At a time of high anxiety over soaring fuel prices and scarce supplies, oil analysts are resorting to satellite imagery to crack one of the industry's biggest unknowns -- whether Saudi Arabia's massive Ghawar field is slipping into depleted old age.

Saudi Arabia has long contended that its famed Ghawar field, responsible for around 7% of global supply, remains in fine shape and will continue to churn out around five million barrels a day for years.

But...