Pritchard-1 will test a series of stacked targets in the predicted oil fairway on the flanks of the Portland Trough.

The primary target is the Pebble Point Formation at the base of the Tertiary at a depth of about 1300m, with secondary targets in the lower Sherbrook Group. The Pebble Point play has generated multiple oil shows and recoveries in PEP 151 and adjacent areas, the company said.

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

Pritchard has a potential mapped volume of 4 million barrels of recoverable oil at the Pebble Point horizon, and 10 million barrels of recoverable oil or 17 billion cubic feet of recoverable gas at the Sherbrook Group reservoir.

Bass Strait Oil chief executive Andrew Adams said the company believed the Portland Trough area of the Otway Basin could contain oil-prone source rocks.

“This oil fairway around the flanks of the Trough is in contrast to other areas of the Otway Basin where older source rocks may have generated oil in the past, but are now deeply buried and generating gas,” Adams said.

“[The company] interprets that oil generated in the Portland Trough could have migrated into the Pritchard-1 target reservoirs. This generation and migration model could also explain oil shows at these levels in nearby wells, including Henke-1and Lindon-1 and -2.”

However, a commercial oil play has not been discovered in the Otway Basin for 139 years.

The Lindon wells in PEP 150 that were drilled in 1983 and 1991, encountered oil pay in the Pebble Point Formation, with Lindon-2 also recovering oil samples with an API gravity of 29 degrees.

Adams said many existing Otway Basin wells were drilled on sparse and poor quality seismic data and failed to intersect valid structural closures.

Several prospects and leads have been identified in PEP 150 and PEP 151, indicating a series of potential follow-up targets in this oil fairway, he said. Prominent features in PEP 151 include the Battersby and Bulley prospects.

Under recently formalised farm-in terms with permit operator Essential Petroleum, Bass Strait can earn a 25% interest in the PEP 151 permit by contributing to the Pritchard-1 well. In addition, 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.