AN ARRANGEMENT RELATING TO A DRILLING TOWER

Abstract: A derrick (1-4) for drilling of petroleum wells is on one of its columns (1) provided with an elevator (9) for hoisting drill pipes, casing pipes and weight pipes independently of the elevator arrangement (4) for the drill string (5) in the derrick. The elevator (9) co-operates with an iron roughneck (13) for screwing together single pipe lengths (10) into three-pipe lengths, which by means of a pipe handling unit (7) are placed in a storage device (6). The elevator (9) further co-operates with a pipe holder (14), which brings the single pipe lengths (10) between a horizontal and a vertical position. The pipes (10) are supplied to the pipe holder (14) from a pipe storage (15) by means of a conveyor (22), wiich may be telescoping in order to compensate for the varying distance between the derrick and the pipe storage.

Description: AN ARRANGEMENT RELATING TO A DRILLING TOWER The present invention relates to an arrangement relating to a drilling tower or derrick having a central area where at least the lifting equipment for a drill string can move vertically, said derrick preferably comprising a storage device for pi.pe joi.nts, casi.ng pi.pes and weight pipes, a handling unit for such pipes, and a separate lifting device for said pipes arranged outside said central area. In well drilling for the petroleum industry one has gradually reached very large depths. Thus, well depths of 5000 m are no longer impossible. It will be understood that such wells are very costly and that it is therefore necessary that the drilling be performed as effectively as possible in order to reduce the costs. Furthermore, it will be understood that it is important at all times to have the drilling under control, not the least due to the very high pressures prevalent at such large depths . Both as regards keeping the costs down and optimizing the safety during drilling it is important that the drilling takes place as continuous as possible. This is even more so when drilling from fixed or floating platforms at sea, considering the further difficulties and factors of uncertainty this entails . All commercial well drilling for the petroleum industry today involves joining pipe lengths of about 30 m in order to minimize the number of operations and inter¬ ruptions during the drilling. These pipe lengths are called "stands" and are screwed together from three single pipes, so-called "joints ", having a length of about 10 m. These three-pipe stands are today made up in the derrick. The single pipe lengths are brought from horizontal position in a storage outside the derrick, in through a so-called V-door, whereupon they are lifted in place in the derrick and screwed together three and three. It will be understood that these operations are cumbersome and time consuming, and at the same time the continuity in the drilling operations is reduced to a considerable degree, with consequences for economy and safety. The present invention aims at avoiding the draw¬ backs and deficiencies of the previously known devices of the type mentioned by way of introduction. This is obtained according to the invention by bringing said lifting device in line with a pipe screw joining device and by combining it with a transporting device for pipe lengths which is arranged to transport the pipe lengths between a generally horizontal storage position and a generally vertical position below the lifting device. By means of such a device it becomes possible to build up or break down three-pipe pipe lengths while the drilling operations are in progress . This means a considerable increase in well safety, i.e. better hole quality and reduced possibilities for blow-outs, while concurrently the drilling costs for the well are reduced as much as 30%. Furthermore, it becomes possible to mechanize almost all operations in connection with transport and building up/breaking down drill pipe lengths , with the advantages this entails in the form of reduced handling time and manual labour, which in turn results in reduced possibilities for working accidents . The invention is particularly advantageous for derricks of the type described in the applicant's Norwegian application No. 85 2691, where the drilling tower is shaped like a portal and formed by two columns and an upper transverse element. According to the invention it is suggested that the lifting device be arranged movably along tooth rack rails mounted on one of " the columns of the derrick. Accordingly, the drilling device may operate relatively protected without special precautions and without its own supporting structures and, besides, it will not take up valuable space or in any other way hinder the drilling operations . A particularly advantageous transporting device comprises a pipe holder which is pivotable in a vertical plane about an axis lying perpendicularly below the lifting device. Consequently, the pipe parts are brought quickly and safely from horizontal to vertical position. Furthermore, the pipe holder may be provided with a movable extending means which is activated when the pipe holder has been pivoted to a vertical position, so that the pipe length in the pipe holder may be displaced upwards against the lifting device and can be gripped by the latter for further transport. For drilling rigs on fixed platforms at sea the drilling rig may often be moved horizontally in order to drill a plurality of wells next to each other. However, the pipe storage will be fixed, which means that the movements of the drilling rig will lead to a varying distance between itself and the pipe storage. In order to prevent this from creating problems for the pipe transport from the pipe storage to the derrick, it is suggested according to the invention that the transporting device is provided with a variable length conveyor arranged between the pipe holder and the pipe storage. The conveyor may for instance be telescoping. The transporting device may thus function in accordance with its purpose regardless of the distance between the pipe storage and the drilling rig. The pipe handling unit arranged in the derrick according to the invention may for instance be of the type described in Norwegian application No. 84 2425. According to the invention it is suggested that the lifting device is placed within the reach of the pipe handling unit. In this way it becomes possible to avoid almost any manual handling of drill pipes in the derrick, and if the transporting device mentioned above is included, one will obtain a system where all pipe handling is mechanized. The inherent advantages will be quite obvious, both as regards economy and accident frequency. For the better understanding of the invention it shall be described more closely with reference to the exemplifying embodiment shown in the appended drawings . Fig. 1 shows perspectively a derrick provided with a device according to the invention, where some parts have been removed for the sake of clarity. Fig. 2 shows a part of Fig. 1 at a larger scale, where further parts have been removed for the sake of clarity. Fig. 3 shows the derrick and the adjacent area in side view. Fig. 4 shows schematically a side view of the pipe holder shown in Figs . 1 and 2. Fig. 5 shows a front view of the pipe holder in Fig. 4. Fig. 6 shows a plan view of the pipe holder in Fig. 4. The derrick shown in Fig. 1 comprises two vertical columns 1, 2, which at the top are connected by means of a transverse member 3. Between the columns a central area is formed where an elevator 4 for a drill string 5 can move vertically. The elevator also comprises a drilling machine for the drill string. Furthermore, the derrick comprises a storage device, a so-called finger table 6, for three-pipe drill pipe stands, casing pipes and -weight pipes for use during well drilling. These different types of pipes are moved between the storage device 6 and the position of the drill string 5 by means of a handling unit 7. On one of the columns 1 it is mounted tooth rack rails 8, of which only fragments are shown for the sake of clarity. These rack rails serve as guides and supports for an elevator 9, which may handle drill pipe lengths 10 which are brought up into vertical position through a slot 11 in the working platform 12 of the derrick. The elevator 9 is alingned with a pipe screw joining device 13, which is arranged at a level above the working platform 12 of the derrick. Commercially available devices of the type, which within the oil drilling business are often labelled iron roughnecks^may be used as such a pipe screw joining device. The elevator 9 may be driven by hydraulic motors mounted in the elevator, for instance according to the same pinciple as in the elevator 4 for the drill string 5. For further details of the elevator 4 it is referred to the Norwegian application No. 85 2691 mentioned above. It will be understood that the rack rails 8 extend sufficiently high along the column 1 for the elevator 9 to handle so-called stands, i.e. drill pipe lengths screwed ■ together from three single lengths 10. Furthermore, it will be understood that the rack rails 8 are positioned so that the handling unit 7 may move the stands between the elevator 9 and the storage device 6 or the position for 10 the drill string 5. In order to bring the pipe lengths 10 to vertical position so that the may be gripped by the elevator 9, resp. the pipe screw joining device 13, a pipe holder 14 is arranged below the column 1 of the derrick, the pipe- 15 holder being integrated in a transporting device which performs the transport of the pipe lengths between the elevator 9 and a horizontal pipe storage 15 outside the derrick. The pipe holder 14 consists basically of a chute having U-formed cross-section, which chute is hinged about 20 an horizontal axis 16 lying generally vertically below the elevator 9. By means of two hydraulic cylinders 17 the chute 14 may be pivoted between horizontal and vertical positions, as suggested in Fig. 4. As is best apparent from Figs. 4 - 6, the pipe 25 holder 14 is provided with an extender or pusher 18, which is activated by a hydraulic cylinder 19 via a flexible tension means 20, which is attached to the pusher and runs over a sheave 21 on the piston rod of the hydraulic cylinder 19. By means of the pusher 18 the pipe length 10 30 may be pushed out of the pipe holder 14, whether this is in the vertical or horizontal position. In the first case the pusher serves the purpose of bringing the pipe length 10 in contact with the elevator 9, while it in the other case will push the pipe length over into a conveyor 22 35 which forms a link between the pipe holder 14 and the pipe storage 15. The latter operation is of interest when three pipe lengths are broken down and transported to the pipe storage, for instance when the drilling is finished, or for replacement or repair . As it will best appear from Fig. 3, the conveyor 22 consists of two parts, 23 and 24, respectively. These two parts are telecopingly arranged so that the length of the conveyor 22 may be varied as necessary. This is of importance when the drilling rig, generally designated 25, is moved for drilling several wells next to each other. While this is taking place the distance between the drilling rig and the pipe storage 15 is changed, a fact that creates difficulties and much manual handling in most of the previously known systems. Associated with the pipe storage 15 is also a handling crane 26, which takes pipe lengths 10 from the storage and place them in the conveyor 22. The conveyor itself may be provided with transporting means known per r se, such as rollers, conveyor belts, step transporters or the like. It will be understood that,in accordance with the invention, one has not only succeeded in mechanizing the pipe handling associated with drilling operations, but also that one concurrently has succeeded in liberating large space on the working platform of the drilling rig which otherwise would have been needed for i.a. the pipe ramp and manual handling of the pipes . This space may now be used for other work or equipment, e.g. equipment for control and supervision of the drilling operations, which further facilitates quick and safe drilling. It will also be understood that the invention may be varied and modified by the skilled person in a number of ways within the scope of the appended claims .

Claims: C l a i m s 1. An arrangement relating to a drilling tower or derrick having a central area where at least elevator equipment (4) for a drill string (5) may move vertically, which derrick preferably comprises a storage device (6) for three-pipe drill pipe lengths, casing pipes and weight pipes, a handling unit (7) for such pipes, and a separate elevator (9) for said pipes arranged outside said area, c h a r a c t e r i z e d in that the elevator is aligned with a pipe screw joining device (13) and that it is combined with a transporting device (14, 22) for single pipe lengths (10), which is arranged to transport single pipe lengths between a generally horizontal storage position and a generally vertical position below the elevator (9) . 2. An arrangement according to claim 1, c h a r a c t e r i z e d in that the pipe screw joining device (13-) is fixedly arranged at a level above the working platform (12) of the derrick. 3. An arrangement according to claim 1 or 2, c h a r a c t e r i z e d in that the elevator (9) is movable along tooth rack rails (8) mounted to ' or on a column (1) of the derrick. 4. An arrangement according to a preceding claim, c h a r a c t e r i z e d in that the transporting device comprises a pipe holder (14) which is pivotable in a vertical plane about an axis (16) lying generally vertically below the elevator (9). 5. An arrangement according to claim 4, c h a r a c t e r i z e d in that the pipe holder (14) is provided with a movable extending or pushing means (18) which preferably is activated by a hydraulic cylinder (19) . 6. An arrangement according to claim 4 or 5, c h a r a c t e r i z e d in that a conveyor (22) of variable length is arranged between the pipe holder (14) and a pipe storage (15). 7. An arrangement according to a preceding claim, c h a r a c t e r i z e d in that the elevator (9) is arranged within the working area of the pipe handling unit (7) .

Inventors: GABRIELSEN JONNY, HOLTE KETIL, GABRIELSEN, JONNY, HOLTE, KETIL
Applicants: BIRD TECHN AS, BIRD TECHNOLOGY A/S
Application year: 1987
Main classification: E21B19
IPC codes: E21B19