To further emphasize the issue here is the production of an oil refinery module split down into the first transportable item:
Crude oil:
- Heavy Oil
- Light Oil
- Petroleum
- Lubricant
- Light Oil
- Flamethrower Ammo (Transportable)
- Solid fuel (Transportable)
- Petroleum
- Flamethrower Ammo (Transportable)
- Solid fuel (Transportable)
- Sulfur (Transportable)
- Plastic (Transportable)
- Solid fuel (Transportable)
- Electric engine unit (Transportable)
- Express transport belt (Transportable)
Current "module" output: Flamethrower Ammo, Solid fuel, Sulfur, Plastic, Electric engine unit, Express transport belt
You could argue that Iron Gear Wheel could be manufactured on the spot thus only needing Iron Plate. But there is still the need for very high tier materials as input to this module to craft the items that need lubricant. With Lubricant Barrels the "module" could be changed into the following, much simpler, which only requires "low tier" materials as input":
New "module" input: Crude oil, water, coal (for plastic), Iron Plate (for Flamethrower Ammo)
New "module" output: Flamethrower Ammo, Solid fuel, Sulfur, Plastic, Lubricant barrel
All above sounds exactly like something that would be made in an area handling oil and its products. Finally, I also added the wish for Water barrels, this is much more of a luxury problem where a factory part can be very far from a water source, simply having barrel support would alleviate the frustration of being far from the water.