Occidental Petroleum  (OXY) gained more than 1%. Warren Buffett's Berkshire Hathaway  (BRKB) bought 2.1 million shares of the oil company between June 26 and 28, according to a SEC filing .   Shares are in a long consolidation and have not yet overcome the downward 50-day period. Occidental Petroleum Corporation (often abbreviated as Oxy due to the symbol and logo) is an American company engaged in hydrocarbon exploration in the United States and the Middle East, as well as petrochemical production in the United States, Canada and...