Shares in Bahamas Petroleum jumped 15% after surveys confirmed evidence of numerous structures "significantly larger than previously expected" in offshore licenses at the Bahamian fold belt.The results "provide evidence of 'giant' size structures in the southern licences...capable of holding several hundred million barrels of oil," the statement said."These structures are exceptional in the size and extent of the 4-way closure, indeed I am not aware of any anticlines of this size in the Gulf of Mexico - Caribbean region. We look forward to testing these structures with the drill bit to determine if hydrocarbons are present," said non-executive chairman Alan Burns.The group notes that these results are preliminary and the full 'pre-stack time migration' processing of the 2011 2D seismic data is due for completion by April.