Guwahati: Asia’s largest underwater hydro-carbon pipeline, below the river Brahmaputra connecting Jorhat and Majuli in Assam has been completed by the Indradhanush Gas Grid Limited (IGGL), the company’s CEO Ajit Kumar Thakur said on Saturday.
The challenging task of laying a 24-inch diameter hydrocarbon pipeline beneath the mighty Brahmaputra river by Horizontal Directional Drilling (HDD) method was completed on Friday, marking the completion of a major milestone in the construction of the North East Gas Grid (NEGG) connecting North East India to the National Gas Grid.
The total length of the pipeline in this single HDD crossing is 4,080 metre across the main water channel of Brahmaputra river.
This is the longest river crossing by any hydrocarbon pipeline of size 24-inch diameter and above in Asia and the second longest in the world, he claimed.
This one of a kind HDD river crossing was executed by intersection method, where two HDD rigs simultaneously started drilling from the two sides of Brahmaputra with intersection of the two drilling heads in the middle at 30 metre beneath the river bed.
The laying of 4,080 metre pipeline section was completed by overcoming numerous hurdles faced mainly due to monsoon rains and flood, he said.
The total length of HDD crossing across the Brahmaputra river considering all major and minor water channels is 5,780 metre.
The pipeline was laid in three separate HDD sections of length 1000 M, 4080 M and 700 M with the first and the third sections completed earlier.
The next step will be tie-in of the three sections at two points, which will be located at 15 M and 8 M below Natural Ground Level (NGL).
“With the completion of the Brahmaputra HDD, IGGL has achieved more than 71 per cent physical progress of the NEGG Project and will be able to complete the Guwahati-Numaligarh section of the project by February 2024”, Thakur said.
He thanked the Assam government for being extremely supportive in implementing the project.
Indradhanush Gas Grid Limited, is a joint venture company of five major Oil PSUs – IOCL, ONGC, GAIL, OIL and NRL. It is implementing the North East Gas Grid Project connecting the major cities and demand centres of North East India with the National Gas Grid.
The 1656 km long natural gas pipeline is constructed at a project cost of Rs 9,265 crore.