It's called Spratly shoal (islands is a misnomer/ they are bare rocks the highest point of which is about 1 meter above current sea level. It's 125 miles from my wife's home town in Zambales/ northern Philippines.
Firstly there is no way known the Philippines or Vietnam are going to take on China militarily. They have virtually nothing to do so with.
Also, rich allies like the USA and Australia are not getting involved. In fact, Australia just cancelled our annual charity to the Philippines, which was last year close to 1 billion $AUD. I am sure this is to appease our biggest emerging trading partner. The USA is offering to offload some old boats and helicopters to the Philippines, but so far this appears to be all hot air. No American or O/S agency has shown any serious interest in arguing the Philippines case; despite the fact that it clearly has a claim under the same articles of international Law as Australia holds much of it's offshore resources/ through the 'Exclusive economic zone' 200 NM limit, along with the continental shelf rule.
(Neither of which are enforceable currently)
There may be oil there, maybe not. Philippines needs China's help to do anything about it regardless. Vietnam's claim seems absurd.