The Geophysical Survey and Exploration Contract 99 (GSEC-99) covers an area of around 1.3 million hectares and is co-owned with Spex by local Filipino firm South China Resources Inc.

Malampaya has estimated reserves of around 3.5 trillion to 4.0 trillion cubic feet. And, according to Spex managing director, Jeremy Cliff, the Spex - South China Resources partnership is looking to equal that.

"We are hoping that the field would have proven reserve that could match that of Malampaya," said Cliff.

Under the terms of GSEC-99, the two companies must initially acquire, process and interpret around 2,000 km of seismic, gravity and magnetic data in the deepwater section of the block. They are also allowed to drill two test wells and - should the seismic survey results prove conclusive - have the option to convert it into service contracts.

Once drilling begins, as much as US$15 million to US$20 million is expected to be invested in the project, which could yield an initial potential reserve of around 2.0 trillion cubic feet. Drilling depth is between 100 feet to 65,000 feet with licensing cover of around 215,000 square km.