ONGC (NSE:ONGC, BSE:500312) reports a major new oil discovery offshore western India.
Previously, D1 was known to have initial oil in-place of about 600 MMbbl. The latest result suggests more than 1 Bbbl. D1 is primarily an oil-producing field, about 200 km (124 mi) west of Mumbai, in a water depth of 85-90 m (279-295 ft). It extends over four blocks, D1-4, D1-12, D1-14, and D1-2/5.
The first well in D1-4 was drilled in 1976. However, the low gas-to-oil ratio and limited understanding of the reservoir at the time slowed the pace of exploration and appraisal.
First development of the D1 field was confined to the D1-4 block where a total of 12 wells were drilled in two phases. After Phase-II was completed, oil production peaked at 17,500 b/d in 2009, and currently averages 12,500 b/d.
ONGC is implementing an integrated development plan for D1. Three new wellhead platforms – D1-B, D1-C, and D1-D – have been commissioned for the D1-4, D1-12, and D1-14 blocks. Development drilling is under way in blocks D1-4 and D1-14, and is expected to increase production to 36,000 b/d by February 2013.
The first development well (D1-D#1) in block D1-14, which spudded in May was planned to be drilled to 2,648 m (8,687 ft). However, when oil was detected in the 2,635-2,640 m (8,645-8,661 ft) zone, drilling was extended 100 m (328 ft) further, with the entire deepened section encountering oil-bearing sand. The well was subsequently drilled to a depth of 2,830 m (9,284 ft).
ONGC says this discovery has uncovered an additional oil-bearing zone of about 142 m (466 ft). On completion of the D1 field development, production is expected to rise to 60,000 b/d.
ONGC’s Sudhir Vasudeva said: “This discovery indeed has come up with a lot of promise signifying a substantial increase in the production for the company. Finally, we have made it to a large discovery which eluded us so long.”
Another ONGC exploratory well in Mumbai Offshore block WOFF 123 has flowed 43° API oil at 280 b/d and gas at 114,447 cm/d (4 MMcf/d), underlining the potential of the basal clastic /basement play.