The recent and significant drop in oil prices shouldn't have much effect on Falcon unless prices stay very low for 3 or more years. The price for natural gas supplied to Northern Australia, for the LNG plant that is being built in Darwin, should hold up fairly well especially with a probable three year timetable before any gas would be running from the Beetaloo. The pricing for natural gas that will be shipped by LNG carriers from Darwin to Japan has longer term pricing that is fairly strong given the massive 29 billion dollar investment in the LNG plant.
The timetable for the Karoo for any natural gas production is even farther away than the Beetaloo with domestic pricing in South Africa that is quite strong as well. The potential for gas fired electrical production that eliminates rolling black outs and cuts pollution should also keep prices a bit stronger in South Africa as well.