Subject to gaining the necessary approvals, the survey is scheduled to start in April and the data is to be combined with reprocessed seismic to provide a 3D view of the subsurface, according to Sun.

Sun said this would help define areas for the recording of new seismic in the most prospective part of the 3947-square-kilometre licence for drilling.

Carnarvon as operator has flagged the possibility of re-drilling the Bong Nua-1 exploration well in late 2008, depending on joint venture and government approvals.

Sun said the Bong Nua-1 well encountered positive oil shows when it was first drilled.

"However, due to testing limitations, a flow to surface was not achieved," the company said.

"The operator considers that a redrill together with required artificial lift may result in a commercial oil discovery."

According to the partners, the lightly explored basin was geologically analogous to the nearby Phetchabun Basin, which Carnarvon and Pan Orient Petroleum had successfully explored over the past 12 months.

The Phitsanulok Basin also contains the Sirikit field, the country's largest onshore oil and gas accumulation with more than 200 million barrels of oil.