| Autor: |
Sebastian Cravero, Radovan Rolovic, Martin Valdez, Bruce A. Reichert |
| Rok vydání: |
2018 |
| Předmět: |
|
| Zdroj: |
Day 2 Wed, March 28, 2018. |
| Popis: |
The new coiled tubing (CT) manufacturing technology that uses new steels with optimized chemical compositions and full microstructure transformation heat treatments has been proven in field applications over the last three years. The observed useful field life is typically two to four times longer than the life of comparable conventional CT strings in similar operations in the same operating regions. The most common reason for the new technology CT string retirement or failure has been CT string mechanical damage, such as gouges, plough marks and dents. In this study the field life of new technology strings mechanically damaged in field operations is compared to the field life of a large population of similar conventional CT strings used in similar operations in the same regions. Additionally, laboratory testing results for both undamaged and damaged CT are presented and compared to conventional CT results for the same CT damage and test conditions. Full size CT samples were used for laboratory testing of damaged CT. Sharp transverse tubing cuts were made to specific wall thickness depths and tested in the standard fatigue machine to failure under different internal pressures. Some samples with operational damage were also tested in the fatigue machine to determine the remaining life of CT strings with real-life field damage.Laboratory test results show that the new technology CT grades do not only keep the large advantage observed for undamaged CT but also increase the fatigue life advantage for the same CT damage, even when the higher strength HT-125 grade is compared to the lower strength conventional CT-110 grade. Testing of new technology CT sections containing real-life operational damage shows that there is still a substantial life remaining even after relatively severe CT damage. Field data show that mechanically damaged new technology CT strings have had, on average, more than twice as long operational life compared to the average operational life of conventional CT-110 and CT-100 strings used in similar operations in the same regions. This shows that the new technology CT is more damage tolerant, which provides additional reductions in operational risks and cost and enables more reliable and longer CT string utilization even when the CT string suffers damage of usual operational nature and severity. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
|
