The invention relates to a piping or tubular structure, for use in an oil or gas environment, wherein the piping is provided with an RFID tag for identification purposes.

During drilling operations, for example as it is common in connection with the recovery of petroleum, a relatively great number of pipes are used, the pipes being screwed together into a pipe string. The pipe string may also include other equipment, for example controls and valve sections. A well of this kind is normally lined with casing in order to secure the borehole.

In order to keep track of the number of pieces of equipment and their physical condition, it has turned out to be useful to monitor the service time and stresses of the i ndividual pipes and associated equipment, and also to keep track of the number and where the individual pipe is located in the pipe string.

It is known for an electronic ID tag to be placed on the pipe or equipment, which is read manually by means of matched equipment when the pipe is run into the well and when it is pulled from the well. US patent 5142128 thus discloses an apparatus for identifying equipment related to the recovery of oil, which is also arranged to keep track of the service time of the equipment. The document describes a hand-held reading device for electronic ID tags.

Electronic ID tags of the kind concerned here, are mounted on the outside of the pipes near the connecting means of the pipes. Thereby, the ID tags can be read when passing an antenna. This positioning entails that the ID tags are subjected to wear during the moving of the pipe in the borehole and to damage from, for example, power tongs during make-up and break-out operations. It has also turned out that the attachment of the ID tags in the pipes is adversely affected by relatively large pressure variations in the well.

Equipment according to the prior art exhibits drawbacks related to applicability and/or reliability, as, among other things, the range of signals from the ID tags is relatively small, the ID tags are subjected to wear and may be damaged during the assembling of the pipes. WO2006/041306A1, which is from a patent family owned by the applicant, discloses an RFID system that is provided on a pipe segment for identification purposes. This document is incorporated by reference in its entirety. In this specification RFID technology as such is considered to be well known and will therefore not be further explained. Various RFID tags having various dimensions are available on the market. The current invention does not aim to improve upon those tags as such nor upon the system for reading out such RFID tags when provided on a piping or tubing.

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

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

The invention is defined by the independent patent claims. The dependent claims define advantageous embodiments of the invention.

In a first aspect the invention relates to a piping for use in an oil or gas environment. The piping is provided with an RFID tag for identifying said piping. Said piping comprises a first end section for being coupled to a second piping and a second end section, wherein said piping further comprises a mid-section in between said end sections. The RFID tag is provided in an elongate recess that is formed in the piping and wherein said recess extends in a tangential direction parallel to a surface of the midsection of the piping.

The effects of the combination of the features of the invention are as follows. By providing the RFID tag in a recess, which extends in a tangential direction parallel to the surface of the mid-section of the piping, it is achieved that the strength of the pi ping is hardly affected by the trench. In contrast with this, the prior art solution include the provision of a recess which extends orthogonal to said surface, which inherently reduces the strength of the piping, and thereby puts severe limitations on the feasibility of applying a tag to a piping.

In an embodiment of the piping in accordance with the invention the recess has been formed as a shallow elongate recess. Making a shallow elongate recess, meaning that the recess is elongate in a direction parallel to a surface in which it is made, has the advantage that the integrity and strength of the piping is preserved as much as possible, in case the RFID tag is positioned at an outer surface of the piping.

In an embodiment of the piping in accordance with the invention the recess has been formed in a threaded section in at least one of said end sections. This embodiment forms a first variant of the embodiment of claim 2. When it comes down to making a recess in the threaded section, there is two advantageous options. The first option is to form the recess in a thread crest. The second option is form the recess in between respective thread crests.

In an embodiment of the piping in accordance with the invention the recess has been formed in the mid-section of the piping. This embodiment forms a second variant of the embodiment of claim 2. Of all embodiments this one is the most counter-intuitive. Expressed differently, there is a general prejudice in the field not to tamper the midsection of a piping. The inventors are the first to realize and establish that this still can be done without reducing the integrity and strength of the piping to dangerous levels. This is particularly so, because the inventors have chosen for a shallow recess, which is elongate in a direction parallel to the surface, wherein the recess is made. Nowadays elongate and thin RFID tags are available on the market, which have appeared to be particularly suitable for this embodiment.

In an embodiment of the piping in accordance with the invention the recess has been formed as a hole in a rim of said piping, wherein the hole extends in a tangential direction parallel to the surface of the mid-section of the piping. This embodiment surprisingly results in a minimum integrity and strength reduction of the piping.

In the following is described an example of a preferred embodiment illustrated in the accompanying drawings, wherein :

Fig. 1 shows a connection of two pipings for use in the oil or gas industry;

Figs. 2a-2c illustrate a first embodiment of a piping in accordance with the invention;

Figs. 3a-3c illustrate a second embodiment of a piping in accordance with the invention;

Fig. 4a illustrates the possibility of a possible further embodiment in accordance with the invention;

Fig. 4b shows an enlarged view of Fig. 4a;

Fig. 4c shows an enlarged view of Fig. 4b;

Fig. 5a illustrates a third embodiment of a piping in accordance with the invention, and Fig. 5b shows an enlarged view of Fig. 5a.

In the embodiments discussed above and described hereinafter illustrate rather than limit the invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as li miting the claim. Use of the verb "comprise" and its conjugations does not exclude the presence of elements or steps other than those stated in a claim. The article "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The invention may be implemented by means of hardware comprising several distinct elements. In the device claim enumerating several means, severa l of these means may be embodied by one and the same item of hardware. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

Fig. 1 shows a connection of two pipings for use in the oil or gas industry. The figure shows a first piping 10 that is connected with a second or further piping 10'. In this embodiment this is done by means of a separate coupling joint 20. However, the coupling joint 20 may also be integrated with one of said pipings 10,10'. In this embod iment the first piping 10 has a mid-section 10-1 and two end sections 10-2 (of which only one is visible). Likewise, the second piping 10' has a mid-section ΙΟ'-l and two end sections 10'-2. The respective end sections 10-2 of the first piping 10 have threaded portions 11, which are matching with threaded portions in said coupling joint 20. Likewise, the respective end sections 10'-2 of the second piping 10' have threaded portions 11', which are matching with threaded portions in said coupling joint 20.

It must be noted that in the example of Fig. 1 the pipings have two male end portions, while the coupling joint has two female end portions. However, the invention is appl icable also to male-female configurations without separate coupling joints, or pipings with two female ends with male coupling joints.

Figs. 2a-2c illustrate a first embodiment of a piping in accordance with the invention. In this embodiment a shallow elongate recess 50 (Fig. 2b) is formed which is elongated in a tangential direction DT with regards to an outer surface S of the mid-section of the piping 10 as illustrated in Fig. 2c. An RFID tag 99 is provided in the recess 50 as also illustrated in Fig. 2c. The RFID tag 99 can be mounted in the recess 50 in various way, for instance by moulding or gluing. Alternatively, the mounting can be done in a mechanical way using threads, slots and the like. It is considered to fall within the normal expertise of a person skilled in the art how to mount or fix the RFID tag in the recess, such that it remains there in operational use of the piping.

Figs. 3a-3c illustrate a second embodiment of a piping in accordance with the invention. In this embodiment a shallow elongate recess 50' is formed in the end section 10-2 of the piping 10, more particularly in the threaded section 11 of the end section 10-2. A small-size RFID tag 99' is placed in the shallow elongate recess 50'. When the RFID tag 99' is placed in the threaded section 11 there is two advantageous options, which have been jointly illustrated in Fig. 3c. The first option is to place the RFID tag 99' in a recess 50' in a thread crest 11-1, and the second option is to place the RFID tag 99' in a recess 50' in between respective thread crests 11-1.

Fig. 4a illustrates the possibility of a possible further embodiment i n accordance with the invention. The figure shows the same piping connection as Fig. 1. Fig. 4b shows an enlarged view of Fig. 4a. Fig. 4c shows an enlarged view of Fig . 4b. In Fig. 4c there is visible "natural cavities" 51 in between the respective threads of the coupling joint and the piping 10. These natural cavities 51 are also suitable for placing an RFID tag. This means that no cavity or a smaller cavity may be used to place the RFID tag in. Expressed differently, the RFID tag may protrude a little bit from the threaded surface.

Fig. 5a illustrates a third embodiment of a piping in accordance with the invention, and Fig. 5b shows an enlarged view of Fig. 5a. The main idea of this embodiment is to place the RFID tag 99" in a deep elongate recess 50" (or hole) in the rim of a piping 10 as best illustrated in Fig. 5b.

It must be noted that the invention is not only limited to pipings that transport oil or gas. Such pipings may also be drill string sections, risers, or pipings for transporting drill cuttings, water or other substances.