Layer | Fill | Outline |
---|
Map layers
Theme | Visible | Selectable | Appearance | Zoom Range (now: 0) |
---|
Fill | Stroke |
---|---|
Collaborating Authors
Results
Laboratory Test to Evaluate Service Life Extension of AISI 304 Flexible Pipe Carcass at Sour Service
de Sousa, Flavio V. Vasques (s/n Cidade Universitária) | Bandeira, Merlin C. E. (s/n Cidade Universitária) | Mattos, Oscar Rosa (s/n Cidade Universitária) | Joia, Carlos J.B.M. (CENPES/Petrobras) | Santos, Fabricio (CENPES/Petrobras)
Abstract The first oil production at Campos Basin started 35 years ago. However the field conditions changed recently as the water injection caused some souring of the reservoir; now small amounts of H2S associated with CO2, in the range of 0.1 to 0.4%, also have to be considered. Therefore a study to assess carcass corrosion resistance to Sulfide Stress Cracking (SSC) and crevice susceptibility is needed. First production lines in Campos Basin used AISI 304 as carcass material and therefore a test program comprised of this material and 316L was launched. All carcass samples tested came from the flexible lines that had operated in the field. Before the tests, carcass samples were inspected and showed no sign of localized corrosion. According to the results, 304SS carcass presented very good corrosion resistance at 60C, 100,000 ppm of Cl- pH 4 and 10% H2S. At higher temperatures pits and chlorine SCC were observed depending on chloride concentration. These results can be used as technical data to support service life extension of 304SS carcass in Campos Basin. Moreover, according to the tests performed, the 316L SS carcass can operate in sour environments up to 70C, pH 4.5, 60,000ppm of Cl- and 10% H2S with balance of CO2. These limits are beyond the ones defined by MR0175/ISO15156 to 316LSS.
- South America > Brazil (1.00)
- North America > United States > Texas > Harris County > Houston (0.17)
Abstract CO2 corrosion is a complex process and a large number of variables are involved, such as: pH, temperature, chloride concentration, fugacity and system total pressure. This work presents electrochemical impedance spectroscopy and gravimetric results of tests carried out at pH 4, which was controlled within the whole experiment time. The impedance diagrams obtained with and without CO2 presented the same interfacial process, suggesting the same corrosion mechanism for both. Therefore, no evidence was found for a direct reaction of CO2 on Fe surface in the experimental conditions presented herein. In specific test conditions, local pH measurements demonstrated huge pH shifts whereas bulk pH remained constant. Thus, a strict controlled pH is mandatory to study corrosion mechanisms. For the same pH, comparing solutions with and without carbon dioxide, the weight loss was six times higher in environments containing CO2 and eight times higher in CO2/brine conditions. The CO2 buffering effect, previously reported in the literature, was only observed in brine condition. The results suggest a very good correlation between electrochemical and gravimetric data obtained at the same pH.
- Well Completion > Well Integrity > Subsurface corrosion (tubing, casing, completion equipment, conductor) (1.00)
- Production and Well Operations > Production Chemistry, Metallurgy and Biology (1.00)
- Facilities Design, Construction and Operation > Pipelines, Flowlines and Risers > Materials and corrosion (1.00)