Two separate events collectively should put pressure on gas prices in the United States in the near-term. First it is that time of year called the Seasonal Blend Switch. This transition from winter-blend to summer-blend fuel, a blend that causes less smog by adjusting the proper Reid vapor pressure (RVP), occurs every spring. It causes a dip in gasoline supplies as refineries in the US shut down temporarily to retool their production facilities. However, what will be driving oil prices is news out of Nigeria today where the rebel Movement for the Emancipation of the Niger Delta (MEND) said its commandos had carried out the attacks on Monday against pipelines located at Isaka River and Abonnema River in Rivers State. In turn the Nigerian Oil Ministry has informed its customers that it will not be able to meet its deliveries for the balance of April and for the month of May. Nigeria is the fifth largest source of oil for the United States. More on this story: Nigerian Rebels Attack Oil Pipelines in Niger Delta