Method for handling tubulars and rigidizer therefor

Abstract

A rigidizer and method for its use in supporting a tubular string during handling operations. The rigidizer includes upper and lower sleeves which pivotally open and close to clamp about the string. The upper and lower sleeves are rigidly connected by a number of structural telescopic legs that allow adjustment to different lengths for accommodating different strings. The rigidizer is installed on the string when the string is in a horizontal position and provides structural support to thin-walled components during upending and handling. Once the string is vertically oriented, the rigidizer is removed prior to being run into a marine riser or well.

What is claimed is: 
     
       A 1 . A rigidizer for strengthening a tubular string comprising:
 upper and lower sleeves each having first and second semi-circular pivotally connected portions, each of said first and second semi-circular pivotally connected portions characterized by having an open configuration and a closed configuration, said upper and lower sleeves being dimensioned to clamp about said tubular string when in said closed configuration; and 
 a first leg rigidly connected between said upper and lower sleeves so as to hold said upper and lower sleeves in coaxial alignment and separated by a first axial distance; whereby 
 said rigidizer is operable to removably clamp about and thereby strengthen said string. 
 
     
     
       A 2 . The rigidizer of claim A 1  wherein:
 said first leg is selectively adjustable so as to hold upper and lower sleeves separated by a second axial distance greater than said first axial distance. 
 
     
     
       A 3 . The rigidizer of claim A 2  wherein:
 said first leg is telescopic, having an elongated inner tubular member slideably disposed within an elongated outer tubular member. 
 
     
     
       A 4 . The rigidizer of claim A 3  further comprising:
 a locking system including a pin removably disposed through apertures formed in said inner and outer tubular members. 
 
     
     
       A 5 . The rigidizer of claim A 1  further comprising:
 second and third legs rigidly connected between said upper and lower sleeves. 
 
     
     
       A 6 . The rigidizer of claim A 1 , further comprising:
 an inner diameter adjustment mechanism coupled to one of the group consisting of said upper sleeve and said lower sleeve. 
 
     
     
       A 7 . The rigidizer of claim A 6 , wherein:
 the adjustment mechanism is a radially extending extension. 
 
     
     
       A 8 . The rigidizer of claim Al, further comprising:
 a latching mechanism coupled to one of the group consisting of said upper sleeve and said lower sleeve. 
 
     
     
       A 9 . The rigidizer of claim Al, further comprising:
 a radial spacer disposed between said first leg and one of the group consisting of said upper sleeve and said lower sleeve. 
 
     
     
       B 1 . A rigidizer for strengthening a tubular string comprising:
 upper and lower sleeves each having first and second semi-circular pivotally connected portions, each of said first and second semi-circular pivotally connected portions characterized by having an open configuration and a closed configuration, said upper and lower sleeves being dimensioned to clamp about said tubular string when in said closed configuration; and 
 a plurality of telescopic legs radially disposed about said upper and lower sleeves and rigidly connected between said upper and lower sleeves so as to hold said upper and lower sleeves in coaxial alignment separated by a first axial distance; whereby 
 said rigidizer is operable to removably clamp about and thereby strengthen said string. 
 
     
     
       B 2 . The rigidizer of claim B 1 , wherein:
 said plurality of telescopic legs include, first, second, third, and fourth telescopic legs, each having an elongated inner tubular member slideably disposed within an elongated outer tubular member. 
 
     
     
       B 3 . The rigidizer of claim B 2  wherein each of said plurality of telescopic legs further comprises:
 a locking system including a pin removably disposed through apertures formed in said inner and outer tubular members. 
 
     
     
       B 4 . The rigidizer of claim B 1 , further comprising:
 an inner diameter adjustment mechanism coupled to one of the group consisting of said upper sleeve and said lower sleeve. 
 
     
     
       C 1 . A method for handling a tubular string comprising the steps of:
 positioning said string in a substantially horizontal orientation; 
 providing a rigidizer including upper and lower sleeves, each upper and lower sleeve having first and second semi-circular pivotally connected portions, each of said first and second semi-circular pivotally connected portions characterized by having an open configuration and a closed configuration, said upper and lower sleeves being dimensioned to clamp about said tubular string when in said closed configuration, said rigidizer further including a first leg rigidly connected between said upper and lower sleeves so as to hold said upper and lower sleeves in coaxial alignment separated by a first axial distance; 
 opening said rigidizer; 
 positioning said opened rigidizer about said string; and 
 closing said rigidizer about said string so as to clamp said rigidizer to said string. 
 
     
     
       C 2 . The method of claim C 1  further comprising the steps of:
 positioning said string having said rigidizer clamped thereto in a substantially vertical orientation; and then 
 opening said rigidizer; and 
 removing said rigidizer from said string. 
 
     
     
       C 3 . The method of claim C 1  further comprising the steps of:
 adjusting said rigidizer so that said upper and lower sleeves are separated by a second axial distance by said first leg. 
 
     
     
       C 4 . The method of claim C 3  wherein:
 said first leg is telescopic, having an elongated inner tubular member slideably disposed within an elongated outer tubular member; and 
 the method further comprises the steps of,
 selectively positioning said inner tubular member within said outer tubular member, and then 
 locking said inner tubular member with respect to said outer tubular member. 
 
 
     
     
       C 5 . The method of claim C 4  wherein the step of locking said inner tubular member with respect to said outer tubular member further comprises the step of:
 disposing a pin through said inner tubular member and said outer tubular member. 
 
     
     
       C 6 . The method of claim C 1  further comprising the step of:
 latching said rigidizer in said closed orientation. 
 
     
     
       C 7 . The method of claim C 1  further comprising the step of:
 adjusting an inner diameter of at least one of the group consisting of said upper sleeve and said lower sleeve.