Quote from TuPaC on November 18, 2020, 11:15 am

Tools Required:

WarDraft
UDTAhack
PUDDraft or War2xEd

How To:
WarDraft (1):
Open up WarDraft, load maindat.war, and decompress entry 278 (extract it then re-import it uncompressed)
Use the speed editor to group the oil tankers with the peasant (don't forget to group the tanker carying oil with the peasant carying gold!)
Save and exit the speed editor.
Extract the UDTA from entry 472 (if you have the expansion) or entry 0 (if you don't have the expansion).
Close WarDraft.

UDTAHack:
Open UDTA hack and load the UDTA you just extracted.
Highlight the oil tanker.
In the pull-down menu on the first tab select land as its type
Select the flags tab. "Multiselectable", "land unit" and "can carry oil" should be the only boxes checked.
Check the "sea unit" box. DO NOT uncheck the land unit box.
Go to the GFX tab. Set the tanker to use the peasant/peon's .GFX
Now highlight group 3 (the peasant carrying gold) and keep track of the .GFX number. Do the same for group 4 (the peon)
Switch the .GFX numbers of group 5 and group 6 (the tankers with oil) to be the same as the peasant and peon.

WarDraft (2):
Open WarDraft, load maindat.war.
Import the UDTA back where you got it (entry 0 for non-expansion useres, 472 for those with the expansion)
Close WarDraft

War2ExEd:
If you are using War2ExEd this will be somewhat tricky. If not, skip to the next section.
First create a map (probably with war2ed95. Put a gold mine where you want the oil patch to be.
In War2ExEd change the movement properties of the ground where the gold mine is to be bridges.
Change the gold mine into an oil patch.
Save and exit.
You're done!

PUDDraft:
This one is easy.
Make a map using PUDDraft.
Set the movement properties of the spot where you want the patch to be to bridge.
place an oil patch.
Save and exit.
You're done!