This COULD be a head-gasket problem. Does the engine overheat when drive a while? If so this is likely a head-gasket issue. It could also a crank-case ventilation problem which is much less costly than a head gasket (and common on your car). I suggest having a shop diagnose the root-cause of the problem and you'll then be able to budget more for the repairs.
Do NOT drive! Need to know how vehicle started to manifest its symptom. Was Temperature Gauge running hot recently prior to smoke? Because i still think if not related to temperature "a possible silver lining" could be Breather system, when restricted could cause blue smoke(crankcase could have too much psi) Hence the oil consumption ie smoke from tailpipe. Agree with other suggestion to have it check out. I would search for a quality Bmw independent near you bimrs(.)org Could help locate a good BMW repair facility. Good luck.