Houston-based Apache Energy found gas and associated liquid hydrocarbons in the Phoenix South-1 well off Western Australia, in the Roebuck basin, before a drill bit failure on 29 July.
Over the past two weeks, Apache drilled to a depth of 4321m and the well will be side-tracked at approximately 4000m, expecting to hit a TD of 4500m to test the sands that were observed in the Phoenix-1 well.
The primary target for the Phoenix South-1 well is the interbedded sandstones, siltstones and claystones of the middle triassic lower karaudren formation and early to middle triassic locker shale.
According to joint venture partner, Carnarvon Petroleum Ltd., the sands are expected to be intersected while drilling this final hole section.
“The observance of gas and associated liquid hydrocarbons validates the conceptual exploration model created by the interpretation of the original Phoenix-1 well outcome drilled by BP in the early 1980’s,” says Adrian Cook, Carnarvon managing director. “These observations are encouraging, although I would caution that they are untested, unquantified and preliminary observations only.
Carnarvon goes on to say that this outcome will encourage Apache to continue drilling and will justify the additional cost and time delay associated with drilling a second side-track well bore.
According to Carnarvon, it is too early to make any conclusions at this stage around the quality of the observed gas or liquid hydrocarbons, their volumes or if they will flow accordingly or could result in commercial development.
Further drilling and evaluation is required before the joint venture is able to be more definitive, says Carnarvon.
Carnarvon reports that the primary target within the early to middle triassic lower keraudren formation sands was intersected as expected at approximately 4160m, around 10m high to prognosis. Through this sand, elevated gas readings were observed, with gas peaks being encountered from approximately 4170m, as the sands being drilled were cleaning up.
After drilling is complete, the joint venture is planning extensive wireline logging and both pressure and fluid sampling.
Pheonix-1 South exploration well was spudded in late May 2014 using the Atwood Eagle semisubmersible drilling rig.
The spudding of the Phoenix-1 South well was delayed and pushed back to Q2 2014 by Apache due to other projects incorporated into Apache’s operational timetable. Carnarvon added that the delay in drilling was also timed to avoid the risk of cyclone activity, which may have affected the project.
Apache Energy is the operator and holds 40% interest along with Carnarvon Petroleum (20%), JX Nippon (20%) and Finder Exploration (20%).
image of Phoenix-1 South from Carnarvon