EP2150674B1 - Method and device for verifying the casing of a pipeline when the pipeline is inserted into a liquid-filled borehole - Google Patents

Abstract

Disclosed are a method and a device usable in said method for verifying the casing (4) of a pipeline (3). According to the invention, the pipeline (3) is inserted into the liquid-filled borehole (6) by means of an electrically non-conductive pulling head (2), whereby a measuring apparatus (5) can verify, when the pipeline is laid, whether the casing (4) of the pipeline (3) is not damaged.

Description

The present invention relates to a method of checking the envelope of a pipeline during installation in a fluid-filled wellbore in a ground, wherein an advancing device exerts a compressive force on a drill head via a pipeline and a device which can be used and an isolation coupling.

State of the art

Various types of construction and techniques are suitable for the trenchless laying of pipelines, eg the controlled horizontal drilling technique (HDD = Horizontal Directional Drilling) or the controlled pipe jacking (Microtunneling). In addition, other techniques have been recently developed and tested, such as the so-called direct pipe (DP) method. In the latter method, a prefabricated pipe string is pushed by a feed device into the ground, wherein the hole position is made by a mounted on the front of the pipe string drill head. This process is described in detail in the patent application DE 10 2006 020 339.9 and US 2007/0053749 A1 described.

US 2007/0053749 A1 EP 0 751 041, which is provided as the closest prior art, discloses a method, a device and a drawing head for laying a pipeline in a borehole in the ground. In this case, a coated pipe is connected to a connecting element, at the front end of the pulling head is arranged. The pipeline itself is with a flexible coating provided, which is fastened with a clamping element on the connecting element. The pulling head is then connected to a drill head and pulled by means of the boring bar located in the borehole by pulling the boring bars.

During the laying process, damage to the anti-corrosive coating of the pipeline may occur if e.g. Sharp-edged stones or other obstacles destroy them by pressure or shear. If such damage has taken place, the pipeline can sometimes be adequately protected against corrosion by additional measures (keyword: active corrosion protection) if the damage is not too great. In the event of major damage, however, it may be necessary to remove the pipeline from the borehole once again in order to be able to repair the damaged areas. As a rule, this retraction of the pipeline succeeds only if it takes place immediately after the drawing-in process, since otherwise the pipeline can be sedimented in the ground and can no longer be moved. In any case, such accidental measures are associated with considerable time and expense.

Whether such damage to the anticorrosive coating occurred during the drawing process or not, can be found so far only after completion of the installation process by appropriate measurements (keyword: sample feed) are performed, with the help of the polarizability of the steel and thus the state of the enclosure are determined can.

In principle, such measurements are made by exposing and cleaning the tubing at both ends so that the tubing does not have an electrically conductive connection to the bottom (e.g., via the drilling fluid). To determine the polarizability of the negative pole of a DC voltage source is then connected to the pipe to be tested and the positive pole to a makeshift earth electrode. By switching the current on and off at certain time intervals as well as measuring the associated switch-on and switch-off potentials, it is possible to conclude the condition of the tube envelope.

So far, these measurements are only possible after installation, as otherwise a current fed in at the end of the pipe would flow directly back through the metallic connections at the drill head into the ground and this current flow could thus provide no information about the condition of the pipe casing.

Technical task

The present invention has for its object to allow such measurements already during the installation process, in order to be able to interrupt the Einziehvorgang promptly to damage occurrence in case of damage to the sheath and the pipe again

The technical problem is solved by the pipeline is connected via a pulling head with the Zuggestänge, although the tensile and compressive forces can transmit, but is electrically non-conductive. As a result, sample feeds can be made during the drawing process, which actually allow conclusions to be drawn about the condition of the coating.

Advantages of the invention

• Zeitnahe Feststellung einer Beschädigung der Umhüllung während des Einziehvorgangs.
• Reduzierung des technischen Risikos (Festwerden der Rohrleitung).
• Reduzierung der mit der Reparatur einhergehenden Kosten.
• Einfache und damit kostengünstige Bauweise des Ziehkopfes.
• Keine oder nur sehr geringe Anpassung der Arbeitsweise für den Einziehvorgang erforderlich.

The main advantages over the previous method of operation are:

• Timely detection of damage to the wrapper during the pull-in process.
• Reduction of technical risk (solidification of the pipeline).
• Reduction of the costs associated with the repair.
• Simple and therefore inexpensive construction of the pulling head.
• No or very little adaptation of the procedure for the Einziehvorgang required.

With regard to the method, the object of the invention is achieved in that the tensile force of a drilling rig is transmitted via a drill pipe and a non-electrically conductive section having a pulling head on a pipe and during the Einziehvorgangs the integrity of the surrounding in the borehole of a liquid sheath of a pipe Measuring apparatus is checked. In this way, it is easy to make the review while retracting.

It is advantageous that the measuring apparatus is located outside of the borehole and / or that the measuring device is arranged mobile and / or is moved during the collection of the pipeline substantially simultaneously with the pipeline.

A further teaching of the invention provides that the pipeline is stored outside the borehole on roller blocks, and / or that one end of the Pipeline electrically separated from the ground and / or the fluid-filled hole.

Furthermore, it is advantageous that the check is carried out electrically.

Another teaching of the invention provides that the tensile force of the drilling rig is transmitted via a shaft located in the pulling head, preferably made of steel, on a body, preferably made of steel, which is located in an electrically non-conductive portion within the pulling head and the introduced Traction over the electrically non-conductive portion transmits to a related to the pipeline bearing plate of the pulling head, whereby the pipe connected to the pulling head is subjected to the tensile force required for the pulling operation.

Furthermore, it is advantageous that the electrically non-conductive portion contains an electrically non-conductive material, preferably concrete and / or plastic, with which the tensile force of the drilling device is transmitted to the pipeline. These materials can provide a simple, well-insulated and cost-effective puller.

Furthermore, the object of the invention is achieved by a pulling head for transmitting a pulling force for drawing a pipeline into a hole filled with a liquid from a pulling device on the pipeline, on one side a connection with a drill pipe of a drilling rig for introducing a tensile force for drawing in the pipeline and on the opposite side has a connection possibility with the pipeline to be recovered, and wherein the pulling head has an electrically non-conductive portion which isolates both connection possibilities from each other.

In such a pulling head according to the invention is advantageous if the pulling device is a drilling device, the electrically non-conductive portion consists of an electrically non-conductive material, the electrically non-conductive material is pressure-resistant and / or tensile strength, and the electrically non-conductive material concrete and / or a plastic is. Furthermore, an advantageous embodiment of the invention provides that the electrically non-conductive portion is protected in the pulling direction by a cover against mechanical damage, wherein preferably the cover has no electrically conductive contact to the pulling head and / or to the pipeline.

A further teaching of the invention provides that the drawing head has a body connected to a shaft, preferably made of steel, preferably made of steel, and a bearing plate and that the electrically non-conductive portion of the body and the bearing plate when introduced via the shaft in such an operative connection causes the body to exert a pressure on the bearing plate and / or that the pulling head has a body connected to a shaft, preferably made of steel, preferably steel, and a rear bearing plate, and that the electrically non-conductive portion is the body and the rear bearing plate brings in pressure introduction via the pipe in an operative connection in such a way that the rear bearing plate exerts a pressure on the body.

Furthermore, the technical object is achieved by a device for checking a casing of a pipeline during a collection in a liquid-filled wellbore in which a previously described drawing head is provided, which transmits the pulling force of a drilling rig via a drill pipe to a pipeline and a measuring apparatus is provided which checks, during the drawing process, the integrity of the tubing casing surrounded by a liquid, the measuring device preferably being located outside the borehole.

drawings

Fig. 1:

Prinzipielle Darstellung des erfindungsgemäßen Verfahrens,

Fig. 2a:

Prinzipielle Ausführungsform der erfindungsgemäßen Vorrichtung,

Fig. 2b bis 2g:

Schnittansichten gemäß Fig. 2a,

Fig. 3:

Beispielhafte Ausführungsform der erfindungsgemäßen Vorrichtung für eine Rohrleitung, und

Fig. 4:

Beispielhafte Ausführungsform der erfindungsgemäßen Vorrichtung für eine Rohrleitung mit 600 mm Außendurchmesser mit Darstellung der für die Zugkrafteinleitung nutzbaren Flächen des druckfesten, elektrisch aber nicht leitfähigen Materials.

The method according to the invention and a device which can be used in this case are illustrated with reference to drawings and explained below, wherein the features shown there have exemplary character. The drawings show:

Fig. 1:

Basic representation of the method according to the invention,

Fig. 2a:

Basic embodiment of the device according to the invention,

2b to 2g:

Sectional views according to Fig. 2a .

3:

Exemplary embodiment of the device according to the invention for a pipeline, and

4:

Exemplary embodiment of the device according to the invention for a pipeline with 600 mm outer diameter showing the usable for the tensile force introduction surfaces of the pressure-resistant, electrically but non-conductive material.

embodiments

In Fig. 1 shows the principal possible use of the method according to the invention and a device which can be used in the process. From a drill 1, a liquid well 7 filled hole 6 is first created according to the usual in the horizontal drilling techniques steps (pilot hole, expansion holes). For the pipe laying final closing process then the drill pipe 13 is connected via a reamer 14, various fasteners 15 and the pulling head 2 with the pipe 3.

The pipeline 3 is mounted on roller blocks 19 outside the borehole. The end of the pipe 3 is in air and is thereby electrically separated from the bottom 16 and the well 6 filled with liquid 7. As a result, corresponding measurements for checking the tube sheath 4 can be carried out by a measuring device 5 at the end of the pipeline 3. In a preferred application, this measuring device 5 is mobile and moves during the Einziehvorgangs substantially simultaneously with the pipe. 3

The measuring device 5 is connected to an earth electrode 20 and the pipeline 3. Between the earth electrode 20 and the pipe 3 is a electrical measurement performed. For this purpose, a voltage source (not shown) is provided. If the sheathing 4 of the pipeline 3 is damaged, then this can be detected by the electrical measured values.

In Fig. 2a and Fig. 3 the basic structure of a device according to the invention is shown. The tensile force of the drilling rig 1 is transmitted via the drill pipe 13 via a reamer 14 and various connecting elements 15 on a steel shaft 8. At the end of this steel shaft 8 is a steel body 9. The steel shaft 8 is partially and the steel body 9 completely surrounded by a pressure-resistant, electrically non-conductive material 10. Fig. 2b to Fig. 2g show sectional views through the pulling head 2 and its internal structure.

The front in the pulling direction of the pulling head 2 is protected in a preferred embodiment by a cover 12 against mechanical damage. Steel shaft 8, steel body 9 and cover 12 are connected via the pressure-resistant, electrically non-conductive material 10.

The tensile force applied by the drilling rig 1 (see Fig. 4 ) is transmitted via the steel shaft 8 and the steel body 9 and the pressure-resistant, electrically non-conductive material 10 on a bearing plate 11. This bearing plate 11 is connected directly to the outer jacket of the pulling head 2 and, in turn, to the pipeline 3. In Fig. 4 the relevant areas for the power transmission are displayed. For this purpose, a pipe with an outer diameter of 600 mm is chosen as an example.

The maximum assumed laying force when using the horizontal drilling technique is assumed to be approx. 2,500 kN. This value is already a special case, because the normal pull-in forces are usually only about 500 - 1,500 kN for very long holes for the considered pipe diameter.

In order to transfer the mentioned 2,500 kN over the steel shaft 8, when using a material with about 250 N / mm ² yield strength Shaft diameter of about 113 mm required. The annular gap between the steel shaft 8 and bearing plate 11 should be 50 mm in the example, so that the bore in the bearing plate 11 has a diameter of 213 mm.

With an outer diameter of the pipe 3 of 600 mm and a wall thickness of 12.5 mm, a free cross section within the pulling head 2 of 575 mm remains. If the steel body 9 is again separated from the jacket of the drawing head 2 by a 50 mm wide annular gap, the steel body 9 has an outer diameter of 475 mm.

The area available for the transmission of the forces introduced results from the sectional area of steel body 9 and bearing plate 11. In the example, this area is 141,573 mm ² .

Assuming that the pressure-resistant, electrically non-conductive material 10 has a compressive strength of, for example, 45 N / mm ² (eg concrete C45 / 55), this results in a maximum possible power transmission of 6,371 kN and thus a multiple of the required 25 force of 2,500 kN.

LIST OF REFERENCE NUMBERS

1

drilling rig

2

Pulling head, electrically non-conductive

3

pipeline

4

wrapping

5

measuring device

6

well

7

liquid

8th

steel shaft

9

steel body

10

Pressure-resistant, electrically non-conductive material

11

bearing plate

12

cover

13

Drill pipe (drawbar)

14

reamer

15

fasteners

16

ground

17

Rear cover

18

stiffening

19

rollerstands

20

earthing

Claims (15)

1. Method for monitoring a coating of a pipeline (3) during its insertion into a borehole (6) filled with liquid (7), characterized in that the pulling force of a drilling unit (1) is transmitted to a pipeline (3) via a drill pipe (13) and a pulling head (2) which has an electrically non-conductive portion and, during the insertion operation, the integrity of the coating (4) of the pipeline (3) surrounded by a liquid (7) in the borehole (6) is monitored by a measuring apparatus (5).
2. Method according to Claim 1, characterized in that the measuring apparatus (5) is situated outside the borehole (6) and/or in that the measuring device (5) is arranged in a movable manner and/or is moved substantially simultaneously with the pipeline (3) during the insertion of the pipeline (3).
3. Method according to Claim 1 or 2, characterized in that the pipeline (3) is mounted outside the borehole (6) on roller blocks (19), and/or in that one end of the pipeline (3) is electrically separated from the ground (16) and/or from the borehole (6) filled with the liquid (7).
4. Method according to one of Claims 1 to 3, characterized in that the monitoring is carried out electrically.
5. Method according to one of Claims 1 to 4, characterized in that the pulling force of the drilling unit (1) is transmitted via a shaft (8), preferably made of steel, situated in the pulling head (2) to a body (9), preferably made of steel, which is situated in an electrically non-conductive portion within the pulling head (2) and transmits the pulling force introduced via the electrically non-conductive portion to a bearing plate (11) of the pulling head (2) that is connected to the pipeline (3), whereby the pipeline (3) connected to the pulling head (2) is subjected to the pulling force required for the insertion operation.
6. Method according to one of Claims 1 to 5, characterized in that the electrically non-conductive portion contains an electrically non-conductive material (10) preferably concrete and/or a plastic, by means of which the pulling force of the drilling device (1) is transmitted to the pipeline (3).
7. Pulling head for transmitting a pulling force for inserting a pipeline (3) into a borehole (6) filled with a liquid (7) from a pulling device to the pipeline (3), characterized in that on one side there is a connection possibility with a drill pipe (13) of a drilling unit (1) for introducing a pulling force for inserting the pipeline (3), and on the opposite side there is a connection possibility with the pipeline (3) to be inserted, and in that the pulling head (2) has an electrically non-conductive portion which isolates both connection possibilities from one another.
8. Pulling head according to Claim 7, characterized in that the pulling device is a drilling device (1).
9. Pulling head according to Claim 7 or 8, characterized in that the electrically non-conductive portion consists of an electrically non-conductive material (10).
10. Pulling head according to Claim 9, characterized in that the electrically non-conductive material (10) is compression-resistant and/or tension-resistant.
11. Pulling head according to Claim 8 or 9, characterized in that the electrically non-conductive material (10) is concrete and/or a plastic.
12. Pulling head according to one of Claims 7 to 11, characterized in that the electrically non-conductive portion is protected in the pulling direction against mechanical damage by a covering (12), wherein the covering (12) preferably has no electrically conductive contact with respect to the pulling head (2) and/or with respect to the pipeline (3).
13. Pulling head according to one of Claims 7 to 12, characterized in that the pulling head (2) has a body (9), preferably made of steel, connected to a shaft (8), preferably made of steel, and a bearing plate (11), and in that, during the introduction of tension, the electrically non-conductive portion brings the body (9) and the bearing plate (11) into operative connection via the shaft (8) in such a way that the body (9) exerts a pressure on the bearing plate (10).
14. Pulling head according to one of Claims 7 to 13, characterized in that the pulling head (2) has a body (9), preferably made of steel, connected to a shaft (8), preferably made of steel, and a rear bearing plate (17), and in that during the introduction of pressure, the electrically non-conductive portion brings the body (9) and the rear bearing plate (17) into operative connection via the pipeline (3) in such a way that the rear bearing plate (17) exerts a pressure on the body (9).
15. Device for monitoring a coating of a pipeline during an insertion into a borehole filled with liquid, characterized in that a pulling head (2) according to one of Claims 7 to 14 is provided which transmits the pulling force of a drilling unit (1) via a drill pipe (13) to a pipeline (3) and a measuring apparatus (5) is provided by means of which the integrity of the coating (4) of the pipeline (3) surrounded by a liquid (7) in the borehole (6) is monitored during the insertion operation, wherein the measuring device (5) is preferably situated outside the borehole (6).

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