EP2440737B1 - Device for connecting electrical lines for boring and production installations - Google Patents

Description

The invention relates to a device for connecting electrical lines to be screwed together, substantially tubular connecting elements of drill pipes. Different examples are in the documents US 3,518,609 US 4,557,538 and US 6, 123, 561 to find.

An essential element in modern oil, gas or geothermal wells is the data acquisition during the drilling process. The same also applies to the construction of the borehole or the subsequent petroleum, gas or hot water production. Only by recording the respective, relevant measured variables can a well be operated safely, efficiently and economically. However, a problem arises in the real-time data transmission of measured data to the surface of the drilling rig. From several kilometers deep, the data is to be transmitted at a high data rate (e.g., 200kBaud).

At present, drilling rigs are sometimes using simple steel tubes without cabling. The tubes are bolted at regular intervals (e.g., 9 meters). In this way, a several kilometers long drill pipe, at the end of which the drill bit is located, emerges. Inside the pipes is the flushing fluid (mud) which fulfills many functions during the drilling process. One of these functions in the prior art is the transmission of data by means of pressure pulses. Since this communication is very slow (e.g., 10 baud), more and more methods have been sought which use other transmission mechanisms (sonar, ground currents, etc.). The most efficient solutions have been presented, which are connected to a wiring of the drill string (electricity, light, etc.). Once the drill pipe is connected by electrical cables or conductive layers, high speed data transmission is possible.

In principle, two methods are possible. Some prototypes work with galvanic connections between the individual tubes of the boom. Partially commercially available systems use a magnetic coupling between the tubes. The currently used magnetic coupling only allows data transmission.

The intention to wire a drill string encounters several problems simultaneously.

Steel pipes must be manufactured or retrofitted with heat-resistant, mud-resistant, pressure-resistant cables without affecting the load-bearing capacity of the drill string and hindering the personnel when screwing the pipes.

In order to enable data transmission in the drill string, the problem of the electrical connection between the pipes has to be solved. The electrical connection must be made reliable, simple and robust in the mechanical connection of the tubes (rotating movement). The biggest challenge in getting an electrical connection which can transmit power and / or data is the screwing movement during the screwing process of the individual drill string (pipes). In addition, the drilling process, due to high pollution and liquids of all kinds, represents a harsh environment. This challenge is to be overcome in order to develop a successful, operational system.

This object is achieved in a device of the type mentioned in that a first electrical contact element is fixedly arranged on a connecting element and that on the other connecting element, a second electrical contact element in the direction of rotation of the connecting element is slidably disposed.

The construction solves the problem that during the screwing of the two connecting elements, two components of movement occur, namely one in the circumferential direction and one in the axial direction of the connecting elements. Due to the fact that one of the two contact element is movable in the circumferential direction, it may rotate in the production of electrical or galvanic connections between the two contact element with the other connecting element, so that the two connecting elements are connected to each other only via the axial movement component have to.

In a preferred embodiment of the invention, the movable contact element is arranged on a rotatably arranged on the connecting element ring, wherein the ring is preferably an outer ring of a slip ring. Slip rings are proven and robust components in electrical engineering, which can also be used in the present case to compensate for the rotating movement component during the connection of the two connecting elements.

The proposed solution is suitable for data transmission in the drill string based on cabled pipes (e.g., steel or CFRP pipes) whose wiring is galvanically connected to the pipe ends.

The wiring can be done with a two-wire, heat-resistant power cable, which is laid in a protective tube (chemical resistance). On the surface, both electrical energy and data can be fed into this cable. In the case of the rotating drill string this is done with slip rings. In the pipe, this cable is routed to a connection element, which produces a good conductive connection to the next pipe.

DC voltage in the mains voltage range can preferably be used for the supply of energy. The adaptation to all possible supply networks takes place once before the feed-in.

In addition to the data communication, the problem of the power supply of the data transmission elements (modem, repeater, transceiver, etc.) can also occur. Because the drill pipe can be several kilometers long (eg 20 km), the problem of data transmission over long lines to solve. High-speed data transmissions (eg fieldbus systems) can only be used for a few 100 meters without a repeater. However, the use of many repeaters requires a sufficient voltage supply. However, this is problematic at long distances and many repeaters due to the voltage drops. The installation of batteries in the repeaters solves the problem of energy transfer, but leads to poorly maintainable, unreliable systems (battery replacement, battery failure). Another problem is the installation of repeaters in the drill pipe due to the lack of space.

To solve the problem is proposed in the invention that a carrier frequency system is connected to the electrical lines.

For the supply of the data by means of a carrier frequency system, a narrow-band OFDM (orthogonal frequency divison multiplex, multi-carrier) method can be used. This method is also known under "Power Line Communication (PLC)". Modems using this method are currently being used in remote power supply remote metering or distributed remote communication (DLC) networks. It succeeds over conventional power supply lines without additional cabling information exchange over several kilometers without repeaters with data rates of a few hundred kilobaud.

With such a modem, the data is modulated onto the power supply in several carrier frequencies, fed with slip rings in the drill string and transferred in the rotating drill string via the connecting elements at the pipe ends to the receiving point (consumer, electronic measuring system) in the borehole. Several such modems can not only receive energy but also data through the connected power supply.

Advantages of this problem solution include the fact that the use of PLC modulation does not require separate cabling for data communication. This solution is therefore economical. For the desired drill string length (about 20km) no repeaters are necessary, which solves space or energy problems. Since no separate data cabling is necessary, eliminating additional galvanic contacts on the pipe connections. Since no repeaters are necessary, the necessary amount of energy is reduced so that in an economical choice of the necessary conductor cross-section (eg 4-6mm ² ) a mains voltage (eg 400V) is sufficient to the required energy (eg 200W) to a ca. 20km to bring distant consumers.

The presence of a permanent power supply allows the cooling of electronic systems in the drill string and thus allows a larger drilling depth (temperature coefficient in the hole about 3.3 ° C / 100m) or longer residence time. Energy and data supply enables a range of new applications. Limiting the supply voltage to, for example, 400V allows the choice of a standard cable (eg 240 / 400V) and reduces the required isolation distances in the mechanical design of the system components compared to high voltage systems.

Further preferred embodiments of the invention are the subject of the remaining dependent claims.

Further features and advantages of the invention will become apparent from the following description of a preferred embodiment of the invention with reference to the drawings.

Fig. 1

eine Ausführungsform einer erfindungsgemäßen Vorrichtung in einer explosionsartigen-Darstellung,

Fig. 2

die Vorrichtung im zusammengebauten Zustand im Schnitt,

Fig. 3

ein Detail der Vorrichtung vom Fig. 2 in vergrößertem Maßstab,

Fig. 4

einen Teil der erfindungsgemäßen Vorrichtung

Fig. 5

ein Detail vom Fig. 4 in vergrößertem Maßstab,

Fig. 6

einen weitern Teil der erfindungsgemäßen Vorrichtung,

Fig. 7

einen anderen Teil der erfindungsgemäßen Vorrichtung

Fig. 8

einen Teil der erfindungsgemäßen Vorrichtung in einer explosionsartigen Darstellung,

Fig. 9

einen Schnitt durch einen Teil der erfindungsgemäßen Vorrichtung,

Fig. 10

einen Schnitt durch anderen Teil der erfindungsgemäßen Vorrichtung,

Fig. 11

ein Gestängerohr mit einer Box und einem Pin und

Fig. 12

ein Detail der Box am Gestängerohr von Fig. 11.

It shows:

Fig. 1

an embodiment of a device according to the invention in an exploded view,

Fig. 2

the device in the assembled state in section,

Fig. 3

a detail of the device from Fig. 2 on an enlarged scale,

Fig. 4

a part of the device according to the invention

Fig. 5

a detail of Fig. 4 on an enlarged scale,

Fig. 6

a further part of the device according to the invention,

Fig. 7

another part of the device according to the invention

Fig. 8

a part of the device according to the invention in an exploded view,

Fig. 9

a section through a part of the device according to the invention,

Fig. 10

a section through another part of the device according to the invention,

Fig. 11

a drill pipe with a box and a pin and

Fig. 12

a detail of the box on the drill pipe of Fig. 11 ,

In Fig. 1 an embodiment of a device according to the invention is shown, which is used for connecting drill pipes 32, for example drill strings in drilling rigs. The device according to the invention comprises a first connecting element 1, which is referred to as a "pin" in the sequence, and a second connecting element 2, which is referred to in the sequence as "box" on. The pin 1 and the box 2 are connected in a manner not shown with drill pipes 32, which may be made for example of steel, CFRP or GRP. The inner diameter of the pin 1 and the box 2 substantially corresponds to the inner diameter of the drill pipe 32, whereas the outer diameter of the pin 1 and the box 2 is larger than the outer diameter of the drill pipe 32.

At pin 1, a slip ring 3 and a catch ring 4 are rotatably received, which are surrounded by an outer ring 5 in the assembled state. The diameter of the outer ring 5 is slightly larger than the diameter of pin 1 and box 2 and made of a wear-resistant material, so that it can serve as a wear part, easily replaced can protect pin 1 and box 2 from excessive wear. At its end facing the box 2 6, the pin 1 has a conically tapered outer diameter with an external thread. In contrast, the box 2, at its end 7 facing the pin 1, has a conically widening inner diameter with the same cone angle and an internal thread. The pin 1 and the box 2 can be screwed together in this way by a few rotations over a relatively long length.

The slip ring 3 is how Fig. 8 shows in detail, from an inner ring 8, which is arranged on the pin 1, and an outer ring 9 which is rotatable relative to the inner ring 8 in the circumferential direction. In the axial direction of the outer ring 9 is fixed relative to the inner ring 8. The slip ring 3 is - apart from the below-explained details - otherwise known as known from the prior art.

On the outer ring 9, two electrical contact elements in the form of contact pins 10 are arranged in the illustrated embodiment, which are electrically connected to brushes of the outer ring 9. It can be the same number of contact pins 10 as sliding contacts on the slip ring 3 may be present. But it is also possible to provide a particularly secure electrical connection, per sliding contacts, for example, two pins 10 provide. Alternatively, it is also possible to provide more sliding contacts than contact pins 10 by default, in order to provide the possibility of further electrical connections between the pin 1 and the box 2, if required.

In the Fig. 5 and 6 the catching ring 4 is shown in more detail. He has four through holes 11 for pins 10 in the illustrated embodiment. In addition, it has on the slip ring 3 side facing receptacles 12 (eleven receptacles 12 in the illustrated embodiment) for compression springs 13, which are supported on the end face 14 of the outer ring 9. The compression springs 13 are completely absorbed in the receptacles 12 in the compressed state. On the receptacles 12 and compression springs 13 opposite side a catch pin 15 is slidably mounted in the axial direction against a compression spring, not shown, on the catching ring 4. On the same side on which the catch pin 15 is located, the passage openings 11 are closed by a seal 16, which, however, can be penetrated by the contact pins 10 and after retraction of the contact pins 10, the passage openings 11 also closes again.

On the outer circumference of the catching ring 4 on the slip ring 3 side facing on a bead 17, a sealing ring 18, for example, an O-ring arranged. The outer ring 5 is screwed by a thread 21 with the pin 1 and the catching ring 4 lies with its sealing ring 18 on the inside of the outer ring 5 sealingly. Furthermore, a groove 19 in the region below the catching ring 4 is arranged on the pin 1, in which a sealing ring 20, for example an O-ring, is located, which also seals against the inside of the catching ring 4. Through the thread 21 and the seal rings 18 and 20, the space in which the slip ring 3 is located, be sealed.

On the catch ring 4 side facing the box 2 on the one hand a catch opening 22 for the catch pin 15 and on the other hand contact elements in the form of two contact sockets 23. Since only two pins 10 are used in the embodiment shown in the drawings, only two contact sockets 23 are present. In addition to the two contact sockets 23 two more receptacles 24 are arranged, which can be equipped with contact sockets 23 if necessary. In Fig. 3 It can be seen that the contact sockets 23 and the receptacles 24 are also closed by a seal 25, which can also be penetrated by the contact pins 10 and after retraction of the contact pins 10, the contact sockets 23 close again. The seal 25 is in Fig. 7 not shown.

The seals 16 and 25 are perforable seals and may for example be made of rubber and be provided from the beginning with a perforation, which facilitates the penetration and withdrawal of the contact pins 10, although it must be ensured that the seals 16 and 25 without pins 10 are so dense that no spark or arc can be skipped or ignited when the pins 10 or contact sockets 23 are under tension to minimize any risk of explosion. In addition, the seal must prevent the risk of contamination and the ingress of various liquids under the harsh conditions of a drilling process.

In Fig. 9 a section of the box 2 is shown, in which a bore 26 leading from the interior of the box 2 at first outward and also a bore 27 which branches off in the axial direction and leads to a recess 28 in which the contact bushes 23 are included. Through these holes 26 and 27 and optionally an unillustrated elbow, the contact sockets 23 can be connected to a arranged in the interior of the drill pipe 32 line. In Fig. 10 is a section through the pin 1 shown, in which a bore 29 can be seen, which leads from the interior of the pin 1 to the slip ring, not shown in this drawing. In this way, a line arranged in the interior of a drill pipe 32, optionally via a pin 1 in the interior of the bore 28 subsequent, not shown elbow, are also connected to the sliding contacts of the inner ring 8.

As a rule, a pin 1 will be arranged on a drill pipe 32 at one end and a box 2 on the other end, the respective contact elements (contact pins 10 and contact bushes 23) being connected to one another via the electrical line extending inside the drill pipe 32. By screwing together of drill pipes 32 via a respective pin 1 and a box 2, a continuous electrical line running along the entire drill string can thus be produced.

The screwing together of pin 1 and box 2 takes place according to the invention as follows. In a separate state of pin 1 and box 2, the catching ring 4 is pushed away from the compression springs 13 so far from the outer ring 9, that its bead 17 and its sealing ring 18 rests against an inwardly projecting projection 30 of the outer ring 5. Since the outer ring 9 is not axially displaceable, the tips of the contact pins 10 are so far in the catching ring 4 pulled inwards that they are behind the seal 16 and do not penetrate. If the box 2 is inserted over the conical end 6 of the pin 1 and thereby twisted to screw the box 2 to the pin 1, the box 2 comes with its end face 31 first in contact with the catch pin 15, against the force of its compression spring is pushed back into the catching ring 4 and at the latest after a complete rotation of the box 2 into the catching hole 22 engages.

From this moment on the box 2 and the catching ring 4 and the contact pins 10 of the outer ring 9 are rotated with. As soon as the thread begins to grip between pin 1 and box 2, the catching ring 4 is pressed further and further against the outer ring 9 until it rests completely against it. During this movement, the pointed catching pins 10 first begin to penetrate the seal 16 and subsequently the seal 25 until they penetrate into the contact bushes 23 and establish an electrical connection. Since the catching ring 4 and the box 2 are aligned by the catch pin 15 in the circumferential direction exactly to each other, an exact entry of the contact pins 10 is ensured in the contact sockets 23.

When the connection between pin 1 and box 2 is disconnected again, when unscrewing pin 1 and box 2, the catch ring 4 is pushed away from the outer ring 9 by the compression springs 13, so that the contact pins 10 are pulled out of the contact bushes 23. The compressive force of the compression springs 13 must therefore be so great that both the friction of the contact pins 10 in the contact bushes 23 and the seals 16, 25 and the friction of the sealing rings 18, 20 can be safely overcome. The length of the contact pins 10 and the spring travel of the catching ring 4 are coordinated so that the catching ring 4 only then releases from the end face 30 of the box 2, when the contact pins 10 are withdrawn so far that they no longer the seals 16, 25 penetrate, so that a safe separation of Pin 1 and Box 2 is guaranteed.

The construction solves the problem that during the screwing of the two connecting elements, two components of movement occur, namely one in the circumferential direction and one in the axial direction of the connecting elements. Due to the fact that one of the two contact element is movable in the circumferential direction, it may rotate in the production of electrical or galvanic connections between the two contact element with the other connecting element, so that the two connecting elements are connected to each other only via the axial movement component have to.

The compensation of the relative movement of the pin 1 and the box 2 for the preparation of the electrical connection during the Verschraubungsprozess can also be done in other ways. Essential is the resolution of the degrees of freedom of movement between the pin 1 and the box 2 in the screw in the circumferential direction and in the axial direction. It must by a device the position of the one contact element 10, e.g. the plug position in pin 1, with the position of the other contact element 23, e.g. the socket position in box 2, while screwing in so aligned that the electrical contact pins hit the electrical sockets. This can preferably but not necessarily be done via spring-loaded or electrically or magnetically activated catch pins 15, which are placed on pin 1 or on the box 2 and ensure positioning of the contact pins during Verschraubprozesses in the circumferential direction.

In Fig. 11 a drill pipe 32 is shown, on which at one end a pin 1 and at the other end a box 2 are arranged. Im in Fig. 11 illustrated embodiment, the drill pipe 32, the pin 1 and the box 2 are made in one piece, which is a possible embodiment. In general, the drill pipe 32, the pin 1 and the box 2 but be separate components, which are firmly connected.

In order to be able to lay an electrical line within the drill pipe 32, in one embodiment of the invention a cable pipe 33 can be arranged within the drill pipe 32, which via elbows 34, 35 to the pin 1 and the box 2 or the bores 26, 29 provided therein are connected. In the holes 26, 29 fittings 36 are used, which seal the holes 26, 29 via conical shoulders 37 against the interior of the drill pipe 32. In these fittings 36, the elbows 34, 35 screwed tight.

One or more electrical lines can be laid in this way from the pin 1 to the box 2, without coming into contact with the flushing liquid located inside the drill pipe 32.

The electrical connection may e.g. be made by means of slip rings, wherein the electrical transmission between the outer ring and inner ring by means of balls (such as a ball bearing), or by means of two mutually abrasive metal rings (such as a plain bearing) or by means of electrical brushes can take place.

However, it is also possible to use a cable to compensate for the rotational movement, e.g. on a cable drum, which is provided with a spiral or coil spring, wound up. It would also be possible, for example, to use a spiral or helical spring itself as an electrical conductor which compensates for the relative movement between the movable contact element and the pin 1 or the box 2.

Claims (16)

1. Device for connecting electrical lines on essentially tubular connecting elements (1, 2) of drill pipes (32) that can be screwed together, characterised in that on one connecting element (1) a first electrical contact element (10) is arranged and movable in a direction of rotation of the connecting element (1), and in that on the other connecting element (2) a second electrical contact element (23) is arranged in a fixed manner.
2. Device according to Claim 1, characterised in that the movable contact element (10) is arranged on a ring (9) that is rotatable on the connecting element.
3. Device according to Claim 2, characterised in that the ring (9) is an outer ring of a slip ring (3).
4. Device according to one of the Claims 1 to 3, characterised in that the contact element (10) on the ring (9) is at least one contact pin protruding from the ring (9) in an axial direction.
5. Device according to Claims 2 and 4, characterised in that in the axial direction ahead of the ring (9) a capture ring (4) is arranged, which has a passage opening (11) for the contact pin (10).
6. Device according to Claim 5, characterised in that the capture ring (4) has a preferably spring mounted capture pin (15) which can engage in a capture opening (22) on the other connecting element (2).
7. Device according to Claim 5 or 6, characterised in that the capture ring (4) is movable in a longitudinal direction of the contact pin (15) relative to the slip ring (2).
8. Device according to Claim 7, characterised in that the capture ring (4) can be moved from a first position, in which the tip of the contact pin (10) lies within the capture ring (4), into a second position, in which the tip of the contact pin (10) lies outside the capture ring (4).
9. Device according to Claim 7 or 8, characterised in that the capture ring (4) is pushed by at least one spring (13) from its first position in the direction towards the second position.
10. Device according to one of the Claims 5 to 9, characterised in that the passage opening (11) has a seal (16) on the side facing away from the slip ring (2).
11. Device according to one of the Claims 4 to 10, characterised in that the contact element (23) arranged in a fixed manner is a contact bush, which has a seal (25) on the side facing towards the other contact element (10).
12. Device according to Claim 10 or 11, characterised in that the seal (16, 25) is a seal that can be perforated, e.g. a rubber seal.
13. Device according to one of the Claims 2 to 12, characterised in that the ring (9) and the capture ring (4) are surrounded by an outer ring (5).
14. Device according to Claim 13, characterised in that the outer ring (5) has an outer diameter that is larger than the outer diameter of the connecting elements (1, 2).
15. Device according to one of the Claims 1 to 14, characterised in that holes (26, 27; 29) are arranged in the connecting elements (1, 2), through which the electrical lines lead.
16. Device according to one of the Claims 1 to 15, characterised in that a carrier frequency system is connected onto the electrical lines.

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