Method for Inspection of Metal Tubular Goods

Abstract

A method for predicting the performance of tubular goods includes using a computer readable three-dimensional representation of tubular good which includes computer readable measurements of discrete segments of the wall of said tubular acquired by ultrasonic detection means, along with associated data representing the position of discrete segment and optionally ovality data to mathematically calculate, by computer means, the effect of stress conditions, including tensile, bending, collapse, burst and aging forces upon said tubular and optionally analyzing sequential inspection of the same tubular good over a period of time predict when failure is likely to occur, and to avoid failure while maximizing the use of the tubular good.

1 . Method for predicting performance of tubular goods under the effect of at least one of tensile, bending, collapse and burst forces on a tubular good, comprising:
 a. positioning an ultrasonic detection means which is capable of measuring the thickness of a discrete section of the wall of a tubular good in a plurality of partially overlapping sampling positions spaced longitudinally and circumferentially along the entire wall of the tubular good;   b. at each sampling position, causing said ultrasonic detection means to measure the thickness of a discrete portion of the wall of said tubular good;   c. for each sampling position, determining the circumferential position of said ultrasonic detection means about the circumference of said tubular good;   d. for each sampling position, determining the longitudinal position of said ultrasonic detection means along the axis of said tubular good;   e. making a computer-readable recording of said measurements of said wall thickness in an associated relationship with their corresponding longitudinal positions and circumferential positions to form a three dimensional representation of the entire wall of the tubular good in a computer-readable format; and   f. causing a computer means to use said recording to make mathematical calculations which predict the effect of at least one of tensile, bending, collapse and burst forces on said tubular good.   
     
     
         2 . The method of  claim 1  further comprising measuring ovality of the tubular good and including ovality data in said recording with said wall thickness measurements, wherein in step (f) said computer means also uses ovality data to make mathematical computations which predict the effect of at least one of tensile, bending, collapse and burst forces on said tubular good. 
     
     
         3 . The method of  claim 1  wherein said step (a) comprises advancing the ultrasonic detection means and the wall of the tubular good longitudinally relative to one another while rotating the tubular good about its longitudinal axis. 
     
     
         4 . The method of  claim 3  wherein in step (b) the ultrasonic detection means is triggered periodically to generate a stream of discrete wall thickness measurements following a substantially helical path on the wall of the tubular good, while detecting and marking in the stream of measurements each complete rotation of the tubular good. 
     
     
         5 . The method of  claim 4  wherein determining the circumferential position in step (c) comprises converting the position of a measurement in the stream to a representation of its circumferential position by reference to the number of measurements made in a complete rotation containing that measurement. 
     
     
         6 . The method of  claim 4  wherein determining the longitudinal position in step (c) comprises generating and recording a longitudinal position signal each time the ultrasonic detection means is triggered. 
     
     
         7 . The method of  claim 6  further comprising repeating the steps (a) to (f) for sequential inspection of the same tubular good and analyzing changes which have occurred over a period of time to predict when failure is likely to occur, and to avoid failure while maximizing use of the tubular good. 
     
     
         8 . The method of  claim 7  applied to the inspection of tubular goods for use in earth-bores for oil and gas wells. 
     
     
         9 . The method of  claim 8  further comprising the step of using a computer means to display the wall of said tubular good in virtual three-dimensional form. 
     
     
         10 . The method of  claim 1  wherein said step (a) comprises advancing the ultrasonic detection means and the wall of the tubular good longitudinally relative to one another while rotating the tubular good about its longitudinal axis. 
     
     
         11 . The method of  claim 10  wherein in step (b) the ultrasonic detection means is triggered periodically to generate a stream of discrete wall thickness measurements following a substantially helical path on the wall of the tubular good, while detecting and marking in the stream of measurements each complete rotation of the tubular good. 
     
     
         12 . The method of  claim 11  wherein determining the circumferential position in step (c) comprises converting the position of a measurement in the stream to a representation of its circumferential position by reference to the number of measurements made in a complete rotation containing that measurement. 
     
     
         13 . The method of  claim 12  wherein determining the longitudinal position in step (c) comprises generating and recording a longitudinal position signal each time the ultrasonic detection means is triggered. 
     
     
         14 . The method of  claim 13  further comprising repeating the steps (a) to (f) for sequential inspection of the same tubular good and analyzing changes which have occurred over a period of time to predict when failure is likely to occur, and to avoid failure while maximizing use of the tubular good. 
     
     
         15 . The method of  claim 14  applied to the inspection of tubular goods for use in earth-bores for oil and gas wells. 
     
     
         16 . The method of  claim 15  further comprising the step of using a computer means to display the wall of said tubular good in virtual three-dimensional form.