API RP 13B-1:2019

This recommended practice provides standard procedures for determining the following characteristics of water-based drilling fluids: a) drilling fluid density (mud weight); b) viscosity and gel strength; c) filtration; d) water, oil, and solids contents; e) sand content; f) methylene blue capacity; g) pH; h) alkalinity and lime content; i) chloride content; j) total hardness as calcium; k) low-gravity solids and weighting material concentrations.