Is it just me or are all oil patches always at exactly 100% yield.

Yes they are, that's intentional, as it says in the mod description.

Quoting the description:
Resources that are already infinite (like oil or some added by other mods) and have other yield settings are unchanged (except for making it so they don't deplete), so they may spawn with yields above or below 100%.

I read that as the exact opposite of what you said.

Although it's fine. I figured out how to change the output to an acceptable amount. Maybe you could update your description though.
data.raw.resource["crude-oil"].minable = { mining_time = 1, results = { { type = "fluid", name = "crude-oil", amount_min = 50, amount_max = 50, probability = 1 } } }

Hmm I see what you're saying, I think the description is just out of date. All resources are set to their normal amount when they spawn. It does make oil kind of low, but if you find that's the case then you should adjust the resource spawning settings so they spawn more frequently. Basically the idea is that all resource entities will have the same yield no matter what, so if you want more, adjust the spawning settings so more of them appear.

Quoting the description:
Resources that are already infinite (like oil or some added by other mods) and have other yield settings are unchanged (except for making it so they don't deplete), so they may spawn with yields above or below 100%.

I read that as the exact opposite of what you said.

Although it's fine. I figured out how to change the output to an acceptable amount. Maybe you could update your description though.
data.raw.resource["crude-oil"].minable = { mining_time = 1, results = { { type = "fluid", name = "crude-oil", amount_min = 50, amount_max = 50, probability = 1 } } }

Hi, where can I change it?

There's a bit of an issue with mods like offshore oil processing where you make boats to collect offshore oil. The resource spread and balance is based around having fewer, richer oil deposits.

It would be nice to be able to disable the oil change.

If you are unhappy with the 100% yield, you can modify it by simply modifying the following lines in control.lua

        resource.initial_amount = resource.prototype.normal_resource_amount
        resource.amount = resource.prototype.normal_resource_amount

I added a multiplier to each, example for 1000% yield:

        resource.initial_amount = resource.prototype.normal_resource_amount * 10 
        resource.amount = resource.prototype.normal_resource_amount * 10

If you simply want to make the mod not affect the initial amount of certain resource like oil, you can just add an exception in control.lua line 7
[code]
if resource.prototype.infinite_resource and resource.name ~= "crude-oil" then
[/code]
Note the depletion is negated in data-final-fix.lua, so adding this exception won't make oil starting to deplete.