British oil and gas company BP intends to buy shale oil and gas fields owned by BHP Billiton, one of the world's largest mining companies, for $10.5 billion, Reuters reports. This deal will be the largest for BP in 20 years. Recently, it reported an increase in quarterly dividends, which has not happened for the last 4 years, and a reverse buy-out of shares worth $6 billion. BHP, in August last year, put up for sale a shale business, on which it spent 19 billion dollars of shareholder funds. BP expects that as a result of the deal its oil and gas resources in the US will increase by 57%, which will help increase its profitability and cash flow.