X0101 EFFECT 33 LIVE 2014-07-16 16:00:00

S-4

0001486159 Oasis Petroleum Inc. 333-197132 0001494070 Oasis Petroleum LLC 333-197132-05 0001525815 Oasis Petroleum North America LLC 333-197132-04 0001530077 Oasis Petroleum Marketing LLC 333-197132-03 0001529745 Oasis Well Services LLC 333-197132-02 0001611773 Oasis Midstream Services LLC 333-197132-01