Transneft East started works on replacement of a section of the underwater crossing across the river Biryusa (Irkutsk Region) of Krasnoyarsk – Irkutsk oil trunk pipeline (OTP), Transneft ‘s press release says.
The works are conducted as part of implementation of the plan of technical upgrading and development of the oil pipeline infrastructure facilities located in the enterprise’s area of responsibility.
The standby leg of the underwater crossing (siphon) across the river Biryusa of Krasnoyarsk – Irkutsk oil trunk pipeline is located at the section Rybinskaya – Tayshet (195.7-855.5 km of the OTP) and is operated from 1981. Replacement of the pipe with a new one with the length of 1,248 metres will be performed during the works.
At the present time dismantling of 918 metres of pipe has been performed; welding of a new section has started, 89 of 111 joints have been welded.
After finishing welding the lengths (several connected pipes) of the siphon will be put to hydraulic tests. Particularly, each length will be tested for strength with pressure of 11.2 MPa (108.5 atmospheres) during 6 hours and for containment – with pressure of 6.3 MPa during 12 hours (59 atmospheres). Additionally the “dry broach” method will be used for specifying strength and longevity of the new oil pipeline section. This method is characterized with the fact that the pipe is inspected for potential defects using an in-line inspection tool before laying into a bottom trench.
As well, in-line inspection using special purpose diagnostic tools will be performed after laying the siphon to the river bottom and commissioning.
The works are planned to be finished in the third quarter of 2017.