from Counterterrorism Blog by Michael Jacobson
It was notable that both Usama bin Laden and Ayman al-Zawahiri issued statements encouraging attacks on oil refineries in the months before the failed attack on the Abqaiq oil-processing plant in Saudi Arabia in February 2006. Considering that Abqaiq is the largest facility of its kind in the world and represents 60 percent of Saudi Arabia's daily output, a successful terrorist attack there would have significantly disrupted global energy supplies. Al-Qaeda in the Arabian Peninsula issued a statement following the attack, stating that it was part of "the war against Christians and Jews to stop their pillage of Muslim riches."
Al-Qaeda's focus on economic targets will likely sharpen under the current economic conditions, prompting more strikes on oil facilities on land or against ships at sea -- a capability already demonstrated by the attack on a French tanker off the coast of Yemen in October 2002.