[Science Scope] "If the Sea Is Blocked, Move to Land?"... Why Pipelines Aren't the Answer

The Higher the Flow, the Greater the Required Pressure and Power
Desert Temperature Swings and Pipeline Corrosion Define the Limits of Flow

Whenever the specter of conflict looms over the Strait of Hormuz—the “artery of energy” through which about 20–30% of the world’s crude oil flows—the international community’s attention naturally shifts from the sea to the land. The “East-West Pipeline,” which stretches across the desert from Saudi Arabia’s eastern oil fields to the Red Sea coast, is frequently cited as a key alternative.

The solution appears straightforward: send crude oil via pipelines instead of oil tankers. The idea is that, even if the strait is blocked, it is possible to bypass maritime blockades or attacks by rerouting oil over land through the desert, thereby avoiding geopolitical risks at sea.

However, in reality, things are far from simple. While “politics” and “military force” can block routes at sea, an entirely different set of obstacles emerges on land. Here, one must contend with invisible and inescapable forces—pressure, heat, and friction governed by the laws of physics.

Creating Flow: Viscosity, Friction, and the Surge of Energy

The principle behind pipeline transport is simple: apply pressure at one end to push the liquid through. Yet the first major barrier is “viscosity.” Crude oil is much thicker than water. As a high-viscosity fluid composed of hydrocarbons with varying molecular weights, it flows through the pipeline while rubbing against the interior walls, continuously consuming energy due to friction.

This phenomenon is known in engineering as “pressure drop.” As fluid moves through the pipe, the roughness of the pipe wall and the stickiness of the fluid combine to create resistance, slowing the flow. No matter how much pressure is applied at the starting point, friction causes energy to dissipate along the way, gradually reducing pressure until the flow eventually ceases.

Illustration showing a 3D-printed oil pipeline overlaid on a map of the Strait of Hormuz. Photo by Reuters/Yonhap News

The problem is that this frictional resistance does not just increase “slightly.” When the flow rate is increased to boost throughput, turbulence—a state where particles collide and swirl inside the fluid—occurs. In engineering, resistance in turbulent flow increases in proportion to the square of the flow rate. For example, if throughput needs to be doubled in a crisis, the required pump pressure and energy do not simply double—they soar to roughly four times the original level.

This is why “pump stations” are essential at regular intervals along the 1,200-kilometer journey. It means a pipeline is not just a simple conduit; it is a “giant fluid machine” that only operates with the continuous input of energy, integrating numerous engines and power grids organically.

Neil Atkinson, Senior Research Fellow at the Oxford Institute for Energy Studies, explained, “A pipeline may look like a simple tube, but in reality, without the constant input of energy, the flow itself cannot be maintained. Physical constraints limit both economic feasibility and supply capacity.”

Norwegian energy analytics firm Rystad Energy also highlighted this vulnerability in a 2023 report, stating, “Even if a single pump station is paralyzed along a long-distance pipeline, the entire transport network can experience a cascade of operational shutdowns, causing overall efficiency to plummet.”

The Desert Variable: The ‘Invisible Forces’ Created by Temperature

The desert presents engineers with the harshest thermodynamic challenge. Daytime temperatures approach 50°C, while at night they can plunge close to 0°C—a dramatic fluctuation that imposes tremendous physical stress on the steel used in pipelines.

When temperatures rise, metals expand; when they drop, metals contract. While the change in length due to thermal expansion may be just a few centimeters per kilometer, over thousands of kilometers, the story changes. The total length can change by hundreds of meters over the entire stretch. If this force is not properly relieved and accumulates, the steel pipes may bend or even buckle upward from the ground—a phenomenon known as “buckling.”

To prevent this, pipelines are not designed in straight lines. Instead, “expansion loops” shaped like a “Z” or “U” are installed at intervals to absorb changes in length caused by temperature fluctuations. However, this design increases the total length of the pipeline and creates additional vortices (eddies) at the curves, which in turn raise fluid resistance—a technical dilemma.

Temperature also alters the physical properties of crude oil itself. The high heat of the desert can lower oil viscosity, improving flow, but conversely, it may vaporize volatile components, abnormally raising internal pressure. On the other hand, the nighttime temperature drop can solidify paraffin in the oil, causing “waxing” that clings to the pipe walls and narrows the diameter.

The U.S. Department of Energy’s Office of Energy Efficiency and Renewable Energy (EERE) identifies “temperature variation” rather than “pressure” as the key risk factor for long-distance pipelines in its design guidelines. The guidelines explain, “Metals repeatedly expand and contract with temperature changes, and the fatigue accumulated during this process can lead to structural damage. Therefore, the design stage must always account for structures that can absorb these effects.”

Invisible Destruction: The Problem of Corrosion and Time

There is yet another risk to consider. The greatest threat to pipelines is not sudden catastrophic failure, but the slow, progressive “degradation” that occurs over time. Degradation is the gradual weakening of materials due to repeated temperature changes, chemical reactions, and friction. In desert environments, fine sand and salt can erode external coatings, while sulfur and moisture in the oil accelerate internal chemical corrosion.

Especially damaging is “erosion corrosion,” where tiny impurities in high-pressure crude oil continuously strike and wear down the pipe wall, drastically shortening the pipeline’s lifespan. This corrosion progresses so slowly that the exterior appears intact, but when a thinned section of the pipe wall reaches a critical point where it can no longer withstand internal pressure, it can instantly result in a massive explosion or leak.

Smart pig for pipeline inspection. A pig (Pipeline Inspection Gauge) is an intelligent device used to inspect and maintain the interior of pipelines. This device moves along the inside of the pipeline, collecting data on internal conditions such as corrosion, cracks, blockages, and deformations. Equipped with sensors and sometimes cameras, the pig enables early detection of anomalies without halting pipeline operations, making it an essential technology for safe and efficient pipeline management. Provided by Ocean Prime Systems

To monitor these risks, “smart pigs” are deployed. These robots travel inside the pipeline, carried by the flow of oil, and use magnetic flux leakage (MFL) or ultrasonic sensors to scan pipe wall thickness with micrometer-level precision.

The challenge is whether such precise inspection systems can continue to function in times of war. Analysts at energy consultancy Wood Mackenzie warned in a recent report, “In regions with geopolitical instability, maintenance systems can collapse, causing technical risks to increase exponentially.”

Norwegian-based global energy certification and risk assessment agency DNV also cautioned in its 2024 report, “In areas of heightened geopolitical risk, it becomes virtually impossible to regularly deploy inspection devices and maintain data analysis infrastructure, which ultimately amplifies the risk of uncontrollable environmental disasters in a nonlinear fashion.”

The Paradox of Fixed Infrastructure: Structural Vulnerability in the Age of Precision Strikes

Pipelines are meant to serve as alternatives to avoid geopolitical risk, but they themselves can become geopolitical targets—a paradox. While oil tankers are “variable assets” that can change routes or adjust speed in a crisis, pipelines are “immovable targets” whose locations are fully known.

In modern warfare, where satellite imagery and reconnaissance drones are commonplace, it is impossible to hide thousands of kilometers of steel lines. If even a single pump station or key valve node is precisely targeted, the entire supply chain can be crippled, revealing the structural vulnerability of pipelines.

Due to these structural limitations, the Center for Strategic and International Studies (CSIS), a U.S. think tank, noted in its 2024 Middle East energy security report, “Pipelines may appear covert, but in reality, they are exposed infrastructure. In modern warfare, dominated by drones and missiles, they are far easier fixed targets than oil tankers.”

Recently, advanced security technologies have been introduced to address these vulnerabilities, such as fiber-optic sensors that detect minute vibrations around pipelines and AI-driven real-time analysis of pressure waveforms to identify signs of intrusion or attack. However, global investment bank Goldman Sachs pointed out, “These security technologies are merely defensive measures for detection and interception. They do not fundamentally resolve the inherent vulnerability of energy supply interruptions caused by physical attacks.”

What Remains: The Honesty of Physical Laws

Ultimately, pipelines crossing deserts can never serve as perfect substitutes for maritime transport. They must be understood as “complementary solutions” with distinct risks and engineering limitations.

The challenge of transporting energy safely does not end with drawing new lines on a map and concluding political negotiations. The oil flowing through those lines continues to encounter fluid dynamic friction, responds honestly to the desert’s temperatures, and gradually succumbs to corrosion over time.

War may allow humans to alter routes, but for those routes to actually deliver energy, they must inevitably pass the difficult checkpoint of physical laws. This most basic and sobering fact is the “wall of physics” that politics can never overcome.

This content was produced with the assistance of AI translation services.