To supporters of drilling oil there, the coastal plain of the Arctic National Wildlife Refuge is a desolate and frozen place whose most interesting features are the natural oil seeps in the rock outcroppings. With President George W. Bush vowing to open the ANWR to drilling and a bill being introduced by Republicans in Congress this week, development supporters say they are optimistic the coastal plain will yield a petroleum bonanza. They tout a recent government estimate of up to 16 billion barrels.