drilling mud

American  

noun

1. a water-based or oil-based suspension of clays pumped into an oil well during drilling in order to seal off porous rock layers, equalize the pressure, cool the bit, and flush out the cuttings.

---

drilling mud British  

noun

1. a mixture of clays, water, and chemicals pumped down the drill string while an oil well is being drilled to lubricate the mechanism, carry away rock cuttings, and maintain pressure so that oil or gas does not escape

---

Example Sentences

The Minnesota agency investigation found that Enbridge violated regulations when it discharged construction storm water into wetlands and inadvertently releasing drilling mud into surface water at 12 locations in June and August of 2021.

From Seattle Times

Some 42,000 gallons of drilling mud spewed across the tundra, and several residents later complained of respiratory ailments.

From Washington Post

Even if the drilling mud was primarily clay, Matteson said, the silt can still harm sensitive aquatic organisms.

From Seattle Times

A couple of days later, 10,000 gallons of drilling mud, or bentonite clay, contaminated a popular recreational lake that also provides drinking water for residents of Chester County.

From Salon

Ten years ago: Engineers began pumping heavy drilling mud into the blown-out Gulf of Mexico oil well in an attempt to permanently plug the leak.

From Washington Times