The listed companies said the vertical well, Maitland-2, and the core hole, Maitland-2CH, had been successfully drilled, with core over the reservoir section recovered.

The horizontal sidetrack well, Maitland-3H had also been subsequently drilled to its total depth, penetrating over 500m of the reservoir, and prepared for testing.

However, testing operations at Maitland-3H had been interrupted due to water influx, believed to be coming from an open zone above the reservoir interval.

The companies said operations were underway to remedy the problem.

Tap said that though the results of the planned flow test were not yet known, the drilling data was consistent with the pre-drill prognosis.

Specifically, a good 500m horizontal section through the gas-charged reservoir had been achieved.

Tap said it understood the water influx was coming from above the reservoir and that it was a mechanical isolation issue associated with the well completion.

This was expected to be remedied within the next few days. Following this, the flow-test program would recommence, Tap added.

Maitland-2 was aimed at further appraising the potential of the Maitland gas field, discovered in 1992, through the evaluation of a stratigraphic trap defined by seismic amplitudes.

One appraisal well, Maitland North-1, drilled in early 1996, found gas and condensate in the Paleocene-aged Maitland sandstone.

Based on new analyses done by operator by Apache Energy, it is estimated Maitland has a gross gas column thickness of at least 23m.

The Maitland field is in Permit WA-33-R, and is held by operator Apache (48.82%), Tap Oil (22.47%), Santos (18.71%) and Pan Pacific Petroleum (10%).