Multizone gas find gauged off Mauritania

By OGJ editors
HOUSTON, Jan. 10 -- A group led by Korea National Oil Corp. subsidiary Dana Petroleum has tested gas from one of four separate gas columns in an exploratory well in the Atlantic off Mauritania.

Cormoran-1 is in Block 7 about 2 km south of the late 2003 Pelican-1 gas discovery (see map, OGJ, Oct. 23, 2006, p. 38).

Cormoran-1’s main purpose was to test the Cormoran prospect, which adjoins but lies at a greater depth than Pelican. A secondary objective was the Petronia prospect beneath Cormoran. A further objective was to provide appraisal data on the Pelican gas discovery.

Cormoran-1 went to 4,695 m below sea level in 1,630 m of water. It encountered generally thin but good quality gas-bearing sands in the Upper Pelican Group at 3,376-3,420 m true vertical depth subsea and in the Lower Pelican Group at 3,691-3,711 m TVD ss.

The well also encountered good quality gas-bearing sands in the Cormoran prospect in the gross interval from 4,351 m to 4,471 m TVD ss and at the top of the Petronia prospect in the gross interval from 4,660 m to 4,695 m TVD ss. Drilling stopped at 4,695 m due to elevated pore pressures, and the well was still in gas-bearing reservoir at total depth.

The well stabilized at 22-24 MMscfd of gas on a 32/64-in. choke on a drillstem test of the Lower Pelican Group at 3,679-3,712 m TVD ss. The flow rate was constrained by the need to avoid sand production. Substantially higher flow rates could have been achieved if not for this operational constraint, Dana Petroleum said.

The company plugged and abandoned the well so that it can be reentered.

Participating interests in Block 7 are Dana Petroleum (E&P) Ltd. 36%, GDF Suez Exploration Mauritania BV 27.85%, Tullow Petroleum (Mauritania) Pty. Ltd. 16.2%, PC Mauritania Pty. Ltd. 15%, and Roc Oil (Mauritania) Co. 4.95%.