ExxonMobil stock has tripled investors' money in five years. Can it do it again?Oil and gas exploration and production (E&P) isn't an easy business. It requires massive amounts of investments, and the earnings and cash flows of E&P producers are directly exposed to the volatility in oil and gas prices.Yet ExxonMobil (XOM -0.23%) -- the largest oil company in the U.S. -- has performed remarkably well over the decades, and its stock has generated rich returns for shareholders. In recent years, ExxonMobil has ...