US 20070221385 A1
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.
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
3. The method of
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
6. The apparatus of
7. The apparatus of
6. The apparatus of
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
11. The apparatus of
12. The apparatus of
13. The apparatus of
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.
The present invention relates to pipe handling apparatuses and, more specifically, to apparatuses and methods for drilling operations wherein stands are formed from tubulars.
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.
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.
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.
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.
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.
Thus, there exists a need for a simple and efficient means for forming stands.
In one aspect, the present invention provides a method of forming a stand from tubulars comprising:
In another aspect, the present invention provides an apparatus for forming a stand from tubulars comprising:
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:
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.
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.
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
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.
As shown in
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.
In operation, as shown in
In the embodiment shown in
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.
Once the two tubulars 20 a and 20 b 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 20 a (i.e. the rollers provided on lifting devices 32 c and 32 d) are rotated in a direction opposite to the rollers engaging tubular 20 b (i.e. the rollers provided on lifting devices 32 a and 32 b). In this way, the two tubulars are rotated in opposite directions. Once axial rotation of the tubulars 20 a and 20 b is begun, the skate 22, now in “push” mode (as shown in
Once the stand, comprising the joined tubulars 20 a and 20 b, 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 20 a and, therefore, urges the stand in a direction towards the front end section 12 and towards the drilling rig (not shown).
As illustrated in
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.
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.
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.
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.
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.
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.
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.