No promises that it will be available in the next patch, just that we're looking into the possibility.
Great! We'll base it on a similar asset. I'm using an ore extractor from Industries (Small Ore Mine) in my example, and you can either start with one of those or import your oil extractor as an ore extractor and then change it. Also, make sure to save it as a new asset and not save over anything as copy/pasting attributes can break an asset if something doesn't get copied.
In any case, once you have your new building open and are ready to turn it into an oil extractor open up ModTools (using ctrl + E). Then open up Expansion 7 > BuildingCollection > BuildingInfo and find Oil Pump 01. If you don't see it on the list it's likely on page two. Use the arrows in the line just below BuildingInfo to browse through all the buildings.
The first thing we'll copy is the BuildingAI (m_buildingAI). Find the correct line and press the Copy button.
Then go to Tool Controller > Tool Controller and expand PrefabInfo for your current building. Find the line for BuildingAI and press Paste. The footprint of the building will change and get stuck, but you can ignore this. Once we save it will be correct - or you can change it later to the correct values.
Next, we do the same for ItemClass. Go to Expansion 7 > BuildingCollection > BuildingInfo > Oil Pump 01 and scroll down until you find ItemClass (m_class). Press copy, go back to Tool Controller > Tool Controller > PrefabInfo and find it for your current building and paste it.
Next is the MilestoneInfo (m_UnlockMilestone) which is further up the list. Find it for Oil Pump 01 first, copy it and then find the same line for your current building and paste it.
Almost there! The next one is the UICategory (m_UICategory). You can copy/paste it too, but I find it easier to just change IndustryOre to IndustryOil manually.
Now save the asset and restart the game. While everything looks correct at this point, the BuildingAI cheats a bit, so we need to change the resource again after saving. After a restart of the game load the asset you just saved, open ModTools (ctrl + E) and go to Tool Controller > Tool Controller > PrefabInfo.
Find and expand BuildingAI (m_buildingAI), then find DistrictPark+ParkType (m_industryType). Click the arrow to open the dropdown menu and select Oil. A little further down you find TransferManager+TransferReason (m_outputResource) which also needs to be changed from Ore to Oil.
Save it again and we're done! At this point you can also adjust the footprint, stats and decorations of the asset. It will have the same stats as the ore building you based it off, so if you aim for the same production as say the Small Ore Mine you can find those stats in Expansion 7 > BuildingCollection > BuildingInfo > Oil Pump 01 under BuildingInfo
This copy/paste works for a lot of things. Typically when changing an asset to something else you will need to copy both the BuildingAI and the ItemClass, as well as change the UICategory (when relevant). Growables and vehicles can have their types changed in similar ways.
If I missed anything, glanced over something or you have trouble with the asset don't hesitate to ask.
