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CTDef Implementation Software
2. Influence of Tubing Rotation
Based on sponsor feedback at the end of the first year, the ability to investigate tubing rotation was added to the CTDef Software, and rotation was shown to have a first order influence. The software was used to make a matrix of 160 runs using the front panel input option, varying the input as follows:
4 values of internal pressure (0, 1000, 2500 and 5000 psi)
4 values of axial force (20k, 40k, 60k and 80k lbs)
10 values of rotation/trip (0, 10, 20, 30, 45, 60, 90, 120, 150, 180 degrees per trip)
The % change in diameter is plotted versus axial force and internal pressure for each rotation value on the next 10 three-dimensional graphs. Flipping from one graph to the next, it is apparent that rotation is not a strong influence on diametral growth. This is apparent on the next graph, which is a standard two-dimensional plot of all the % diametral growth predictions, plotted versus degree of rotation per trip. The two-dimensional plot on the next page shows % change in wall thickness versus rotation. Again the influence is not strong, except for the cases near 0 and 180 degrees per trip.
However, rotation is shown to have a strong influence on axial elongation. The next 10 graphs are three-dimensional plots of maximum elongation versus pressure and axial force. Flipping through these graphs, the strong influence of rotation is apparent, with the most elongation occurring for rotations of 120 degrees per trip, in most cases. The final 3 plots are two-dimensional graphs of maximum elongation versus rotation per trip, one graph for each internal pressure level of 0, 2500 and 5000 psi.
It should be noted that the 160 runs used to generate these plots were made on a laptop computer in less than 3 hours.
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