Oil and gas exploration activity in India is setting new benchmarks for drilling at the deepest water depths. ONGC’s charter-hired Transocean’s ultra-deep-water drill-ship has set a world record for the deepest well drilled by an offshore rig.
According to ONGC, the rig DDKG1 spud (began drilling) well number NA7-1 in exploratory block KG-DWN-2004/1 on the east coast, at a water depth of 3,165 m (10,385 feet) on January 23.
With this, Transocean has surpassed its own prior record of 10,194 feet of water depth, set in 2011 by DDKG2 working for Reliance Industries Ltd, also on the east coast.
Cauvery-Palar basin
The Reliance block where the drilling was done is in the Cauvery-Palar offshore basin. Blocks in the Cauvery-Palar region are called “wild cat” blocks in the exploration industry as they are located in new frontier areas, sources explained.
In its statement, ONGC said, after drilling, the drill-ship has successfully lowered and latched a sub-sea BOP (blow out preventer) and riser (the process of connecting the drill-pipe with the wellhead) on the wellhead on February 9 to drill further to total depth of 5,625 m.
The costs
The ONGC statement is silent on the find at present, as drilling activity is still going on. As regards the investments involved, sources said the rigs are hired at a fixed rate for a given number of days.
“Therefore, it really does not matter at what depth the drilling is done. There are some variables involved in the cost, depending on the kind of drilling, but the numbers are very small,” an industry source said.
Drilling a deepwater well costs Rs 300-400 crore, the source said.