Iran plans to attract 100 billion U. S. dollars of foreign investments in the crude oil sector over the next four years, Iran Daily quoted an oil ministy official as saying on Thursday. Iran has revamped its rules governing oil contracts to facilitate foreign investment in the country, said Mehdi Hosseini, head of the Oil Ministry's Oil Contracts Revision Committee. Iran Petroleum Contract (IPC), which envisages new contract models offered by the Islamic republic, has removed all the problems that existed in oil deals over the past 20 years, Hosseini said. "By solving old contract problems, the ground is prepared for the renewed presence of big oil companies in the country," Hosseini was quoted as saying. He said the IPC is replacing "buy-back" contracts which are no longer attractive to foreign companies. Under the IPC, National Iranian Oil Company will set up joint ventures for crude oil and gas production with international companies which will be paid with a share of the output, though " ownership of reservoirs is not transferable." International companies cut back their presence in Iran as Western countries imposed sanctions on Iran's oil and gas industries during the past few years, resulting in a significant decrease in Iran's oil and gas exports. Progress in nuclear talks between Tehran and the so-called P5+1 group, which includes the United States, Russia, China, France, Britain and Germany, has raised hopes for an investment comeback in Iran.