This invention relates to a pipe joint for joining two pipe ends, for hydraulic or electrical signal- or energy transfer, the pipes have one or more longitudinal bores and/or lines or conduits in their walls.

The joint comprises a pipe union having internal threads with one section threaded to the left and another section threaded to the right, corresponding respectively to external threads on the pipe end sections.

In production of oil- and/or gas from a reservoir in a geological formation it is desirable to transfer signals concerning production- and equipment parameters, or it may be desirable to transmit electrical or hydraulic energy to equipment used in the reservoir, e. g. for controlling or operation of valves or the like. Often it may be desirable to supply a fluid to the reservoir, e. g. a tracer, a packing fluid or a solution/cleaning agent.

Previously it has been attempted to arrange lines in the walls of a production pipe in an oil/gas well, to transfer signals, energy or a liquid as mentioned above. A production pipe of this type consists of several pipe sections interconnected by pipe joints, and this state of the art joints does not satisfy the demand of fluid tightness and does not have the performing characteristics as foreseen.

It is therefore an object of the present invention to provide an improved pipe joint of the above mentioned type, which is durable, simple and inexpensive to produce. A further object of the invention is to provide a joint for easy joining of two pipe ends, where the joint can withstand high pressures.

According to the present invention, the above mentioned advantages are achieved by a pipe joint that is characterised in that the pipe ends are provided with a joining part for mutually centring and locking the two pipe ends, the joining part has joining

sleeves that connect the respective bores or lines with each other, to obtain a tight connection between these, as defined in claim 1. The dependent claims 2-7 defines advantageous features of the invention.

One way of carrying out the invention is described in detail below with reference to drawings that illustrate one specific embodiment in which:

Fig. 1 is an exploded view of a pipe joint in accordance with the invention,

Fig. 2 is on an enlarged scale one of the two similar pipe ends as shown in fig. 1 , viewed at the end and at the section lines A - A,

Fig. 3 is on an enlarged scale a joining part as shown in fig. 1, viewed at the end and at the section lines B - B.

As mentioned above, fig. 1 shows an exploded view of a pipe joint according to the invention. Between the pipes 1, 1' (only end sections shown here) the joint comprises a joining part 2. The pipes 1, 1' and the joining part is adapted to be connected by the means of a pipe union 3, provided with two internal threaded sections 13, 13', one section is threaded to the right, the other to the left. The threaded sections correspond respectively to external right- and left oriented threads 6, 6' at the end sections of the pipes.

The pipes, or more precisely the pipe end sections, in the joint are identical. Therefore, of practicable reasons, only one pipe end 1 is shown in fig. 2. As will be seen, (see also fig. 1) the pipe end section 1 has two external recesses diametrically opposed to each other. The recesses 10 serve as female parts corresponding with male parts 5 formed at the joining part 2 (see a later section).

The pipe 1 may comprise one or more lines 8 for hydraulic fluid, electric cables or the like, longitudinally oriented in a recess or recesses formed in the pipe, where each of said recesses passes on to a bore 7 at the pipe end section. At the end, the bore 7 may advantageously be shaped conical by a reamer, and the line 8 may be expanded into contact with the wall at the outermost part of the conical section 9. Further, the line may advantageously be fixed in the bore 7 at the edge surface of the pipe end by diametrically opposed welded points (not shown) to hold the line in position in the bore before assembling the joint.

As will be seen in fig. 3 (see also fig. 1), and as mentioned above, the joining part 2 has a couple of male parts, shaped as diametrically opposed projections that corresponds with the female parts 10, 10' at the pipe end sections 1 , 1'. Said male and female parts may advantageously have a minor conical shape (at guiding edges 15, 15' and 16, 16'), and serves both as a device for mutual centring of the two pipe end sections 1, 1', and as a locking device to inhibit mutual rotation of the pipe ends.

The joining part 2 is provided with one or more joining sleeves 4 that protrudes through the bores in the joining part corresponding with the line(s) 8/the bore(s) 7. The joining sleeve 4 is provided with conical shaped ends 14, 14', and when assembling the joint it will be pressed inwardly into the opening of the line 8/the bore 7 such that a tight joint between the corresponding parts is achieved.

End surfaces 11 , 11' of the joining part 2 and the end surfaces 12, 12' of the pipes may both advantageously be provided with labyrinth recesses (not shown) to support a lead packing or the like to obtain good tightness between the pipes.

The claimed invention is not limited to the above mentioned device for centring and locking formed as in pairs opposed male and female parts, it may instead be provided with locking pins that protrudes through bores in the joining part and into bores in the two pipe ends 1 , 1' (not shown). The joining sleeves may, instead of being arranged in bores through the joining part, be arranged in longitudinal recesses in said part (not shown).

As mentioned above, the pipes 1, 1' may be provided with longitudinal lines 8 or bores 7. This will depend upon the length of the pipes. Thus, for minor pipe lengths it will be relevant to provide the pipe with bores that pass from one end to the other, the bores terminate in conical sections at the pipe ends. Larger pipe lengths may not be drilled throughout its whole length, these pipes may be provided with thin conduits or lines 8 arranged in recesses in the pipes 1 , 1', each of which passes on to bores 7 at the end of the pipes 1, 1', as described in the embodiment above.