Currently at a depth of 1333m, the well will continue drilling ahead into the Timboon sandstone in the upper Paaratte Formation, and to the deeper Nullawarre and Flaxman targets between 2000m and 2400m.

Essential said the deeper targets within the Sherbrook Group have the potential to host recoverable reserves in excess of 10 million barrels of oil or 17 billion cubic feet of gas. However, a commercial oil play has not been discovered in the Otway Basin for 139 years.

The company added that all prospective zones would be fully evaluated with wireline logs after the well reaches total depth.

The Pritchard Prospect is mapped as a predominantly anticlinal closure, up-dip from fluorescence shows encountered at the Pebble Point level in the adjacent Henke-1 well that was drilled in 1987.

Under recently formalised farm-in terms with permit operator Essential, Bass Strait can earn a 25% interest in the PEP 151 permit by contributing to the Pritchard-1 well. In addition, the company has an option to earn a 15% interest in the adjacent PEP 150 permit application, which contains the Lindon-2 oil discovery.

Early last month, private petroleum firm Inland Oil Resource farmed-in to PEP 151 with a 25% interest.

Essential holds the remaining 50% stake.