Wellbore fluids for casing drilling

摘要

A method of drilling a subterranean hole that includes mixing a base fluid and a micronized weighting agent having a particle size d 90 of less than about 50 microns to form a wellbore fluid; providing a drilling assembly that includes a casing as at least a portion of a drill string; and a drill bit attached at the distal end of the drill string; and drilling said subterranean hole with the drilling assembly using the wellbore fluid is disclosed.