PIPE HANDLING APPARATUS

Abstract: A pipe handling apparatus (35) is disclosed, which is adapted for automated drilling operations. Drill pipes (10) are manipulated between substantially horizontal and vertical positions, and the apparatus is used with a top mounted drilling device (22) which is rotatable about a substantially horizontal axis (1). The appara­ tus comprises a strongback (4) provided with means (6,7,8) to hold and manipulate pipes. The strongback (4) is at one end portion rotatably connected to the same axis (1) as the drilling device (22). The strong­ back (4) moves up or down with the drilling device (22). A brace unit (5) is attached to the strongback (4) to be rotatable about a second axis (2) spaced apart from said first axis (1). The brace unit (5) has one end portion rotatable about a third axis (3).

Description: The present invention relates to a pipe handling apparatus adapted to automatic drilling operations, in which drill pipes are manipulated between substantially horizontal initial or final positions, and approximately vertical drill centre positions, for use with a top mounted drilling device which is rotatable about a substantially horizontal first axis. Automatic systems for drilling operations are previously known which furthermore are able to carry out tripping operations, e.g. when a drill bit is to be replaced or logging or service operations are to be carried out. It is known that to pull out a drill string from oil or gas wells in the conventional way are very time consuming operations. Tripping operations are especially time consuming in case of drilling at greater depths requiring more frequent replacements of drill bits. The total drilling time in case of deep wells is, thus, considerably increased and results in increased costs. US-PS No. 3 404 741 discloses an automated system for drilling and pipe manipulation. Drill pipes are placed in a horizontal position halfway up in the derrick before the pipes are manipulated into a vertical position. The structure comprises a drilling device which is rotatable about a horizontal axis. In its horizontal or lying position the pipe may be inserted into the drilling device which is subsequently raised permitting the pipe to be moved into a vertical position. At its other end the pipe is guided by a carriage moving on rails. During the raising operation the pipes are only supported at their end portions and, obviously, only short pipe lengths can be raised in this way. In order to reduce the time consumption it is, however, common and desirable to day to manipulate pipe sections or stands comprising two or three assembled single pipes, i.e. sections that may be up to 30 m long. US-PS No. 3 986 619 also describes equipment for manipulating pipes in order to move drill pipes from a horizontal into a vertical position. Entire pipe stands are manipulated by this system. The equipment comprises a mechanism elevating the stands in a horizontal position from the drill floor up to a predetermined level. The equipment for manipulating pipes comprises a series of blocks, pulleys and wires and is, apparently not adapted for automated operation. With the equipment according to the invention the pipe handling operation may be automated thus avoiding time consuming and hazardous manual labour. Thus, time consumption, and consequently the total drilling costs may be reduced simultaneously as the work environmental conditions are considerably improved. This is achieved by a pipe handling apparatus of the kind mentioned in the preamble which is characterized by a strongback comprising means for holding and manipulating pipes, said strongback being connected at one end portion independently rotatable about said first axis for movement up or down with the drilling device, a brace unit rotatably connected to said strongback about a second axis spaced apart from said first axis, mounting means about which the end portion of said brace unit is rotatable about a third axis, said axis being arranged in such positions relative to each other that a drill pipe is moved from said horizontal position to the drilling centre in said substantially vertical position, or vice versa. The means for holding pipes may comprise several spaced apart arms including pipe gripping means or clamps and means for operating said clamps to grip around the pipe. The means for holding and manipulating pipes may comprise means for sync. operation of the arms for inserting or retracting drill pipes relative to the drilling device. Said arms may be arranged to be slidable along the strongback, and they may be articulated and provided with arresting means preventing the arms from turning towards the drilling means more than (in an) approximately an orthogonal position relative to the strongback when the arms are manipulated. The space between first and second axis, and the space between second and third axis is, suitably, adjustable, e.g. by means of a rack/pinion which is driven by a motor or the like. Preferably, the third axis is restricted movable in a substantially vertical way in a slot or a coulisse guide, in order to provide a safety margin for the drilling device and the pipe handling apparatus when the drilling device approaches its upper position. In order to ensure that the pipe stand may readily be removed from the drilling centre, the space between the longitudinal axis of the strongback and the longitudinal axis of the pipe stand in a manipulating position is, advantageously longer than the horizontal space between the third axis and the drilling centre, so that a knuckling point is formed in the second axis. Other and further objects, features, and advantages of the invention will appear from the following disclosure of an embodiment which is preferred at present and is meant for illustration together with the accompanied drawings. Fig. 1 is a diagrammatic representation of the pipe handling apparatus according to the invention in a vertical section and in a folded or horizontal position together with a drilling device in a derrick, fig. 2 is a diagrammatic view of the apparatus according to fig. 1, in a partial raised position, fig. 3 is a view of the apparatus according to fig. 1 in an approximately vertical position with the drilling device in its upper position, fig. 4 is a diagrammatic view of the means holding and manipulating pipes in more detail, fig. 5 is a diagrammatic view of the means according to fig. 4 as seen from the derrick, fig. 6 is a diagrammatic view of the adjustable connection between the strongback and the brace unit, fig. 7 is a plan view of the connection in fig. 6, fig. 8 is a diagrammatic front view of the pipe handling apparatus, as seen towards the derrick, and fig. 9 is a perspective view of the pipe handling apparatus according to the invention. An embodiment of the invention is shown in the drawings, in which fig. 1 illustrates the pipe handling apparatus 35, a derrick 20, and a raising/lowering table 25. The drilling device 22 is of the top mounted type, i.e. the drilling device 22 driving the drill string 27 advances with the drill string 27 as the drill bit progress downwardly in the borehole. The derrick 20 with associated drilling device 22 may be of the conventional kind with draw works hoisting means comprising, crown block, a travelling block and wireline arrangements. Other concepts for raising and lowering the drilling means, e.g. hydraulic cylinders, racks and screws may be adapted to the present system for manipulating pipes. A guide carriage 28 with a cross beam 21 guides and supports the drilling device 22 in derrick 20. Drilling device 22 is rotatable about a first axis 1 for approximately 90° permitting the drilling device 22 to occupy substantially horizontal position. The raising/lowering table 25 supplies lying pipes 10 from a drill pipe storage or drill floor 40 up to predetermined level. Table 25 comprises an endless belt 31 with cradles 26 of a rubber material or the like mounted on belt 31, said cradles 26 have recessed grooves for the pipe stands. The endless belt 31 may be driven either ways in order to roughly position pipe 10 in its horizontal position, by means of a motor (not shown). A motor, levers or hydraulic cylinders (not shown) move table 25 from drill floor 40 to a raised position. The pipe handling apparatus 35 comprises a strongback 4 which is rotatably attached to the drilling device 22. The drilling device 22 and strongback 4 are independently rotatable about the same first axis 1. Two or more arms 6 are slidably arranged on the strongback 4, which arms are provided with clamps 7 to grip a drill pipe 10 or a drill pipe stand. The clamps 7 comprise the means (not shown) for actuating said clamps to embrace a pipe, or vice versa, to open the clamps in order to release a pipe. A manipulator rod 8 is linked to the arms 6 in such a way that they enable synchronized operation. The manipulator rod 8 provides the final guidance of drill pipe 10 towards and into the drilling device 22. A brace unit 5 is rotatably attached to the strongback 4 about a second axis 2. The brace unit 5 is attached at one end to be rotatable about a third axis 3. Rotational movements preferably occurs via journals and bearings. A slot or a coulisse guide 13 in a mounting bracket 32 restricts the movement of axis 3. In the lower portion of brace unit 5 a spring 29 is provided, primarily to hold axis 3 in its lower position in slot 13. Brace unit 5 may consist of two inclined legs, as will appear from fig. 8 and 9. Fig. 2 illustrates the apparatus 35 in a raised position. The raising/lowering table 25 is returned to drill floor 40. Fig. 3 illustrates the apparatus 35 in its fully raised position with strongback 4 in a substantially vertical position. The slot 13 provides safety during raising operations of the drilling device 22 and apparatus 35. If the drilling device 22 is moved slightly too high the axis 3 will be pulled upwardly along the slot 13 at the same time as spring 29 attempts to pull the brace unit 5 down. Fig. 4 illustrates an arm 6 with clamps 7 in more detail. Fig. 5 illustrates the same as fig. 4, as seen from the derrick 20. The arm 6 is articulated by means of the link or pivot 19. The arm 6 is slidable on the strongback 4 by means of sliding and guiding faces 12. Manipulator rod 8 is linked to the arms 6 by means of a pin 33. A lug or pawl 11 is provided on the arms 6. The articulated arm 6 and lug 11 cooperating with the manipulator rod 8 permits the arm 6 to turn about the pivot 19 away from the derrick, and conversely towards the derrick until a position where said arm is orthogonal to the strongback 4. By further movement of the arm 6 towards the derrick the lug 11 will cooperate with manipulator rod 8 to prevent further rotation. When the arm 6 is in an orthogonal position relative to the strongback 4, a further pull in the manipulator rod 8 will cause sliding displacement of the arm 6 along the strongback 4 and, thus, linear advancement of a drill pipe. Fig. 6 illustrates the rotatable connection 15 between the strongback 4 and the brace unit 5. These members turn relative to each other about the second axis 2. The strongback 4 and brace unit 5 are provided with means, e.g. in form of racks 18, which may be displaced relative to each other. One or a number of motors may drive pinions 17 so as to adjust the strongback 4 and brace unit 5 to adapt the apparatus to pipe sections of different lengths. Fig. 7 illustrates the connection 15 of fig. 6 in a plan view. A motor 16 is indicated for mutual displacement between the brace unit 5 and the strongback 4. For a more detailed description of the pipe handling operation, reference is given to fig. 1-3. A drill pipe 10 or a drill pipe stand consisting of two or three single pipes is moved from the drill pipe storage or drill floor 40 to a raised level by means of the raising/lowering table 25. When the drilling device 22 is in or approaches its lower position it is able to be turned about axis 1 to a lying or substantially horizontal position. The pipe 10 is roughly positioned relative to the drilling device 22 by means of the endless belt 31 providing only a slight distance between the drive shaft 34 of the drilling device 22 and the drill pipe 10. The clamps 7 embraces the pipe 10 and keeps it fixed. The table 25 may then again be lowered towards the drill floor 40. The arms 6 are depending substantially vertically or orthogonally relative to the strongback 4 and, thus, the lug 11 cooperates with the manipulator rod 8. When the rod 8 is pulled towards the drilling device 22 the drill pipe 10 is pulled towards the drive shaft 34 in the horizontal direction by means of sliding means 12 along the strongback 4. The mutual spaces and structural design will cause the central axis of the pipe 10 to coincide with the central axis of drive shaft 34 when the drill pipe is suspended in the clamps 7. When the pipe 10 is advanced close to the shaft 34 said shaft is spun into the threaded end portion of the drill pipe 10. In order to adapt a vertical position of the drill pipe 10 the drilling device 22 is elevated in the derrick 20 and pulls the strongback 4, thus, raising the entire pipe handling apparatus 35. Successively the drill pipe 10 adapts a more vertical position. The drilling device 22 gradually turns about the first axis 1 while rising in the derrick 20. The brace unit 5 turns about the third axis 3. Due to said structural conditions the drill pipe is transferred directly to the drill centre 14 when the strongback 4 has occupied substantially vertical position. When the clamps 7 and the manipulator rod 8 are released the outer portion of each articulated arm 6 falls down due to its own weight. The arms 6 knuckle about the pivots 19. A roughneck 30 encircles the lower portion of the pipe, whereupon the drilling device and the pipe are lowered towards and into the upper threaded portion of the drill string 27. The pipe is spun into the threaded connection and makes up a predetermined momentum from the roughneck 30. The latter is subsequently removed and drilling may procede. The pipe handling apparatus is designed to prevent axis 1,2 and 3 from being aligned when the drilling device 22 is in its upper position, but axis 2 is slightly offset from an imagined connecting line between axis 1 and 3. Thus, a knee is formed between the strongback 4 and brace unit 5 when the drilling device 22 is again lowered. During the rising and lowering operation a new drill pipe is placed on the raising/lowering table 25 and is transferred from the drill floor to the horizontal initial position of the pipe handling apparatus. When a drill string is retrieved the apparatus works in the opposite sequence. It should further be appreciated that the apparatus naturally can be used for round trip operations as well.

Claims: Pipe handling apparatus adapted for automated drilling operations, where drill pipes (10) are manipulated between substantially horizontal positions and vertical drill centre positions, for use with hoisting means and with a top mounted drilling device (22) which is rotatably connected to the hoisting means about a substantially horizontal first axis (1) and is hoistable up and down in a fixed, upright derrick (20), characterised in that said apparatus includes a strongback (4) carrying means (6, 7, 8) for holding and manipulating pipes (10), said strongback having one end portion rotatably connected to the hoisting means about said first axis (1) for movement up or down along with said drilling device (22), but for rotation independently thereof, a brace unit (5) rotatably connected to said strongback (4) about a second axis (2) spaced apart from said first axis (1), and mounting means (32) provided with a third axis (3) spaced apart from said first and second axes (1, 2), about which one end portion of said brace unit (5) is rotatable. Pipe handling apparatus as defined in claim 1, characterized in that the means for holding pipes (10) comprise several spaced apart arms (6) including clamps (7) and means operating said clamps (7) to grip around said pipes (10). Pipe handling apparatus as defined in claim 2, characterized in that the means for manipulating pipes (10) comprise means (8) synchronously operating said arms (6) for inserting or retracting drill pipes (10) relative to the drilling device (22). Pipe handling apparatus as defined in claims 2 or 3, characterized in that each arm (6) is articulated and is slidable along said strongback (4), and each arm (6) has stop means (11) preventing it from turning towards said drilling device (22) more than approximately an orthogonal position relative to said strongback (4) when the arms (6) are manipulated. Pipe handling apparatus as defined in any of claims 1 to 4, characterized in that the space between said first (1) and said second (2) axis, and the space between said second (2) and said third (3) axis is adjustable by means of pinion (17)/ratchet (18) means driven by a motor (16) or the like. Pipe handling apparatus as defined in any of claims 1 to 5, characterized in that said third axis (3) is restrictedly movable in a substantially vertical way, in a slot or a coulisse guide (13). Pipe handling apparatus as defined in any of claims 1 to 6, characterized in that the horizontal space between said third axis (3) and the drill centre (14) is less than the space between the longitudinal axis of the strongback (4) and the longitudinal axis of the pipe (10) in a manipulating position.

Inventors: SLETTEDAL, PER
Applicants: MARITIME HYDRAULICS A.S.
Application year: 1987
Main classification: E21B19
IPC codes: E21B19