BAKU, Azerbaijan, Oct.15
By Leman Zeynalova – Trend:
After almost four and a half years since the start of construction, the Trans Adriatic Pipeline (TAP), the final leg of the Southern Gas Corridor, which envisages transportation of Azerbaijani gas to Europe, is substantially complete, Trend reports.
TAP is 878 kilometres in length: 773 kilometres onshore and 105 kilometres offshore.
Approximately 55,000 pipes have been used to build the pipeline, weighing circa 520,000 tonnes or the equivalent of 71 Eiffel towers. The pipes were transported to TAP’s main marshalling yards in 79 sea vessel shipments and 158 block trains within Greece. From the main marshalling yards, the pipes were transported further to the local pipe yards near the construction sites along the pipeline route.
Laying steel pipes beneath the Adriatic Sea at depths of more than 800 metres, with a duty of care to the environment, is no easy feat. TAP contracted industry leader Saipem to lay the pipe-string on the seabed, using a specialist semi-submersible vessel.
In February 2018, near the Greek village of Elaiousa, TAP completed one of the longest thrust bores of its type: an 1,820 metre horizontal directional drill beneath the Axios river.
Drilling and reaming (widening of bore holes) operations took place between November 2017 and February 2018, using a 400-tonne rig with reaming tools designed specifically to minimise rotation and pull forces.
TAP’s contractors and their engineers constructed a pipe section, comprising 1.2 metre diameter pipes, and accommodated the welded pipe stretch all in one go. To add to the challenge, the team was required to build this pipe-string along a curved section of the pipeline’s right of way, within a floatation trench, passing below a provincial road.
The controlled installation process took 36 hours and was completed with zero impact on either local communities or the environment.
At the pipeline’s highest point in Albania, at altitudes of more than 1,800 metres, TAP’s engineers were faced with some of the most challenging terrain and difficult geological conditions of the entire pipeline route.
With no option of rerouting, TAP decided to drill a 480-metre micro-tunnel underneath the area to avoid installing the pipeline in unstable ground.
In addition to the technical issues intrinsic to such a challenging project, the teams also had to face tough weather conditions and manage access to a very remote area 12 kilometres from any paved road and a three-hour journey from base camp.
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