, tunneling may resume a distance of about 20 m. The tunneling distance is less than the grouting curtain to provide some safe working area for another series of risers to be installed around the tunnel to create another set of risers and grouting holes 96 to form another grouting curtain. By terminating the tunneling within the scope of the grouting curtain, further tunneling operations can be safely performed and water entering the tunnel is kept at a minimum level.

It should be noted that the riser 10 may be installed ahead of the tunnel advance during drilling and blasting operations. In this case, the riser 10 is destroyed during blasting and produced during excavation.

In a tunneling operation using a Tunnel Boring Machine (TBM), the riser 10 is installed around the tunnel such that the TBM cutting head does not strike steel of the riser 10.

It is contemplated that the pilot holes 16 and the grout holes 96 may be drilled with a machine such as a hydraulic drill or a drill carriage, or formed by other means.

It is contemplated that the shut off valves of the delivery tube 12 and riser 10 may be unscrewed from the swaged tube 14 after the grout curtain has set. In this manner, the pipe 12 and shut-off valve may be retrieved from the riser 12, cleaned to remove the grout set therein, and reused in subsequent tunneling operations.

Example

The following numbered examples are further embodiments of the present invention.

1. The riser 10 as described herein above, wherein the expansion tool is a high energy device (HERD) capable of rapidly expanding the swaged tube 14 into contact with the inner wall of the pilot hole 16.

2. The riser 10 as described in example 1, wherein the HERD is a high pressure liquid, such as water, that is explosively injected into the swaged tube 14.

3. The riser 10 as described in example 1, wherein the HERD is an explosive charge located in the bore 44 of the swage tube 14 and detonated to cause the swage tube 14 to expand into contact with the pilot hole 16.

4. A riser 10 as described in example 1, wherein a blowout preventer (BOP) is attached to an upstream end of the riser 10 for providing "wellhead control" by allowing management of high pressure groundwater encountered during subsurface exploration drilling, such as during mining or construction or tunneling. In this example, a drill-through blowout preventer and shut-off valve, as known in the art, are also required to control the flow of water from a borehole in the formation 22.

INDUSTRIAL APPLICABILITY

The groutless expandable riser 10 and method of use thereof of the present invention is suitable for injecting grout into a formation 22 to create a grout curtain to protect tunnel structures in the formation 22 and for stabilizing the formation 22 in underground mining operations and the like.

The groutless expandable riser 10 and the method of use thereof of the present invention exist and operate in the fields of civil and mechanical engineering, and in particular in the field of underground tunnel construction, and more particularly in the field of formation consolidation.

As a result of using the groutless expandable riser 10 of the present invention, no grouting is required to seal and anchor the riser into the pilot hole, and thus a tunnel can be constructed faster because the time to install the groutless expandable riser 10 is less than about 30 minutes compared to the length of up to about 24 hours required to grout a conventional riser into the pilot hole.

Reference numerals

The present specification uses the following reference numerals:

10. grouting-free expandable riser 61 high-pressure pump

12. Pipe 62 top connector

14. Swage tube 64 push rod

16. Guide hole 66 expansion type packer

18. The rock wall 70 central flow path

20. Blind end 72 lifting ring

22. Formation 76 borehole

30. Pin end 80 packer mandrel

32. Pin end 82 ferrule

40. Tube 84 ferrule

42. Rubber cover 86 packer element

43. Swaged seal 87 top joint

44. Bore 88 cavity

46. Expansion passage at the underground end 90

48. Centralizer 92 sliding end connector

50. Connector 96 grouting hole

52. Blind end of flange 98

54. Hole 100 rock drill

60. Swage packer tool

Advantages are that

The grouting-free expandable riser 10 and method of the present invention have the following advantages: they do not require grout to anchor and seal the riser 10 into the formation 22. This has the advantage of reducing the time to set the riser from as long as about 24 hours to less than about 30 minutes for prior art risers that require grouting. This time saving represents a significant cost saving in the excavation and construction process.

In addition, the delivery tube 12 and shut-off valve may be unscrewed from the swage tube 14 and retrieved for further and subsequent use after the grout curtain has cured, thereby further saving costs and avoiding the extension of risers into the excavation area.

The groutless expandable riser 10 and method of the present invention also has the following advantages: by attaching a blowout preventer (BOP) to the riser 10, a driller is allowed to control any high pressure water encountered during drilling (referred to as "wellhead control").

The groutless expandable riser 10 and method of the present invention has the following further advantages: the seal and anchor may be maintained without having to maintain pressure on the inflatable packer element or energy on the mechanical packer element. Sealing the riser into the pilot bore 16 using an inflatable or mechanical packer element has the following disadvantages: if they leak, high pressure water may be allowed to flow back into the tunnel area, which is dangerous.

The groutless expandable riser 10 and method of the present invention has the further advantage that it can withstand much higher groundwater pressure conditions than mechanical packer type risers.

The inflatable packer 66 of the groutless expandable riser 10 of the present invention has the following advantages: which can be reused when installing multiple risers, whereas prior art mechanical packers for setting prior art risers can only be used once, with one mechanical packer per prior art grout-sealed riser.

Modifications and variations

It should be understood that references herein to "one example" or "an example" of the invention, etc. (e.g., "such as") are not to be taken in an exclusive sense. Various substantially and specifically practical and useful exemplary embodiments of the claimed subject matter are described herein in text and/or graphics for use in performing the claimed subject matter.

Thus, one example may demonstrate certain aspects of the invention, while other aspects are demonstrated in a different example. These examples are intended to assist the skilled artisan in carrying out the invention and are not intended to limit the overall scope of the invention in any way, unless the context clearly indicates otherwise.

Any method steps, processes, and operations described herein should not be construed as necessarily requiring their performance in the particular order discussed or illustrated, unless specifically identified as an order of performance. It should also be understood that additional or alternative steps may be employed.

Variations (e.g., modifications and/or enhancements) of one or more embodiments described herein may be employed. For example, other grades of ductile metals may be used for the components of the groutless expandable riser 10. In addition, other sizes of the groutless expandable riser 10, pilot hole 16, and grouting holes 96 may be used. Other alternatives are also contemplated.

Claims

1. A method of anchoring and sealing an expandable riser into a formation, comprising the steps of:

forming shallow pilot holes in the formation;

inserting a majority of the expandable riser into the pilot hole; and

expanding the riser radially outwardly to anchor and seal into the pilot hole;

2. A method of grouting a subterranean formation with an expandable riser, the method of grouting a subterranean formation comprising the steps of:

forming shallow pilot holes in the formation;

inserting a majority of the expandable riser into the pilot hole;

expanding the riser radially outwardly to anchor and seal into the pilot hole;

forming a grout hole through the bore hole of the expandable riser into the formation ahead of the pilot hole; and

injecting grout into the formation through the riser and through the grout hole;

3. The method of claim 1 or claim 2, wherein the expandable riser further comprises a swage seal, and wherein the step of inserting the expandable riser into the pilot hole further comprises the step of positioning the swage seal near the blind end of the pilot hole.

4. The method of claim 3, wherein the step of positioning the expandable riser into the pilot hole leaves a space between 150mm and 500mm between the insertion end of the expandable riser and the blind end of the pilot hole.

5. A method as claimed in claim 3, wherein the step of expanding the riser includes the step of expanding the swage seal to anchor and seal the riser into the pilot hole.

6. The method of claim 1 or claim 2, wherein the step of forming the pilot hole comprises the step of making the length of the pilot hole about the same as the length of the expandable riser.

7. The method of claim 5, wherein the step of expanding the swage seal is performed with an inflatable packer.

8. The method of claim 5, wherein the step of expanding the swage seal is performed with a high energy device (HERD) capable of rapidly expanding the swage seal into contact with the inner wall of the pilot hole.

9. The method of claim 8, wherein high pressure liquid constitutes the HERD and is explosively injected into the swage seal to cause the swage seal to expand into contact with the pilot hole.

10. The method of claim 8, wherein an explosive charge forms the HERD and is located in a bore of the swage seal and detonated to cause the swage seal to expand into contact with the pilot hole.

11. A groutless expandable riser for anchoring and sealing into a pilot hole in a formation without grouting, the expandable riser being operable to pump grouting into a grout hole in the formation, the expandable riser comprising:

the swage tube is positionable in the pilot hole to a position proximate a blind end of the pilot hole, the swage tube being expandable radially outwardly with an inflatable packer element to contact the pilot hole; and

Wherein grout can be pumped into the grout hole through the elongated tube to stabilize the formation surrounding the grout hole.

12. The groutless expandable riser pipe of claim 11, wherein the swage seal has an elastomeric layer on its outer curved surface for conforming to the interior of the pilot hole.

13. The groutless expandable riser of claim 12, wherein the elastomeric layer has a toothed longitudinal cross section to better conform to the shape of the interior of the pilot hole.

14. The groutless expandable riser of claim 11, further comprising an expansion tool for expanding the swaged seal.

15. The groutless expandable riser of claim 14, wherein the expansion tool comprises an inflatable packer.

16. The groutless expandable riser of claim 15, wherein the inflatable packer has a unitary structure and is capable of multiple inflation and deflation for insertion into or removal from the swage seal.

17. The groutless expandable riser of claim 15, wherein the inflatable packer is expandable to at least 130% of its original diameter, and wherein the inflatable packer is capable of collapsing from its expanded diameter to about 100% of its original diameter.

18. The groutless expandable riser of claim 14, wherein the expansion tool is a high energy device (HERD) capable of rapidly expanding the swaged seal into contact with the inner wall of the pilot hole.

19. The groutless expandable riser of claim 18, wherein the HERD is a high pressure liquid that is explosively injected into the swaged seal.

20. The groutless expandable riser of claim 18, wherein the HERD is an explosive charge located in a bore of the swage seal and detonated to cause the swage seal to expand into contact with the pilot hole.

21. A groutless expandable riser system for pumping grout into grout holes formed in a subterranean formation, the expandable riser system comprising: