BMW recommends certain BMW branded oils or aftermarket oils with certain manufacturers with whom BMW has arrangements. The BMW recommended aftermarket brand of oil has changed from time to time.
Until 2015, oils that I found were suggested to meet BMW standards included BMW TwinPower Turbo Engine Oils, Mobil 1 SAE 0W-40 and Castrol Syntec European Formula SAE 0W-30. From 1999 through 2014 Castrol supplied the oil sold by BMW. Shell (including Shell's Pennzoil brand) now has an arrangement to be BMW's recommended aftermarket motor oil supplier.
http://www.bmwblog.com/2015/05/12/pe...r-bmw-engines/
Do you use the oil recommended for your X3 when it was manufactured or change to the current recommended oils offered by BMW or Shell/Pennzoil? My expectation is that any of the recommended oils would be fine. An oil that meets long life tests (LL-01 certification) is recommended if you will follow BMW's extended oil change intervals. I expect a BMW dealer would use its current BMW branded oil formulation made by Shell of the appropriate viscosity if servicing your 2012 X3.
http://www.autoevolution.com/news/bm...ier-88737.html
There is some discussion of the BMW branded oils vs Pennzoil and Castrol products at the following link:
https://bobistheoilguy.com/forums/ub...pics/4010356/1