CHARACTERIZATION AND CONTROL OF FINE PARTICLES INVOLVED IN DRILLING.

An automated particle-size analyzer was used successfully in the laboratory, as well as in the field, for characterizing fine particles involved in drilling. Particle-size distribution data were obtained on weighting materials, clays, and field mud samples in the range of a fraction of 1 to 192 mu . Size analysis is a useful quality control tool to limit undesirable sized fractions (e. g. , less than 2 mu and greater than 74 mu ) in weighting materials. The median size measured for clay systems is found to represent the flocculation state of the clays in various salt environments. The measured size distributions of the solids in fresh, unweighted, water-based field muds are shown to be a good indicator of the operation of the solids removal equipment.