U.S. oil and gas supermajor Exxon Mobil Corp. (NYSE:XOM) is likely to post a good earnings report after disclosing it received a $2.1 billion boost to third quarter earnings from higher oil prices and robust refining margins, only partially offset by a fall in profits by its chemicals segment. According to the company, rising crude prices contributed to a gain of ~ $1.1 billion over the previous quarter, while refining profits increased by ~$1 billion, the company revealed in a filing on Wednesday. Meanwhile, an …