Iranian Deputy Oil Minister Mohsen Khojasteh-Mehr announced that the country needs to invest $48 billion to spur development of its oil and natural-gas industries.Development of the South Pars gas field, the world\'s largest deposit of the fuel, is a priority, and funds will be channeled there for as long as necessary, he said. Some $16 billion needs to be invested at the field, which Iran shares with Qatar, Khojasteh-Mehr said, without specifying a date. In 2009, Iran said that development of the remaining phases of South Pars required investment of $40 billion over 10 years.