| Autor: |
Roberto Morana, Bill M. Bailey, Halvor Kjørholt, Taro Ohe, Perry Ian Nice, Masakatsu Ueda, Dennis G. Jiral, Bob Smith, Havard Nasvik, Robert Chapman Ross, Andrea Bufalini, Mark K. Adam |
| Rok vydání: |
2010 |
| Předmět: |
|
| Zdroj: |
All Days. |
| Popis: |
While expandable tubular technology significantly increased traction within the oil&gas industry in the last few years, materials behavior knowledge for expandable casing has not progress sufficiently. This is due to the lack of a diffused definition of the most appropriate procedures to verify post-expansion material performance and to the difficulties in performing investigation activity. These investigations rely on post-expanded material, which is costly and time-consuming to obtain, especially for the range of very large plastic deformations applicable to Monobore applications. Consequently, an extensive testing program was started by Statoil to define an appropriate testing procedure for the evaluation of material performance after expansion and to characterize candidate materials. This paper presents the testing methodologies developed and the results obtained for several carbon steel grades and CRAs. These evaluations included tests of the mechanical performance and the resistance to aggressive environments. The assessment of mechanical performance was carried out through several conventional and innovative tests and evaluation activities. Conventional tests included tensile tests in longitudinal and transverse direction, at room and elevated temperature, impact tests and residual stress evaluation. Collapse tests were performed on expanded pipes. Novel methods with optical strain measurements were adopted for improved tensile tests. Finite Element Analysis of the expansion process was also used to further investigate post-expansion mechanical performance. The resistance to stress corrosion cracking or sulphide stress corrosion was evaluated by means of FPB and C-ring tests. Carbon grades were tested in a mild sour environment while CRAs were tested in aggressive environments representative of possible field conditions. All experimental tests were carried out on materials before and after expansion. The effect of strain aging was also evaluated for carbon steel grades applying a defined aging cycle to expanded material. The experimental methods adopted are described and discussed. The test results highlighted the main mechanical parameters to be considered and allowed ranking the different materials tested. At least one carbon steel grade and one CRA possess adequate mechanical and environmental performance even after 30% expansion. The test methodology adopted was therefore considered adequate for the aimed purpose. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
|
