Belford Dolphin spuds east coast wildcat for ONGC

Vol 8, PW 22 (09 Feb 05) Exploration & Production
     

ONGCs ambitious deepwater drilling campaign crossed an important milestone on 8th February when drillship Belford Dolphin spud the deepest ever well in Indias eastern offshore.

Well GR-L-1 sits in NELP-I block KG-DWN-98/5 in water depths of 2530 metres and will be drilled to a target depth of 5000 metres. This will be a record off the east coast in terms of both water depth and target depth, reveals ONGC.

It will be a very challenging well and is expected to reach target depth in about three months. ONGC said GR-L-1 is an absolute wildcat because, except for 3D seismic there is not much information from past drilling in and around the location.

Belfords objective at this well is the younger, Oligocene and Miocene era sediments. (But) during drilling we will penetrate the Cretaceous era sediments by about 200 or 300 metres.

We are told that the targeted zone indicates sand bodies within the Godavari Clays. ONGC is alive to the typical problems of drilling off the east cost in such water depths.

One of the main problems we are likely to face is sediment fracture because of the unconsolidated nature of the sediment. Then there could be problems caused by mud loss, shallow gas, gas hydrates and high pressure.

We have designed a specific kind of mud to handle sediment fracture, we are told. The moment our down hole sensors tell us that the formation around the hole is collapsing we will case it.

GR-L-1 is Belford Dolphins first well off the east coast after a string of eight dry holes off the west coast. Her last well off the west coast (KS-1) showed only florescence and was abandoned.

After this ONGC decided to move Belford to the eastern offshore where she is expected to remain drilling at all deepwater locations beyond 1500 metres water depth. ONGC tells us three locations are available at KG-DWN-98/5 and KG-DWN-98/4.