Coiled Tubing studies at the University of Tulsa have produced two software packages: FlexorTU Life Prediction Software and CTDef Implementation Software.

Both programs are available to Members of TU-CTMRC. The Flexor Life Prediction is also available as an online application.  Click to try the demo

FlexorTU Life Prediction Routine

A work in progress, the FlexorTU program facilitates life predictions on coiled tubing samples in the lab or the field. The coiled tubing life prediction module in FlexorTU is based on that used in the CTES Achilles software package. The program enables the user to make quantitative estimates of the influence of a wide variety of surface defects. It also allows the user to evaluate the effectiveness of repairing a defect. The semi-empirical prediction algorithms are based on the over 1,400 tests conducted on actual coiled tubing samples. The model will continue to evolve analytically and functionally as tests are conducted on new defect geometries, tubing materials and sizes.

FlexorTU enables members to conduct “what-if” calculations. In the example below, CTDef quantifies the benefits of repairing pitted tubing.

Defect-Free 1¾-inch, 90 ksi Tubing at 5,000 psi
Trips to failure: 47

 

1¾-inch, 90 ksi Tubing with a 0.024-in Deep External Pit at 5,000 psi
Trips to failure: 28

 

Expected life of same tubing if pit is repaired using procedure defined by TU research.
Trips to failure: 41

In general, repairing is not always beneficial, as defects with repairs can show lower fatigue lives than tubing containing defects. Feedback from several sponsors indicate that they have made several critical successful decisions in the field based on analyses with FlexorTU!