Indradhanush Gas Grid Limited (IGGL), on Friday, April 21, accomplished the arduous task of laying a 24-inch diameter hydrocarbon pipeline beneath the Brahmaputra River through the Horizontal Direction Drilling (HDD) method, The Meghalayan reported on Saturday, April 22.
According to the report, the record-breaking pipeline links Jorhat and Majuli in Assam, marking a significant milestone in constructing the Northeast Gas Grid (NEGG) to connect the Northeast to the National Gas Grid.
"With the completion of the Brahmaputra HDD, IGGL has achieved more than 71% physical progress of the NEGG project and will be able to complete the Guwahati-Numaligarh section of the NEGG by February 2024," said Ajit Kumar Thakur, CEO of IGGL.
The 4080-meter pipeline, stretching across the primary water channel of the Brahmaputra, is the longest river crossing ever accomplished by any 24-inch or larger diameter hydrocarbon pipeline in Asia, making it the second-longest in the world.
IGGL executed this unique HDD river crossing using the Intersection method comprising two HDD rigs simultaneously drilling from opposite sides of the Brahmaputra until their drilling heads met in the middle, 30 meters beneath the riverbed of the Brahmaputra river.
Despite numerous challenges due to monsoon rains and floods, laying the 4,080-meter pipeline section was completed, with the total length of HDD crossing across the Brahmaputra measuring 5,780 meters, considering all major and minor water channels.
The construction was done in three separate HDD sections 1,000 meters, 4,080 meters, and 700 meters.
Earlier, the 1,000-meter and 700-meter sections were completed, and the next step was the tie-in of the three sections at two points, located 15 meters and 8 meters below Natural Ground Level (NGL).
The Indradhanush Gas Grid Limited is a joint venture company of five major oil PSUs, including IOCL, ONGC, GAIL, OIL & NRL, that is implementing the North East Gas Grid Project (NEGGP), connecting the major cities and demand centers of the Northeast with the National Gas Grid.
The 1,656 km long natural gas pipeline is constructed at a project cost of Rs 9,265 crore, with 60% received as a grant from the Union government.