WO2013032343A1

WO2013032343A1 - Apparatus for preparation and lubrication of a threaded portion of a drill pipe

Info

Publication number: WO2013032343A1
Application number: PCT/NO2012/050156
Authority: WO
Inventors: Gisle FRANTZEN
Original assignee: Frantzen Gisle
Priority date: 2011-08-31
Filing date: 2012-08-29
Publication date: 2013-03-07
Also published as: NO334307B1; NO20111187A1

Abstract

An apparatus (1) for preparing and lubricating an internal threaded portion (21) in the box (20) of a drill pipe (2), the apparatus (1) being provided with a collar (61) arranged to rest against an upper edge portion (22) of the box (20), the collar (61) being provided with a through bore (610) for a displaceable tool (6) arranged to be moved projectingly into the box (20), the displaceable tool (6) being provided with at least one first channel (63) which is in communication, in terms of fluid, with a preparation-fluid reservoir (593) or a lubricant reservoir (595), and the tool (6) further being provided with one second channel (67) which is in communication, in terms of fluid, with a receiving reservoir (597).

Description

APPARATUS FOR PREPARATION AND LUBRICATION OF A THREADED PORTION OF A DRILL PIPE

The invention relates to the preparation of an internal female threaded portion of a drill pipe and the application of a lubricant to the female threaded portion. More particularly, the invention relates to an apparatus which prepares and applies a lubricant to the female threaded portion as a drill string is being pulled out of a borehole or a well and before the drill pipe is stored.

In petroleum recovery, a drill string is used to drive a drill bit which is drilling a hole or a well in the bedrock. The drill string is constituted by various types of drill pipes. This is known within the art and is not discussed any further. The drill pipes are provided with a threaded portion at either end. In the position of application, the upper threaded portion is constituted by a threaded female part, termed a box within the art. The lower threaded portion is constituted by a threaded male part termed a pin end.

A lubricant, referred to as dope within the art, is applied to threaded portions. Dope is used to prevent wear on the threaded portions in connection with making up and breaking out the pipe connections. Make-up and break-out may be done with machines, so-called iron roughnecks. These may be remote-controlled and the makeup or break-out takes place at great speed.

The pulling-out of the drill string is done by the driller running a draw-works in such a way that a block with a pipe collar, a so-called elevator, gets down to the upper end portion of the drill string, which is projecting up through a drill floor. The elevator is closed around the drill string, holding the drill string fixed. The driller runs the block up in a derrick with the entire drill string hanging on the elevator. When one or more joints of drill pipe has/have been pulled up above the drill floor, the drill string is locked to the drill floor. At the same time, manipulator arms come out, grip around the drill string and hold the drill string fixed. The elevator is opened and the block is run down towards the drill floor again. At the same time, the iron roughneck is run out, and it unscrews the threaded connection. The free drill pipe is lifted by the manipulator arms so that the pin end comes up from the box. The drill pipe is withdrawn from the longitudinal axis of the drill string, also termed the well centre, and is put down in a so-called "set back" area which may include a fingerboard. The iron roughneck is run back and, again, everything is ready for the block to pick up the next drill pipe. The method is repeated until the entire drill string is out of the well and has been brought up to the drill floor.

It is known that when the drill string is pulled out of the well and separated into the individual drill pipes, there will be residues of old dope left in the threaded portions of the drill pi pes. After the separation of the drill pipes, the drill pipes are placed in the fingerboard of the derrick. If new dope is not applied to the female part after separation, the old dope will dry out during the time for which the drill pipe is stored until the d rill pipe is again made up to form the drill string.

When the drill pipes are pulled out of the well and placed in the fingerboard, they may still be wet inside from a medium that has been pumped through the drill string, or from a medium that is in the well. There will always be liquid in the well. The medium may be a drilling mud or a drilling fluid, so-called mud. As the drill string is being separated, the residues of this medium will run out of the drill pipe at the pin end and contaminate the threaded portion in the box at the top of the drill pipe projecting above the drill floor.

The optimum way of applying dope to the threaded portion of the drill pipe is by manually applying dope to the threads in the box by means of a brush or the like. This is done when the drill string is being pulled out, as the box is projecting up through the drill floor. For safety reasons, access to the drill floor has been restricted more and more. The method of running the drill string into the well and pulling the drill string out is remote-controlled. Today, in many jurisdictions, it is not allowed for personnel to be present on the drill floor until all equipment is at a standstill. In consequence of this, dope is not applied manually to the threaded portion of the box as the drill pipes are being separated. Dope should optimally have adherence to clean metal and should not be applied to a newly washed, wet threaded portion.

A problem in preparing the threaded portion of the box is that there may be mud in the drill pipe. The mud completely or partially covers the threaded portion of the box. The mud must be removed and the threaded portion dried before dope may be applied to the threaded portion. There is no need to apply dope to the threaded portion at the pin end if dope is applied to the threaded portion of the box. However, the threaded portion at the pin end must be clean before the drill pipes are screwed together.

Solutions in which dope is applied to the pin end are known. This application does not take the dried-up dope in the box into account. This is a considerable drawback to the connection that is formed between two drill pipes, where the connection is to be subjected to large stresses. The making-up of two successive drill pipes in a drill string is carried out until a moment of force determined by the dimensions and type of threads of the drill pipes is achieved. The correct moment of force is achieved when the threads are clean and have had the correct amount of dope applied to them. Some of the moment of force will have to be spent to overcome the resistance from contaminants in the threads, like old, dried-up dope, for example.

Some iron roughnecks are arranged to be able to apply dope to the threaded portion of the box as the drill string is pulled out of the well. Patent document W095/25216 discloses an iron roughneck which is provided with a manipulator arm. The

manipulator arm may carry a tool up to the well centre and away from the well centre and position the tool vertically for adjustment to the free end of the drill string above the drill floor. The tool may include a cleaning tool and a lubricating tool for the threaded portion of a box. It appears from the last paragraph on page 3 of the description that cleaning and lubricating are carried out as the pipe string is made up. The method assumes that there is no fluid standing in the box. The manipulator arm may also be provided with a collector for mud running out of the pin end of the drill pipe as the drill pipe is disconnected from the drill string. The apparatus is not arranged to remove fluid from the box.

Patent document US2004/0049905 discloses an iron roughneck which includes an apparatus for cleaning and applying dope to a threaded portion, and a collector unit for mud running out of the pin end of the drill pipe as the drill pipe is disconnected. It appears from page 6, paragraph [0055], of the description that cleaning and lubricating are carried out as the pipe string is being made up. The method assumes that there is no fluid standing in the box and the apparatus is not arranged to remove fluid from the box.

Patent document WO 2007/037698 discloses a power tong in which the gripping jaws are provided with nozzles for the application of a detergent and dope to the internal threaded portion of the box and the external threaded portion of the pin end. The application takes place as the drill pipe is screwed together with the drill string. Patent document WO 99/60245 discloses an apparatus for cleaning and lubricating the threaded portion of a box and the threaded portion of a pin end of a drill pipe which has been withdrawn from the well centre and before the drill pipe is placed in a fingerboard. Fluid in the drill pipe has run out of the drill pipe prior to cleaning and lubrication. The apparatus is not arranged to remove fluid from the box.

Patent document WO2005/093203 discloses an apparatus for cleaning and applying dope to the external threaded portion of the pin end. The threaded portion is first washed with water, then it is blow-dried with air and then dope is applied to it. This takes place in an area in the vicinity of the well centre before the well string is made up or after the drill pipe has been separated from the drill string. This is known within the art as the "Dysvik bucket" (Norwegian: "Dysvikb0tten"). One disadvantage of this apparatus is that the metal does not have the time to dry before dope is applied to it. Dope is applied to wet metal and adherence between dope and threads will be poor because the metal is wet. Parts of the dope will run off before the drill pipes are screwed together. The apparatus is not arranged to clean and lubricate internal threads in a box.

Patent document US 3971442 discloses an apparatus for cleaning the external threaded portion of the pin end before the drill pipe is screwed together with the drill string. The apparatus does not apply dope to the threaded portion. Patent document 4160457 discloses a hand-held apparatus for cleaning the threaded portions of the pin end and box with pressurized water and without the use of brushes. The apparatus does not apply dope to the threaded portion. Patent document US 4011617 discloses an apparatus for cleaning the pin end and box by means of brushes before the drill pipe is screwed together with the drill string. The apparatus does not apply dope to the threaded portions.

There is thus a need for an apparatus and a method in which the threads of the box are prepared and have dope applied to them before the drill pipe is put aside in a fingerboard. The apparatus should be able to operate in a work zone on a drill floor and in such a way that the efficiency or the rate at which the drill pipes are pulled out of the hole is not reduced. The apparatus must be easily removable from the operative zone on the drill floor for maintenance. The operative zone on the drill floor is the zone to which personnel does not have access during a drilling operation.

A remote-controlled apparatus is provided, which is arranged to first prepare the internal threaded portion of the box and then apply dope to the internal threaded portion. If necessary, the apparatus removes mud from the box as part of the preparation. The apparatus is operated independently of the iron roughneck and moves towards or from the well centre from a different side to that of the iron roughneck. In one embodiment, this may be from the opposite side of the iron roughneck or, in another embodiment, 90° to the moving direction of the iron roughneck.

While the block is on its way down the derrick and the iron roughneck is being withdrawn from the well centre, the apparatus is moved up to the well centre and prepares the internal threaded portion in the box of the well pipe projecting through the drill floor, and applies dope to the internal threaded portion.

In one embodiment, the apparatus is moved along rails in the drill floor which is arranged for guiding a tong for screwing together casing, a so-called casing tong. Many drill floors are provided with such rails. Moving the apparatus up to the well centre and moving back from the well centre may be performed with a first actuator, for example a hydraulic cylinder corresponding to a hydraulic cylinder like one with which many casing tongs are provided. The apparatus may be provided with an undercarriage adapted to the rails.

The apparatus is moved up to the well centre, and an arm which is provided with a tool arranged to clean the box and apply dope is raised so that the tool gets into its starting position. This starting position will typically be at the well centre right above the drill pipe which is held fixed in the drill floor. For example, the box of the drill pipe will be 1.5 metres above the drill floor. The arm may be raised into its starting position while the apparatus is moved forwards towards the well centre. In the starting position, the tool is moved downwards by means of a second actuator and is moved into the box. The working length of the second actuator may be, for example, approximately 1 metre. The ideal height for the box of the drill pipe above the drill floor will be, for example, approximately 1 metre.

The tool may include three concentric pipes. The pipes may be connected, in terms of fluid, with respective reservoirs via a valve housing. The inner pipe is connected to a pump to suck up fluid from the box. The middle pipe carries dope to the box for dope to be applied to the inner threaded portion of the box. The outer pipe is for supplying a preparation fluid, such as pressurized air.

While the tool is being lowered down inside the box, mud is sucked out of the box. At the same time, pressurized air is supplied, blowing the internal threaded portion clean. While the tool is lifted up and out of the box, the internal threads are sprayed with dope. The tool is arranged to suck mud in the box, so that the fluid level is brought to be lower than the lowermost part of the internal threaded portion. This may be, for example, 30 cm below the upper edge portion of the box. If there is not any mud in the box, the tool and/or the valve block may be arranged to leave out the sucking of mud. In such a case, the box will be blown clean with pressurized air while the tool is being lowered, and dope is applied to the threads while the tool is being lifted. When the tool has been lifted so high that the lower portion of the innermost pipe is higher than the upper edge portion of the box, the apparatus is moved away from the well centre by means of the first actuator.

The enclosed figures show schematically and in further detail the structural features of the apparatus.

The invention has for its object to remedy or reduce at least one of the drawbacks of the prior art or at least provide a useful alternative to the prior art.

The object is achieved through features which are specified in the description below and in the claims that follow.

In a first aspect, the invention relates to an apparatus for preparing and lubricating an internal threaded portion in the box of a drill pipe, the apparatus being provided with a collar arranged to rest against an upper edge portion of the box, the collar being provided with a through bore for a movable tool arranged to be moved projectingly into the box, the movable tool being provided with at least one first channel which is in communication, in terms of fluid, with a preparation-fluid reservoir or a lubricant reservoir, and the tool further being provided with one second channel which is in communication, in terms of fluid, with a receiving reservoir.

The first channel of the apparatus may be in communication, in terms of fluid, with the preparation-fluid reservoir and the tool may further be provided with a third channel which is in fluid communication with the lubricant reservoir.

The third channel of the apparatus may be formed as an annulus between an inner pipe and a middle pipe. The first channel may be formed as an annulus between an outer pipe and a pipe lying within. The first channel and the second channel may be formed as annulus between concentric pipes. The first channel, the second channel and the third channel may be formed as annulus between concentric pipes.

A suction opening which is in communication, in terms of fluid, with the second channel may project beyond a preparation nozzle which is in communication, in terms of fluid, with the first channel. The suction opening may project down beyond a lubricating nozzle which is in communication, in terms of fluid, with the third channel. At least one of the first, the second and the third channels may be provided with a valve for controlling the fluid flow through the channel.

The apparatus in accordance with the invention may be provided with an actuator for moving the tool into the box and out of the box along an axis substantially coinciding with the axis of a well centre. The apparatus may be provided with a pivotable arm for horizontally and vertically positioning the tool above the box of a drill pipe which extends above a floor. The apparatus may be provided with a movable trolley arranged to accommodate the arm. The trolley may be arranged to be moved linearly in towards and away from the well centre. The trolley may be arranged to be moved linearly in towards and away from the well centre in a different direction from that of an iron roughneck.

In what follows, an example of a preferred embodiment is described, which is visualized in the accompanying drawings, in which :

Figure 1 shows a schematic side view of an apparatus for preparing and lubricating the box end of a pipe string projecting above a deck;

Figure 2 shows the apparatus of figure 1 from another side;

Figure 3 shows, on a larger scale, a section through the tool of the apparatus for cleaning and lubrication and an enlarged detail;

Figure 4 shows, on a smaller scale than figure 3, a section through the tool and the channels of the tool, an enlarged detail and, schematically, the fluid reservoir of the tool; and

Figure 5A-C show, on yet another scale, examples of the position of the tool in a box.

In the drawings, the reference numeral 1 indicates an apparatus for cleaning and lubricating an internal threaded portion 21 in the box 20 of a drill pipe 2 as shown in figures 5A-C. In one embodiment, the apparatus 1 may include a trolley 3 which can be moved back and forth along a deck 9 by means of a hydraulic cylinder 31. The wheels 33 of the trolley 3 may be arranged to be moved along a guide (not shown) in the deck 9. The guide may be rails. The trolley 3 may be provided with a frame 35 and a lifting member 37. In figure 1, the lifting member 37 is shown as an eye. A base 40 is secured to the bottom portion 39 of the trolley 3. In an alternative embodiment (not shown), the base 40 may be rotatably secured to the bottom portion 39 of the trolley 3 around a vertical axis. An arm 42 is pivotably attached, at its first end portion 43, to the upper end portion of the base 40. The arm 42 is pivoted around its pivot axis by means of at least one actuator 44. In figures 1 and 2, this is shown as two hydraulic cylinders 44, one hydraulic cylinder 44 on either side of the base 40.

At its second end portion 45, the arm 42 is provided with a cleaning and lubricating unit 5. The cleaning and lubricating unit 5 is pivotably attached to the end portion 45 and can be pivoted relative to the arm 42 by means of an actuator 46 which is attached, at its one end portion, to the arm 42 and is attached, at its other end portion, to the cleaning and lubricating unit 5.

The cleani ng and lubricating unit 5 includes a tool frame 50 which is pivotably attached to the end portion 45 of the arm 42. The tool frame 50 is provided with an actuator 52 which, in its working position, is arranged to move a tool 6 up and down along a guide 54 following an axis 8.

The tool 6 is shown in the greatest detail in figure 3. In this exemplary embodiment, the tool 6 is shown with three concentric pipes, an outer pipe 62, a middle pipe 64 and an inner pipe 66, respectively. The outer pipe 62 and the middle pipe 64 form, between them, a first annulus which constitutes a first channel 63. The inner pipe 66 forms an internal second channel 67. The middle pipe 64 and the inner pipe 66 form, between them, a second annulus which constitutes a third channel 65. One end portion of the pipes 62, 64, 66 has been passed through a collar 61 in a through bore 610. The collar 61 may be moved along the jacket surface 620 of the outer pipe 62. The collar 61 may substantially be constituted by a soft material such as rubber.

At their lower end portions, the pipes 62, 64, 66 are provided with different tips 7, respectively a cleaning tip 72, a lubricating tip 74 and a suction tip 76. The cleaning tip 72 forms a preparation nozzle 73 directed substantially radially, projecting radially outside the jacket 620 of the outer pipe 62. The preparation nozzle 73 is in

communication, in terms of fluid, with the first channel 63. In figure 3, the preparation nozzle 73 is shown with an upper part 730 which is threadedly attached to the pipe 62, and with a lower part 732 which is attached to the upper part 730 by a screw connection 734. The number of preparation nozzles 732 is adapted to be such that preparation fluid is distributed evenly around the inside of the box 20. The collar 61 may rest on the upper part 730 of the preparation nozzle 73. The suction tip 76 forms an axial extension of the inner pipe 66, and the suction tip 76 is threadedly attached to the pipe 66. The suction tip 76 forms a suction opening 760 which is in communication, in terms of fluid, with the second channel 67. At its lower portion, the third channel 65 is defined by a sealing ring 740 which is threadedly attached to the outer jacket 660 of the inner pipe 66. The lubricating tip 74 is provided, at its distal portion, with lubricating nozzles 75 directed substantially radially. In its simplest form, this may be constituted by radial bores 75 at the distal portion of the pipe 64, as it is shown in the drawings. In other embodiments, nozzles of a type known per se may be used. The lubricating nozzle 75 is in communication, in terms of fluid, with the third channel 65. The number of lubricating nozzles 75 and the positioning of the lubricating nozzles 75 in the lubricating tip 74 are adapted to be such that lubricant is distributed evenly over the entire internal threaded portion 21.

The pipes 62, 64, 66 are terminated, at their upper end portions, in a connection block 56 as it is shown in figure 4. The connection block 56 is provided with connection ports 563, 565 and 567. The connection port 563 is in communication, in terms of fluid, with the first channel 63. The connection port 565 is in communication, in terms of fluid, with the third channel 65. The connection port 567 is in communication, in terms of fluid, with the second channel 67. Figure 4 shows an example of how the pipes 62, 64 and 66 have been attached to the connection block 56 and connected to the connection ports 563, 565 and 567. This is not discussed any further as a skilled person will know how this can be done and that this can be done in different manners known per se. Necessary sealing means, such as gasket elements, are not shown in the figures.

Figure 4 shows schematically that the connection ports 563, 565 and 567 are connected, in terms of fluid, to respective reservoirs, 593, 595 and 597, respectively, through the channels 583, 585 and 587. The channels 583, 585 and 587 can be opened and closed with valves (not shown) in a valve housing 58. The valves in the valve housing 58 may be manually or automatically controlled, as it is known within the art. The reservoir 593 may be a container for pressurized gas. The reservoir 595 is a container for lubricant. The reservoir 597 is a receiving reservoir for fluid which is pumped out of the box 20 by means of a pump 59. Necessary pumps, valves, power supply and controls are not shown, and the skilled person will know how this can be arranged.

In figure 5, the tips 7 are shown in different positions when the tool 6 is placed above a box 20 so that the longitudinal direction of the tips 7 along the axis 8 substantially coincides with the axis of the well centre. The actuator 52 moves the tool 6 into the box 20. The loose collar 61 will abut against the upper edge portion 22 of the box 20 and rest against the upper edge portion 22 while the tool 6 is moved further into the box 20, as shown in figure 5A. When the cleaning tip 72 is substantially at the height of the upper edge portion 22 of the box 20, as shown in figure 5B, preparation fluid may flow out of the preparation nozzle 73 to clean the inner threaded portion 21. The preparation fluid may be pressurized air. Pressurized air will blow away loose particles from the inner threaded portion 21 and have a drying effect on the internal threaded portion 21. In an alternative embodiment, the preparation fluid may be a cleaning fluid, and pressurized air may be supplied to the box by means of a fourth channel (not shown).

If there is fluid in the box 20, this is sucked out through the tip 76 while the tool 6 is moved down the box 20. At the desired depth, as shown in figure 5C, the downward movement of the tool 6 is stopped. The supply of preparation fluid through the preparation nozzle 73 is stopped. A lubricant, such as dope, is forced out through the lubricating nozzles 75 and the lubricant coats the cleaned internal threaded portion 21.

In an alternative embodiment, the tool 6 includes two concentric pipes 62 and 66 that, between them, form an annulus which constitutes the first channel 63. The channel 63 is alternatingly connected, in terms of fluid, to the reservoir 593 and the reservoir 595. As the tool 6 is lowered into the box 20 the preparation fluid flows from the reservoir 593 and out of the nozzle 73. As the tool 6 is lifted in the box 20, the lubricant flows from the reservoir 595 and out of the nozzle 73. The valve housing 58 is arranged, in a manner known per se, to switch the fluid flow between the reservoirs 595, 595 and the first channel 63.

Claims

C l a i m s

1. An apparatus (1) for preparing and lubricating an internal threaded portion (21) in the box (20) of a drill pipe (2), the box end of the drill pipe (2) projecting above a deck, the apparatus (1) being provided with a collar (61) arranged to rest against an upper edge portion (22) of the box (20), the collar (61) being provided with a through bore (610) for a displaceable tool (6) arranged to be moved projectingly into the box (20), the displaceable tool (6) being provided with at least one first channel (63) which is in communication, in terms of fluid, with a preparation-fluid reservoir (593) or a lubricant reservoir (595), c h a r a c t e r i z e d i n that the tool (6) is further provided with one second channel (67) which is in communication, in terms of fluid, with a receiving reservoir (597).

2. The apparatus (1) in accordance with claim 1, c h a r a c t e r i z e d i n that the first channel (63) is in communication, in terms of fluid, with the preparation-fluid reservoir (593) and that the tool (6) is further provided with a third channel (65) which is in fluid communication with the lubricant reservoir (595).

3. The apparatus (1) in accordance with claim 2, c h a r a c t e r i z e d i n that the third channel (65) is formed as an annulus between an inner pipe (66) and a middle pipe (64).

4. The apparatus (1) in accordance with claim 1, c h a r a c t e r i z e d i n that the first channel (63) is formed as an annulus between an outer pipe (62) and a pipe (64; 66) lying within.

5. The apparatus (1) in accordance with claim 1, c h a r a c t e r i z e d i n that the first channel (63) and the second channel (67) are formed as annulus between concentric pipes (62, 64; 62, 66).

6. The apparatus (1) in accordance with claim 2, c h a r a c t e r i z e d i n that the first channel (63), the second channel (67) and the third channel (65) are formed as annulus between concentric pipes (62, 64, 66).

7. The apparatus (1) in accordance with claim 1, c h a r a c t e r i z e d i n that a suction opening (760) which is in communication, in terms of fluid, with the second channel (67), projects down beyond a preparation nozzle (73) which is in communication, in terms of fluid, with the first channel (63).

8. The apparatus (1) in accordance with claim 2, c h a r a c t e r i z e d i n that a suction opening (760) which is in communication, in terms of fluid, with the second channel (67) projects down beyond a lubricating nozzle (75) which is in communication, in terms of fluid, with the third channel (65).

9. The apparatus (1) in accordance with claim 1, c h a r a c t e r i z e d i n that at least one of the first channel (63) and the second channel (67) is provided with a valve for controlling the fluid flow through the channel (63, 67).

10. The apparatus (1) in accordance with claim 2, c h a r a c t e r i z e d i n that at least one of the first channel (63), the second channel (67) and the third channel (65) is provided with a valve for controlling the fluid flow through the channel (63, 65, 67).

11. The apparatus (1) in accordance with claim 1, c h a r a c t e r i z e d i n that the apparatus (1) is provided with an actuator (52) for moving the tool (6) into the box (20) and out of the box (20) along an axis (8) substantially coinciding with the axis of a well centre.

12. The apparatus (1) in accordance with claim 1, c h a r a c t e r i z e d i n that the apparatus (1) is provided with a pivotable arm (42) for positioning the tool (6) horizontally and vertically above the box (20) of a drill pipe (2) projecting above a deck (9).

13. The apparatus (1) in accordance with claim 12, c h a r a c t e r i z e d i n that the apparatus (1) is provided with a movable trolley (3) arranged to accommodate the arm (42).

14. The apparatus in accordance with claim 13, c h a r a c t e r i z e d i n that the trolley (3) is arranged to be moved linearly in towards and away from the well centre.

15. The apparatus in accordance with claim 14, c h a r a c t e r i z e d I n that the trolley (3) is arranged to be moved linearly in towards and away from the well entre in a direction different from that of an iron roughneck.