(Reuters) - Halliburton Co, the world's second-largest oilfield services provider, said it would buy smaller rival Baker Hughes Inc for about $34.6 billion in cash and stock.

Halliburton said the offer was worth $78.62 per Baker Hughes share, based on Halliburton's closing on Nov. 12.

The offer is a 31 percent premium to Baker Hughes' Friday close on the New York Stock Exchange.