WO1999010674A1

WO1999010674A1 - An apparatus and a method for mounting a coherent conduit in a groove in a pipe string

Info

Publication number: WO1999010674A1
Application number: PCT/NO1998/000251
Authority: WO
Inventors: Karluf Hagen
Original assignee: Karluf Hagen
Priority date: 1997-08-27
Filing date: 1998-08-26
Publication date: 1999-03-04
Also published as: NO973934L; AU9008698A; NO973934D0; NO305668B1

Abstract

A signal cable (14) is mounted within a longitudinal groove in a production riser string (12) being lowered down into an oil/gas well. A cable mounting robot (10) is adapted to mill out a longitudinal groove cross-sectionally, mainly complementarily conforming to the signal line (14), and to place the line (14) into the groove simultaneously with the lowering of the production riser (12) down into the well. By means of the cable mounting robot (10), the groove is formed through a plurality of grinding/milling operations, so that the outermost pipe wall material at the groove mouth can be folded up and, thereupon, back again, the line (14) being inserted in an intermediate operation. When the line (14) is positioned within the groove, adjusted rollers (44, 46, 48) roll over the groove edge portions folded out at the mouth, and roll these back over the line (14) for protective, partial encapsulating and fixing thereof, at least at intervals, longitudinally and laterally.

Description

AN APPARATUS AND A METHOD FOR MOUNΗNG A COHERENT CONDUIT IN A GROOVE IN A PIPE STRING

The invention relates to an apparatus and a method for mounting a continuous line, conduit, cable, hose, etc. within 5 a longitudinal groove in a pipe string assembled or being assembled, respectively, of individual pipes having screw threads at interconnectable ends, said pipe string being intended for installation in an oil/gas well.

Usually, the threaded pipe ends consist of an internally 10 threaded joint socket at one end and a therewith cooperating, externally threaded joint pin at the other end, one pipe's pin end being screwed into an adjacent pipe's socket upon relative rotation of the pipes.

The line may consist of an electric line/optical signal 15 cable/power line assumed to be continuous; this in opposition to a line assembled of a larger number of line lengths which have to be jointed by means of end connectors substantially more comprehensive in the radial direction than the line itself. Such joined electronic lines may often give rise to a 20 number of sources of error. Therefore, it is aimed to offer favourable conditions for using a continuous electronic conductor extending non-joinedly in the full length thereof from a surface position to a downhole instrument/downhole tool.

Today, in order to maintain a connection between e.g. permanently installed downhole measuring instruments within a deep well ( > 2000 metres) and surface position, it is used a reinforced electric line suspended on the outside of the production riser, substantially parallelly thereto. The line is attached to the riser string at intervals of 10 metres by means of steel clamps.

When the production riser string is lowered down into the casing set within the well, it will twist according to the course of the bore hole path and give rise to radially directed forces which may result in that the line becomes stuck between the production tubing string and the casing.

In order to make the line withstand these forces without being damaged, it is often built in to a protecting reinforcement, protective clamps being mounted between line and pipe string at equal intervals, most often across each individual pipe ' s threaded socket where the outer diameter is the largest.

This reinforcement which may consist of a wire, as well as the protective attaching clamps cause that the reinforced line's diameter becomes larger than what is required for the signal transfer and the insulation, about 80 % of the reinforced line's entire thickness being constituted by the wire which is to accommodate the weight of the whole reinforced line, the remaining 20 % being constituted by a steel jacket surrounding the conductor, protecting the conductor proper and the insulation against damages caused by clamping. Thus, such a reinforced line attains quite a considerable thickness, requiring that the clearance between the production riser and the casing is kept within a maximum measure range, reducing the diameter of the production riser. However, in spite of the vigorous shape and design, it was found that such reinforced lines were subjected to breakage as a result of previous clamping damages.

If an (non-reinforced) electronic conductor, e.g. in the form of a signal/power line, could be drawn radially into a longitudinal groove formed in a pipe's outer wall layer, the line would achieve a mounting in which the pipe accommodates the forces which previously had to be accommodated by the reinforcement when the line was mounted on the outside of the pipe. Simultaneously, the pipe wall portions defining the longitudinal groove will form partially surrounding protection wall portions efficiently preventing the line drawn into the pipe from being squeezed and damaged between production riser string and casing. A line protected in this way comprises only the conductor core and the insulation, and it is, consequently, very thin in comparison to reinforced, encapsulated lines. Thus, the longitudinal accommodating groove in the pipe wall does not have to exhibit a large opening cross-sectionally . Increasing the pipe wall thickness of a pipe having a longitudinal groove with an adequate opening cross-section for a line of this kind with about 20 % as compared to those pipes used today, one can avoid the heavy, expensive and space-demanding reinforcement, and still maintain the same strength properties of a pipe having a groove as those of a pipe having a somewhat smaller wall thickness and lacking a groove.

In principle, this may be achieved in that a non- reinforced/unprotected line of the kind concerned is mounted within a groove formed in the outer wall layer of a pipe. Such a groove may substantially have the same depth and width as the diameter of the line. It is known per se to form such a longitudinal groove in a pipe for protective accommodation of a hydraulic hose; confer Norwegian laying-out publication No. 178,836, in which a production tubing portion is provided with a longitudinal groove in order to accommodate a hydraulic line, the characteristic features being defined to consist in that the groove is filled with a fixing agent (a soldering material) around the hydraulic line, so that the tubing portion exhibits a continuous tubular surface.

U.S. patent specification No. 4,683,944 deals with very thick-walled drilling pipes/production tubes for use in connection with sub sea wells, wherein, in the pipe wall, are formed longitudinal, axially extending fluid channels or, respectively, between two concentric pipelines, are disposed a number of small pipelines; each of which may convey a special fluid of its own.

These are very expensive special pipe strings to be used when the sub sea well produces a plurality of mutually differing fluids.

A substantial disadvantage of prior art technique is that the line placed into the longitudinal groove and secured therein can not be taken out again, i.e. that it has to be considered as permanently interconnected with the pipe string. Another substantial disadvantage of prior art technique is that it presupposes the use of a line assemblable of line lengths, giving rise to a number of sources of error. Therefore, according to the invention, it is a basic presupposition that one continuous, non-joined electronic signal conductor/ power line could be used, said line extending from a surface position to the bottom of the sub sea well.

Such joints must be pressure tested, and each pressure test for each joint takes about 30 minutes. The joint connectors have considerable lateral dimensions and would not have appropriate space in a longitudinal groove substantially dimensioned on the basis of the line diameter. In accordance with the present invention, one has aimed at remedying deficiencies, disadvantages and restrictions of use associated with known technology.

Said objects are realized by means of an apparatus and a method distinguished through features as defined in following claims.

In accordance with a first aspect of the present invention, the longitudinal groove is first machined/ milled/cut in the individual pipe lengths, i.e. prior to their screwing together to form a pipe string. This is known per se from Norwegian laying-out publication No. 178,836. However, according to the present invention, favourable conditions have been offered in order to secure that the formed grooves subsequently to the screwing together, constituting the second working operation, come into alignment with each other in the longitudinal direction of the pipe line being built up.

By means of technique known per se it is possible to secure a sufficient degree of accuracy at the mutual alignment of the individual pipe grooves. One may use mechanical screwing based on the allotment of exactly the same torsional moment at each revolution, so that the rotation is stopped after a certain number of revolutions upon the completion of the screwing operation and adjacent longitudinal grooves are substantially aligned. Such a screwing process based on use of the same torsional moment may be combined with special threads, so-called "'stop shoulder threads'' (delivered e.g. from Vallourecs VAM and Mannesman BDS) .

According to the invention, the pipe wall material milled out during the configuration of the groove may be rolled back in place again when the line is being mounted within the groove. A pipe string having a line inserted into and secured within the groove thereof can be rotated; this may not be possible with a known pipe string where several lines are joined and exhibit laterally comprehensive connectors.

In accordance with a special feature of the invention, a cable mounting robot machines a groove adjusted for the line, simultaneously as the pipe string is being lowered down into the sub sea well. Thus, adaption of the course of the longitudinal grooves of the individual pipes is avoided, and the whole process is simplified.

In the protected and relieved position of the line, where it is drawn radially into the longitudinal groove in the pipe string, the line is locked firmly to the groove-defining pipe wall faces, both laterally and longitudinally, so that the need for the line to carry its own weight is eliminated.

Apparatus and method according to the present invention is further explained in the following specification, reference is being made to accompanying drawings, in which:

Figure 1 shows in partial side elevational view an apparatus (a cable mounting robot) mounted with support legs on a drill floor and surrounding a vertically orientated tubing from two opposite sides; the drill floor being shown in cross-section;

Figure 2 shows a corresponding partial side elevational view, as seen from the right hand side in figure 1 (arrow II) ;

Figure 3 is a top plan view, showing a grinding disk in the process of forming/grinding a longitudinal groove in the vertically orientated tubing;

Figure 4 is an enlarged detail view of a portion in figure 3 and shows a rectangular cross-sectional shape exhibited by the longitudinal groove formed in the outer wall portion of the tubing; Figure 5 corresponds to figure 3 , but here the grinding disk is substituted by a milling disk, which is the first of two milling disks (confer figure 7) which, in the next working operations, mill out the side walls of the groove, below the uppermost edge of the groove, corresponding to the cross- sectional shape of the line;

Figure 6 corresponds to figure 4, but here is shown an enlarged portion in figure 5;

Figure 7 corresponds to figure 5, but here is shown the other milling disk in operation;

Figure 8 corresponds to figures 3, 5 and 7, but here the operational tool (e.g. the milling disk in figure 7) is substituted by a plough-shaped wedge folding up and laterally outward pipe wall portions defining the upper edges of the groove;

Figure 9 is an enlarged portion in figure 8, illustrating the cross-sectional shape of the groove compared to the contours of the wedge;

Figure 10 corresponds to figures 3, 5, 7 and 8, illustrating how the mentioned line is pressed into position within the groove by means of a guide pulley;

Figure 11 is an enlarged portion in figure 10, illustrating the embedment of the line as seen from above, and showing milled-out pipe wall portions/ flanges, one at either side of the line;

Figure 12 corresponds to figures 3, 5, 7, 8 and 10, but here the operational tool consists of a first one of two profiled rollers (confer figure 14) rolling the flanges gradually back into the original position, so that they partially cover the inserted line, keeping it in position in the longitudinal groove in the pipe string;

Figure 13 is a portion in figure 12, shown in an enlarged partial view;

Figure 14 corresponds i.a. to figure 12, but here the first profiled roller is substituted by the other profiled roller for rolling in the other flange portion of pipe wall material;

Figure 15 is a portion in figure 14 shown in an enlarged detail view;

Figure 16 corresponds to figures 3, 5, 7, 8, 10, 12 and 14, but here the operational tool consists of a smooth (non- profiled) roller rolling across the groove opening defining portions, pressing inwardly projecting portions, aligned with the pipe surface, so that the line is trapped within the groove;

Figure 17 is a portion in figure 16 shown in an enlarged detail view;

Figure 18 shows two mutually aligned pipe end portions intended to be screwed together and which, prior to the screwing operation, is formed with a longitudinal individual groove each; said grooves shall be brought into alignment with each other subsequently to the screwing operation.

First, reference is made to figures 1 - 3. A cable mounting robot 10 is shaped, designed and adapted to be installed on the outside of a pipe 12, preferably a tubing riser included in a riser string to which a coextensive electric signal line 14 is to be assigned. The line 14 should, in a continuous condition, be capable of being inserted in a continuous groove (e.g. figure 6), following a substantially aligned course from one single pipe to another single pipe.

Reference numeral 18 denotes the drill floor and 20 the wedge hole.

The cable mounting robot 10 rests with support legs 22 on the drill floor 18 and surrounds the production tubing riser 12 as well as bears against the mantle face thereof with two groove depth adjusting wheels 24 and a counter wheel 26, the framework 28 of the cable mounting robot 10 being assigned two hydraulic pressure cylinders 30 adapted to create a constant clamping force independently of changes in the outer diameter of the pipe 12.

When the tripping in of the tubing riser 12 is started, it will pass the various operational tools 32, 34, 36, 38, 40, 44, 46 and 48 (to be further described later) of the robot 10, figures 1 and 2, said tools following each other successively and being positioned along a vertical working path for the pipe 12. During the downward feeding of the pipe, the robot 10 carries out milling of the groove 16, folding out thereof, the insertion of the line 14, folding in of groove-defining edge portions at the opening and clamping in thereof in order to lock the line 14 within the groove 16 by means of working operations following each other successively, distributed across a short, concentrated, longitudinal portion of the pipe being treated.

Reference numeral 50 denotes a drive motor operating a first treating tool, a rotary grinding disk 32 adapted to grind out a coarsely shaped groove to be later treated and adapted to conform to the cross-sectional shape of the line 16. The ground groove is adjusted to the diameter of the line 16, the depth of the groove being adjustable by means of the two groove depth adjusting wheels 24 mounted parallel with the grinding disk 32 spaced therefrom a distance adjusted according to the thickness of the line 16.

When these groove depth adjusting wheels 24 which simultaneously function as guide wheels for the grinding disk 32, meet an internally threaded joint socket having a larger diameter than the pipe 12 proper, they will roll up on the portion having the larger diameter, simultaneously raising the grinding disk 32. This effect secures that the dimension of the groove at any time can be kept within the measures allowed.

The grinding disk 32 secures grinding of a coarse originating groove 16 defined by a straight bottom and two opposed straight side walls.

By means of two milling disks 34 and 36 following after the grinding disk 32 and after each other in the vertical direction, the walls of the groove 16 are milled out in the next working step, below its outermost edge, on the right and left hand side, respectively, complementarily corresponding to the cross-sectional shape of the line, figures 5 and 7.

According to figure 8, the tubing 12 has arrived at the working tool 38 of the robot 10, consisting of a plough- shaped wedge engaging into the groove 16. By means of this wedge 38, the outermost edges of the groove 16 are folding out laterally, such as appearing from figure 9. Thus, a kind of funnel is formed, guiding the line 14 into the groove 16.

Subsequently to the plough-shaped wedge 38, the hitherto formed groove 16 in the pipe 12 meets a set of guide wheels 42 for a controlled insertion of the mentioned line 14 into the groove 16, see figures 1, 10 and 11, where an end portion of a line 14 is threaded inbetween two pairs of guide wheels; each pair comprising two opposing wheels, the line's end portion being guided slopingly in toward the bottom of the groove with the free outer end thereof, which immediately meets a working tool 44 in the form of a first profiled roller (a roller for rolling down the left edge flange) followed by a second profiled roller 46 (a roller for rolling down the right edge flange) . The rollers 44 and 46 roll the flanges back to take their original positions, and the cross- sectional shape of the rollers 44 and 46 is adjusted to the shape of the respective flanges. During these rolling operations, the flange portions F at the groove mouth are pressed partially over the line 14, figures 14 and 15.

In figure 16, the place on the pipe/groove 12/16 which at any time is being worked for the very last time, has arrived at a level on the robot 10 where a completion roller 48 having a smooth outer mantle face is mounted. This roller enters into activity when said flange portions F have been folded towards each other, and clamps them inwardly, evenly with the pipe surface, so that the line 14 is firmly locked within the groove as shown in figure 17. Thus, the line 14 is practically encapsulated within the pipe wall and well protected against mechanical influence from external forces. The locking of the line 14 within the groove 16 will also secure the accommodation of the weight of the line 14, so that the line does not have to exhibit such a large tensile strength as known lines for the same purpose.

Figure 18 shows in a partial side elevational view two vertically mutually aligned pipe end portions 12a and 12b intended to be screwed together in order to be included in a tubing riser string assembled of many such joined single pipes.

Each of the two partially shown pipes 12a and 12b is formed with an internally threaded socket end 52a and an externally threaded pin-shaped connecting end 52b. Each of the pipes 12a, 12b is prior to the screwing operation, i.e. contrary to the the embodiment according to figures 1 - 17, formed with a longitudinal groove 16a and 16b, respectively.

In opposition to the embodiment in figures 1 - 17 , one has to take appropriate measures in order to bring the longitudinal grooves 16a and 16b to flush with each other at the same time as the pipe ends are screwed finally together to end the screwing operation. One may use screwing mechanisms where the torsional moment exerted is the same for each revolution, or similar mechanisms where the milled out longitudinal groove in one pipe upon the achievement of a predetermined maximum moment is brought to stop at a fixed point. The above- mentioned mechanisms may possibly be combined with the use of so-called stop shoulder threads which come to bear when one has carried out the desired relative rotation of the pipes 12a, 12b which, from mutual rotational starting positions between the pipe ends, dictates the simultaneous achievement of the completion of the screwing operation and the alignment or approximate alignment, respectively, of the longitudinal grooves 16a, 16b.

Claims

C l a i m s

1. An apparatus for forming at least one longitudinal groove (16) in a pipe string (12) consisting of a plurality of single pipes (12a, 12b) screwable together and to be installed in an oil/gas well, and for mounting and attaching at least one continuous electric line/conductor, cable, hose, etc., e.g. a signal line (14), within said longitudinal groove (16), c h a r a c t e r i z e d i n that said apparatus comprises a cable mounting robot (10) adapted to machine a line-adjusted longitudinal groove (16) in the pipe string (12) for the line (14) , the line (14) being mounted within the longitudinal groove (16) simultaneously as the pipe string (12) is being lowered down into the well.

2. An apparatus as set forth in claim 1, c h a r a c t e r i z e d i n that the cable mounting robot (10) is adapted to fold pipe wall material (F) at the groove mouth laterally outwards and, thereupon, to mount the line (14) at the bottom of the longitudinal groove (16) , and that the robot (10) further is adapted to roll pipe wall material (F) folded outwards back into position when the line (14) is in place within the longitudinal groove (16) in order to encapsulate it partially.

3. An apparatus as set forth in claims 1 and 2 , c h a r a c t e r i z e d i n that the robot (10) is adapted to roll pipe wall material (F) folded outwards over and inwardly against installed line (14) , so that the latter is fixed/locked at least at intervals within the longitudinal groove (16) longitudinally as well as laterally, so that the pipe string (12) is brought to accommodate the weight of the line (14) .

4. An apparatus as set forth in claim 1, 2 or 3, char a ct e r i z ed i n that the cable mounting robot (10) comprises the following working tools, calculated from a position (32) in which the working of the pipe (12) starts and from there in succession: a grinding disk (32) a first milling/grinding disk (34) , a second milling/grinding disk (36) , a plough-shaped wedge steel (38) , a set of guide wheels for guiding a signal line (14) inwards to the bottom of the internally formed groove (16) , whereupon follows a roller, preferably a profiled roller (44) , for rolling out projecting pipe wall material, and thereupon another roller, preferably a profiled roller (46) , for a corresponding purpose, whereupon, possibly, follows a smooth roller (48) .

5. An apparatus as set forth in claim 4 , c h a r a c t e r i z e d i n that the robot's (10) framework (28) , in opposed relation to said working tools (32-38, 44-48), has a counter roller/wheel (26) which, in a position of use, will roll on the opposite side of the pipe (12) as compared with the remaining tools.

6. A method for mounting a continuous electric line/conduit/conductor, cable, hose, etc., such as a signal line (14) , within a longitudinal groove (16) in a pipe string (12) which is assembled by means of single pipes (12a, 12b) screwable together, said pipe string (12) together with said line (14) being intended to be installed in a sub sea oil/gas well, c h a r a c t e r i z e d i n that the pipe string (12) , simultaneously as it is being lowered down into said well, is worked in order to form a longitudinal groove (16) therein, the cross-section thereof being adjusted according to the cross-section of a continuous line (14) , said longitudinal groove (16) , in an intermediate condition being formed with projecting flanges (F) of pipe wall material at the groove mouth, said flanges (F) being rolled back subsequently to the line's (14) insertion into the groove (16) , so that the line (14) is partially encapsulated within the groove (16) and, wherein, pipe wall material rolled back, at least at intervals, lock the line (14) to the faces/corners between faces defining the groove (16) .

7. A method as set forth in claim 6, c h a r a c t e r i z e d i n that the pipe string (12) , in order to form a longitudinal groove (16) therein, as well as to insert, partial encapsulate and lock the line (14) is subjected to the following treating working operations in succession: grinding of a consecutive longitudinal groove (16) , milling/grinding side portions defining the groove (16) , corresponding to the cross-section of the line (14) , preferably in two milling/grinding operations carried out internally within the ground, coarsely formed groove; guiding the signal line (14) therein, whereupon follows rolling of laterally projecting pipe wall material in the area of the mouth of the groove (16) , preferably carried out in two working operations, in order to partially encapsulate and fix the line (14) within the groove and, possibly, concluding external rolling along the groove mouth in that, preferably, one or more counter wheels (26) are disposed, bearing against the pipe's (12) outer mantle face at the opposite side of the treating tool.

8. A method for mounting an electric line/conduit/conductor, cable, hose, etc., such as a signal line (14), in a pre- machined, longitudinal groove (16) in a production riser string (12), c h a r a c t e r i z e d i n that a cable mounting robot (10) folds pipe wall material (F) at the groove mouth outwardly laterally and, thereupon, places the line (14), etc., into the pre-machined, longitudinal groove (16) , at the bottom thereof, and that the robot (10) further rolls pipe wall material folded out, back into place when the line (14) takes its position within the longitudinal groove (16) in order to, thus, encapsulate the line at least partially.

9. A method as set forth in claim 8, ch a r a c t e r i z e d i n that the robot (10) rolls pipe wall material folded out, across and inwardly against the line (14) laid into the pre-machined longitudinal groove (16) , so that the line (14) is fixed/locked, at least at intervals, within the longitudinal groove longitudinally as well as laterally.