Downhole tubing or umbilical with sensor and method for manufacturing it

1. An umbilical comprising:

an outer tube;

at least one system including an inner structure coated with at least one layer of at least one plastic material; and

at least one support line,

wherein the at least one system and the at least one support line are placed in the outer tube,

wherein the inner structure includes at least one inner tube made of stainless steel and at least one sensor device with at least one sensor to measure at least one condition of the system,

wherein the at least one sensor device comprises a wireless data coupling element, the wireless data coupling element is operatively connected to the at least one sensor to receive a signal from the at least one sensor, and the wireless data coupling element is arranged to transmit the signal received from the at least one sensor,

wherein at least one groove extends in an outer surface of at least one of the at least one inner tube in a longitudinal direction of the at least one inner tube,

wherein at least one signal line which is operatively coupled to the at least one sensor device is placed in the at least one groove,

wherein the system is a control line for offshore applications, and

wherein the at least one sensor is provided to measure at least one condition in the control line.

2. The umbilical according to claim 1 , wherein the inner structure comprises:

at least two inner tubes made of stainless steel, and

at least one spacer placed between each of the two neighbouring inner tubes.

3. The umbilical according to claim 1 , wherein at least one of the at least one inner tube is a seamless tube or a longitudinal seam welded tube.

4. The umbilical according to claim 1 , wherein at least one cavity extends in at least one of the at least one inner tube,

wherein the at least one cavity has a radial extension from an outer surface of the at least one inner tube, and

wherein the at least one sensor device is placed in the at least one cavity.

5. The umbilical according to claim 1 , wherein the at least one sensor is chosen from an acceleration sensor, a vibration sensor, a conductivity sensor, a pressure sensor, a temperature sensor, a strain gauge, a corrosion sensor, a magnetic field sensor, a heat flux sensor, a torque sensor or a combination thereof.

6. The umbilical according to claim 1 , wherein the inner structure comprises at least one signal line operatively coupled to the at least one sensor device to at least transmit a signal from the at least one sensor device, and

wherein the at least one signal line extends in a longitudinal direction of the system.

7. The umbilical according to claim 6 , wherein the at least one signal line is chosen from a line for an electrical signal, a line for an electromagnetic signal, a line for an optical signal or a combination thereof.

8. The umbilical according to claim 1 , wherein the at least one support line is selected from a chemical injection tube, a telecommunications cable, an optical fibre and an electrical cable.

9. The umbilical according to claim 1 , wherein the control line actuates valves for fluid production.

10. The umbilical according to claim 1 , wherein the control line is a hydraulic line to provide hydraulic power to subsea or to distribute hydraulic power subsea.

11. A method for manufacturing the umbilical according to claim 1 , the method comprising the steps of:

forming the inner structure of the system including the at least one inner tube of stainless steel and the at least one sensor device with the at least one sensor to measure at least one condition of the system; and

coating the inner structure with the at least one layer of the at least one plastic material.

12. The method according to claim 11 , further comprising the steps of:

providing at least two inner tubes of stainless steel;

providing at least one spacer; and

placing the at least one spacer between each two neighbouring inner tubes.

13. The method according to claim 11 , wherein the step of coating comprises extruding at least one layer around the inner structure.

14. The method according to claim 11 , wherein the step of providing the at least one inner tube comprises cold working at least one hollow into at least one of the at least one inner tube.

15. The method according to claim 14 , wherein the step of providing the at least one inner tube comprises cold drawing the at least one hollow into the at least one inner tube through a drawing matrix with at least one protrusion to form at least one groove in the outer surface of the at least one inner tube, and wherein the at least one sensor device is placed in the at least one groove.