Two big factors contribute to the persistence of high oil prices. First is labor unrest in both Nigeria and Norway, as this Telegraph article explains. Norwegian strikers are protesting poor working conditions, Nigerian rebels are disrupting production and transportation there. Both Norway and Nigeria produce light sweet crude, which has low sulfur content. The oil that Saudi Arabia has available for sale is heavier crude, with more sulfur. There are refineries in the US that can process light sweet crude, but not heavier crude, so the Saudi production is not a perfect substitute for the Nigerian and Norwegian.
Second, hurricanes in the Gulf of Mexico damaged rigs and pipelines sufficiently that it will take over a month for some of them to come back online. Furthermore, those same hurricanes damaged some natural gas pipelines, so already-high natural gas prices are starting to rise more dramatically.