oil

Is it oil bloom or oil boom?
I believe it's the 2nd but here is the definition of bloom:

bloom1
–noun
1. the flower of a plant.
2. flowers collectively: the bloom of the cherry tree.
3. state of having the buds opened: The gardens are all in bloom.
4. a flourishing, healthy condition; the time or period of greatest beauty, artistry, etc.: the bloom of youth; the bloom of Romanticism.
5. a glow or flush on the cheek indicative of youth and health: a serious illness that destroyed her bloom.

If you are referring to the increase in price of oil that would be oil BOOM.

What about referring to when oil was first discovered?

"oil boom" makes reference to the economic term "boom" which means a rise in economic prosperity. It means a period when oil is acting as a source of a large amount of wealth. A similar term would be the "dot-com boom", for example, which occurred in the '90s when many star-tup dot-com companies got large investment capital.

I have never heard of an "oil bloom". I don't think there is such a term.

It is oil boom and oil companies bloom

"If you are referring to the increase in price of oil that would be oil BOOM. "

I'd call it an oil spike.