As the industry matured, huge multi conglomerate oil companies were created. There were oil rights, leases, drilling, marketing, and product development that were involved in bringing products to market. The demand for oil increased steadily as nations were emerging as industrialized countries. It seemed overnight, that the coal industry was replaced by the petroleum industry.

Since petroleum is a non-renewable resource, new areas needed to be explored. The leaders in the petroleum industry were the Americans. The companies soon realized that oil was an international product. Nations like Saudi Arabia, Venezuela, Indonesia, and Russia contained vast resources, while other countries in Europe and North America used these resources. The birth of these multinational companies, were referred to as the "The Seven Sisters." These petroleum companies included Exxon, Gulf, Texaco, Mobil, Socal, British Petroleum and Shell, had influence throughout the world from the mid 1900's to the end of the 1960's.

Venezuela, 1921