The find “will catapult D1 to become the third largest field in western offshore after prolific Mumbai High and Heera”, Oil and Natural Gas Corp said in a statement on Saturday.
D1, which is currently producing 12,500 barrels per day (bpd), had an approved peak output of 36,000 bpd. With the new discovery, the peak output would jump to 60,000 bpd or three million tonnes a year.
“Earlier, the D1 was known to have initial oil in-place (or inplace reserves) to the order of 600 million barrels (82.20 million tonnes of oil equivalent). After the discovery of the new pool, its total in-place reserves are expected to be in excess of one billion barrels,” it said.
D1, primarily an oil producing field, is situated about 200 km west of Mumbai city in Deep Continental Shelf at a water depth of 85 to 90 metres. The first well in D1-4 block was drilled in the year 1976.
The low gas-to-oil-ratio (GOR) and the then understanding of reservoir led to slow pace of exploration and appraisal of the field.
“As a result, the first development scheme for the D1 field was confined only to the D1-4 block in which a total 12 wells were drilled in two phases. After completion of Phase-II, the field achieved a peak oil production of 17,500 barrels per day in the year 2009. Currently, D1 is producing on an average of 12,500 bpd,” it added.
In the next phase of development, ONGC is implementing an integrated development plan for the entire D1 field. This would raise the output to 36,000 bpd by February, 2013.