In the coming weeks readers will increasingly see two rarely used phrases in stories covering our dwindling worldwide oil inventories: "operational minimum" and "tank bottoms." The phrases more or less signify the same thing, though the former is more abstract and precise, while the latter is more visual. They signify rapid depletion of existing oil inventories and presage price spikes to come due to the loss of oil supplies from the Persian Gulf because of Iran's closure of the Strait of Hormuz, the maritime artery through which 20 percent of the world's oil previously flowed.
Think of it this way: Let's say you are currently spending your entire weekly salary for living expenses. Then, you suddenly have your salary cut by 20 percent. Believing that the cut is temporary, you dip into your savings account to make up for the loss of income. At the current rate of withdrawal, your savings will last four months. As the weeks go by, your savings account balance dwindles as you continue to live in the style to which you were accustomed before the salary cut. Your boss tells you (frequently!) that your full salary will soon be restored. So rather than cut back on your expenses, you keep spending down your savings believing that all will return to normal before you exhaust your bank account.
That's what is happening in the global economy which had about four months of buffer stocks—essentially, an "oil savings account"—to draw from at the beginning of March. We are getting closer and closer to using up those savings which are in the form of commercial inventories. We are rapidly drawing down those inventories to make up for the loss of oil and oil products from the Persian Gulf.
In fact, a recent analysis suggests that the world oil system will start to experience "operational stress" sometime in June. Operational stress "is the point at which the system begins to experience significant functional strain: price volatility becomes extreme, rationing of refined products begins in the most exposed markets, and the margin for error in supply chain management drops to near zero." This analysis takes into account ongoing strategic petroleum reserve releases around the globe and states that "[e]ven full deployment of strategic reserves buys weeks, not months, at current drawdown rates."
