The Saudi king today became the first OPEC leader, and first Saudi leader ever to travel to Beijing. Last year Saudi oil sales to Beijing rocketed 59% higher than in previous years and with growing Chinese demand for oil are set to continue to rise.
China has been agressively seeking oil-contracts to feed its ever-increasing energy demand, a situation which could cause further strain on US-Chinese relations as the competition for access to Mid Eastern oil increases dramatically.
China is the #2 oil consumer in the world after the USA, but have much more substantial economic growth and a strong budget surplus in recent years. With US debt increasing and the US government having to "tighten the belt" on expenditure it looks like China will soon be the #1 consumer of oil, and India is quickly on its way to overtaking the USA for position #2.
Any lull in availability of oil could cause these two economic powerhouses to sign oil-deals at prices most nations would consider outrageous; in order to gaurantee sustainable amounts of energy for their massive populations and growing economies.
here's an article: Saudi king to sign on China oil deal