TIME's Sally Donnelly reports that a crucial international decision to unlock what could be the largest untapped oil reserves in the world may be made this week. The question: where to locate a massive pipeline from the vast oil fields of the former Soviet republics of Azerbaijan and Kazakhstan. When completed, the $1 billion project would transport 100,000 barrels a day to a Black Sea port, and the governments of Russia, Georgia and Iran are all lobbying hard for the enormous financial windfall. "When the decision is made, a new pipeline will run through the two countries' powerful neighbor to the north, Russia, or through their weak and destabilized neighbor to the west, Georgia. Or maybe, as recent betting has it, through two new pipelines." U.S. companies including Chevron and ARCO are lobbying for the last option, in order to protect their multibillion dollar commitments to developing the fields. "Washington is pushing for the new pipeline to go south, linking those vast oil reserves with friendly nations like Turkey," Donnelly says. "But not too far south: the U.S. is leaning on the Azeri government in Baku to turn down Iran's repeated offers of assistance and financing."