Australian gas giant Santos (ASX: STO) has successfully completed its fully underwritten A$500 million institutional placement at A$12.55 per share. The energy firm informed ASX this morning that the placement was heavily oversubscribed with strong demand from institutional shareholders.

Santos launched the equity raising on Friday to fund its share of the $16 billion coal seam gas-fed Gladstone LNG export project in Queensland state.

The gas giant on Friday said it had sold a 7.5 per cent stake in GLNG to Korean Gas Corp (KOGAS) and another 7.5 per cent to France's Total for a combined $665 million.

KOGAS will also buy 3.5 million tonnes of liquefied natural gas (LNG) per year from Gladstone for 20 years starting in 2015.

Santos chief executive David Knox on Monday said the equity raising completed Santos's funding needs for its share of GLNG.

"Santos is very pleased with the strong support shown by institutional shareholders for the placement," Mr Knox said in a statement.

"The placement was heavily oversubscribed with strong demand from institutional shareholders."

The successful fundraising clears the way for a final investment decision next week in the 7.2 million tonne-per-year, $15 billion project, which will be among the first to utilise Queensland's massive coal seam gas reserves.

Santos emerged strongly from a share trading halt on Friday.

By 1141 AEDT on Monday, shares in the company gained more than 5 per cent, at $13.67, after reaching as much as $13.79 in early trade.