Definition - What does Fluid Density mean?
Fluid density refers to the mass per unit volume of drilling fluid. It is typically measured in pounds per gallon (ppg), lb/gal or pound cubic feet (pcf). Drilling fluid, or mud, is cycled through the bore as the drilling operation is conducted and is treated as it exits, to remove large contaminants, in order to maintain a workable fluid density when recycled back inside the bore.
Fluid density may also be called mud weight.
Trenchlesspedia explains Fluid Density
A low fluid density is paramount in drilling operations because as fluid density and viscosity increases the penetration rate of the cutting bit is slowed. Treating and recycling the fluid to control the density keeps the rate of penetration at acceptable levels and decreases the overall cost of the job as it also preserves the drilling fluid material and reduces time on site. Maintaining fluid density helps the drilling fluid continue to suspend and remove cuttings from the hole, cool and lubricate the drill bit, stabilize the bore hole and control fluid loss at optimal levels.