The oil circulates with the refrigerant gas so you don't get lube w/o having gas
. Anyway, the clutch won't activate w/o refrigerant pressure as the low pressure cut off switch (on the receiver/dryer) prevents it from engaging in order to protect the compressor. The clutch beariung is packed with grease, much like a wheel bearing, and it will be fine if you don't replace the A/C belt for a while.