Steep terrain challenges pipeline crews.
As proposed, the gas-based power plant was to receive gas from Petronet's LNG Terminal in Dahej, in the state of Gujarat. GAIL was given the responsibility of constructing the 30-inch, 116-mile bi-directional pipeline to transport the gas from Dahej to Dabhol.
Prior to the start of construction, GAIL officials decided to divide the project into two parts. Part A included a 70-mile segment from Panvel to upstream of Savitri River crossing; Part B was a 46-mile segment that extended from upstream of the Savitri River crossing to the Dabhol terminal. The project also required construction of two Intermediate Pigging (IP) stations and seven Sectionalizing Valve (SV) stations.
In Part B, there are a number of major river crossings on the project, two of which have been made using Horizontal Directional Drills (HDDs), namely a 1,100-meter crossing at the Vashishthi River and a 560-meter crossing the Savitr River.
Punji Lloyd and the Zangas-Kalpataru Consortium of Mumbai won international tenders to complete the two segments. Part A was awarded to Punji Lloyd and Part B, the more difficult of the two segments, to the Zangas--Kalpataru Consortium.
Part B posed the greatest construction challenge because it was located in extremely rough terrain. Over the course of the route, the elevation ranged from 18 to 260 meters.
The entire team of the Zangas--Kalpataru Consortium, under the guidance of Gyan Prakash, president and CEO of Kalpataru, accepted the challenge of completing Part B which required the crossing of six major rivers, seven state highways, 20 village roads and the construction of four SV stations and one receipt terminal.
To further complicate matters, while the water depth at the Vashishthi River is only 16 meters, near the banks on both sides hills are prevalent, making pipe stringing difficult.
To successfully complete the 46-mile job, Kalpataru Power Transmission Ltd's pipeline group deployed a wide array of pipeline equipment that included the 250-metric ton rig to perform the HDD crossing, 32 side booms, mostly with a 70-ton capacity; 19 dozers, of which the majority were Cat D-8 dozers, 45 excavators, four welding crews; and a wide selection of equipment, tools and tackle.
Crews constructing both segments relied on semi-automatic welding technique.
The Panvel to Dhabol Pipeline was completed in June 2007.
By Sandip Sharma, Director, Kalpataru Energy Ventures Pvt. Ltd., New Delhi, India
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|Publication:||Pipeline & Gas Journal|
|Date:||Sep 1, 2007|
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