Determination of drilled solids in a drilling fluid depends on an accurate determination of the mud weight, the total solids in the drilling fluid, and the density of the drilling-fluid ingredients. For example, with a freshwater 11-ppg drilling fluid containing 2.6 SG low-gravity solids and 4.2 SG barite, a change in only 1%vol measured solids concentration makes a 2%vol change in calculated low-gravity solids. In Table 12.4, for an 11-ppg drilling fluid, a 13%vol solids concentration would indicate 6%vol, and a 12%vol solids concentration would indicate 4%vol.
Solids Concentration in an 11-ppg Drilling Fluid
VLG=volume of low-gravity solids; Vs=volume of total suspended solids;