Dry Sieve Analysis

Purpose

Determine the particle-size distribution of dried drilling-fluid solids, lost-circulation materials, or weighting agents (e.g. barite) by mechanically sieving a dry sample through a stack of calibrated wire-mesh screens. Results confirm product compliance, guide solids-control equipment setup, and inform bridging-material selection.

Equipment

• Nested sieve set (ASTM or Tyler series, mesh sizes as required for the material)
• Receiving pan
• Mechanical sieve shaker (or hand-sieving frame)
• Analytical balance (0.01 g resolution)
• Drying oven (105 °C)
• Brush for screen cleaning

Procedure

1. Dry the mud sample or material in the oven at 105 °C until constant mass is achieved; allow to cool in a desiccator.
2. Weigh the dry sample to the nearest 0.1 g; record as initial mass.
3. Nest the screens in descending order of mesh size (coarsest on top) with the receiving pan at the bottom.
4. Place the weighed sample on the top screen; assemble the stack on the sieve shaker.
5. Sieve for the specified duration (typically 10–15 minutes at medium amplitude) or hand-sieve until no further material passes.
6. Weigh the material retained on each screen and the pan to the nearest 0.01 g.
7. Sum all retained masses and compare to the initial sample mass to verify material balance (acceptable loss typically < 1%).

Calculations

• % retained on each screen = (mass retained / initial mass) × 100
• Cumulative % passing = 100 − cumulative % retained

Notes

• Report percent retained and cumulative percent passing for each screen size.
• Clean each screen with a soft brush between tests; do not force particles through the mesh.
• Material balance closure confirms no significant loss; if > 2%, repeat the test.
• For bridging-material evaluation, plot cumulative passing curve and compare to ideal packing theory.