NCOC announces reasons of leakage on gas pipeline from Kashagan field

The reason of leakage on the gas pipeline from the Kashagan field in Kazakhstan is cracking of the pipeline under influence of sulfide combinations, reads the statement of NCOC released on Friday. The data has been confirmed by the laboratory analysis.

The statement reads that inspection of the Kashagan pipeline continues.

Oil extraction on the Kashagan field started on September 11, 2013, but the pipeline operation was suspended on Septemebr 24, 2013 after gas leakage was detected on the ground pipeline from the D island to Bolashak plant (Karabatan).

The extraction was  resumed, but was suspended on October 9 again after detection of a leakage. Other places of potential leakage have been detected during the hydraulic tests.

After the first leakage the consortium has created a special group for inspection and initial analysis.

Some damaged sections of the pipeline have been sent to Cambridge (in the laboratory of TWI company). The examination proved that the direct reason of leakage of was the pipe cracking under influence of sulfide combinations.

Such damage is possible when a firm steel is exposed to high concentration of H2S in presence of water, which leads to micro cracks in steel. H2S content in the products on the Kashagan field is among the highest in the world. 

The statement reads that the pipes and the methods ofthe pipeline construction have been designed specially considering high H2S content in water and were approved by the state as suitable for the above-mentioned pipeline. 

At present the consortium has been working with the pipe suppliers to determine the reasons of the accident.

Although there was no gas leakage on the offshore gas pipelines and the oil pipelines, the consortium has decided to inspect the both pipelines.

The equipment for the diagnostic pipe control is ready and it will be used after the pipe cleaning is completed.

The final results of interpretation of the diagnostic pipe control data will be ready in early 2014.

The ground works are conducted on oil and gas pipelines as an additionl measure for detection of potential problems. No signs of leakage, such as reduction of pressure, were detected on the offshore section of the pipeline. 

The statement reads that discussion of the correction measures and the terms of their implementation as well as reliable forecasting of production resumption is possible only after detection of the reason of defect.—0—