Heat treated coiled tubing

Abstract

Embodiments of a method of heat treating a coiled tube, in particular coiled tubes for use in the oil and gas industry, and pipes produced from the methods. In particular, embodiments of the heat treating method can utilized tempering without bending in order to avoid the generation of subsequent defects.

1 . A method of heat treating a tubing comprising:
 providing the tubing in an uncoiled configuration;   heating the tubing in the uncoiled configuration to a temperature above Ac3;   quenching the tubing in the uncoiled configuration;   tempering the tubing in the uncoiled configuration, wherein the tempering is executed in a straight tube heat treatment;   a second tempering stage wherein the pipe is tempered while bent; and   coiling the tubing after the tempering.   
     
     
         2 . The method of  claim 1 , wherein the amount of tempering introduced into the pipe before any bending is at least 10% of the total tempering. 
     
     
         3 . The method of  claim 2 , wherein the amount of tempering introduced into the pipe before bending is at least 50% of the total tempering. 
     
     
         4 . The method of  claim 3 , wherein the amount of tempering introduced into the pipe before bending is at least 90% of the total tempering. 
     
     
         5 . The method of  claim 1 , wherein the tubing comprises a pipe. 
     
     
         6 . A method of heat treating a coiled tubing, the coiled tubing comprising a pipe, wherein the method comprises:
 unspooling the coiled tubing;   heating the unspooled coiled tubing to a temperature above Ac3;   quenching the unspooled coiled tubing;   tempering the unspooled coiled tubing, wherein the tempering is executed in a straight tube heat treatment; and   a second tempering stage wherein the unspooled coiled tubing is tempered while bent.   
     
     
         7 . The method of  claim 6 , wherein the amount of tempering introduced into the pipe before any bending is at least 10% of the total tempering. 
     
     
         8 . The method of  claim 7 , wherein the tempering performed prior to bending is at least 50% of the total tempering. 
     
     
         9 . The method of  claim 8 , wherein the tempering performed prior to bending is at least 90% of the total tempering. 
     
     
         10 . The method of  claim 6 , further comprising coiling the unspooled coiled tubing after the tempering. 
     
     
         11 . A method of heat treating a tubing, wherein the tubing comprises a pipe, wherein the method comprises:
 providing the pipe in an uncoiled configuration;   heating and quenching the pipe in the uncoiled configuration;   tempering the pipe in the uncoiled configuration without any bending of the pipe during the tempering, wherein the yield strength of the pipe as-tempered is less than the yield strength of the pipe as-quenched, and wherein the tempering is executed in a straight tube heat treatment; and   applying an additional tempering to the pipe while the pipe is being bent.   
     
     
         12 . The method of  claim 11 , wherein the pipe is uncoiled from a spool prior to tempering. 
     
     
         13 . The method of  claim 11 , further comprising coiling the pipe after the tempering. 
     
     
         14 . A method of producing tubing, comprising:
 providing a pipe in an unspooled configuration;   heating the unspooled pipe to a temperature above Ac3;   quenching the unspooled pipe;   tempering the unspooled pipe in a first tempering operation, the first tempering operation being applied to the unspooled pipe with the unspooled pipe in a straight configuration without bending; and   tempering the pipe in a second tempering operation, wherein the pipe during the second tempering operation is bent in a coiling process to coil the pipe onto a spool.   
     
     
         15 . The method of  claim 1 , wherein tempering the tubing comprises tempering the tubing to a yield strength of about 110 ksi to about 140 ksi.