RAS TANURA, Saudi Arabia — This port, on the calm blue waters of the Persian Gulf, operates with militarylike precision. Black- and red-hulled super oil tankers must ask for permission to load months in advance. Detailed records go back 30 years to trace any vessels that have broken the rules by dumping oil or using substandard equipment. High-tech radars constantly scan for potential troublemakers, like boats sent from Iran.

At the top of the hexagonal control tower, staff dressed in neat white uniforms with officers’ epaulets keep watch, looking over the sweep of countless storage tanks and ships. “If a target tries to hide behind a ship, we can see him,” said Salah al-Ghamdi, the chief pilot at the facility.

Thousands of ships depart these waters annually, transporting the wealth of crude beneath the Saudi Arabian desert to gas-guzzling nations. The kingdom accounts for almost one-sixth of world oil exports, and even a minor disruption here could send shudders through global markets.

The state-run oil giant that operates the port, Saudi Aramco, is the economic force behind Saudi Arabia’s transformation into a regional powerhouse. The deep oil reserves, which the company extracts, transports and sells, have made the country an important part of a geopolitical equation that includes the United States, China and Russia. Leveraging its engineering expertise, Saudi Aramco has built schools, roads, hospitals and much of the other infrastructure that girds Saudi society.