Have you checked the oil pan gasket?
Usually engine tray gathers the oil and you hardly see oil on the ground.
Take it to local garage and get it properly checked.
Also have a good look around the engine. Possible suspects (depending on your car)
Vaccum pump O-ring
Vanous Solenoid O-Rings
Oil pan gasket
mileages of your car?
Away for 4 weeks. PM only if its urgent.