I have been reading some old RTW threads and wondered if I could create a building that gave oil as a "resource" as opposed to a bonus on a tile. i.e. synthetic oil.

Wonders like "Broadway" create "Hit Shows" as a resource. Could I use the same idea to create "oil". Note: the building would need access to "coal"

Yes you can.

Thanks I'll try that. Having oil deposits in "Gemany" is not really appropriate.

Specifically, what you want are the tags :

<FreeBonus>BONUS_MOVIES</FreeBonus>
<iNumFreeBonuses>-1</iNumFreeBonuses>

Thanks for that. Already found and added to my mod. Synthetic Oil plants now exist :D

The question is really this:

Your building creates oil with no problem, but what happens if you lose access to coal? Do you still get oil then? I've been thinking of including this in Blood and Iron (steel and gasoline). If not, I'll just try and add in this: Unit Fuel Mod (http://forums.civfanatics.com/showthread.php?t=269430)

If not, I'll just try and add in this: Unit Fuel Mod (http://forums.civfanatics.com/showthread.php?t=269430)When I learn SDK, I'll add it.

Your building creates oil with no problem, but what happens if you lose access to coal? Do you still get oil then? I've been thinking of including this in Blood and Iron (steel and gasoline). If not, I'll just try and add in this: Unit Fuel Mod (http://forums.civfanatics.com/showthread.php?t=269430)

If you want the building to require an continuing input resource to provide the output, this method doesn't work. Making it work requires SDK work.

Fortunately, such work was done several years ago by TheLopez for Warlords. A moderate familiarity with the SDK should make it easy-ish to convert to BtS.
http://forums.civfanatics.com/showthread.php?t=179993