Mobile coiled tubing drilling apparatus

Abstract

A mobile, coiled tubing drilling apparatus, the apparatus including a non-rotating mast on a mobile platform, the mast having mounted thereon a coiled tubing reel, an injector having a mounting allowing the injector to rotate or move in and out of a borehole centreline, and a tubing control system, wherein the tubing control system is between the reel and the injector. The reel is mounted for rotation such that, during movement of the injector, the tubing can be maintained generally above the injector, and the injector and reel can be simultaneously moved away from the borehole centreline such that loads can be loaded in and out of the borehole using a lifting arrangement such as a winch located above the injector.

Description

MOBILE COILED TUBING DRILLING APPARATUSFIELD OF THE INVENTION

[0001] The present invention relates to a mobile coiled tubing drilling apparatus.

[0002] In particular, the present invention relates to a mobile coiled tubing drilling apparatus primarily for use in drilling for surface boreholes and wells such as geothermal wells, where the coiled tubing is not required to rotate about its longitudinal axis in order for the drilling apparatus to operate.BACKGROUND OF THE INVENTION

[0003] Geothermal well drilling historically uses rotating drill strings (being a series of attached rigid pipe sections), with drill bits attached at one end to drill subterranean holes in an effort to drill boreholes for installation of tubing for heat extraction or displacement. As the rotating drill bit drills into the earth to form a borehole, additional pipe sections are added in order to drill deeper, while the opposite occurs as the drill bit is withdrawn from the borehole. A significant amount of time and energy (and therefore cost) is consumed in adding and removing these pipe sections to assemble and disassemble drill strings during drilling.

[0004] Coiled tubing has been developed as an alternative to the use of drill strings (albeit typically for use in the oil industry, not for geothermal well drilling). The coiled tubing is typically a ductile metal available in virtually unlimited lengths. The use of coiled tubing involves the uncoiling of a tube from a reel carrying such tubing, typically by an injector located above located close to a borehole, the injector being responsible for raising and lowering the tubing. The reel is typically located horizontally away from the injector and the borehole, with a curved guide (often referred to as a ‘gooseneck’) used between the reel and the injector to guide the tubing from the reel across the apparatus to the injector. An example of this is illustrated in Figure 6 of US Publication No. 2013 / 03341001 A1.

[0005] In most coiled tubing drilling, a bottom hole assembly (BHA) located at thebottom of the tubing typically includes a mud motor that powers and rotates a drill bit (given that the coiled tubing does not itself rotate), the mud motor being powered by the motion of drilling fluid pumped from the surface. In other forms of coiled tubing drilling, above-ground apparatus has been developed to allow for the rotation of the coiled tubing about its longitudinal axis. Needless to say, substantial and complex above-ground apparatus is required to be able to rotate an entire reel of coiled tubing to achieve such rotation of the tubing, and the present invention does not relate to rotating coiled tubing drilling of this type.

[0006] US Patent No. 7,284,618 (“Geddes et al”) is a prior art example of a nonrotating coiled tubing drilling apparatus. Geddes et al describes a difficulty with the use of many types of coiled tubing apparatus, namely the problem of bend related stresses causing fatigue in the ductile metal tubing as a result of the uncoiling and recoiling of the tubing on the reel. Geddes et al also points out that the traditional horizontally spaced location of a reel with respect to an injector, and the consequent use of one or more goosenecks to guide the tubing to the injector adds to the number of bend events experienced by the tubing. This significantly shortens the life of the tubing, requiring the reel to be replaced reasonably often, resulting in increased costs due to down time and reel and tubing replacement.

[0007] The solution offered by Geddes et al is to locate a reel on a movable cart vertically spaced from an injector, with the reel pay-off point of the tubing thus located directly above the injector. The movable cart of Geddes et al can then be actively positioned during operation by an automated control system and positioning means as the tubing uncoils from the reel, so that once the tubing is off the reel there are no further bend events. The aim of Geddes et al is thus to only have one bend event (namely the uncoiling of the tubing from the reel and its direct entry into the injector) during drilling, and one bend event (the tubing being recoiled after passing out from the injector) during withdrawal of the tubing from the borehole.

[0008] The automated control system of Geddes et al is a system that monitors the position of the tubing entering the injector and then moves the movable cart, in response to the tubing moving away from centre, to return the tubing to centre. The teaching of Geddes et al is thus to avoid applying force to the tubing between its pay- off point and the injector during both uncoiling of the tubing (during entry to theinjector) and recoiling of the tubing (during exit from the injector), so as to reduce to an absolute minimum the bend events on the tubing.

[0009] However, Geddes et al has failed to recognise the impact of also being able to moving the injector, and thus the Geddes et al apparatus do not offer access to the borehole from above the injector when the coiled tubing is retracted out of the borehole and the injector, reel and tubing is shifted aside to provide a clear passage for tools, bottom hole assembly, instruments and drill rods to be lowered in and hoisted out of the borehole. In prior art publication number WO 2018 / 132861 (“Soe”), a mobile coiled tubing drilling apparatus is disclosed attempting to alleviate the issues faced by Geddes et al. However, Soe also fails to recognise the impact and issues arising from being unable to move the injector, leading to increased operational time and costs when loads need to be raised or lowered into and out of the borehole. The invention disclosed in Soe would require the entire drilling apparatus to be moved in order to allow unrestricted access to the borehole from above.

[0010] Before turning to a summary of the present invention, it must be appreciated that throughout this description, terms such as “horizontal” and “vertical”, “upper” and “lower”, and “before” and “after” will be used. It should be understood that these and other similar orientation-type descriptive terms are made in relation to the orientation of an operational drill rig, which would normally be located on a reasonably flat (and thus horizontal) surface at ground level, and with respect to a normal tubing pathway on and off a reel and down and up a borehole. The terms are not, however, intended to bring operational limitations, or a requirement for parts of the apparatus to be perfectly horizontal or perfectly vertical.

[0011] It would thus be desirable to provide an improved mobile coiled tubing drilling apparatus. It is therefore an object of the present invention to overcome or ameliorate a problem of the prior art or at least provide the public with a useful alternative.

[0012] Any reference to background or related art, including to any documents, herein is intended to facilitate an understanding of the present disclosure only and shall not be considered as an admission that such background or related art formspart of the prior art, or that such background or related art is widely known or forms part of the common general knowledge in the relevant field in Australia or in any other country.SUMMARY OF THE INVENTION

[0013] According to an aspect of the invention, there is provided an apparatus for use as a ladder, the apparatus comprising: a mobile coiled tubing drilling apparatus, the apparatus comprising a non-rotating mast on a mobile platform, the mast having mounted thereon an injector, and coiled tubing reel comprising tubing, wherein: the injector, reel, and tubing are configured to be able to be shifted towards and / or away from a centreline of a borehole, thereby providing a clear line of sight or passage for loads to be lowered into and raised out of the borehole without intersecting the injector, reel, or tubing; the reel, injector and tubing configured for movement such that, during hoisting in or out of the borehole, the reel, injector, and tubing can be maintained generally away from the borehole centreline; and the reel, injector, and tubing configured for movement to allow the reel, injector, and tubing to be maintained generally above the borehole centreline when the apparatus is in operation.

[0014] In an embodiment, the mobile coiled tubing drilling apparatus further comprises a winch attached to the mast, wherein the winch is configured to raise and lower loads into and out of the borehole when the tubing, reel and injector are shifted away from the borehole.

[0015] In an embodiment, the winch is pivotally attached to the mast.

[0016] In an embodiment, a weight is attached to the winch.

[0017] In an embodiment, the mobile coiled tubing drilling apparatus comprises a tubing straightener located above the injector.

[0018] In an embodiment, the mast is a telescoping mast.

[0019] According to a second aspect of the invention, there is provided a method of operating a mobile, coiled tubing apparatus, the apparatus comprising a nonrotating mast on a mobile platform, the mast having mounted thereon an injector, a coiled tubing reel comprising tubing, wherein the injector, reel, and tubing are adapted to be able to be shifted towards and away from a centreline of a borehole; wherein when the apparatus is in operation, the injector, reel, and tubing are maintained above the borehole centreline; and wherein a load is required to be raised or lowered into the borehole, the injector, reel, and tubing are shifted away from the borehole centreline allowing for loads to be raised or lowered into or out of the borehole.

[0020] In an embodiment of the second aspect, the mobile coiled tubing apparatus comprises a winch attached to mast for raising and lowering loads into and out of the borehole.

[0021] In an embodiment of the second aspect, the winch is pivotally attached to the mast.

[0022] In an embodiment of the second aspect, the mobile coiled tubing apparatus comprises a tubing straightener located above the injector.

[0023] In an embodiment of the second aspect, the mast of the mobile coiled tubing apparatus is a telescoping mast.

[0024] It should be noted that any one of the aspects mentioned above may include any of the features of any of the other aspects mentioned above and may include any of the features of any of the embodiments described below as appropriate.BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The above and further features of the present disclosure are more fully described in the following description of several non-limiting embodiments thereof. This description is included for the purposes of exemplifying the disclosure. It shouldnot be understood as a restriction on the summary or description of the disclosure as set out above. The following description is made with reference to the accompanying drawings, in which like reference signs designate like parts and in which:Figure 1 provides a perspective view of a mobile coiled tubing drilling apparatus according to an embodiment of the invention;Figure 2 provides a perspective view of the embodiment of Figure 1 , having its injector, tubing, and reel shifted inwards for hoisting loads into and out of a drilled hole;Figure 3 provides a front view of the mobile coiled tubing drilling apparatus of Figure 1 ;Figure 4 provides a front view of the mobile coiled tubing drilling apparatus of Figure 2;Figure 5 provides a side view of the mobile coiled tubing drilling apparatus of Figure 1 ; andFigure 6 provides a side view of the mobile coiled tubing drilling apparatus of Figure 2.

[0026] The accompanying drawing figures are included to provide further understanding of the present disclosure and are incorporated in and constitute a part of this specification. The drawings illustrate particular embodiments of the disclosure and together with the description serve to explain the principles and operation thereof. Other embodiments of the disclosure and many of the attendant advantages will be readily appreciated as they become better understood with reference to the following detailed description.

[0027] It will be appreciated that common and / or well understood elements that may be useful or necessary in a commercially feasible embodiment are not necessarily depicted in order to facilitate a more abstracted view of the embodiments. It will also be understood that certain actions and / or steps in an embodiment of a method may be described or depicted in a particular order ofoccurrences while those skilled in the art will understand that such specificity with respect to sequence may not actually be required.DETAILED DESCRIPTION OF THE INVENTION

[0028] Illustrated in Figure 1 is a mobile, coiled tubing drilling apparatus 10 in its upright drilling position, while Figure 2 shows the same apparatus 10 with the injector 18 shifted. The apparatus 10 generally includes a mast 12 mounted on a mobile platform 14 in a manner such that the mast is not rotatable about a vertical axis when in its upright drilling position. The apparatus also includes a coiled tubing reel 16, and an injector 18 with injector guide rollers 19.

[0029] The vertical axis mentioned above is designated in Figure 1 as the z-axis in the identified coordinate system comprising an x-axis, y-axis, and z-axis. The x- and y-axes are designated as horizontal axes.

[0030] The mobility of the platform 14 is provided in this embodiment by a continuous track propulsion system 15 or alternatively mounted on another carrier such as but not limited to a truck, while most of the ancillary drilling equipment provided in the mobile platform (such as fluid pumps, air compressors, nitrogen purge systems, a diesel engine, hydraulic pumps and valves, and suitable control and operating systems) have been omitted from the figures for ease of illustration. Additionally, in this embodiment, the reel 16 is mounted on the mast 12 for vertical (z-axis) movement by way of the mast 12 having a telescoping configuration (not shown).

[0031] As illustrated in Figure 2, the reel 16 may be rotated about the y-axis. Rotation of the reel 16 is simultaneously accompanied by a shifting of the injector 18 and straightener 32 along the x-axis, thereby shifting the injector away from or aligning with the centreline of a drilled borehole. The injector 18 is attached to the mast 12 via a sliding guide 28 which facilitates x-axis shifting of the injector as desired. Such shifting of the injector may be facilitated by, but not limited to hydraulic power.

[0032] The reel 16 is configured to rotate about the y-axis through pivoting arms 40, such pivoting movement effecting a movement of the entire reel 16 towards andaway from the mast 12 (as required, either before, during, or after drilling). The pivoting arms 40 may be controlled to pivot towards and away from the mast 12, which occur simultaneously with the shifting of the injector 18 along the x-axis.

[0033] In an embodiment, shifting the injector, straightener, coiled tubing, and reel also makes space for a separate conventional rotation unit, such as a drilling head, to travel up and down the mast (not pictured). Such drilling heads are known in the art.

[0034] When the injector 18 is shifted or moved away from the centreline of the borehole, a clear passage providing access to the borehole is created allowing for the raising and lowering of tools, bottom hole assemblies, instruments, and drill rods into and out of the borehole. This presents the operator with significant cost reductions over the prior art, wherein significant time and inputs are required in adding and removing equipment, such as pipe sections, precisely into and out of the borehole during drilling.

[0035] In an embodiment the invention comprises an adjustable tubing straightener 32. The tubing straightener 32 being adjustable such that it can engage tubing 30 entering or exiting the injector 18 and utilised to provide more or less (or no) force to tubing 30 entering or exiting the injector 18. For example, the tubing straightener may be in engagement with the tubing 30 entering the injector 18 (during pay-out), and not in engagement with the tubing 30 when it is exiting the injector 18 (during take-up). The adjustable straightener 32 may be but is not limited to a single hydraulic powered roller configured to engage with tubing against a fixed abutment.

[0036] In an embodiment, the invention comprises a winch or hoist 26 pivotally attached to the mast 12 through a pivoting winch arm 24. The winch 26 is attached to the mast 12, and facilitates the raising and lowering of loads such as equipment, tools, bottom hole assemblies, instruments, drill rods and the like into and out of the borehole. The pivoting arm 24 allows the winch 26 to be positioned directly above the centreline of a borehole when the injector 18, reel 16 and tubing 30 is pivoted away, such that any loads may be freely raised or lowered into and out of the borehole without abutting the coiled drilling apparatus.

[0037] The winch can be powered hydraulically or utilise a drum or lift-wheel with a wrapped rope or chain to raise and lower loads. However, it should be understood that the invention is not limited to these specific hoist types, and other hoist arrangements commonly known in the field may also be employed.

[0038] In an embodiment, attached to the winch 26 is a weight, such cylindrical steel bar, commonly referred to as a ‘stinger’ 27. A common scenario for using the stinger 27 is in closed-loop geothermal systems which utilise pipes and fitting buried in the ground, which involves the installation of U-shaped pipes. It is common to find boreholes drilled in these systems to be partially or significantly full of water. The stinger 27 acts as a weight, adapted to be attached to the centre vacant section of a U-shaped pipe, acting to assist in lowering the pipe to the bottom of the drilled borehole. It is to be understood that the stinger 27 is not limited to assisting in installation of U-shaped pipes, and may be employed to facilitate the installation or lowering of any tools, instruments, or loads into the borehole at any stage.

[0039] The winch 26 may be pivoted towards the centre of the borehole through pivoting arm 24, creating a clear opening to the centreline of the borehole. This similarly allows for the raising and lowering of tools, bottom hole assemblies, instruments, and drill rods into and out of the borehole. This presents the operator with significant cost reductions over the prior art, wherein significant time and inputs are required in adding and removing equipment, such as pipe sections, into and out of the borehole during drilling.

[0040] In an embodiment, the winch may not be mounted on a swing arm 24, but instead directly mounted onto the mast 12 right above the borehole and above the injector. This embodiment still allows for any raising and lowering of tools into and out of the borehole without intersecting the shifted injector, tubing, and reel.

[0041] In another embodiment, the winch may instead be located external of the mobile coiled tubing drilling apparatus 10. The winch may instead be an external crane, or may be located on a separate logging truck. These embodiments still allow for the raising and lowering of tools into and out of the borehole without intersecting the shifted injector, tubing, and reel.

[0042] In all embodiments of the invention, the hoist or winch allows for the liftingand lowering of loads into and out of the borehole without requiring the apparatus 10 to be moved.

[0043] Although specific embodiments of the invention are illustrated and described herein, it will be appreciated by persons of ordinary skill in the art that a variety of alternative and / or equivalent implementations exist. It should be appreciated that each exemplary embodiment is an example only and is not intended to limit the scope, applicability, or configuration in any way. Rather, the foregoing summary and detailed description will provide those skilled in the art with a convenient road map for implementing at least one exemplary embodiment, it being understood that various changes may be made in the function and arrangement of elements described in an exemplary embodiment without departing from the scope as set forth in the appended claims and their legal equivalents. Generally, this application is intended to cover any adaptations or variations of the specific embodiments discussed herein.

[0044] It will also be appreciated that, unless the context requires otherwise, the terms "comprise", "comprising", "include", "including", "contain", "containing", "have", "having", and any variations thereof, used in this document are intended to be understood in an inclusive (i.e. non-exclusive) sense, such that the process, method, device, apparatus, or system described herein is not limited to the features, integers, parts, elements, or steps recited but may include other features, integers, parts, elements, or steps not expressly listed and / or inherent to such process, method, device, apparatus, or system. Further, the terms "a" and "an" used herein are intended to be understood as meaning one or more unless explicitly stated otherwise. Moreover, the terms "first", "second", "third", etc. are used merely as labels, and are not intended to impose numerical requirements on or to establish a certain ranking of importance of their objects. In addition, any reference to positional terms, such as “lower” and “upper”, used in the above description are to be taken in context of the embodiments depicted in the figures, and are not to be taken as limiting the invention to the literal interpretation of the term but rather as would be understood by the skilled addressee in the appropriate context.

[0045] The phrase “and / or”, as used herein in the specification and in the claims, should be understood to mean “either or both” of the elements so conjoined, i.e.,elements that are conjunctively present in some cases and disjunctively present in other cases. Multiple elements listed with “and / or” should be construed in the same fashion, i.e., “one or more” of the elements so conjoined. Other elements may optionally be present other than the elements specifically identified by the “and / or” clause, whether related or unrelated to those elements specifically identified. Thus, as a non-limiting example, a reference to “A and / or B”, when used in conjunction with open-ended language such as “comprising” can refer, in one embodiment, to A only (optionally including elements other than B); in another embodiment, to B only (optionally including elements other than A); in yet another embodiment, to both A and B (optionally including other elements); etc.LIST OF COMPONENTS

[0046] The drawings refer to the following reference numerals:10 mobile coiled tubing drilling apparatus12 mast14 mobile platform15 track propulsion system16 reel18 injector19 injector guide rollers24 winch arm26 winch27 stingerinjector guide track coiled tubing tubing straightener pivoting arms

Claims

CLAIMS1. A mobile coiled tubing drilling apparatus, the apparatus comprising a nonrotating mast on a mobile platform, the mast having mounted thereon an injector, and coiled tubing reel comprising tubing, wherein: the injector, reel, and tubing are configured to be able to be shifted towards and / or away from a centreline of a borehole, thereby providing a clear line of sight or passage for loads to be lowered into and raised out of the borehole without intersecting the injector, reel, or tubing; the reel, injector and tubing configured for movement such that, during hoisting in or out of the borehole, the reel, injector, and tubing can be maintained generally away from the borehole centreline; and the reel, injector, and tubing configured for movement to allow the reel, injector, and tubing to be maintained generally above the borehole centreline when the apparatus is in operation.

2. The apparatus according to claim 1 further comprising a winch attached to the mast, wherein the winch is configured to raise and lower loads into and out of the borehole when the tubing, reel and injector are shifted away from the borehole.

3. The apparatus according to claim 1 wherein the winch is pivotally attached to the mast.

4. The apparatus according to claims 2 or 3, wherein a weight is attached to the winch.

5. The apparatus according to any of the previous claims, further comprising a tubing straightener located above the injector.

6. The apparatus according to any of the previous claims, wherein the mast is a telescoping mast.

7. A method of operating a mobile, coiled tubing apparatus, the apparatus comprising a non-rotating mast on a mobile platform, the mast having mounted thereon an injector, a coiled tubing reel comprising tubing, wherein the injector, reel, and tubing are adapted to be able to be shifted towards and away from a centreline of a borehole; wherein when the apparatus is in operation, the injector, reel, and tubing are maintained above the borehole centreline; and wherein a load is required to be raised or lowered into the borehole, the injector, reel, and tubing are shifted away from the borehole centreline allowing for loads to be raised or lowered into or out of the borehole.

8. The method of claim 7, wherein the mobile coiled tubing apparatus comprises a winch attached to mast for raising and lowering loads into and out of the borehole.

9. The method of claim 8, wherein the winch is pivotally attached to the mast.

10. The method of claims 7-9, wherein the mobile coiled tubing apparatus comprises a tubing straightener located above the injector.

11. The method of claims 7-10, wherein the mast of the mobile coiled tubing apparatus is a telescoping mast.

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