The Egyptian issue goes far beyond oil. The Mubarak regime has been a close ally to the United States since the Reagan administration. We've been dumping billions of dollars of, mainly military, aid to the country for the last three decades for two reasons. The first, the Mubarak regime was one of the few friends that Israel has in the region. The second, Egypt under Mubarak is a secular state and has been an integral part of the war on terror.
As of right now the United States is in a foreign relations conundrum. If the U.S, backs Mubarak, then there might be a chance of holding onto a key ally in the region...but we also run the risk of a massive black eye if Mubarak is toppled. If the US backs the protestors then they run the risk of alienating a close ally. So sure, oil does factor in one way or another. But to think that US interests in Egypt is purely that of oil, is to misunderstand the situation that the US foreign policy makers are currently dealing with.