Contrary to Russia, China is really hungry for the oil and natural gas reserves of the Middle East, ands she is the best client right now. All the rich countries of the Middle East are looking to China and the other Asian countries in order to sell their goodies, since the US has significantly reduced its purchases from the region, and Europe mainly buys from Russia.
The following table is from the Energy Information Administration article, titled “How much petroleum does the United States import and from where”, which shows from which countries the US imported its oil in 2013. The US still buys from Saudi Arabia, but the US oil imports from Saudi Arabia are expected to fall even more in the future, while exactly the opposite is expected to happen with the Chinese imports.
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http://www.eia.gov/tools/faqs/faq.cfm?id=727&t=6
At the following article of National Public Radio, titled “U.S. Rethinks Security As Mideast Oil Imports Drop”, November 2012, you can see with sky blue the current Chinese, American and European oil imports from the Middle East, and with dark blue what their imports are expected to be in 2035.
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Source: http://www.npr.org/2012/11/14/165052133/u-s-rethinks-security-as-mideast-oil-imports-drop
You can see that the Chinese imports are expected to be very high in the next decades, the American ones are expected to almost disappear, while the European ones will be somewhere in the middle. Therefore the prosperity of the Gulf countries relies to a large extent on China.
China is not only becoming the best customer in the region, but she has also managed to avoid making enemies until now, by keeping her army away from the Gulf, leaving that role to the Americans. Therefore China has managed to be in relatively good terms with all the countries of the Gulf, something that the Americans, the Russians and the Europeans have not managed to do. China's aim is to work with all the rich in natural gas and oil countries of the Middle East, without getting militarily involved, which would cost her billions of dollars, and which would make rivalries with the Gulf countries unavoidable. China wants to appear in the region as a peaceful businessman.
However as the temperature in the Middle East rises, this becomes increasingly difficult, because all regional players are asking for China's support.