The companies have signed a farm-out agreement for a 50% interest in the offshore permit to be transferred to Apache subsidiary Apache Northwest.
Apache will pay $9 million to reimburse back costs for seismic acquisition.
The company will also fund 90% of the cost of one exploration well on the permit capped at a value of $63 million.
This well fulfils the obligations for the third year of the initial work programme.
Apache will take over operatorship of the permit and has committed to drilling a well in the first half of 2015.
Karoon announced earlier this month that the permit held a best net un-risked prospective resource of 2.2 million barrels.
The company received independent reports from DeGolyer and MacNaughton regarding resources across its global plays.
Karoon completed its 3D seismic shoot late last year covering 2387 square kilometres to delineate leads and other prospects.
The Geo Caspain seismic streamer vessel collected data for the survey.
Karoon took its 100% interest in the permit from US junior Liberty Petroleum back in 2012.
The primary targets of the block are the intra Mungaroo levels, with some potential in some high-rick shallower targets above that level.
Apache already operates off the coast of Western Australia in the Browse basin.
Karoon said it was positive as the company had experience with drilling in the region.