Rotary drill head for coiled tubing drilling apparatus

Abstract

A mobile, coiled tubing drilling apparatus with a rotary drill head, includes a non-rotating mast on a mobile platform. The mast has mounted thereon an injector below a coiled tubing reel. The injector defines an operational axis for the coiled tubing. The rotary drill head is pivotally mounted on the injector so as to be movable between a retracted position away from the operational axis and an operating position in line with the operational axis. The rotary drill head includes a top swivel for non-rotating connection to the coiled tubing and a bottom spindle for rotating connection to a pipe section. The top swivel and the bottom spindle provide fluid communication between connected coiled tubing and connected pipe section during operation.

Claims

1. A mobile, coiled tubing drilling apparatus with a rotary drill head, the apparatus including a non-rotating mast on a mobile platform, the mast having mounted thereon an injector below a coiled tubing reel, the injector defining an operational axis for the coiled tubing, wherein the rotary drill head is pivotally mounted on the injector so as to be movable between a retracted position away from the operational axis and an operating position in line with the operational axis, the rotary drill head including a top swivel for non-rotating connection to the coiled tubing and a bottom spindle for rotating connection to a pipe section, the top swivel and the bottom spindle providing fluid communication between connected coiled tubing and connected pipe section during operation.

2. Apparatus according to claim 1, including elongate arms mounted at one end to the injector for pivotal movement and at the other end to opposing sides of the rotary drill head, so as to allow movement of the drill head between the retracted position and the operating position.

3. Apparatus according to claim 1, wherein movement of the drill head between the retracted position and the operating position is achieved by a hydraulic ram mounted between the injector and the drill head.

4. Apparatus according to claim 1, wherein the top swivel is fixed with a bottom portion thereof received within an upper portion of a main shaft in a manner that permits the swivel to move axially within the upper portion and the main shaft to rotate relatively to the swivel.

5. Apparatus according to claim 4, wherein the main shaft is floating to allow for axial movement thereof while pipe section is connected to the bottom spindle.

6. Apparatus according to claim 1, the coiled tubing reel having a tubing pay-off point associated therewith, and a tubing control system, wherein: the tubing control system is between the reel and the injector, and includes a tubing abutment adjacent the tubing pay-off point for applying an opposite bend to the tubing during pay-out of the tubing; and the reel is mounted for horizontal (x,y) movement such that, during pay-out of the tubing, the tubing pay-off point can be maintained generally above the injector, and can also be moved towards or away from the tubing abutment.

7. Apparatus according to claim 1, wherein the reel is mounted for horizontal (x,y) movement such that, during pay-out of the tubing, the tubing pay-off point can be maintained generally above the injector but away from the injector's operational axis.

8. Apparatus according to claim 7, wherein the reel is mounted for horizontal (x,y) movement such that, during take-up of the tubing, the tubing take-on point can be maintained directly above the injector at a point along the injector's operational axis.

9. Apparatus according to claim 1, wherein the tubing control system also includes an adjustable tubing straightener after the tubing abutment and before the injector.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) Having briefly described the general concepts involved with the present invention, a preferred embodiment of a mobile coiled tubing drilling apparatus will now be described that is in accordance with the present invention. However, it is to be understood that the following description is not to limit the generality of the above description.

(2) In the drawings:

(3) FIG. 1 is a perspective view from above of a mobile, coiled tubing drilling apparatus in accordance with a preferred embodiment of the present invention, deployed in its drilling position;

(4) FIG. 2 is a side view of the apparatus of FIG. 1 in a transport position;

(5) FIGS. 3(a) and 3(b) are schematic side views of the mast and reel of the apparatus of FIG. 1 when in tubing pay-out mode (FIG. 3(a)) and tubing take-up mode (FIG. 3(b));

(6) FIGS. 4(a) and 4(b) are schematic top views of a preferred reel mounting configuration for use with the apparatus of FIG. 1 when in tubing pay-out mode (FIG. 3(a));

(7) FIGS. 5(a) and 5(b) are perspective and side views of an embodiment of a rotary drill head pivotally mounted on an injector, being suitable for use with the apparatus of FIGS. 1 to 4, showing the rotary drill head in its retracted position away from the operational axis (in the first mode of operation for the drilling apparatus);

(8) FIG. 6 is a perspective view similar to FIG. 5(a) but showing the rotary drill head in its operating position in line with the operational axis (in the second mode of operation for the drilling apparatus); and

(9) FIG. 7 is a section view through the rotary drill head of FIG. 5(a).

DETAILED DESCRIPTION

(10) Illustrated in FIG. 1 is a mobile, coiled tubing drilling apparatus 10 in its upright drilling position, while FIG. 2 shows the same apparatus 10 in its lowered transport position. 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, an injector 18 (with injector guide rollers 19) and a tubing control system in the form of an elongate tubing abutment 20. As will be better understood from the following description, point A in FIG. 1 is a point on the reel and is the general location of both a tubing pay-off point and a tubing take-up point (referred to later as A′).

(11) The vertical axis mentioned above is designated in FIG. 1 as the z axis in the identified x-y-z coordinate system, with the x axis (or x direction) being the direction of movement for the tubing pay-off point A (and thus also the reel 16) towards and away from the tubing abutment 20. The y axis (or y direction) is then the direction of movement for the tubing pay-off point A (and again also the reel 16) along the longitudinal axis of the reel 16. It will be appreciated that references to pay-off and take-up of the tubing are references to the first mode of operation of the apparatus, utilising the coiled tubing as the primary drilling means.

(12) The mobility of the platform 14 is provided in this embodiment by a continuous track propulsion system 15, while much of the ancillary drilling equipment provided on 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 FIG. 1 and FIG. 2 for ease of illustration. Additionally, in this embodiment, the reel 16 is mounted on the mast 12 for vertical (z) movement by way of the mast 12 having a telescoping configuration (not shown).

(13) As mentioned above, such vertical movement of the reel 16 is advantageous in providing for relatively small vertical movement of a drill bit (for example), located at the bottom of the tubing in a borehole, into and out of contact with the bottom of the borehole. This is in preference to such movement having to be provided by rotating the reel 16 to raise or lower the drill bit, which, if avoided, can further reduce the stresses placed on the tubing, further increasing the operating life of the tubing.

(14) The mast 12 of the apparatus 10 also includes, below the injector 18, a pivotally mounted, retractable, rotary drill head 22 (only partly shown) that can be used for drilling with a conventional rotating drill string in a second mode of operation. In this second mode, the apparatus 10 can be used to install casing or the like to the borehole, or to connect and disconnect the different elements of a bottomhole assembly, or simply to drill with a rotating drill string, using fluid provided through the coiled tubing, which will be described in more detail below with reference to FIGS. 5(a), 5(b), 6 and 7.

(15) Referring now to FIGS. 3a and 3b, the reel 16 can be seen mounted for horizontal (x,y) movement, with the x direction being left-right across the page and the y direction being into and out of the page, such that, during pay-out of the tubing 30, the tubing pay-off point A can be maintained generally above the injector 18 but away from the injector's operational axis, the operational axis being defined by the pathway through the injector 18 of the longitudinal axis of the tubing 30 therein.

(16) In this embodiment, the tubing control system of the apparatus 10 also includes an adjustable tubing straightener 32 after the tubing abutment 20 and before the injector 18, the tubing straightener 32 being adjustable such that it can engage tubing 30 entering or exiting the injector 18 and be utilised to provide more or less (or no) force to tubing 30 entering or exiting the injector 18. In this embodiment, the adjustable tubing straightener 32 is shown in FIG. 3(a) as being in engagement with the tubing 30 entering the injector 18 (during pay-out), but in FIG. 3(b) is shown not engaging with the tubing 30 exiting the injector 18 (during take-up), for reasons that will be outlined below. The adjustable straightener 32 is a single hydraulic powered roller configured to engage with tubing against a fixed abutment.

(17) The tubing abutment 20 is shown fixed with respect to the mast 12 so that the movement of the reel 16 to maintain the tubing 30 pay-off point A generally above the injector 18 during pay-out of the tubing 30 also positions the tubing pay-off point A adjacent the tubing abutment 20 so that the tubing 30 engages with the tubing abutment 20. As mentioned above, this engagement with the tubing abutment 20 places an opposite bend in the tubing 30 during pay-out (such a bend being “opposite” to the bend in the tubing 30 that already exists in the coiled tubing from it being coiled on the reel 16), which in this embodiment occurs before the tubing 30 passes through the adjustable tubing straightener 32 and the injector 18.

(18) The tubing abutment 20 is an elongate abutment beam, fixed generally vertically to the mast 12 with an upper end 20a and a lower end 20b, and with the upper end 20a being the end located above the tubing pay-off point A of the reel 16 during operation. The uncoiling tubing 30 engages with the abutment beam and is guided along the abutment beam to the adjustable straightener 32 and then to the injector 18 during pay-out of the tubing 30. The elongate abutment beam is substantially straight and elongate, and has a channel 36 therealong that is capable of receiving and guiding therealong tubing 30 from the reel 16.

(19) As mentioned above, the application of this opposite bend to the tubing 30 at a location closely adjacent to the tubing pay-off point A has been found to minimise stress on the tubing 30 (and thus increase the operational life of the tubing 30) while reasonably accurately aligning the tubing 30 with the adjustable tubing straightener 32 and the injector 18. The application of the opposite bend has also been found to reduce any residual plastic bend remaining in the tubing 30 before entering the borehole, assisting in avoiding subsequent difficulties with the control and direction of the borehole.

(20) In contrast, and referring to FIG. 3b which shows the re-coiling of the tubing 30 when the tubing 30 is being withdrawn from the borehole (not shown), the tubing 30 entering the injector 18 from below has of course already been straightened, and thus is not subjected to the same existing bend that is present with coiled tubing 30 being uncoiled (FIG. 3(a)). In this phase, the tubing abutment 20 is not utilised by the apparatus 10 during tubing take-up, and a tubing take-on point A′ (being essentially the same point during re-coiling as the tubing pay-off point A during uncoiling) is made as close as operationally possible to a point along the injector's operational axis, and thus will be directly above the injector 18.

(21) With reference to FIGS. 4(a) and 4(b), as mentioned above the reel 16 is mounted on the mast 12 for horizontal (x,y) movement such that the tubing pay-off point A can be maintained generally above the injector 18 during pay-out of the tubing 30 and such that the tubing take-on point A′ can be maintained directly above the injector 18 during take-up of the tubing 30.

(22) In this respect, and identifying movement in the x direction as being movement of the reel towards and away from the mast 12 (left and right on the page), and movement in the y direction as being movement of the reel 16 along its own longitudinal axis (axis Y-Y in FIGS. 4(a) and 4(b)), the x direction movement is provided by mounting the reel 16 on the mast 12 via pivoting arms 40 that are controlled to pivot towards and away from the mast 12.

(23) Such pivoting movement therefore moves the entire reel 16 towards and away from the mast 12 (as required, either before, during or after drilling) and thus towards and away from the tubing abutment 20. Mounting the reel 16 in this manner provides for movement of the longitudinal axis Y-Y of the reel 16 towards and away from the tubing abutment 20, and of the coiled tubing 30a, 30b on the reel 16 towards and away from the tubing abutment 20, and thus of the pay-off point A of the tubing towards and away from the tubing abutment 20.

(24) Indeed, during drilling, this movement permits the tubing 30a. 30b at the pay-off point A to be continually urged towards and against the tubing abutment 20 as the tubing 30a, 30b uncoils from the reel 16 and as the diameter of the tubing 30a, 30b coiled on the reel 16 decreases, as is shown from FIG. 4(a) where the reel 16 is full of tubing 30a through to FIG. 4(b) where the tubing 30b is almost entirely unwound from the reel 16.

(25) In this respect, it will be appreciated that the pay-off point A of the tubing 30a, 30b will move along the longitudinal axis Y-Y of the reel 16 as the reel rotates about its longitudinal axis Y-Y and as the tubing 30a, 30b uncoils. With the reel 16 being adapted to provide for continual adjustability of the reel 16 along its longitudinal axis Y-Y, the reel can be moved in the y direction in response to the pay-off point A moving in the y-direction, thus keeping the pay-off point A adjacent to the tubing abutment 20 as required, and also keeping the tubing 30a, 30b at that point in engagement with the tubing abutment 20 to apply the requisite opposite bend thereto.

(26) FIGS. 5(a), 5(b), 6 and 7 illustrate an embodiment of a rotary drill head 22 pivotally mounted on an injector 18, being suitable for use with the apparatus of FIGS. 1 to 4, showing the rotary drill head in its retracted position (FIGS. 5(a) and 5(b)) away from the operational axis (in the first mode of operation for the drilling apparatus, as described above) and in its operating position (FIGS. 6 and 7) in line with the operational axis (in the second mode of operation for the drilling apparatus, as will now be described.

(27) FIG. 5(a) illustrates the use of elongate arms 50 mounted at one end 52 to the injector 18 for pivotal movement and at the other end 54 to opposing sides of the rotary drill head 22, so as to allow movement of the drill head 22 between the retracted position of FIGS. 5(a) and 5(b) and the operating position of FIG. 6.

(28) FIG. 5(b) also shows that movement of the drill head 22 between the retracted position and the operating position is achieved by a hydraulic ram 56 mounted between the injector 18 and the drill head 22.

(29) The second mode of operation illustrated in FIGS. 6 and 7 is a rotating drill string mode where the coiled tubing 30c connects to a top swivel 60 of the rotary drill head 22 and moves no further than that, while pipe sections (not shown) are connected to a bottom spindle 62 of the drill head 22 forming therebelow a rotating drill string. In this respect, the swivel 60 is fixed and does not itself rotate, with the bottom portion thereof being received within the upper portion 63 of the main shaft 64 in a manner that permits the swivel 60 to move axially within the upper portion 63 and the main shaft 64 to rotate relatively to the swivel 60, while maintaining a suitable fluid/air seal therebetween.

(30) Of course, the main shaft 64 is powered by hydraulic motors 65 connected thereto via gears, providing rotation for the bottom spindle 62. The main shaft 64 can be floating to allow for axial movement thereof while, for example, drill rods are being threaded onto the spindle 62.

(31) Fluid communication is provided between the connected coiled tubing 30 and the connected pipe sections (not shown) during operation to permit drilling fluid to be provided for drilling via the coiled tubing 30, through the bore of the top swivel 60, through the hollow drive shaft 64, and through the bore of the bottom spindle 62, there thus being no need to provide alternative fluid handling equipment or an alternative fluid source. By pivotally mounting the rotary drill head 22 on the injector 18, the rotary drill head 22 may be moved out of the way of the coiled tubing 30 during the first mode of operation and may be moved back into an operational position for this second mode of operation.

(32) Finally, there may be other variations and modifications made to the configurations described herein that are also within the scope of the present invention.