Composite coiled tubing with embedded fiber optic sensors

Abstract

The present invention provides spoolable continuous composite coiled tubings made from substantially nonmetallic materials for use in wellbores. The composite coiled tubing has a selected thickness and a through passage. The composite coiled tubing preferably includes a plurality of layers of composite materials. A fiber optic string is disposed in the composite coiled tubing, preferably during the manufacture of the composite tubing. A plurality of spaced apart sensor elements on the fiber optic string provide measurements of one or more downhole parameters of interest during the wellbore operations. The fiber optic string may be embedded or placed along the composite coiled tubing. A liner may be disposed inside the composite coiled tubing to isolate the inner surface of the coiled tubing and the fiber optic string from the drilling or the wellbore fluid passing through the coiled tubing.

What is claimed is:  
     
         1 . A spoolable coiled tubing conveyable into and out of a wellbore, comprising: 
 a substantially nonmetallic continuous tubular member of sufficient length to reach a desired depth in the wellbore, said tubular member having a wall of a selected thickness and a through passage; and    a fiber optic string in the nonmetallic tubular member, said fiber optic string having a plurality of spaced apart sensor elements for providing measurements of one or more downhole parameters of interest.    
     
     
         2 . The spoolable coiled tubing of  claim 1 , wherein the fiber optic string is disposed inside a tubing.  
     
     
         3 . The spoolable coiled tubing of  claim 2 , wherein said tubing is affixed to an inside wall of the nonmetallic tubular member.  
     
     
         4 . The spoolable coiled tubing of  claim 2 , wherein said tubing is disposed around the outside of the nonmetallic tubular member.  
     
     
         5 . The spoolable coiled tubing of  claim 1 , wherein the fiber optic string is disposed in a channel formed along the inside wall of the nonmetallic tubular member.  
     
     
         6 . The spoolable coiled tubing of  claim 1  further including an inner liner disposed along the inside of the nonmetallic tubular member to isolate the fiber optic sensors from the passage through the nonmetallic tubular member.  
     
     
         7 . The spoolable coiled tubing of  claim 1 , wherein the sensor elements provide measurements selected from a group consisting of (i) temperature, (ii) pressure (iii) vibration, and (iv) fluid flow.  
     
     
         8 . The spoolable coiled tubing of  claim 2 , wherein said tubing has an outside corrugated surface.  
     
     
         9 . The spoolable coiled tubing of  claim 2 , wherein the tubing is hermetically sealed to provide protection to the fiber optic string from the downhole environment.  
     
     
         10 . The spoolable coiled tubing of  claim 2 , wherein the tubing is U-shaped enabling said fiber optic string to return to a common end of said nonmetallic tubular member.  
     
     
         11 . The spoolable coiled tubing of  claim 2 , wherein the fiber optic string is pumped into said tubing after placing the tubing in the nonmetallic tubular member.  
     
     
         12 . The spoolable coiled tubing of  claim 2 , wherein the fiber optic string is embedded into the nonmetallic tubular member during the manufacture of the nonmetallic tubular member.  
     
     
         13 . The spoolable coiled tubing of  claim 1  further comprising a second fiber optic string in the nonmetallic tubular member for communicating data signals.  
     
     
         14 . The spooled coiled tubing of  claim 1 , wherein the fiber optic string has an end accessible for connection with a source of optical energy.  
     
     
         15 . The spoolable coiled tubing of  claim 1 , wherein the nonmetallic tubular member is made from a composite material.  
     
     
         16 . The spoolable coiled tubing of  claim 15 , wherein the composite material is selected from a group consisting of (i) graphite, (ii) aramid fiber, and (iii) fiberglass.  
     
     
         17 . The spoolable coiled tubing of  claim 6 , wherein the liner is made from a material selected from a group consisting of a (i) metal, (ii) polyurethane, (iii) nylon and (iv) fluoropolymer.  
     
     
         18 . The spoolable coiled tubing of  claim 1 , wherein the nonmetallic tubular member includes a plurality of layers of composite materials.  
     
     
         19 . The spoolable coiled tubing of  claim 18 , wherein the substantially nonmetallic tubing includes a layer of metallic material.  
     
     
         20 . A spoolable coiled tubing conveyable into and out of a wellbore, comprising: a substantially nonmetallic continuous tubular member of sufficient length to reach a desired depth of the wellbore, said tubular member having a wall of a certain thickness and a through axial bore; and a fiber optic string disposed in the nonmetallic tubular member in a manner that is one of (i) at least partially inside the wall of the nonmetallic tubular member (ii) inside a tubing that is further disposed at least partially inside the wall of the nonmetallic tubular member (iii) at least partially inside a channel made along the inside wall of the nonmetallic tubular member (iv) helically placed along the outside wall of the nonmetallic tubular member, and (v) disposed in a channel made along the outside of the nonmetallic tubular member.  
     
     
         21 . The spoolable coiled tubing of  claim 20 , wherein the nonmetallic tubular member further comprises: a plurality of overlapping layers of substantially nonmetallic materials bonded together by a suitable resin.  
     
     
         22 . The spoolable coiled tubing of  claim 21  further comprising a metallic material disposed in the nonmetallic material to provide durability to the nonmetallic material.  
     
     
         23 . The spoolable coiled tubing of  claim 20 , wherein the nonmetallic tubular member includes a plurality of notches, for accommodating sensors for providing selected downhole measurements.  
     
     
         24 . The spoolable coiled tubing of  claim 23 , wherein said sensors are selected from a group consisting of (i) electromagnetic radiation sensor, (ii) an acoustic sensor, and (iii) a nuclear magnetic resonance sensor.