To date, what percentage of oil discoveries have occurred in anticline formations?

To date, what percentage of oil discoveries have occurred in anticline formations?

• A. 50%
• B. 60%
• C. 80%
• D. 70%

Answer: (D)

Anticlines create prime structural traps: when rocks are folded upward into an arch, oil and gas migrating upward are stopped by an impermeable cap rock over the crest, so they accumulate in the crest of the fold where the reservoir rock can hold them. Because many oil-bearing basins formed with compressional forces that produce lots of anticlines, this trap type has been a dominant source of discoveries. Historically, roughly seven out of ten oil discoveries have been in anticline traps, making this formation the most prolific among discovery traps. The other options don’t match the long-run pattern: the share isn’t as low as half or sixty percent, nor is it as high as eighty percent.

Anticlines create prime structural traps: when rocks are folded upward into an arch, oil and gas migrating upward are stopped by an impermeable cap rock over the crest, so they accumulate in the crest of the fold where the reservoir rock can hold them. Because many oil-bearing basins formed with compressional forces that produce lots of anticlines, this trap type has been a dominant source of discoveries. Historically, roughly seven out of ten oil discoveries have been in anticline traps, making this formation the most prolific among discovery traps. The other options don’t match the long-run pattern: the share isn’t as low as half or sixty percent, nor is it as high as eighty percent.