Expect another 'Vadtal 3' at CB-ONN-2004/2

Vol 16, PW 24 (27 Jun 13) Exploration & Production

Buoyed by three back-to-back discoveries, ONGC is planning eight exploration wells at CB-ONN-2004/2 in a Rs70cr ($11.7m) drilling campaign.

Two years ago the Vadodara-based western onshore exploration wing reported discoveries: Vadtal-1, Vadtal-3 and Vadtal-5 at this NELP-VI block. “Vadtal-3 is why we are planning this campaign,” says ONGC.

Vadtal-3, he says, indicates a ‘fault closure’ or sub-surface ‘trap’ holding oil. ONGC will use the new exploration campaign to look for similar ‘fault closures’ in northern parts of the block.

“Eight drilling locations have been identified,” adds ONGC. All the wells will be drilled to between 1200 and 2000-metre depths in the Kheda and Anand districts within the 423-sq km block boundary.

On May 2, ONGC received environmental clearance, paving the way for a 1000-hp rig tender, expected in September. ONGC made the first discovery in 2010-11 when well Vadtal-1 was drilled to 1784-metres and found to be oil bearing from 1148 to 1137-metres in the ‘EP-IV’ formation of mid-Eocene age.

On conventional testing the well flowed oil at the rate of 37 cm/d (about 278 b/d) through a 6-mm bean. At Vadtal-3, oil flowed at the rate of 22.5 cm/d (141 b/d) and gas at 3758 cm/d.

ONGC tells us the 41-degree API light oil is of good quality. At Vadtal-5, oil was found in the Middle Eocene Kalol formation at 1598 to 1604 metres.

Vadtal-5 is a new pool discovery, tapping a new reservoir. Note: ONGC has high hopes for this block.

After announcing the discoveries in 2011 it prepared a production profile that pegs oil production at between 1375 to 1450 b/d. "But these aren't final figures," says ONGC.

"This block is going to be as good as the Ankleshwar or Jambusar fields.” ONGC (55%) shares CB-ONN-2004/2 with GSPC (45%).

Suntera Resources, an Indo-Russian joint venture, earlier held 10% but was stripped of its stake in 2009 after failing to honour a $1m cash call. Prize Petroleum initially wanted the Suntera stake but changed its mind.

Suntera’s 10% was then divided equally between ONGC and GSPC. Reliance bid for the block in NELP-VI as did a consortium of Kuwait Foreign Petroleum Exploration (30%), IndianOil (35%), Canada's Pan Orient (20%) and NTPC (15%).

The PSC was signed on March 2, 2007 and the PEL issued on May 28, 2007.