More trouble with Discoverer Seven Seas for ONGC

Vol 9, PW 19 (12 Jan 06) Exploration & Production

ONGC is again having problems with deepwater drillship Discoverer Seven Seas hired from Transocean.

Trouble began around mid-December when Discoverer was drilling at location A-1 at eastern offshore block KG-DWN-98/2, where Cairn Energy holds 10%. Drilling reached 2609 metres when Discoverers Dynamic Positioning System (DPS) failed due to loss of power, we are told.

The rig drifted and floated away for some distance. As a result drill pipes sheared away and fell into the well.

More, the riser snapped from the Blow Out Preventor. ONGC was all the more alarmed by the incident because it happened in perfectly normal weather conditions.

It happened all of a sudden catching everybody by surprise, we hear. The whole drilling was messed up.

Transocean carried out a trouble-shooting operation and set things right but this took a fortnight, delaying ONGCs drilling schedule. The pipes that fell into the well had to be fished out, adds a source.

The riser and the BOP had to be checked. Discoverer was back in action at the well early January and ONGC began final logging over three days from 5th January, followed by testing.

This is expected to take a fortnight. Luckily for ONGC, the latest collapse of Discoverers DPS was not as bad as an incident on 8th September, which also took place on the same block, but at prospect D while the final 9 5/8-inch casing was being lowered.

That incident was the most serious so far and forced ONGC to abandon a promising well source of a very public row with the DGH over premature discovery announcements. Within ONGC and the oil ministry serious concerns are being raised about the repetitive nature of the accidents at Discoverer.

A source tells us the latest failure of the DPS is the fourth since Discoverer began drilling for ONGC in February 2004. One was a minor incident when the DPS failed, we hear.

The rig began to drift but within a few minutes the power came back and everything was normal.