Map of europe cold war for Oil’s importance as a global issue is intensified due to the fact that most of the world’s petroleum deposits are found in a few large fields. Most oil fields are small and insignificant, but perhaps half of the world’s original oil reserves are located in fields known as supergiants, which contain more than five billion barrels. There have been fewer than 40 supergiants discovered since exploration began in the mid- 19th century, and less than 5 percent of the world’s known fields have produced about 95 percent of all of oil. Most of these large fields are located in the Persian Gulf region of the Middle East, making the area a flashpoint in international political and economic relations. Early oil booms in the United States and Russia. The first significant oil boom in the world took place in Pennsylvania when hard-rock drilling began in 1859. For the first time, inexpensive oil was available for widespread use. Map of europe cold war 2016.