Astana, Kazakhstan, Dec. 6
By Daniar Mukhtarov - Trend:
Direct cause of leaks in the gas pipeline at Kashagan field in Kazakhstan was its cracking under the influence of sulfide compounds, according to a message from the NCOC consortium.
These findings were confirmed by laboratory tests. The inspection of the Kashagan pipeline is continuing, according to the message.
Oil production at Kashagan started on September 11, 2013, but on September 24 its operation was suspended after detection of a gas leak from the ground pipeline stretching from the Island D to the Bolashak factory (Karabatan).
Production was resumed, but again suspended on October 9 after detection of a leak. Hydro-testing was conducted, which identified other potential leaks.
After the first leakage, the consortium organized a special group, which began inspection and initial analysis. Some of the pipeline's damaged parts were sent to Cambridge in the UK, (to the laboratory of TWI company). Analyses revealed that the direct cause of pipeline leaks was cracking under the influence of sulfide compounds.
Such damage occurs when the hard/fragile steel is exposed to high concentrations of H2S in the presence of water, which leads to the appearance of micro-cracks in the steel. The amount of H2S in products of the Kashagan field is among the highest in the world.
The technical requirements of steel for the pipeline, methods of construction of these pipelines were specially designed to meet the high levels of H2S in the presence of water and were approved by the state as being suitable for the specified pipeline, according to the report.
Currently the consortium is cooperating with pipe suppliers to identify the causes of the incident. Despite the fact that the gas leakages were not observed in marine gas pipelines or oil pipelines, the consortium decided to conduct a full inspection of both pipelines.