Roc Oil downgrades reserves at Basker-Manta field

Rick Wilkinson
OGJ Correspondent

MELBOURNE, Feb. 4 -- Roc Oil Co., Sydney, has flagged a likely downward revision of remaining oil reserves in its Basker-Manta field development in Bass Strait.

Based on preliminary results from the company’s first integrated full-field reservoir simulation model of the thin interbedded reservoirs, Roc expects the remaining 2P reserves to drop 70-80% to 3-5 million bbl down from previous estimates of 18 million bbl. The company has emphasized that the results are preliminary and that further optimization work has yet to be carried out.

In addition, the Basker-Manta joint venture has not yet reviewed Roc’s work and a commissioned independent review by Resource Investment Strategy Consultants has not been completed.

The result, nevertheless, has caught Roc by surprise. Currently the fields produce 6,000 b/d of oil via subsea wells into the Crystal Ocean floating production, storage, and offloading vessel and Basker Spirit and storage-offtake vessel.

The company is expecting to maintain an average of 5,000 b/d throughout 2010.

Roc admitted that the downgrade was a blow and it is now reviewing previous plans for further oil extension development and an associated gas project.

Roc holds 30% interest in the development, which Beach Energy holds 30%, Cieco Exploration & Production 20%, Sojitz Energy 10%, and Pertamina 10%.