Poseidon-2 poses questionsUS supermajor ConocoPhillips is...

Poseidon-2 poses questions
US supermajor ConocoPhillips is preparing to plug and abandon the Poseidon-2 exploration well in the Browse basin off north-west Australia after problems with perforating the well in the Montara reservoir hampered a second drillstem test.
Upstream staff Wednesday, 03 February, 2010, 08:16 GMT
Karoon Gas, ConocoPhillips?s partner on WA-398-P, said the supermajor had decided to move the semi-submersible Transocean Legend to drill on a new site after reviewing flow and pressure data from the well.

Karoon said it believed there was probably no connection between the well bore and the reservoir.

The well was the first to strike the Montara formation reservoir sands on the Poseidon field and Karoon said mudlog data suggested moveable gas exists in the levels. However, this was unable to be confirmed by the testing.

Meanwhile, a drillstem test of the underlying Plover B sands flowed gas to the surface at a rate of up to 850 cubic feet per day. Karoon said it believed the high permeability seen in cores taken from these levels suggested gas could flow at a higher rate.

The company said its own interpretation of the results was that brine from the well completion was still present in the hole, restricting gas flows.

Karoon said the Poseidon-2 well had successfully tested the extent and quality of the Motara and Plover formations six kilometres downdip from the Poseidon-1 discovery well.

It said the well had revealed gas in the Montara levels and confirmed the presence of moveable gas in the Plover B sands. The company said it was its view that the Plover A and C sands had better quality overall in the field than the interbedded B sands.

Karoon said ConocoPhillips would now drill the Kronos-1 exploration probe. The well would test the Plover B sands updip from Poseidon-2 and would also test whether apparently higher-quality Plover C reservoir sands existed higher up on the structure.

Karoon said ConocoPhillips did not necessarily share its interpretations of results from the wells.

ConocoPhillips operates the Browse WA-398-P permit with a 60%stake, with Karoon Gas holding the remaining 40%. Karoon?s assets off Australia were last year bought by Indonesian explorer PTT Exploration & Production.

Gas from the permit could be used to feed ConocoPhillips planned LNG plant at Darwin in the Northern Territory.

Published: 03 February 2010 08:16 GMT | Last updated: 03 February 2010 08:16 GMT