Edit: And 7-8 liters/100km for a Tesla seems optimistically low. But maybe 18kwh is also optimistic.
Looking at the US statistics for 2019, it seems refineries used 47 140 million kWh of electricity [1], and produced 3 199 032 thousand barrels of Finished Motor Gasoline [2], plus a lot of other products. That makes 0.093 kWh per litre, for the package of a litre of gasoline plus a bundle of other products. If gasoline is half of the output of refineries, then the rate is more like 0.05 kWh per litre.
This is just for refining, and doesn't include the energy cost of drilling, transport, etc. But 0.05 is a long way from 1.5.
[0] https://greentransportation.info/energy-transportation/gasol...
[1] https://www.eia.gov/dnav/pet/pet_pnp_capfuel_dcu_nus_a.htm
[2] https://www.eia.gov/dnav/pet/pet_pnp_refp_dc_nus_mbbl_a.htm
If it's actually drilling that makes a big difference because drilling might not be done where the oil is raffined