Ann: Large Prospect to be Drilled in Alaska - 1Q 2019 (Revised), page-4

Ok the additional information apart from "investor be wary statements" required by ASX:-

The leases are located immediately adjacent to the Horseshoe#1/1A well, drilled by Repsol SA and Armstrong LLC, which discovered oil in 2017.

So I did a quick google research:-
"After discovering one of the largest U.S. onshore hydrocarbon reservoirs in Alaska’s North Slope, Armstrong Oil & Gas Inc. has agreed to sell interests in its North Slope find as part of a deal worth up to (My note this is USD as per oilsearch annoucement) $850 million.

Australia’s Oil Search Ltd. said Nov. 1 it will purchase interests in the conventional Pikka Unit, Hue Shale and Horseshoe Block from Denver’s Armstrong and GMT Exploration Co. LLC for an initial price of $400 million.

Armstrong is selling half of its interests and Oil Search has an option through June 2019 to purchase the remaining interests from the companies for $450 million."

https://www.oilandgasinvestor.com/armstrong-selling-stake-largest-us-oil-discovery-decades-1667211

MAMAMIA!!