The World's Deepest Man-Made Well: Bertha Rogers in Kansas

When it comes to plumbing the Earth's depths, one U.S. state holds the record: Kansas. In the remote reaches of Cimarron County (Oklahoma Panhandle border), the Bertha Rogers Well descends a staggering 31,441 feet (9,583 meters)—nearly 6 miles straight down.

The Well That Touched the Mantle

• Operator: Lone Star Producing Company
• Spud Date: 1972
• Target: Natural gas in the Anadarko Basin's deep granite basement.
• Result: Dry hole. No commercial hydrocarbons found.
• Record: Deepest well in the world (1974–1979), surpassed by Soviet Kola Superdeep Borehole (40,230 ft). Still deepest in U.S. & Western Hemisphere.

Why Kansas? The Anadarko Basin

The Anadarko Basin, centered in Oklahoma but extending into Kansas and Texas, is one of North America's most prolific hydrocarbon provinces. Its deepest trough—the "Deep Anadarko"—lies under Cimarron County. In the 1970s, high gas prices and new drilling tech (top drives, better bits) sparked a "depth race" to tap suspected gas in Precambrian granite.

Engineering Extremes

• Temperature at TD (Total Depth): ~500°F (260°C)
• Pressure: ~25,000 psi
• Drilling Fluid: Specialized high-temp mud systems.
• Casing: Multiple strings; final 7" liner at depth.
• Time to Drill: ~1.5 years (remarkably fast for depth).

Legacy & Lessons

Bertha Rogers proved ultra-deep drilling was technically feasible but economically marginal. It advanced:

• High-temperature logging tools
• Drill bit metallurgy (PDC/TSP bits)
• Mud rheology at extremes
• Geosteering in non-seismic basement

Today, the well is plugged and abandoned. The site is on private ranchland, unmarked. But in drilling lore, "Bertha" remains the benchmark—a Kansas well that kissed the Mohorovičić discontinuity and came back with data, not gas.

Fun Fact

The Kola Superdeep Borehole (Russia) reached 40,230 ft (12,262 m) in 1989—the true world record. But Bertha Rogers held the Western title for decades and remains the deepest *drilled* well in the Americas. (Deeper *measured depths* exist via horizontal drilling, e.g., Sakhalin-I Z-44 at 40,604 ft MD, but Bertha is deepest *true vertical depth*.)