For years Iran has threatened that if it were no longer able to export oil because of U.S. sanctions, then no one else would be able to either. The Sept. 14 attacks on Saudi Arabian Oil Co.'s Abqaiq and Khurais oil processing complexes and two earlier attacks on the Saudi oil sector gave life to longstanding fears of Iranian attacks on Saudi critical infrastructure. Iran has clearly made the strategic decision to escalate its attacks against oil industry targets in the region in response to U.S. sanctions pressure and Washington's departure from the Iranian nuclear deal, known as the Joint Comprehensive Plan of Action.
Tensions between the United States and Iran remain high as the United States continues to implement significant sanctions on Iran and Tehran retaliates by trying to increase the cost to the United States of doing so. This has brought U.S. allies, quite literally, into the crossfire, with Saudi oil infrastructure experiencing significant attacks. Should Iran continue its escalation against the United States and its allies, more Saudi facilities could be targeted.
The attacks on Abqaiq and Khurais have fundamentally altered Saudi Arabia's threat perception regarding Iran. While Iran's Houthi proxies in Yemen have been conducting attacks along Saudi Arabia's southwest border for years, Iran's willingness and ability to directly hit Saudi Arabia and the rest of the world where it hurts the most — Saudi oil production — has forced Riyadh to recognize the threat of additional attacks, especially if sanctions continue to bite. The challenge for Saudi Arabia will be trying to protect a large number of critical targets across its large territory. But unfortunately for Saudi Arabia, the billions of dollars it spends annually on defense — including a planned $51 billion in 2019 — simply cannot protect all Saudi infrastructure from potential Iranian strikes.
Iranian Capabilities, Saudi Vulnerabilities
Given Iran's general conventional military inferiority relative to the United States and U.S. allies, Tehran has placed considerable emphasis on building up asymmetric forces that could give it an advantage in a conflict with its better-armed adversaries. Cruise and ballistic missiles are key to this strategy, as is leveraging Iran's strategic position on the Strait of Hormuz and proximity to the critical infrastructure of its regional rivals.
Originally comprised largely of imprecise ballistic missiles, Iran's missiles are now increasingly precise and of varying types and flight profiles; defending against them is a significant challenge. Over the past decade, Iran has devoted many resources to improving its missile forces. This has involved introducing large numbers of cruise missiles into its arsenal, fielding more drones (including so-called suicide versions), and working to replace its previously inaccurate ballistic missiles with much more accurate versions. Iran now has some missiles capable of striking anywhere in Saudi Arabia, though most of its missiles have shorter ranges. Even these, however, can reach nearly all key petroleum facilities in the kingdom, since most of these are on or near the Persian Gulf.
In several cases, Patriot missile systems failed to intercept their targets, either due to the Saudi crews' inexperience or due to equipment malfunction.
In the face of this threat, the Saudis have built up — at least on paper — a capable air defense force with a large number of modern air defense systems. The Royal Saudi Air Defense Forces has about 50,000 personnel and is largely equipped with U.S.-made air defense systems such as the Patriot surface-to-air missile system. The Patriot is the mainstay of Saudi air defense against missiles and air targets, and Saudi Arabia has six battalions with about 200 launchers a piece. The Saudis have steadily upgraded these systems, acquiring the more advanced Patriot PAC-3 in July 2015. Raytheon, the principal U.S. company that produces the Patriot, insists the system has intercepted more than 100 ballistic missiles fired by Houthis from Yemen since 2015.
In several cases, however, Patriot missile systems failed to intercept their targets, either due to the Saudi crews' inexperience or due to equipment malfunction. The Yemen conflict has also illustrated that even a relatively well-equipped air defense force cannot adequately defend against sustained missile (and drone) attacks. A large number of incoming missiles can overwhelm surface-to-air missile batteries, which is one reason why the swarm attack involving a reported 20 or more drones and cruise missiles in last week's attacks on Abqaiq and Khurais proved effective.
Compounding the problem for Riyadh, Saudi Patriots — like the Terminal High-Altitude Area Defense (THAAD) anti-ballistic missile defense system Saudi Arabia has ordered — are predominantly configured to strike against ballistic missiles and high-altitude targets. Both the Patriot and THAAD are not ideal against low targets such as cruise missiles and some types of suicide drones, which were used in the Sept. 14 attacks.
Complicating matters for Riyadh, Saudi air defenses have a relatively large geographic space to protect. Finally, most Saudi air defenses are currently focused on defeating air and missile threats originating from Yemen. These factors mean Saudi air defenses have significant vulnerabilities to large missile and air attacks by Iran, whether launched directly from Iran or via Iraq.
Critical Infrastructure in Saudi Arabia
Thus far, attacks against Saudi Arabia more closely linked to Iran — that is, not launched by the Houthis — have aimed at petroleum facilities. This is likely to remain Iran's response of choice to U.S. sanctions on its oil exports, though it might branch out to water desalination plants and other industrial targets or even to airports.
Striking Saudi Arabia's central processing facilities, export terminals and refineries would do the most damage to the country's oil production. Abqaiq and Khurais, Saudi Arabia's two most important central processing facilities, were attacked because they are critical chokepoints in the upstream petroleum sector. Saudi crude oil production typically passes through gas-oil separation plants and then central processing facilities where crude stabilization towers strip out volatile hydrogen sulfide before the product is sent to oil terminals for export.
Abqaiq and Khurais are the most important of Saudi Arabia's central processing facilities. According to Saudi officials, before the attack, Abqaiq was processing 4.9 million barrels per day (bpd) of crude oil coming from two of Iran's largest oil fields, Ghawar and Shaybah, as well as some smaller fields, and it is now processing 2 million bpd. Before the attack, Khurais was processing about 800,000 bpd of crude oil from the Khurais oil field, which has a capacity of 1.45 million bpd, and from smaller satellite fields. Riyadh hopes most of its production capacity can be brought online later this month, and all of its production capacity (although not all of its processing capacity) by the end of November. Regardless of whether Saudi Arabia hits those targets, it will still be rebuilding at least five stabilization columns at Abqaiq and making other repairs at Khurais at the end of November. And until those repairs are completed, Saudi Arabia will have less redundancy in the event of another strike on its processing facilities.
Should Iran expand its target set beyond Saudi Arabia's upstream oil and gas sector, Saudi oil refineries and petrochemical plants in the Red Sea come into play.
Most of Saudi Arabia's other important central processing facilities are closer to the Persian Gulf and primarily process the country's offshore fields; their location makes it easier for Iranian missiles and drones to strike. The Safaniya processing plant on the Persian Gulf processes oil produced at the Safaniya offshore oil field, the world's largest oil field with a production capacity of 1.3 million bpd. The Manifa plant does the same for the offshore Manifa oil field, which has a capacity of 900,000 bpd. The Qatif-Abu Safa plant processes crude oil from the country’s Qatif and Abu Safa oil fields, which have a production capacity of 500,000 bpd and 320,000 bpd, respectively. The Tanajib processing facilities process oil from the Marjan offshore oil field, which can produce 600,000 bpd. Other key facilities for various oil and gas processing are the Berri Gas Plant, Jubail plant, the Juaymah facility and the previously targeted facilities for the remote Shaybah oil field. While all of these facilities play an important role in Saudi Arabia's energy sector, only one is as vital a role as Abqaiq or Khurais: the onshore facilities for the Safaniya oil field. This is because of the sheer volume of oil production involved.
Loading terminals are another type of petroleum facility that could be targeted to take a significant amount of oil production offline. Saudi Arabia's most important export terminals, and probably the most tempting for Iran to target, are the Ras Tanura and Ras al-Juaymah terminals in the port city of Ras Tanura, which can export about 3.4 million bpd and 3.1 million bpd, respectively. Saudi Arabia's other major export terminal is at Yanbu on the Red Sea at the end of the East-West Pipeline. The pipeline — Saudi Arabia's most important, which can send 5 million bpd of crude oil from eastern Saudi Arabia to the Red Sea for export at Yanbu and other smaller ports — was attacked earlier this year.
Should Iran expand its target set beyond Saudi Arabia's upstream oil and gas sector, Saudi oil refineries and petrochemical plants in the Red Sea come into play. This would include three of the country's largest refineries — the Saudi Aramco-owned 550,000 bpd Ras Tanura refinery, the jointly-owned Saudi Aramco-Total 400,000 bpd refinery in Jubail and the jointly owned Saudi Aramco-Shell 310,000 bpd refinery in Jubail — all on the Persian Gulf.
While attacks beyond Saudi Arabia's oil, gas and petrochemical sector are less likely, Iran could, if it wished, strike main ports, like the King Abdulaziz Port in Dammam and the King Fahd Industrial Port in Jubail. It could also target water desalination plants, of which Saudi Arabia has 31 and which provide about half of the country's drinking water. These potential targets include the world's largest desalination plant at Ras al-Khair on the Red Sea, which desalinates more than 1 million cubic meters of water per day.
Saudi airports could also be potential targets, although this raises the risk of civilian and foreign casualties. Such risks have not stopped Iran's Houthi allies from targeting airports in southwestern Saudi Arabia, but Iran has thus far eschewed attacks that could lead to significant losses of life.