It seems that using this mod with Cargo Ships causes offshore oil to not generate properly, instead you get weird oil patches on ice that you can't put a rig on.

I've double-checked, and offshore oil appears to generate correctly with Cargo Ships + Dredgeworks (Cargo Ships 1.0.11, Dredgeworks 0.5.3), with regular land-based crude oil not generating. Tested this with "Offshore oil on Deep Water only" active and inactive, and it appears to function correctly in both cases. Can you provide more details?

(Note: Space Age caused the ice generation under the conventional oil patches on water. Without Cargo Ships involved, this is standard behavior while Space Age is enabled, if a little odd.)

Welp, I think this thread can be closed.

For context I had this issue on 0.5.2 of Dredgeworks and when I encountered it I may have gotten annoyed and just took off the mod, restarted the save, and assumed it was broke. I only made this report now, a couple weeks or so late, as I wanted to check if there were any updates to the mod and didn't see anything in the changelog that might indicate a fix..

However I just booted up a new world in the map editor with both mods enabled and was able to find offshore oil...
So I guess - freak occurence? I definitely had both mods enabled on the old save. I don't have the world anymore though, I saved over it with a new run.

Sorry for wasting your time

All good. Cargo Ships alters ore generation a lot more than it used to, and the compatibility element in Dredgeworks might still have some edge cases I haven't accounted for, even if this wasn't that.

mmm weird i dont have cargo but i have those weird oil patches on ice. so its normal with space age?

Yep. Space Age causes crude oil to generate ice around it because that's the normal condition in which it expects crude oil on an ocean to exist; without Cargo Ships and its offshore oil, you'd typically pave over the deposit with refined concrete even if you don't have Space Age because it's a convenient construction material with Dredgeworks' changes and you'll need at least some pipes to get the oil out of the pumpjacks.