WARNING: This page is about a different car, the 2011 Chevrolet Cruze. However, it is still accessible from the selected car via links, so may be relevant.
Fig 1: Oil Pan And Bolts
Courtesy of GENERAL MOTORS CORP.
Remove the 15 oil pan bolts (1) from the engine block.
Use a suitable tool to remove the oil pan (2) evenly all the way around.