US independent Apache has successfully sidetracked an exploration well off Western Australia after a tool became stuck in the original well.
Joint venture partner Carnarvon Petroleum revealed on Tuesday that Apache had started drilling operations in the sidetrack wellbore and said the well was drilling ahead at roughly 1960 metres to the 9.6-inch casing point of about 3700 metres.
The sidetrack is being drilled about 30 metres from the original wellbore and Carnarvon said the positioning and forward plans for the sidetrack wellbore would not compromise the evaluation of the Phoenix South-1 prospect.
Carnarvon said the upper portion of the previously set casing was cut and retrieved along with the casing tool before the original wellbore was plugged with cement and drilling of the sidetrack started on 5 July.
The well is being drilled using the semi-submersible Atwood Eagle and is now expected to reach total depth by mid-August.
Carnarvon has previously assessed Phoenix South as a multi-trillion cubic foot gas prospect that is in proximity to proven gas in lower Triassic reservoirs in the existing Phoenix-1 discovery, which lies about 13 kilometres to the north.
If the well intersects hydrocarbons, the joint venture plans to carry out extensive wirelogging, pressure and fluid sampling, and collect reservoir core samples before plugging and abandoning the well.
Apache is operator of WA-435-P, which contains the Phoenix South prospect, holding a 40% stake, with joint venture partners Carnarvon, JX Nippon and Finder Exploration each holding a 20% share in the well.