Holding device insertable into the central bore of a tubular drill string component, and corresponding tubular drill string component

1. A drill string component, comprising:

a holding device inserted into a central bore of the drill string component, the central bore having

a first diameter along at least part of a central portion of the drill string component and

a second diameter proximate ends of the drill string component, the second diameter being lower than the first diameter,

the holding device comprising:

an elongated body forming at least partly a housing for a transmission line, the elongated body having transversal dimensions lower than the second diameter; and

a plurality of distinct arcuate elements arranged along the elongated body and distinct from and attached to the elongated body, the arcuate elements being elastically bendable to be able to move through the second diameter and having a largest chord greater than the first diameter in a free state to be able to expand within the first diameter once past the second diameter, each arcuate element being independently and freely movable relative to the other arcuate elements.

2. A holding device according to claim 1 , wherein the arcuate elements have an angle between 180° and 360° in a free state.

3. A holding device according to claim 1 , wherein ends of the arcuate elements each include a cutout in a longitudinal position of an opposite end of the arcuate element.

4. A holding device according to claim 1 , wherein the elongated body comprises two convex surfaces, the housing being arranged therebetween.

5. A holding device according to claim 1 , wherein the elongated body comprises two lateral aisles opposite the housing.

6. A holding device according to claim 1 , wherein the elongated body is obtained from a profile and the housing is a longitudinal channel.

7. A holding device according to claim 1 , wherein the elongated body has a tubular shape, an inside of the tubular shape forming the housing.

8. A holding device according to claim 1 , wherein the holding device includes a restraining element secured to the transverse ends of the arcuate elements to keep a maximum chord of the arcuate elements less than the second diameter in a restrained state before and during insertion of the holding device inside the drill string component.

9. A holding device according to claim 8 , wherein the restraining element includes a rope in a thermoplastic material.

10. A method to install the holding device of claim 8 , comprising:

inserting the holding device in the central portion of the tubular drill string component having the first diameter as an inner diameter; and

flowing hot air with the bore of the tubular drill string component to rupture the rope and let the arcuate elements expand against the first diameter portion.

11. A holding device according to claim 1 , wherein the arcuate elements have ends which are only in contact with the central bore.

12. A holding device according to claim 1 , wherein a space between two successive arcuate elements is between 500 and 3000 mm.

13. A holding device according to claim 1 , wherein a length along a drill pipe axis of the arcuate elements is between 10 and 100 mm.

14. A tubular drill string component comprising:

a tubular member and a holding device inserted therein;

the tubular member comprising a central bore having a first diameter along a central portion of the tubular member and a second diameter proximate ends of the tubular member, the second diameter being lower than the first diameter;

the holding device is insertable into the central bore of the tubular member,

wherein the holding device includes an elongated body forming at least partly a housing for a transmission line, the elongated body having transversal dimensions lower than the second diameter, and a plurality of distinct arcuate elements arranged along the elongated body and distinct from and attached to the elongated body, the arcuate elements being elastically bendable so as to be movable through the second diameter, having a largest chord greater than the first diameter in a free state to expand within the first diameter once past the second diameter, each arcuate element being independently and freely movable relative to the other arcuate elements.

15. A tubular drill string component according to claim 14 , wherein the arcuate elements maintain the elongated body against the first diameter portion of the central bore by elastic springback force, the arcuate elements exerting a radial force on a surface of the first diameter portion.

16. A tubular drill string component according to claim 14 , wherein the elongated body comprises two convex surfaces, the convex surfaces having a curvature adapted to the first diameter.

17. A holding device according to claim 14 , wherein the elongated body comprises two lateral aisles opposite the housing, the aisles being in contact with a surface of the first diameter portion.

18. A holding device according to claim 14 , wherein the arcuate elements have ends arranged distant one to another in a final position after insertion within the first diameter portion of the central bore.

19. A holding device according to claim 18 , wherein the arcuate elements have ends arranged to be just in contact or distant one to another during insertion through the portion of the central bore having a second diameter.

20. A holding device according to claim 14 , wherein the arcuate elements have an angle of more than 360° in a final position.

21. A holding device according to claim 14 , wherein the arcuate elements have ends which are only in contact with the central bore.

22. A holding device according to claim 14 , wherein a space between two successive arcuate elements is between 500 and 3000 mm.

23. A holding device according to claim 14 , wherein a length along a drill pipe axis of the arcuate elements is between 10 and 100 mm.