The Hindu Business Line : ONGC facing problems in Sunderbans

"The problem is double-edged. On the one hand, we have our own preferences on location of the wells, based on geo-physical findings. On other hand, the rig owner feels that risks are too high and take decisions on the advice of its insurer," an official said.

Kolkata , Jan. 3

ONGC is facing problems prospecting for oil and gas in the world's largest delta — the Sunderbans.

The company has reached the targeted depth at the first well, three months after the scheduled date of completion, but is now at its wit's end to find suitable locations for the remaining three exploratory wells.

The total project cost for drilling four wells has been estimated at Rs 500 crore.

Apart from high pressure conditions which makes drilling operations accident-prone, the company is now facing a situation where the rig, Trans Ocean Nordic, is turning down offers to drill wells at locations preferred by ONGC, citing unsuitable sea bed conditions. Sources indicate that the absence of insurance cover for drilling in such conditions may also be a reason for the rejection of the offers.

The rig has so far rejected seven locations identified by ONGC.

The company identified Trans Ocean Nordic after a two-year-long search. The rig is apparently capable of undertaking drilling operations in 13 to 20 metres of shallow water on a muddy seabed in conditions of high underwater current. It is a heavy Jacob's rig capable of drilling at close to 5,000 metres depth resting on three legs.

Keeping in mind the cyclone prone conditions of the delta, this particular rig was preferred to floaters commonly used in shallow waters.

"However, as it seems now, the seabed is extremely muddy making it difficult for the Jacob's rig to rest on its legs," the official said.

"We (ONGC and Trans World) are trying all possible combinations to locate a suitable site for drilling the next well. Recently, we convinced them to carry out a test at a particular location to which they agreed. We are now hoping for the best," the official said.

In case the rig is changed to the "mat rig" type (which has a flat bottom and rests on the sea-bed itself), the entire drilling process could turn out to be costly and also time-consuming. The present project cost is more than Rs 120 crore per well," the official added.