... mudInitial loss, ml>250>250Filtration, ml>300>300Add 4% of sample to basic mudInitial loss, ml≤5.0≤25.0Filtration, ml ... ≤1.0Density, g/cm32.70±0.102.50±0.10Calcium carbonate content, %≥97.0≥97.0Acid insoluble content, %≤1.0≤1 ... moisture or injury to the package drilling fluid super-fine calcium carbonate