When drilling from a MODU the weight in air of tubular goods on the racks is reduced when run into the drilled hole because of the effect of __________.

Correct Answer: Option A — buoyancy of the mud

Archimedes' principle dictates that any object submerged in a fluid experiences an upward buoyant force equal to the weight of the displaced fluid. In drilling, the density of the mud creates significant buoyancy, effectively reducing the hook load of the drill string compared to its weight in air.