U.S. patent application number 11/689279 was filed with the patent office on 2007-09-27 for apparatus and method for forming stands.
This patent application is currently assigned to Saxon Energy Services Inc.. Invention is credited to Tim Braun, Kevin Jonah.
Application Number | 20070221385 11/689279 |
Document ID | / |
Family ID | 38520916 |
Filed Date | 2007-09-27 |
United States Patent
Application |
20070221385 |
Kind Code |
A1 |
Braun; Tim ; et al. |
September 27, 2007 |
Apparatus and Method for Forming Stands
Abstract
A catwalk apparatus for forming stands from individual tubulars
comprises a frame having a top surface adapted to receive tubulars.
The apparatus also includes a skate mechanism capable of pushing
and pulling the tubulars once loaded on the apparatus. The
apparatus is adapted to receive at least two tubulars in a coaxial
arrangement. The apparatus includes a rotating means for oppositely
rotating the tubulars along their longitudinal axes. The skate
mechanism is used to advance the tubulars together during rotation
so as to allow cooperatively threaded ends of the tubulars to
engage thereby forming a stand. The skate mechanism is also used to
urge the stand towards the drill rig for subsequent hoisting and
orienting vertically. A method and system for forming tubulars is
also provided.
Inventors: |
Braun; Tim; (Calgary,
CA) ; Jonah; Kevin; (Calgary, CA) |
Correspondence
Address: |
BLAKE, CASSELS & GRAYDON LLP
BOX 25, COMMERCE COURT WEST
199 BAY STREET, SUITE 2800
TORONTO
ON
M5L 1A9
CA
|
Assignee: |
Saxon Energy Services Inc.
Calgary
CA
|
Family ID: |
38520916 |
Appl. No.: |
11/689279 |
Filed: |
March 21, 2007 |
Current U.S.
Class: |
166/379 ;
166/380; 166/77.51 |
Current CPC
Class: |
E21B 19/155
20130101 |
Class at
Publication: |
166/379 ;
166/380; 166/077.51 |
International
Class: |
E21B 19/16 20060101
E21B019/16 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 21, 2006 |
CA |
2,540,820 |
Claims
1. A method of forming a stand from tubulars comprising: providing
a supply of tubulars; providing an elongate stand forming apparatus
comprising a front end, rear end and mid section; loading a first
tubular on the stand forming apparatus, wherein said first tubular
is positioned generally parallel therewith; pulling the first
tubular towards the rear end of the apparatus; loading a second
tubular on the stand forming apparatus, wherein said second tubular
is positioned generally parallel therewith and wherein the second
tubular is positioned in general coaxial alignment with said first
tubular; rotating said first and second tubulars about their
longitudinal axes and in opposite directions; advancing the first
tubular against the second tubular during said rotation whereby
cooperating threads on each opposing end of the first and second
tubulars are engaged to form a stand.
2. The method of claim 1 further comprising advancing the stand
towards the front end of the apparatus.
3. The method of claim 3 further comprising engaging the stand by a
hoist and lifting said stand into vertical alignment.
4. An apparatus for forming a stand from tubulars comprising: a
generally horizontal, elongate catwalk having a frame with a top
surface adapted to receive at least two of said tubulars aligned in
a coaxial manner, said frame having a front end, a rear end, and a
mid section; a pulling means adapted to grip and pull a first of
said tubulars towards the rear end of the catwalk; a pushing means
adapted to advance said first tubular to the front end of the
frame; a rotating means for rotating said tubulars about their
longitudinal axes.
5. The apparatus of claim 4 wherein said pulling means is adapted
to grip and pull a first tubular loaded on the catwalk.
6. The apparatus of claim 5 wherein said pushing means is adapted
to bear against the first tubular and to advance said first tubular
towards the front end of the catwalk.
7. The apparatus of claim 6 wherein said rotating means comprises
motor driven rollers.
6. The apparatus of claim 7 wherein said rollers are connected to
arms.
9. The apparatus of claim 8 wherein said arms are actuatable and
are capable of being raised and lowered with respect to the catwalk
frame.
10. The apparatus of claim 9 wherein said rollers are adapted to
rotate said at least two tubulars in opposite directions.
11. The apparatus of claim 9 wherein said catwalk front end is
inclined upwards.
12. The apparatus of claim 11 wherein said catwalk top surface
includes a groove to receive said tubulars.
13. The apparatus of claim 12 wherein said catwalk front and rear
ends are foldable over said mid section.
Description
CROSS REFERENCE TO PRIOR APPLICATIONS
[0001] This application claims priority from Canadian application
number 2,540,820, filed on Mar. 21, 2006, the entire contents of
which are incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The present invention relates to pipe handling apparatuses
and, more specifically, to apparatuses and methods for drilling
operations wherein stands are formed from tubulars.
DESCRIPTION OF THE PRIOR ART
[0003] Various ground drilling operations are known such as
exploring and/or extracting oil from subterranean deposits. The
drilling operation is conducted on a drill rig comprising a raised
drilling platform located above the drilling location. A denick is
provided on the platform to raise, support and rotate a drill
string. A drill string includes a drill bit for boring into the
ground. As the drilling operation continues, tubular members,
commonly referred to as "tubulars" are connected in an end to end
manner to form a drill string. Tubulars are commonly about 30 feet
in length and have opposing female and male ends. The ends are
threaded in a complementary manner so that opposing male and female
ends can be joined together.
[0004] The addition of a tubular to an existing drill string is a
relatively time consuming and dangerous procedure. Tubulars are
provided on a rack from which they are individually rolled onto a
horizontal support, such as a catwalk. Both the rack and catwalk
are generally located adjacent to the drilling platform with the
catwalk being generally positioned perpendicular to the platform.
Once on the catwalk, one end of the tubular is attached to a hoist
connected either directly of indirectly to the derrick and raised
to a vertical position on the drilling platform. The lower end of
the tubular is then oriented over the existing drill string and
connected to the terminal, surface end of thereof. Following
connection of the tubular to the drill string and "torquing" to
establish a tight connection, the drilling operation is continued.
As indicated above, tubulars are generally about 30 feet (10 m) in
length. As such, the frequency of adding tubulars to the drill
string is high and, therefore, the efficiency of the drilling
operation is hampered. In addition, the above described
manipulation of the tubulars often requires manual handling and,
therefore, increases the risks to the drill rig personnel.
[0005] Various apparatuses and methods have been proposed for
handling tubulars such as those provided in the following U.S. Pat.
Nos. 4,547,110; 4,486,137; 6,220,807; 6,705,414; 6,854,520;
6,969,223; 6,976,540; and 6,997,265. The entire disclosures of
which are incorporated herein by reference.
[0006] In order to increase the efficiency of the drilling
operation, various methods have been proposed to pre-connect at
least two tubulars, to form a "stand", prior to connection to the
drill string. Such a process is often referred to as
"standbuilding". As will be appreciated, such pre-connection step
involving two tubulars will reduce by half the number of
connections required to be made to the drill string and, therefore,
allows the drilling process to continue with fewer interruptions.
An example of such a standbuilding procedure is provided in related
U.S. Pat. Nos. 6,976,540 and 6,997,265. In these references, a
tubular is rolled from a rack onto a ramp positioned adjacent the
drilling platform. One end of the tubular is raised by a hoist to a
vertical orientation above the drilling platform. The tubular is
then inserted into an opening in the drilling platform adjacent to
the existing drill string. A further tubular is then vertically
hoisted and aligned above the first tubular. The opposing ends are
of the two tubulars are then connected together to form a vertical,
dual tubular stand. The stand is then raised and secured to the
drill string. During formation of the stand, the drilling operation
is continued without interruption.
[0007] Another example of a standbuilding operation is provided in
U.S. Pat. No. 6,705,414. In this reference, a stand is formed on a
horizontal catwalk associated with a drilling platform. According
to the disclosed method, two pairs of tubulars are positioned end
to end on the catwalk. A "bucking machine" is then used to join the
two tubulars. The bucking machine includes jaws that grasp and
axially rotate the tubulars in opposite directions so as to engage
the threads on the respective ends and to torque the connection to
the desired value. Two stands are formed in this manner, which are
then loaded onto a "trolley". The trolley, carrying the two stands,
is hoisted onto the drill rig platform and oriented vertically. The
stands are then removed from the trolley and either connected to
the drill string or stored in the vertical position for later
connection to the drill string.
[0008] Thus, there exists a need for a simple and efficient means
for forming stands.
SUMMARY OF THE INVENTION
[0009] In one aspect, the present invention provides a method of
forming a stand from tubulars comprising: [0010] providing a supply
of tubulars; [0011] providing an elongate stand forming apparatus
comprising a front end, rear end and mid section; [0012] loading a
first tubular on the stand forming apparatus, wherein the first
tubular is positioned generally parallel therewith; [0013] pulling
the first tubular towards the rear end of the apparatus; [0014]
loading a second tubular on the stand forming apparatus, wherein
the second tubular is positioned generally parallel therewith and
wherein the second tubular is positioned in general coaxial
alignment with the first tubular; [0015] rotating the first and
second tubulars about their longitudinal axes and in opposite
directions; and, [0016] advancing the first tubular against the
second tubular during the rotation whereby cooperating threads on
each opposing end of the first and second tubulars are engaged to
form a stand.
[0017] In another aspect, the present invention provides an
apparatus for forming a stand from tubulars comprising: [0018] a
generally horizontal, elongate catwalk having a frame with a top
surface adapted to receive at least two of the tubulars aligned in
a coaxial manner, the frame having a front end, a rear end, and a
mid section; [0019] a pulling means adapted to grip and pull a
first of the tubulars towards the rear end of the catwalk; [0020] a
pushing means adapted to advance the first tubular to the front end
of the frame; and, [0021] a rotating means for rotating the
tubulars about their longitudinal axes.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] These and other features of the invention will become more
apparent in the following detailed description in which reference
is made to the appended drawings wherein:
[0023] FIG. 1 is a side elevation of a stand forming apparatus
according to an aspect of the invention with a first tubular loaded
thereon.
[0024] FIG. 1a is a front elevation along the line A-A of FIG.
1.
[0025] FIG. 2 is a plan view of the apparatus of FIG. 1.
[0026] FIG. 3 is a side elevation of the apparatus of FIG. 1 with a
second tubular loaded thereon.
[0027] FIG. 3a is a front elevation along the line B-B of FIG.
3.
[0028] FIG. 4 is a side elevation of the apparatus of FIG. 1
wherein the formed stand is elevated towards a drilling rig.
[0029] FIG. 4a is a front elevation along the line C-C of FIG.
4.
[0030] FIG. 5 is a side elevation of the apparatus of FIG. 1 shown
in a folded state without tubulars.
DETAILED DESCRIPTION OF THE INVENTION
[0031] As described further below in more detail, the present
invention provides an improved apparatus for forming stands from
individual tubulars. In general, the invention comprises a catwalk
onto which are loaded two tubulars. The tubulars are positioned
generally coaxially on the catwalk in an end-abutting arrangement.
The catwalk is provided with lifting devices comprising, in one
aspect, actuating arms having rollers that contact and raise the
tubulars above the level of the catwalk. The rollers are driven by
one or more motors and are arranged so that the tubulars are
axially spun in opposite directions with respect to each other.
During the spinning operation, the tubulars are advanced against
each other whereby the complementary threads on each end engage to
form a connection, thereby forming a dual tubular stand. As will be
understood, the tubulars are arranged so that the male and female
ends are in abutting arrangement so as to permit engagement. The
arms are then lowered whereby the now formed stand is allowed to
rest on the catwalk, preferably in a trough or groove provided
thereon. The stand is then pushed towards the drilling rig. A ramp
provided either on the catwalk or on the rig causes one end of the
stand to be raised during the pushing process up to a point where a
hoist on the drill rig can engage and pull the stand to the desired
vertical position over the drilling platform. The stand can then be
stored or immediately connected to an existing drill string. The
apparatus of the invention is transportable and certain sections
can be folded to facilitate such transport.
[0032] Thus, the invention provides a simple and efficient means of
forming a stand. The invention can also be operated to load
individual tubulars as well directly onto a rig in situations where
a stand is not needed. In another aspect, the apparatus of the
invention can operate in the opposite manner wherein stands are
received from the rig and then separated or dismantled into
individual tubulars.
[0033] FIG. 1 illustrates an embodiment of the apparatus of the
invention. The catwalk apparatus 10 comprises a frame having a
front end section 12, a rear end section 16 and a mid section 14.
The structure of the frame is commonly known and may comprise
struts and support members and the like. As will be understood by
persons skilled in the art, various structures for the frame are
possible. In one embodiment, the apparatus 10 is adapted to rest on
the ground; however, in other embodiments, the apparatus may
include tracks, wheels or other such devices upon which the frame
rests. The front end 12 of the apparatus 10 is inclined upwards and
is preferably adjustable so as to reach to the level of the
drilling platform. In general, the front end 12 can be inclined to
a point where a tubular or stand resting thereon can be grasped by
a hoist or similar device provided on the drill rig. In another
embodiment, the catwalk apparatus 10 does not include a front end
portion 12 as shown in the accompanying drawings. Such a situation
may occur where the drilling rig itself includes a suitable ramp
that functions in the same manner as the front end 12.
[0034] The catwalk 10 includes a top surface 17 which receives and
manipulates tubulars as will be described further below. In a
preferred embodiment, the top surface 17 includes a groove or "V"
or "U" shaped surface for locating the tubular in a desired
location thereon. An example of such a groove is illustrated as
element 19 in FIG. 4a. Various other means for retaining tubulars
on the top surface 17 will be known to persons skilled in the art.
It will be understood that such retaining means serve to prevent
tubulars from rolling or other such unwanted movements.
[0035] In operation, the catwalk apparatus 10 is first positioned
adjacent a drilling rig (not shown) such that the catwalk extends
generally perpendicularly from the rig and such that the front end
section 12 is adjacent the rig. As indicated above, the front end
section 12 is inclined upwards so as to be roughly at the level of
drilling platform (not shown) of the rig. As mentioned above, in
another aspect, the catwalk apparatus 10 does not include a front
end section 12 and such functionality is instead provided by a ramp
provided on the drill rig.
[0036] FIG. 2 illustrates a plan view of the catwalk apparatus
wherein the front end section 12 is not shown for convenience.
Moreover, various other elements of the catwalk 10 such as decking
etc. are not illustrated but will be apparent to persons skilled in
the art. As shown in FIG. 2, a supply rack 18 containing a supply
of tubulars 20 is positioned adjacent to the catwalk apparatus 10.
The tubulars 20 are preferably provided in a generally parallel
arrangement on the rack 18. As discussed above, the tubulars, as
commonly known in the art, have male and female ends each provided
with complementary threads. Thus, in a preferred embodiment, the
tubulars 20 on the rack 18 are arranged so that all of the
respective male and female ends are positioned in the same
orientation. More preferably, in order to facilitate the present
method, the tubulars are oriented such that all female ends are
pointed towards the catwalk front end 12 (i.e. pointed towards the
drilling rig). The purpose of such preferred arrangement will be
apparent from the following description.
[0037] As shown in FIG. 2, the supply rack 18 is positioned close
to the catwalk 10 so as to facilitate transfer of tubulars 20 from
the rack 18 to the catwalk 10. In one embodiment, the catwalk 10
and rack 18 are arranged so as to allow a tubular to roll from the
rack onto the top surface 17 of the catwalk 10. As will be
understood, in such arrangement, the catwalk top surface 17 would
be slightly lower than the rack 18 so as to allow such rolling. In
one embodiment, the catwalk apparatus 10 would be vertically
adjustable whereby the catwalk could be lowered to allow a tubular
to roll thereon from the rack. The catwalk can then be raised to a
height above the rack so that, during a stand dismantling operation
(discussed further below), the tubulars can roll from the catwalk
onto the rack. It will be understood that in other embodiments, any
difference in height may also be overcome by using a forcing means
to urge tubulars between the catwalk and the rack. In such case, a
difference in height would not pose a problem for the tubular
transfer step. In yet another embodiment, tubulars can be
transferred between the rack 18 and the catwalk apparatus 10 by
means of a crane or any other similar device. Various other tubular
transfer mechanisms will be known to persons skilled in the
art.
[0038] The catwalk apparatus 10 of the invention also preferably
includes a skate 22 that is arranged to generally traverse the
length of the catwalk from the rear end section 16 to the front end
section 12. The skate 22 includes a clamp to grasp one end,
preferably the male end, of a tubular after being loaded on the
catwalk top surface 17 and to pull same towards the rear end
section 16 of the catwalk apparatus. The skate 22 also includes a
bearing surface for pushing the tubular along the length of the
catwalk towards the front end section 12. The skate 22 can be
provided on a track or groove on the catwalk. One example of an
arrangement for the skate is taught in U.S. Pat. No. 6,969,223
wherein a "pusher" member is described for advancing tubulars
longitudinally along a catwalk. As will be apparent to persons
skilled in the art, the skate 22 can be advanced in either
direction by a mechanical means (such as using a cable attached to
a motor), a hydraulic means (such as by using a cylinder and piston
combination) or any other means. Further, as described above, the
skate is provided with a clamp for attaching to an end of one
tubular. Such clamps are commonly known in the art and any suitable
clamp mechanism can be used for the skate. For example, one such
clamp is shown in U.S. Pat. No. 6,976,540, which teaches a
"gripping device" for grasping an end of a tubular. It will be
understood that the skate 22 may, in one embodiment, include a
threaded portion (not shown) with threads that are complementary to
those provided on the end of the tubular. In this way, instead of
clamping or grasping a tubular, the threaded portion of the skate
22 may be rotated to engage the end of the tubular. Rotation in an
opposite direction would then disengage the skate. Various other
gripping means for the skate will be apparent to those skilled in
the art.
[0039] In operation, as shown in FIGS. 1 and 2, a first tubular 20a
is rolled or otherwise placed onto the top surface 17 of the
catwalk apparatus 10. As shown, in the preferred arrangement, the
female end 24 of the tubular 20a is directed towards the front end
of the catwalk apparatus 10. The skate 22 is then advanced towards
the tubular and grips the male end 26 thereof. The skate 22, in a
"pull" mode, is then retracted to the rear end portion 16 of the
catwalk apparatus 10. In this way, the first tubular 20a is pulled
towards the rear end portion 16. This position is illustrated in
FIG. 1 which also shows the skate 22 gripping the tubular 20a. Once
the skate 22 has reached its terminal point on the catwalk
apparatus 10, the gripping mechanism is released. This position is
shown in FIG. 3. As will be understood by the discussion herein,
the terminal position of the skate 22 on the rear end 16 of the
apparatus 10 is the position that pulls the first tubular 20a a
sufficient distance so as to allow another tubular 20 to be loaded
onto the top surface 17.
[0040] FIG. 3 illustrates the next step in the process wherein a
second tubular 20b is provided on the top surface 17 of the catwalk
apparatus 10. As with the first tubular 20a, the second tubular 20b
is oriented with its female end 28 directed towards the front end
section 12 of the catwalk apparatus 10. The male end 30 of the
second tubular 20b is positioned adjacent and in opposition to the
female end 24 of the first tubular 20a. Further, as can be seen in
FIG. 3, both tubulars 20a and 20b are positioned on the top surface
17 of the catwalk 10 and aligned so as to be coaxial with each
other. As will be understood, the groove 19 (as shown in FIG. 4a)
serves to maintain the desired alignment of the tubulars 20a and
20b. Once the two tubulars 20a and 20b are provided on the top
surface 17, a plurality of lifting devices 32 (a-d), provided on
the catwalk apparatus 10, are actuated. The lifting devices 32
preferably, and in one aspect, comprise actuating arms 33 at the
ends of which are provided driven rollers 34. Such lifting devices
are illustrated in FIGS. 1a, and 3a. As can be seen, according to
one embodiment, each arm is provided with a pair of opposed
rollers. As shown in FIG. 1a, the rollers are arranged so as to
form a pinch point 31 there-between, which is adapted to receive a
portion of a tubular as explained further below.
[0041] In the embodiment shown in FIGS. 1 and 3, the catwalk
apparatus 10 is provided with four lifting devices, 32a to 32d,
such that each of the first and second tubulars, 20a and 20b, are
engaged by two lifting devices. Thus, as shown, lifting devices 32a
and 32b engage the second tubular 20b while lifting devices 32c and
32d engage the first tubular 20a. In operation, the roller-bearing
ends of actuating aims 33 are raised by any known means, such as
hydraulically, mechanically etc. In such manner, the rollers 34 are
raised up to receive the tubular within the pinch 31 there-between.
The arms 33 are raised further so that the tubular is raised above
the top surface 17 of the catwalk apparatus 10. For example, FIG.
3a illustrates the second tubular 20b contained between two rollers
34 and raised above the top surface 17.
[0042] It will be understood that the top surface 17 of the catwalk
is provided with openings through which the rollers 34 and/or arms
33 may be extended. The rollers 34 are driven either directly or
indirectly by motors and the like so as to rotate the tubular
engaged therein about its longitudinal axis. In one embodiment, the
rollers 34 are reversibly driven as will be further explained
below. It will be understood that the arms 33 and rollers 34 are
designed with sufficient strength to support the tubular. It will
also be understood from the present description that the rollers 34
are made of a material that includes a sufficient coefficient of
friction to cause rotation of the tubular. Such materials and other
specifications will be apparent to persons skilled in the art. In
addition, although two pairs of lifting devices are described for
the purpose of lifting the entire lengths of each of the tubulars,
it will be appreciated that any number of devices may also be
provided for achieving the same purpose. For example, it would also
be possible to include only one lifting device per tubular in which
case, the rollers may be elongated to support the length of the
tubulars.
[0043] Once the two tubulars 20a and 20b are raised above the top
surface 17, the rollers are activated as mentioned above. However,
it should be noted that the rollers engaging the first tubular 20a
(i.e. the rollers provided on lifting devices 32c and 32d) are
rotated in a direction opposite to the rollers engaging tubular 20b
(i.e. the rollers provided on lifting devices 32a and 32b). In this
way, the two tubulars are rotated in opposite directions. Once
axial rotation of the tubulars 20a and 20b is begun, the skate 22,
now in "push" mode (as shown in FIG. 3) is used to advance the
first tubular 20a towards the front end 12 of the apparatus 10.
Thus, the female end 24 of the first tubular 20a is advanced
towards the male end 30 of the second tubular 20b. Due to the
opposite rotation of each tubular, and the complementary threading
between the male and female ends (as discussed above), the first
and second tubulars are allowed to engage one another thereby
forming a stand. In this process, it will be understood that the
rotation directions of each of the rollers associated with the two
tubulars are selected so as to allow the respective male end to be
threaded onto the respective female end and vice versa.
[0044] Once the stand, comprising the joined tubulars 20a and 20b,
is formed, the lifting devices 32 are lowered so as to allow the
stand to rest on the top surface 17 of the catwalk apparatus 10.
The skate 22 continues in the "push" mode and is advanced towards
the front end section 12 of the apparatus 10. In this way, the
skate 22 bears against the male end 26 of the first tubular 20a
and, therefore, urges the stand in a direction towards the front
end section 12 and towards the drilling rig (not shown).
[0045] As illustrated in FIG. 4, due to the inclination of the
front end section 12, the section of the stand proximal to the
front end section is gradually elevated as the skate 22 is
advanced. Such elevation continues until the female end 28 of the
second tubular 20b reaches a height wherein a hoist mechanism (not
shown) provided on the drilling rig is able to reach and grip the
end of the stand. The hoist mechanism then raises the stand to its
vertical orientation on the drilling platform and the stand is then
either connected to the existing drill string or is stored in the
vertical position for future connection. It will be understood that
the stand may require torquing on the drilling rig to provide a
sufficiently tight connection between the tubulars 20a and 20b.
Such torquing can be effected by known devices commonly provided on
the rig.
[0046] As will be known to persons skilled in the art, the
terminal, surface exposed end of a drill string is normally the
female end. As such, the lower end of the now vertical stand should
comprise the male end in order to mate with the existing drill
string. As will be understood from the above description, by
positioning the tubulars on the rack with the female ends directed
towards the front end section 12 of the catwalk apparatus 10, the
formation of the stand takes place in such a manner that the formed
stand, when oriented vertically, is in the desired position with
the male end pointed downwards. It will also be understood that the
opposite orientation of the tubulars and stands will be required
should the exposed drill string end be male.
[0047] As will be understood by persons skilled in the art, the
above described process can also be operated in reverse order to
dismantle stands. That is, the hoist on the drilling rig can first
extract a stand from a drill string and lower it on to the front
end section 12 of the catwalk apparatus. The skate 22 is then
advanced and activated to grip the free end (usually the male end)
of the stand. The skate is then retracted towards the rear end
section 16 of the catwalk apparatus 10 until the stand is rests on
top surface 17 in a generally horizontal orientation and wherein
each tubular segment of the stand is positioned above the
respective pairs of lifting devices 32. The lifting devices 32 are
then activated as above to raise the stand above the top surface
17. The rollers are then actuated to rotate in opposite directions
as before, but in this case, such rolling is used to disconnect
(i.e. unscrew) the tubulars. Once separated, one of the tubulars is
then loaded onto the rack 18 by either rolling or by means of a
device such as a crane etc. The remaining tubular is then pushed by
the skate 22 to a position on the top surface 17 that enables the
tubular to be moved to the rack as well.
[0048] Another feature of the present invention is the capability
to automate the standbuilding operation. That is, as described
above, very little manual manipulation of the tubulars or stands is
needed. Thus, the entire process can be coordinated by an operator
positioned away from the catwalk. In this way, the present
invention provides a stand make-up and break-up system which
comprises a safer alternative than processes known in the art. It
will be understood that the apparatus discussed above will include
suitable and commonly known electrical connections and/or
processors etc. to enable such automation. For example, the system
of the invention would include a control system to enable one or
more operators to control various mechanisms on the catwalk 10, the
rack 18 and/or the drill rig (i.e. the hoist). In such case, the
rack may be provided with an automated feeder to feed single
tubulars to the catwalk top surface 17. The skate 22 and lifting
devices 32 may in turn be controlled remotely by means of commonly
known control circuitry. Similarly, the hoist described above may
also be controlled remotely by the same operator so as to cause
vertical lifting of the stand onto the rig. In one embodiment, the
system may be controlled by a computer based control system, which
can coordinate all of the above functions.
[0049] FIG. 5 illustrates a further feature of the invention. As
shown, the front end 12 and rear end 16 sections of the catwalk
apparatus 10 can be folded over the mid section 14. In this way,
the apparatus 10 can be reduced in size to facilitate
transportation between sites.
[0050] The above description has focussed on "making up" a dual
tubular stand. However, it will be appreciated that the present
apparatus also provides a safe and efficient means of loading even
single tubulars onto a drilling platform. In such a process, a
tubular is loaded onto the top surface 17 of the catwalk apparatus
10 as described above and the skate 22 is used to push the tubular
towards the rig. As described above, the combination of the pushing
action by the skate 22 and the inclination of the front end section
12, causes the front end of the tubular to be raised towards the
drilling platform. A hoist mechanism (as described above) on the
drill rig can then be used to raise the tubular to a vertical
orientation and positioned on the drilling platform. As discussed
above, the automation of the process enables an operator or a
control system to remotely control this operation.
[0051] It will be understood that the above description has
focussed on the formation of stands including two tubulars (i.e. a
dual make-up stand). However, the apparatus described above may
also be adapted to form stands with any number of tubulars. Persons
skilled in the art will recognize that a functional limit in the
length of stands lies in the height of the derrick provided on the
drill rig.
[0052] In the above description, the skate 22 has been described as
performing two functions, namely the "pulling" and "pushing" of
tubulars. However, it will be understood that such dual role of the
skate is a preferred embodiment. In other embodiments of the
invention, each of these functions can be performed with two
separate skate-like devices. Thus, one device may comprise a
gripping mechanism to pull tubulars while a second device may
comprise a bearing surface for pushing tubulars.
[0053] Although the invention has been described with reference to
certain specific embodiments, various modifications thereof will be
apparent to those skilled in the art without departing from the
spirit and scope of the invention as outlined herein. The
disclosures of all prior art recited herein are incorporated herein
by reference in their entirety.
* * * * *